EV Digest 4867
Topics covered in this issue include:
1) RE: battery water temp ?
by "Harris, Lawrence" <[EMAIL PROTECTED]>
2) Two motors and the difference between split voltage and split current
by "Rodney" <[EMAIL PROTECTED]>
3) Re: Looking for info about production EVs...
by Nick Viera <[EMAIL PROTECTED]>
4) Dynasty VLRA Stecifications.
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
5) Re: Heater Options..Heated Water vs Ceramic
by Victor Tikhonov <[EMAIL PROTECTED]>
6) Re: Bits and Pieces - air vs water cooling
by "Phil Marino" <[EMAIL PROTECTED]>
7) RE: Radiator
by Cor van de Water <[EMAIL PROTECTED]>
8) RE: Radiator
by Cor van de Water <[EMAIL PROTECTED]>
9) Re: Radiator
by Eric Poulsen <[EMAIL PROTECTED]>
10) Modifying an E-tek motor
by Marc Breitman <[EMAIL PROTECTED]>
11) OJ2 to run at Mason Dixon on Nov. 5th
by [EMAIL PROTECTED]
12) Deka Dominator Peukert exponent?
by Tom Hudson <[EMAIL PROTECTED]>
13) Re: Bits and Pieces - air vs water cooling
by Eric Poulsen <[EMAIL PROTECTED]>
14) Re: Dynasty VLRA Stecifications.
by "John Luck Home" <[EMAIL PROTECTED]>
15) Water filling systems.
by Rush <[EMAIL PROTECTED]>
16) Re: Radiator
by "Phil Marino" <[EMAIL PROTECTED]>
--- Begin Message ---
Roland, my understanding is that the 'auto' part does not mean continuous,
only that you don't have to manually check and fill each cell.
What these do is allow you to fill the cells from a central filling point
but only when you want to. You would charge your pack and probably do an
equalizing charge and then add water to the filling point until it flows
back out the overflow. Each cell has a check valve that bypasses the water
intake when the level is high enough. If you pack your cells into areas
that are hard to reach a system like this is very useful.
You are right it would be a disaster to water them when they were discharged
but these systems don't do that except in cases of operator error :-)
Lawrence
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Roland Wiench
Sent: Friday, October 28, 2005 10:15 AM
To: ev@listproc.sjsu.edu
Subject: Re: battery water temp ?
I was about to use these auto filling systems on my 2 volt cells, than I
said wait a minute. How does it know when my cells are at discharge and the
electrolyte level is down at that time. Would they add some water at the
time which would cause the electrolyte higher into the fill neck when the
battery are at full charge?
Also what prevents the tubing from becoming a conductive path between cells?
Some people that use them, say that's very minor and nothing to worry about.
To see if there is any voltage conduction between any battery fill caps,
just take your volt meter and read between two fill necks on the battery and
see what you come up with.
If my next set of batteries have a fill neck, (not seal), I am going to
install The Water-Miser Vent Caps. These have plastic pellets, located
inside of these caps, that capture up to 90% of the electrolyte solution,
which also reduces the exposure to acid fumes and liquid. You do not have to
remove this cap to add any water.
They WEB site is:
http://www.backeastsolar.com/pr_batteries_accessories_watermiser<http://www.
backeastsolar.com/pr_batteries_accessories_watermiser>
Note: if this web address doubles up on you, just delete half of it. For
some reason all the web address I send through the EV list doubles up, but
it does not double up going to other people.
Roland
----- Original Message -----
From: Dewey, Jody R ATC (CVN75 IM3)<mailto:[EMAIL PROTECTED]>
To: 'ev@listproc.sjsu.edu'<mailto:'ev@listproc.sjsu.edu'>
Sent: Friday, October 28, 2005 10:21 AM
Subject: RE: battery water temp ?
Has anyone ever tried to link ALL the cells together with tubing to a
common
overflow tank that you fill all the batteries in the bank up
simultaneously?
Wouldnt that be easier than always worrying about filling each battery?
-----Original Message-----
From: Roland Wiench [mailto:[EMAIL PROTECTED]
Sent: Thursday, October 27, 2005 7:15 PM
To: ev@listproc.sjsu.edu<mailto:ev@listproc.sjsu.edu>
Subject: Re: battery water temp ?
How it should be done, but it may be too much hassle for some people is to
check the level at 50% discharge. If its just at the top of the grids,
add
just enough water to get about 1/8-1/4 inch above the grids.
Then charge it to 100% and check the level again. If its looks like its
1/2
inch below the bottom of the fill neck, then record that on a battery
chart
which is made on a graph paper.
The next time you discharge it to 50% than add 1/2 inch of water to that
battery that you mark 1/2 on the battery chart. Adding water at the
beginning of the charging cycle makes it mix better with the acid. Only
add
the indicated amount or you may dilute the acid or overflow the filling
neck.
I was told how to do this over 30 years ago, when I visit a battery
assembly
plant where I pick up large 300 AH cells that had a large filling well
above
the grids that was 3 inches high.
In a high AH cells, it is normal for the electrolyte level to drop 2
inches
during discharge and rise that level when charging.
