peter.parr...@calsolareng.com
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885
-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of R Ray
Walters
Sent: Sunday, September 12, 2010 3:10 PM
To: RE
a voltage issue, for arrays over 250 v?
I'm sure I'm missing something.
I recall you once saying that UL doesn't even use the grounding hole when
testing modules, that they just clamped an alligator clip to the frame?
Thanks for giving us the NEC and beyond viewpoint,
Ray Walters
We need a more
and possibly get wet.
thx,
jay
Peltz Power
On Sep 11, 2010, at 7:45 PM, R Ray Walters wrote:
The nice folks at BZ Products have made me small custom voltage controllers
before, for just that application.
Prices, as I recall were less than a C40, and much smaller footprint/
weight
A picture is worth a thousand words, (hopefully this will upload)
Here's a traditional Ilsco Lug after less than 5 years near the ocean:
inline: DSC00611.jpg
IMHO, this is a galvanic reaction between the Cu, Al, and (our loser) the Lug
which became the anode.
No other corrosion was near this
The nice folks at BZ Products have made me small custom voltage controllers
before, for just that application.
Prices, as I recall were less than a C40, and much smaller footprint/ weight,
which is an issue on a mobile application.
R. Walters
r...@solarray.com
Solar Engineer
On Sep 10,
I've used the Pathfinder for decades, so I'm partial to them. Great for on-site
discussions of shading issues with the customer, as multiple people can see the
shading at the same time on the spot.
I've also used their Assistant software, and it works pretty well. You take a
photo of the actual
If its a large commercial array, I would consider using larger centralized
inverters, and then monitor with National Semiconductor's Solar magic
monitoring system. It has string level current taps, so (theoretically at
least) you could see a single module failure by the reduced string output.
I know, as Bill pointed out, that the Deltas are supposed to be mounted on the
exterior to allow the damage to stay outside of the combiner box. But I've also
seen a lot of old Deltas damaged by the sun, and seen them cracked off at the
1/2 nipple attachment point, which then leaves exposed
Oh boy, just when we thought all we had to worry about was getting electrocuted
or falling off a roof.
The cooked dummy at the end of the last video is a very serious reminder.
Besides the arc flash gear, are there other things we should be watching for to
prevent this from happening? (we
system that sucks water out of the swimming pool
and pumps it to roof sprinklers with fire retardant added to
the water. I'll forward your email to my colleague who has
the details.
Best regards,
Joel Davidson
- Original Message - From: R Ray Walters r...@solarray.com
To: RE-wrenches
Little beyond a pair of Outbacks, possibly a pair of Magnasine inverters, or a
quad stack of Outbacks.
R. Walters
r...@solarray.com
Solar Engineer
On Aug 26, 2010, at 2:41 PM, Joel Davidson wrote:
Wrenches,
Our customer has a fire protection pumping system that operates at 240VAC and
I think the issue is that some installers are wanting the supplementary
electrode for the array tied to the building grounding system in two places. I
saw this in BIll Brooks seminar too, but then he said it wasn't necessary.
Basically the EGC system already ties both electrodes together as
I found utter world wide confusion upon more research on this issue.
http://en.wikipedia.org/wiki/Three-phase_electric_power has a table that lists
color coding for different countries, US is black, red, blue, (common
practice),
while our neighbors in Canada, use Red, black, blue.☺ Europe is
We don't often get to take picture, as the point of failure is hard to find,
and the entire underground line is just abandoned and a new cable is installed.
Most failures I've seen (not actually seen) were on improperly installed runs,
done by DIYers.
On the other hand, the majority of
Interesting, there isn't a code requirement to color code for phase rotation,
but it is common practice for black, red, blue to correspond to clockwise
rotation. Also notice on the DC table, that John Wiles recommends (but isn't
NEC required) color coding for a positive grounded system:
white
http://www.tecratools.com/ is a decent company to work with.
I've been pretty happy with both of my tool cases I've gotten from them. I used
the tool back pack for years, and recently got a padded flight case with tool
pallets, meters are padded in the bottom.
R. Walters
r...@solarray.com
I'd say that at this point, with all the old solar systems, flat roofs, and
snow we get in New Mexico and Colorado, that if it hasn't been a problem, it
won't be a problem.
It definitely is not going to lift the panels; worst case is that it could
build up and get past flashings, which is a
Bob's idea of strapping them together is good. We do the same thing to move
batteries on horrible washboard roads, it definitely keeps them upright.
Also, consider the altitude change in flight, as that could pressurize an
unvented battery to dangerous levels. You definitely want to keep them
I usually recommend retorqueing all connectors once the panel is mounted.
Whether its an E-panel or one we built at the shop, those washboard roads can
loosen stuff that would never have had a problem
otherwise. I'm actually surprised we haven't had more problems like this, even
with internal
I try to keep it in copper for DC, as I had always heard of trouble with
Aluminum on DC. (True or Old Wrenches Tale?)