Before I had these high AH batteries, I would just add water like
everybody
else after the charging. Then when I discharge and charged it again, the
water rise higher in the filling neck because the cold water expanded when
heated.
If you are only work with batteries below 200 AH, this is not as critical
because the electrolyte level may only rise about 1/8-1/4 inch into the
filling
neck.
For the majority of the people, it is lot easier to used a auto filler
that
will stop filling the water in a standard battery neck length. But with
High AH fill necks that could be 2 inches long, you have to extend the
fill
tube with a plastic tube to get to the right level. Its also a big hassle
to
have several fill bottles with different length tubes for adjusting the
level before charging.
I now have 260 AH Trojan batteries where I just fill them with the auto
filler with room temperature water with the fill tube extend about 1/8
inch
below the filler neck about 24 hours after charging. I never had any
problem with any electrolyte overflowing.
The heavy acid normally settles to the bottom and the water will stay on
stop, until you can charge it again, so it will mixed.
Roland
----- Original Message -----
From:
[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]
no.com<mailto:[EMAIL PROTECTED]>>
To:
ev@listproc.sjsu.edu<mailto:ev@listproc.sjsu.edu<mailto:ev@listproc.sjsu.edu
<mailto:ev@listproc.sjsu.edu>>
Sent: Thursday, October 27, 2005 3:16 PM
Subject: battery water temp ?
Hi all
When adding distilled water to a flooded battery after charging,
what would be better ? Cold water to a warm battery so the cold water
drops towards the bottom to mix with the acid since there is no more
bubbling to mix it, warm water to keep the batteries warm, or doesn't it
make any difference ?
John
--- End Message ---
--- Begin Message ---
Hi All
I'm a bit of a newbie, but I have been reading up alot before attempting my
first custom home built (not converted) EV. I was reading about the Zilla
controllers and the auto switching between two motors in series/parallel.
>From what I have read, it seems that the Zilla starts with the motors in
series, so full Amps (and half volatage) across both motors, which I assume
maximises the torque and therefore low end acceleration. Then as the motors
rev up, it auto switches them across to full voltage (half current) to both
motors so that they can rev up higher again (thus increasing the drive
ratio?). It has been described as a two speed electric (controller based)
tranny. Any ideas about the actual numbers (how the electric two speed
theory actually translates to gear ratios or speed)?
I would love to have my EV as direct drive (no tranny or clutch), but not
sure what gear ratio I should use (thinking of about 3-4). Top speed isnt
that important to me, as long as it can hit the 140 km/hr or so mark, thats
fine, but power and acceleration are definately the more important things
for my EV!
Any suggestions or explanations would be appreciated!
Rod
--- End Message ---
--- Begin Message ---
Hi,
Thanks for all the info so far, everyone.
Maybe I missed it, but does anyone know approximately how many RAV4 EVs
and Altra EVs are still around driving today?
--
-Nick
http://Go.DriveEV.com/
1988 Jeep Cherokee 4x4 EV
---------------------------
--- End Message ---
--- Begin Message ---
http://www.cdstandbypower.com/products/market/batteries/other_apps/deep_cycle.htm
These batteries seem to be a good possibility for EV use.
Lawrence Rhodes
Bassoon/Contrabassoon
Reedmaker
Book 4/5 doubler
Electric Vehicle & Solar Power Advocate
415-821-3519
[EMAIL PROTECTED]
--- End Message ---
--- Begin Message ---
John Wayland wrote:
Hello to All,
I've found the ongoing discussion on heated liquid type vs ceramic type
heaters very interesting.
I know already John what type you like :-)
Ryan Bohm wrote:
How long does it take when using this unit for hot air to begin
flowing on a really cold morning?
Victor Tikhonov wrote:
About 3 min. I do realize people will brag about 3 seconds for
their ceramic heaters. I'm sure they won't die if waiting 3 minutes.
I've always used the things an EV does better than a gas car, as a
selling point with those not yet convinced.
I don't sell cars. If I'd want to do it and instant heat would help,
I'd used them. (tat is, to sell, not to heat).
The instant-on heat that a
properly done ceramic heater provides, is such an item. I also,
absolutely hate shivering in my car waiting, and waiting, and waiting
for the damn infernal combustion engine to make its water hot enough to
provide warmth.
We're not discussing ICE cars, do we? I don't wait and wait and wait.
I just wait 3 min - works for me. If it would be instant with water
heater (ev type) I use, it would certainly be better. But compare to
trouble making it safe and installing one, not worth it for me.
If you absolutely hate to wait even 3 min, well, water heater
is not for you then. Simple as that.
How often do you hear complaints about that?
All the time, actually.
Again, comparing to ICE?
Conversely, especially when I had Red Beastie
with its twin elements, everyone loved the instant heat on those c-cold
frosty Winter mornings. It got to where my wife and I wouldn't want to
be in any of our other cars when it got really cold out, as we'd head
straight for the electric pickup with its instant-on killer heater.
Perhaps I'm not as sensitive to cold as you and your wife :-)
It's sure nice to have as short time as possible, but it is not
acceptable (to me) to jeopardize safety for few more dollars.
I'd have to disagree with you on this, my friend. There is far more
inherent danger in a a temp regulator or pressure switch failing and
having steam build up and burst pipes and or hoses to spray scalding
steam on persons, than in a ceramic element melting things.
What are you talking about my friend? What pressure switch? Are you
still comparing to ICE? The water temp in my system is set to 80'C
and of course there are redundant sensors to make sure it isn't
exceeded. There is no pressure at all, flexible rubber hoses connecting
the heater to the core, designed to withstand far more temp.
Scalding steam sprayed on persons sound like salesman tactic, sorry
for comparison. There is no steam possible, as the temp is far from 100'C.
The key to
both systems though, is a properly done installation. I've always
mounted the ceramic elements with an aluminum shroud around them so that
plastic is not adjacent to the element.
How much work is that, not mentioning tearing dash apart?
An over-temp cutout module ...
Which can fail...
> can also be added near the element in the case of a fan failure.
> Liquid type
heaters, too, can have the appropriate safety protections. I think the
safety aspect comparing both types, is a wash.
Not ripping the dash apart by using a warmed liquid type is very
attractive. Ripping the dash apart in order to get instant on heat
without any liquid that can leak and spill, is also very attractive. The
idea of having a bad heater core than can get clogged or leak and ooze,
goes away with a ceramic element, too.
Do you want to count everything that can go wrong with ceramic heater?
It can crack. Wires can sag, vibrate and break. Relays get stuck or the
contacts oxidize enough to became heaters themselves (and we know how
long they would last then, don't we?
Point is, looking at what can be wrong with a system does not
automatically makes alternative one better. Why don't you mention
all the things that can go wrong with ceramic heaters?
In 20+ years of using these elements in perhaps 40-50 EV conversions,
not once, has that problem ever happened to me...that's a pretty good
record.
I don't have as much experience (only 10 years overall and 5 years
using liquid heater), but it never happened to me either.
On the other hand, the warmed liquid heaters I've had in EVs
'have' had bad hoses, bad clamps, leaks, etc.
Oh, c'mon John. Why didn't you pick better clamps then?
I'm positive you picked clamps and hoses
for liquid cooled Zilla so they don't leak :-)
Plumbing the heater is no different.
What you describe is poor craftsmanship in particular car(s)
(if your clamp cannot keep a hose on the fitting without leak),
rather then fundamental heating principle). It's the same
as I'd say "in all EVs I had, I had contact screws to
the heating element getting loose... So ceramic
heaters are worse. Solution of course is tightening better
instead of complaining on the operation principle.
And 'all' of them made me
wait for heat and were nearly as miserable on cold mornings as a gas
car's heater.
I wonder what type/model was that. Can you tell?
Wonder why no OEM is even considering something like that. 10x (or more)
cheaper! Who can resist?
Victor, you're wrong on this. The first gen. Prius used a lower power
rated ceramic heater to supplement the warmed liquid type that blew cold
air when the ICE was off. The GM EV1 also had a ceramic element to
supplement its lame heat pump system. If batteries had way more storage
capacity and conserving precious amps wasn't such a high priority, all
factory EVs would have ceramic elements. Hybrids with their ICEs of
course, have all that hot water in them anyway, so of course they'll
always make use of it.
On the flip side... the newer cars are far harder to work on when it
comes to the dash and its often times hidden heater core. The warmed
liquid type heater is a nice option for these, and as Victor says, it
does only take about 3 minutes to get heat output, and for many, that's
an acceptable compromise.
I'm glad you said this.
I may add, that if I'll ever do scratch build EV, I'd likely
use ceramic heater option John defends so hard. It will make
sense because everything is open and exposed.
I'd use ceramic heater in my EV if I'd had no other option.
I don't mind do the work, you know that. I do mind if
waste time doing the work if I can easily avoid it and the result is
very acceptable to me. Perhaps my time worth too much :-)
I love using the ceramic elements and vastly prefer using them over
warmed liquid type heating systems. On the other hand, if I ever tear my
Insight apart and convert it over to pure electric, I would consider
using a warmed liquid type system that would allow me to keep the car's
excellent heater-AC system in tact, and then probably complain about
having to wait for the thing to warm up all the time :-)
Those nifty instant heat producing ceramic elements can really spoil you.
All you need John is a motion sensor near the inner door to your garage,
turning the heater on remotely. As soon as you walk in, by the time
you walk to the car, open overhead door, open car's door, seat
comfortably and ready to drive, the cabin will be pre-heated.
That may spoil you to the point you'll hate to wait for an
instant ceramic...
See Ya....John Wayland
Victor
--- End Message ---
--- Begin Message ---
From: Victor Tikhonov <[EMAIL PROTECTED]>
Reply-To: ev@listproc.sjsu.edu
To: ev@listproc.sjsu.edu
Subject: Re: Bits and Pieces - air vs water cooling
Date: Fri, 28 Oct 2005 11:03:30 -0700
Phil Marino wrote:
I can see at least one major disadvantage to water cooling - reliability.