We definitely go to Al on long AC runs, as its whats available, and the cost
difference becomes remarkable.
I've seen small cuts in Al, later corrode completely through the
since 1988
-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf
Of R Ray Walters
Sent: Friday, July 23, 2010 7:46 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] calculating DC voltage drop
I try to keep
I use actual operating current, without multipliers. I also use actual
temperatures, not the worst case temperatures that many use.
I created a spread sheet that uses the NEC adjustments for wire temperature,
(see NEC chapter 9, table 8, FPN 2)
It makes quite a difference!
Volt drop and the
...@lists.re-wrenches.org] On Behalf Of R Ray Walters
Sent: Thursday, July 22, 2010 3:45 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] calculating DC voltage drop
I use actual operating current, without multipliers. I also use actual
temperatures, not the worst case temperatures that many use
Kent;
Your table shows just what I found as well: too large a battery bank actually
isn't as cost effective.
Also, based on the Trojan chart, you can see that a regular L16 isn't even as
good as golf cart battery, but that the 2 v version doubles the cycle life.
(which makes sense, cycle life
See below:
R. Walters
r...@solarray.com
Solar Engineer
On Jul 1, 2010, at 7:09 AM, Jeff Clearwater wrote:
Dear Colleagues,
Well this one's for me! Nice to do solar for oneself after installing for
others my whole life!
I'm putting together an small RV system in my Sprinter Van that
http://www.bb-battery.com/
they should sell direct. I'd look at the MPL-90 battery, its a sealed deep
cycle battery 12 v 90 aH. Make sure and ask for the flag terminal, the post
terminals are too small for 2/0 cable.
We've used them on grid tie w/ battery backup, and off grid stuff that
IF those L 16s are much over 5 years old, they could be gone. L16s (of any
brand) have less cycle life than a golf cart battery, just check the charts.
They also don't fair very well long term in float charge.
You can probably EQ them back to life as already mentioned, but then after 6
months to
Box 657
Petaluma, CA 94953
Cell: 707-321-2937
Office: 707-789-9537
Fax: 707-769-9037
From: R Ray Walters r...@solarray.com
To: RE-wrenches re-wrenches@lists.re-wrenches.org
Sent: Tue, June 29, 2010 8:59:15 PM
Subject: Re: [RE-wrenches] Interstate UL-16 HC problem
IF those L 16s
I agree Peter, the seals are not exposed like a normal flashing, so that will
help. But the Oateys will still see some reflected UV radiation. I've seen
other parts protected by the array, totally deteriorate in 5 years (UV
resistant tie wraps anyone?). In Hawaii, roofing supply houses only
Float valves too have been problematic. Seals wear and leak after several
years, and just a couple of months ago, we had the brass shaft that connects
the float to the valve break off. In this case the tank had an over flow that
went into the septic. So nothing was damaged by the over filling,
Jeff's idea is good, but I think the only potential violation of the listing of
the service panel, would be if you drilled and tapped into the buss bar.
Tapping the cable w/ a listed connector shouldn't cause any trouble to the
service panel. (230.33 specifically allows the service cable
Windy was our best resource for DC air pumping. I recall brush wear, and other
high voltage arcing problems.
I remember using an AC air pump (simple magnetic coil) with a rectifier, also.
Never heard from those customers again,
so 'No news= Good News?
R. Walters
r...@solarray.com
Solar
I've run a 3 Hp pump on a pair of Outback inverters, but it's not a done deal.
As the pumps age, they start getting stickier (read more start up current
needed to get them going) and wells often have silt which builds up in the pipe
and pump, adding to the start up surge.
I recently had a
Mick,
To calculate the lifetime amp-hrs, as you wanted, you first have to have the
Cycle Life vs. DOD (depth of discharge) info for your battery, then multiply
the cycles at your proposed DOD, by the amp hrs rating of the battery by the
DOD% (cycle # x battery AMpHr x DOD%)
One thing I can
We've had no problems with Outback inverters and AFCI breakers, other than the
inverter can't actually generate the 70 amps necessary to make an AFCI trip.
(an inspector's AFCI tester didn't trip when expected) I think there should be
an exception to the AFCI requirement, when the power supply
I agree with your I-V curve interpretation Bill, I had never considered the
counteracting influences on voltage of reduced irradiance and reduced temp.
Very interesting. Also funny how most manufacturers quit publishing IV
curves
One way to check it Peter, is to turn each subarray on
remain in place.
- Original Message -
From: R Ray Walters
To: RE-wrenches
Sent: Tuesday, May 18, 2010 6:47 PM
Subject: Re: [RE-wrenches] Whats with Kyocera
Interesting, because we quit working with all three Manufacturers mentioned
for the following reasons:
Kyocera had
PVC doesn't look as professional, especially when it starts browning in the sun
after a few years.