Air cooling components (blowers and heat sinks) indeed may never fail
although I suspect a blower may require more than 10x power to cool
controller's semiconductors to about the same temp.
Well, Victor, I suspect it requires less power, so we're even here.
You also haven't considered the additional weight of a water-cooled system -
it takes power to haul all of that around.
So you stress
your controller more which will cut off sooner while air cooling
indeed didn't help. Have you ever stand near tzero with its 150kW
inverter and blower on?
My car will never produce anywhere near 150 KW, so that doens't apply to me.
In a book about sailing that I read many years ago; - I can't recall the
name of the book - William F Buckley defined a luxury on a sailboat as
anything that " when it breaks down, you can fix it at sea".
Applies to any system. How do you "fix" your vehicle if it keeps
cutting back power to maintain safe temp
Victor - you missed the part where I said an "adequate" air-cooled system.
In all of my years of driving, I have had to have a car towed (
unrepairable by me on the side of the road) three times. Once was an
electrical problem, and twice it was cooling system failure ( loss of
coolant due to component failure).
That was a poor choice for that component then. Was it a fish tank pump?
Claiming that water cooled choice is worse because of your own
experience with marginal hardware is not terribly scientific.
My fault for the misunderstanding here - these were ICE cars, with OEM
equipment. No "fish-tank" pumps.
As far as avoiding overheating - that depends on the design of the system,
not on the method.
It's opposite.
I disagree. If you were right, a poorly designed water-cooled system would
perform better than a well designed air-cooled system. By definition,
that's not true.
As far as expenses I have < $200 water pump and few feet of
clear tubing from home depot.
How much are your fins, heat sinks, individual blowers and
electrical wiring to them, fuses, etc?
About $15 total - I found the heat sinks ( fins included) cheap at a surplus
place. The relay is a couple of bucks.
Having a blade fan on the motor shaft does not count, you
can't slow down under load and have change driving strategy
(down shift) because of this limitation.
DC series motors are very inefficient at low RPM, so they should not be used
that way anyway, even if the cooling system would allow it.
The standard for DC series motors in EV's is to use the built-in mechanical
fan. It works.
Any system can be designed right or wrong. For many - air cooling
is adequate and justified (VW bugs).
You make your calculations if you know how, or pure guess.
Saying that the system *may* leak without ever having one,
carries little weight. Like me saying a fan motor brush can
be cracked or a bearing fail, so air cooling is less reliable.
Yes, you can still have mechanical failures, but since ( as I said) I am
using two blowers, there is no single-point, catastrophic, mechanical
failure mode.
There are MANY possiblities for a single point failure in a liquid cooled
system. Every seal, and every liquid connection, as well as the pump
itself and the radiator.
Phil
I'm off this topic.
Victor
_________________________________________________________________
Express yourself instantly with MSN Messenger! Download today - it's FREE!
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--- End Message ---
--- Begin Message ---
Roland,
Most likely cause of the longer run time at 6 GPM is that the
heater is seeing already pretty hot water coming in, so it needs
to be "modulated" by either switching off/on or by reducing its
heat (burner) output, to avoid boiling the water in the heater.
This way, it needs a longer time to put the same heat into the
water.
For the amount of heat given off by the floor - as long as the
entire loop is at an average 120 or 130 or whatever temp; the
same temp will result in the same heat transfer to the floor,
no matter how fast or slow it runs.
You will notice that at slower rates due to the drop in temp
between inlet and outlet, the average is lower and thus the
heat transfer to the floor is lower.
This is not reflected by your run time of the thermostats,
though there can be many variables affecting the thermostat
operation, so please do not rely on the room thermostats as
they are part of a control loop with a lot of latency and
therefore the thermostats have "advancers" that heat up the
actual thermostat sensor, to make it switch off early as they
otherwise sense the temp rise way too late and your room would
seriously cycle from too cold to way too hot.
The only good way to monitor the heat transfer is to look at
water temperatures and to see the energy input you should
check your gas meter.
Success,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3673 eFAX: +31-84-717-9972
Proxim Wireless Networks eFAX: +1-501-641-8576
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Roland Wiench
Sent: Friday, October 28, 2005 6:42 AM
To: ev@listproc.sjsu.edu
Subject: Re: Radiator
I just turn on my floor heating system on last week. I than went back to
see the difference of heat removable, by adjusting one zone to 1 gallon per
minute vs 6 gallon per minute.
When the zone loop is up to temperature, 140 degrees, it circulates its in
own loop until its gets down to 120 degrees. At 120 degrees, the boiler hot
water is added or in the circulation loop of the boil to bring the
temperature back up to 140 degrees.
I have a elaspe time clock on the boiler startup and shut down and a
another clock on the zone loop. I did this years ago to see how long the
boiler is on per 24 hours a day at a certain outside to inside temperature
difference monitor by outside/inside thermostats. The outside thermo can
vary the flow of the pumps if I put it into Auto position.
I also have floor temperature sensors, one at ceiling and one at 60 inches
off the floor.
I put the pump control on manual position and one zone to 1 gpm. I than
time when the room thermostat come on. The zone temperature was up to 140
degrees at the feed and in one minute of circulation, the return temperate
was at 80 degrees.
The wall thermostats have a 2 degree differential, 1 degree up and 1 degree
down below the set temperature and is set to 72 degrees. The outside
temperature is 39 degrees.
The thermo trip off in 1 minute and 55 seconds.
The zone feed temperature is now 133 degrees, and the return is 83 degrees.
The next day when the same outside temperature was the same and the room
temperature set at 72 degrees. Both days, there is no wind and its cloudy.
I now adjusted the same zone pump to 6 gpm with the same 140 degree feed
temperature. This time the zone return temperature quickly rise to 110
degrees in 1 minute. The room thermostat took 4 minutes and 23 seconds to
turn off which is the same run time as the zone pumps. The boiler
temperature is again at 133 degrees after that amount of time.
The Heat Way floor heat manual and even talking to one of there engineers,
they say its best to have the zone flow values adjusted so that the
temperature difference between the feed and return not to be less than 20
degrees, other wise the heat absorbing takes longer making the pumps run
longer.
Now, I'am going have to go and test out that 160 degree themostat vs a 195
degree thermostat in my sports car engine. My engine does not used a set in
themostate. It uses a remote electric circulation pump and electric fan,
that is thermostat operated by a thermo sensor on the thermo housing which
is a standard intake manifold.
This type of system shuts down the circulation threw the radiator and the
water is circulated threw the engine only during warm up.
It does seems very logical to me, that the lower thermo will allow higher
temperature water return back to engine, because its does not hold the
coolent longer in the radiator.
It will be awhile, before I test this out, because this car is undergoing a
complete overhauling and customizing.
Roland
----- Original Message -----
From: Cor van de Water<mailto:[EMAIL PROTECTED]>
To: ev@listproc.sjsu.edu<mailto:ev@listproc.sjsu.edu>
Sent: Friday, October 28, 2005 4:31 AM
Subject: RE: Radiator
Roland,
In an attempt to bring some science to the stories:
When you move 1 gal/m and lose 60 deg in your floor
or you pump 6 gal/m (6 times as much) and you lose
20 deg in each of those 6 gals, means that although
the temp delta is only 1/3 it happened to 6 times
as much water, so in total you did move twice as
much heat into the floor by pumping 6 gals/min.
Your radator comparable, but it depends on the
relative speeds (as you already indicated):
- if you are pumping fast enough that there is
a "gradient" (constant increase/decrease) of
temperature along the path of water flow, then
your reasoning holds: pumping slower causes a
steeper gradient, so the water coming out of the
radiator is much cooler that it enters, since
the same temp difference happens across the
heat generator, you can also see that the water
exiting the heatsink is much hotter than the water
entering the heatsink when it is moving slower.
That means that in average the heatsink will be
hotter when pumping slower, because your reasoning
that the output temp is lower is false: in practice
the output temp of the radiator will not change so
much (it will go down a little), but the INPUT temp
of the radator will go up and this you will see as
a larger temp delta across the radiator.
In your words:
> This is what I meant, The faster the coolant rate,
> the hotter the coolant is as it exits the radiator.
> Therefore if it's at a slower rated than it must
> exit at a cooler rate. Roland
And I am saying that your BTU calculation is right,
but your reasoning is the wrong direction:
- The faster the coolant flows, the >colder< the coolant
is as it >enters< the radiator. (lower overall temp)
- Therefore if it's at a slower rate, then it must
>enter< at a >higher< temp.
- if you are not pumping fast enough, the transport
of water will affect the heat transfer and no longer
the radiator cooling by air will be the dominant
factor in the cooling.
You will see the effect that the water entering the
radiator will be cooled mainly be the first part of
the radiator, then the temp difference with the
ambient is getting so low that there is no more
cooling in the remainder of the radiator. It does
not help to have such a large radiator that the
water is at ambient temp before is exits, the
cooling is in a limited area, determined by the
flow of water.
Conversely if the flow through the heatsink is too
low, it will quickly heat up the water and the
cooling will mainly be done by the first part
of the heatsink, then the water is at the
heatsink temperature, so only part of the area
is effectively cooling, the termal resistance will
go up and the temp of the transistors will rise.
Again, the cooling is mainly determined by the
speed of water flow at too low speeds.
In all above cases does it make sense to speed up
the flow to achieve better cooling and a larger
heat transfer and lower temperature differences.
That is an effect that you will see everywhere in
nature as it is one of the thermodynamics laws.
NOTE that it depends on *where* you measure temp
to see these effects. For example if you have
the thermometer at the *exit* of the radiator
(I would not know why, maybe install error?)
then you could indeed see the temp go down when
you lower the flow, even though the cooling
would reduce and the *other* side of the cooling
system runs much hotter!
Hope this clarifies,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]> Private:
http://www.cvandewater.com<http://www.cvandewater.com/>
Skype: cor_van_de_water IM:
[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3673 eFAX: +31-84-717-9972
Proxim Wireless Networks eFAX: +1-501-641-8576
Take your network further http://www.proxim.com<http://www.proxim.com/>
-----Original Message-----
From: [EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>
[mailto:[EMAIL PROTECTED]
Behalf Of Roland Wiench
Sent: Wednesday, October 26, 2005 9:55 PM
To: ev@listproc.sjsu.edu<mailto:ev@listproc.sjsu.edu>
Subject: Re: Radiator
----- Original Message -----
From: Phil
Marino<mailto:[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>>
To:
ev@listproc.sjsu.edu<mailto:ev@listproc.sjsu.edu<mailto:ev@listproc.sjsu.edu
<mailto:ev@listproc.sjsu.edu>>
Sent: Wednesday, October 26, 2005 9:56 PM
Subject: Re: Radiator
>From:
[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]<mailt
o:[EMAIL PROTECTED]>>
>Reply-To:
ev@listproc.sjsu.edu<mailto:ev@listproc.sjsu.edu<mailto:ev@listproc.sjsu.edu
<mailto:ev@listproc.sjsu.edu>>
>To:
ev@listproc.sjsu.edu<mailto:ev@listproc.sjsu.edu<mailto:ev@listproc.sjsu.edu
<mailto:ev@listproc.sjsu.edu>>
>Subject: Re: Radiator
>Date: Wed, 26 Oct 2005 23:00:48 EDT
>
>In a message dated 10/26/2005 6:30:22 PM Pacific Standard Time,
>[EMAIL PROTECTED]
>writes:
>
><< This should hold true pumping hot water threw a radiator, if you
pump
>it
>too fast threw the radiator, it does not stay in long enough for the
water
>to
>cool down. >>
>
>That is an old wives tale.
>Faster liquid flow transfers more heat.
>(must be my turn to be brusque and borderline inconsiderate..)
>
>Ben
>
The old wives were right.
Here's why:
The heat that a radiator can lose to the air is predominantly determined
by
the air-to-radiator interface, not the liquid-to-radiator interface, as
long
as you have above a minimum efficient coolant flow. So, the rate of
heat
loss ( BTU/hour) of a given radiator is pretty much constant for a given
coolant-air temperature difference, and a given air flow through the
radiator. It doesn't depend on the coolant flow rate.
So, this means that, for example, if you double the liquid coolant
flow,
the BTU/hour that the radiator dissipates to the air (and draws from the
liquid coolant) stays essentially the same. But, now twice as much
liquid
passes through the radiator per hour. SO, twice as much coolant loses
the
same number of BTU's, and the temperature drop of the liquid is about
half
of what it was at the lower coolant flow rate.
The faster the coolant rate, the hotter the coolant is as it exits the
radiator. There is no free lunch.
This is what I meant, The faster the coolant rate, the hotter the
coolant
is as it exits the radiator. Therefore if it's at a slower rated than it
must exit at a cooler rate. Roland
Phil
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--- Begin Message ---
Actually you have found your problem by giving these numbers:
Water boils at 212 at sea-level pressure.
Seeing your temp going to 220-230 means that it's already
super-heated and likely boiling inside your engine, unless
you have a high pressure in your cooling system.
You only need about 15 PSI higher pressure inside your cooling
system (double atmosferic pressure, like a pressure cooker)
to rise the boiling point to approx 250 F (inside engine!)
so if your larger-throughput low-temp Thermostat gives you
a low pressure in your cooling system, it will not only cause
your coolant to boil (destroying any good cooling possibility)
but it will REDUCE the max temp of the water entering the
radiator and therefor it will reduce the capability of sufficient
cooling as the temperature DIFFERENCE between radiator and ambient
air is usually the limiting factor in heat flow from the coolant
to the ambient.
Bring your system to higher pressure, rise the max temp it can
feed to the radiator (remove risk of a blown engine by boiling)
and cool your motor better by a larger difference between the
radiator temp and ambient air.
(you *want* the water to the radiator to have a high temp to
achieve maximum cooling. With a given pump, this is achieved
by reducing the water flow to create enough pressure, that is
most likely the science behind the "misunderstanding" that lower
flow will cause better cooling - it does not.)
Increasing the flow (at constant pressure) will actually help
to reduce the difference between the hottest point (in the motor)
and the *average* temp of the radator - again, the higher the
average temp of the radiator, the larger the cooling.
Additional benefit is that there is a smaller difference between
internal motor temp and radiator so less chance of
over-heating (boiling) inside the motor.
Critical is that you need to increase flow while keeping the
pressure up.
So - no "large-flow" thermostats, but a larger pump may work well.
Hope this helps,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3673 eFAX: +31-84-717-9972
Proxim Wireless Networks eFAX: +1-501-641-8576
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Dewey, Jody R ATC (CVN75 IM3)
Sent: Friday, October 28, 2005 2:56 AM
To: 'ev@listproc.sjsu.edu'
Subject: RE: Radiator
Nope. Two different 160 Thermostats did the same thing. The problem was
the 160 thermostat was ALWAYS open so with the same amount of flow the
radiator couldnt cool it down in the one pass it got. When I put in the 195
thermostat it would close the engine off to the radiator and that gave the
radiator extra time to cool the water before it was pumped back into the
engine. Since my temp sender is right above the thermostat I can watch it
open and close on the dial. When the 160 was in there you could watch the
temps rise to 160 then drop to about 100 as soon as the thermostat opened.
Then the next round it would be 160 open drop to 110. This would continue
until it stayed at 160 and slowly rise all the way to 200. When I switched
to the 195 it would cycle between 200 and 180 and remain relatively
constant. In fact, with the 160 thermostat it was not uncommon for the car
to hit 220-230 when pulling the boat up hills. With the 195 it would go to
210 on the hill and immediately drop to 180-200 after that.
-----Original Message-----
From: Cor van de Water [mailto:[EMAIL PROTECTED]
Sent: Thursday, October 27, 2005 12:55 PM
To: ev@listproc.sjsu.edu
Subject: RE: Radiator
I think your first thermostat was broken.
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3673 eFAX: +31-84-717-9972
Proxim Wireless Networks eFAX: +1-501-641-8576
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Dewey, Jody R ATC (CVN75 IM3)
Sent: Thursday, October 27, 2005 3:08 AM
To: 'ev@listproc.sjsu.edu'
Subject: RE: Radiator
I can speak from experience on that point. My JEEP Cherokee, with a 160
thermostat, ran 210 pulling my boat. When I switched to a 190 thermostat
the engine ran 190 max 195. Giving the radiator time to cool the water
enabled the engine to manage its heat more effeciently.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: Wednesday, October 26, 2005 11:01 PM
To: ev@listproc.sjsu.edu
Subject: Re: Radiator
In a message dated 10/26/2005 6:30:22 PM Pacific Standard Time, [EMAIL
PROTECTED]
writes:
<< This should hold true pumping hot water threw a radiator, if you pump it
too fast threw the radiator, it does not stay in long enough for the water
to
cool down. >>
That is an old wives tale.
Faster liquid flow transfers more heat.
(must be my turn to be brusque and borderline inconsiderate..)
Ben
--- End Message ---
--- Begin Message ---
Danny Miller wrote:
That is incorrect, with certainty. There is no "sweet spot"; lower
flow rates will always mean a higher heatsink temp. The limiting
factor is, as mentioned before, how much flow it is practical to pump
while still getting enough useful gains to justify the added pressure,
pumping power, and possibly the need to redesign the system with
more/wider passages.
Higher flow rates will mean the heatsink will get cooler. Actually if
a device generates 100W of heat then the system will dissipate 100W of
heat regardless of flow rate, it's a matter of how hot the heatsink
and its semiconductors will be (and the goal here is to keep them
cool). A low flow system not only runs higher heatsink temps but the
ultimate power rating is decreased. A system with good flow might be
able to dissipate 500W without overheating the semiconductors whereas
setting the same system at lesser flow might overheat at 200W.
Not necessarily. You need to remember that this is a closed cooling
system with a heat source (controller) and a heat sink (radiator) If
you only look at the heat source side of it, you're correct. Faster
flow removes more heat. However, since it's a closed system, and more
flow through the heat source also means more flow through the heat sink,
which means the coolant cools less. Overall, the coolant spends less
time away from the heatsink. Consider:
Q = M x C x Delta T
Q = Heat transfer
M = Mass of coolant flow
C = is a Constant (specific heat of water)
Delta T = coolant temp in - coolant temp out
With higher flows in a closed system, the Delta T (coolant temp in -
coolant temp out) will be lower, meaning less heat removal, meaning
warmer heat source.
With a sufficiently large heat sink (radiator), this is a non-issue.
Obviously, with this equation, if your rate is too low, then you'll also
suffer with poor heat removal, while your Delta T will be high.
--- End Message ---
--- Begin Message ---
I know ive seen some of these modified, and i know electric motors in some
cases can be modified to gain more power...
First question is...will it lose efficiency and draw more then normal
battery life? or will it still fit its current efficiency curve?
Its a 12 hp i believe 8cont briggs and straton e-tek.
Second question is...if the above question is that it will remain
efficient...how do i go about doing it, or where can i get a handbook or
manual on it?
~Marc
--- End Message ---
--- Begin Message ---
We just brought the OJ2 dragster back from the East Coast Electric Expo
in Philly where it was a huge hit. Chris, thanks for the kind words.
It was a pleasure to meet you and talk shop. I'm not exagerating when I
say that HUNDREDS of people were shocked to find out an electric
dragster could run under 11 secs at 120 mph in the 1/4 mile. I sent
all of them to the NEDRA site for more info. Now that OJ2 is done
showing for the year it is imperative that we get in some runs with the
new Lemcos before the January race in Florida. Quaker City is closed
for the season but if the weather allows we will be traveling to and
racing at Mason Dixon Dragway on Nov 5th. It's a pretty good haul down
there but will give us a chance to redeem our sub-par showing at Power
of DC earlier in the year. Don't worry Rich, we are going to run with
only one 1.8K Zilla this trip. If any of you are nearby, make plans to
come out. Who knows what will happen?
Shawn Lawless
--- End Message ---
--- Begin Message ---
Anybody know what the Peukert exponent is for Deka Dominator sealed gel
batteries? Any difference between group 24 and group 27?
And what is the customary low-end per-battery voltage for 12V lead-acid
batteries under load? 10V?
Thanks!
-Tom
--
Thomas Hudson
http://portdistrict5.org -- 5th District Aldermanic Website
http://portev.org -- Electric Vehicles, Solar Power & More
http://portgardenclub.org -- Port Washington Garden Club
http://portlightstation.org -- Light Station Restoration
http://klanky.com -- Animation Projects
--- End Message ---
--- Begin Message ---
Phil Marino wrote:
An air-cooled system will never fail because of a leak.
Tell that to the pneumatic bellows in my Corvair. =) At least it
fails-safe; max cooling, but it takes forever to warm up.
As far as avoiding overheating - that depends on the design of the
system, not on the method.
You can have an inadequate water-cooled system, and you can have a
well designed, more than adequate, air cooled system.
More complex and expensive isn't always better.
--- End Message ---
--- Begin Message ---
Yes, I have 36 of the 88 A/H in the Green Bedford CF at the moment. They
are two strings of 18 to give me 216 at 160 A/H.
They seem to work O.K although I am about to change them out in favour of
the Yuasa AGM 6-160.
John
----- Original Message -----
From: "Lawrence Rhodes" <[EMAIL PROTECTED]>
To: "Electric Vehicle Discussion List" <ev@listproc.sjsu.edu>; "Zappylist"
<[EMAIL PROTECTED]>
Sent: Friday, October 28, 2005 7:52 PM
Subject: Dynasty VLRA Stecifications.
>
http://www.cdstandbypower.com/products/market/batteries/other_apps/deep_cycle.htm
> These batteries seem to be a good possibility for EV use.
>
> Lawrence Rhodes
> Bassoon/Contrabassoon
> Reedmaker
> Book 4/5 doubler
> Electric Vehicle & Solar Power Advocate
> 415-821-3519
> [EMAIL PROTECTED]
>
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.1.361 / Virus Database: 267.12.5/149 - Release Date: 25/10/2005
>
>
--- End Message ---
--- Begin Message ---
On another thread there was a question about filling systems.
Here are some links:
http://www.aquapro.net/
http://www.batteryfillingsystems.com/default.asp
I looked into getting a system and it seems that the cost was from about $6 to
$9 per cell, so for a trojan that would be $18 to $24. I have a 30 battery
system so it would have cost $540 to $720. more than I wanted to spend.
They are both pretty similar systems.
I talked with both companies and they would give a quantity order a discount.
Anybody want to order some?
Rush
Tucson AZ
www.ironandwood.org
--- End Message ---
--- Begin Message ---
From: Eric Poulsen <[EMAIL PROTECTED]>
Reply-To: ev@listproc.sjsu.edu
To: ev@listproc.sjsu.edu
Subject: Re: Radiator
Date: Fri, 28 Oct 2005 12:40:29 -0700
Danny Miller wrote:
That is incorrect, with certainty. There is no "sweet spot"; lower flow
rates will always mean a higher heatsink temp. The limiting factor is, as
mentioned before, how much flow it is practical to pump while still
getting enough useful gains to justify the added pressure, pumping power,
and possibly the need to redesign the system with more/wider passages.
Higher flow rates will mean the heatsink will get cooler. Actually if a
device generates 100W of heat then the system will dissipate 100W of heat
regardless of flow rate, it's a matter of how hot the heatsink and its
semiconductors will be (and the goal here is to keep them cool). A low
flow system not only runs higher heatsink temps but the ultimate power
rating is decreased. A system with good flow might be able to dissipate
500W without overheating the semiconductors whereas setting the same
system at lesser flow might overheat at 200W.
Not necessarily. You need to remember that this is a closed cooling system
with a heat source (controller) and a heat sink (radiator) If you only
look at the heat source side of it, you're correct. Faster flow removes
more heat. However, since it's a closed system, and more flow through the
heat source also means more flow through the heat sink, which means the
coolant cools less. Overall, the coolant spends less time away from the
heatsink. Consider:
Q = M x C x Delta T
Q = Heat transfer
M = Mass of coolant flow
C = is a Constant (specific heat of water)
Delta T = coolant temp in - coolant temp out
With higher flows in a closed system, the Delta T (coolant temp in -
coolant temp out) will be lower, meaning less heat removal, meaning warmer
heat source.
With a sufficiently large heat sink (radiator), this is a non-issue.
Obviously, with this equation, if your rate is too low, then you'll also
suffer with poor heat removal, while your Delta T will be high.
Eric - you missed something really important here.
You're right that Delta T goes down if you increase the flow rate. But, M -
Mass of coolant flow- is higher ( after all, that is why Delta T drops) ,
so Q will never drop with increasing coolant flow.
Your last statement is correct : there is a minimum coolant flow rate that
allows the radiator and heat sink to operate effectively. But, above that
flow rate, it neither helps nor hurts. There is no sweet spot.
Phil
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