We still use it a lot though, as its durable, nonconductive, and easy to use.
5 things we do to make PVC better:
No long exposed runs (to avoid expansion problems)
Use Sch 80 coming out of the
Interesting, because we quit working with all three Manufacturers mentioned for
the following reasons:
Kyocera had that 1999 bad batch that is still giving them a bad name in the
back woods here. So glad I never sold those.
BP bought Solarex, and starting making crappy polycrystalline stuff,
I've also seen failures/ nuisance tripping due to loose connections at the
breaker. The heat then wreaks havoc on the breaker internals.
R. Walters
r...@solarray.com
Solar Engineer
On May 17, 2010, at 8:23 AM, jay peltz wrote:
HI Drake
I don't know if this could apply to your situation,
I only use this signage, when its true.
Gridtie inverters interrupt output in milliseconds, so I don't use it on AC.
My understanding is that it does apply to array disconnects, as the inverter
capacitors could still have a charge, that would render the live on both
sides idea true on DC.
I
My understanding was that the din mountable QOU breakers were rated to 125 vDC,
and are internally the same as the QO. The difference was the connectors, and
the mounting method.
I've used the QOUs reliably at 120 v nom on an EV, (but don't try this at home,
kids)
We still use the QOs sometimes
It all depends on how its done. If each electrode is attached to the next
electrode by the #2 and Cadweld directly, and also connected through the
required EGC, then there is a loop. Once you have the loop, the low resistance
#2 cable only increases its ability to generate current from an
I like the SW4024, but I never liked the SW5548. It actually had less surge
capability than its little brother.
Either way, I would never recommend the Trace SW series for grid tie. They are
very inefficient in that mode.
(As for the noise, I seem to recall an issue with old SWs where the
Its all too bad, because for an oil company, BP was at least trying to do some
solar. (but their panels sucked)
All the other oil companies bailed on solar years ago (Shell, Arco), or never
even bothered in the first place. (Exxon)
Unfortunately, unless you magically don't use any petroleum
All of my this ought to work? experiments in module mixing and matching did
work, but always under performed.
If the customer wanted to play around with them, put them on a decent rack,
and hide the mess from view, it will still provide some usable amps.
I wouldn't even waste an MPPT controller
I still think the venerable Solar Pathfinder coupled with their Pathfinder
Assistant software is just as good or better, for much less money.
I did some very detailed shading analysis with the Pathfinder (as you may
recall)
You do have to provide your own digital camera though.
R. Walters
On the venting vs insulating issue, I too have wondered about that.
If insulation is needed, we insulate around the battery bottom and sides very
tightly, but leave the top exposed. Venting is only for the top of the battery,
the sides do not need to be vented.
Gases are coming from the caps,
HI Bob;
I've done a bunch of that rewire stuff. Reusing the modules? I would, if they
were on a decent mount.
Since a) they're not on a good mount, and
b) none of those are top shelf panels,
I'd probably trade them in or have the customer resell them. Many folks just
starting out could use
I haven't seen a problem with concrete, but wood definitely rots out when
exposed to acid, including pressure treated.
(Saw a system with Battery shelving made from wood where the top shelf
collapsed from acid rot..)
Acid also eats foam board, unsticks silicon seal, and gets under and
years so my info may be out
of date but the steel case on the older HUP batteries had drain holes on the
bottom.
Kent Osterberg
Blue Mountain Solar, Inc.
R Ray Walters wrote:
I haven't seen a problem with concrete, but wood definitely rots out when
exposed to acid, including
Funny, I was just considering this to create an AC battery charger that could
be used for different battery voltages.
I have a couple of small electric vehicles that have 12, 24, 36, or 48 v packs
depending on fast I want to let the kids go.
I only need about 3 amps output (150 watt max)
Any
HI Allan
I would strongly encourage separate MPPT controllers for the different module
types. Even if you get an acceptable voltage match under some conditions, it
will never be optimal for all conditions.
I'd even consider using the venerable C40 with the old modules, as they have
less to
Jeff;
Is this a belated April Fool's Joke?
Or just an April Fool?
That module shouldn't be used for anything over the voltage it was designed and
intended for: 12 Volts!
And it shouldn't be used on anything but a non-NEC automotive application. In
this case, I'd consider tattling to the
I think to make any energy production warranty fair, it would have to include
an on-site monitoring package that tracked cell temp, insolation, and grid
conditions. Then the installed system would be off the hook if the grid was out
of spec, insolation levels were low, cell temp too high, etc.
At this point, there are much better products for splicing than split bolts.
The insulated splice blocks don't need tape, and are easy to check later too.
I just don't see a reason to use uninsulated splices anymore. All your time
spent wrapping (and unwrapping) will more than pay the difference
is that the heavier gear is more likely
to get in your way, thus causing a trip hazard.
I'm a big fan of the new sliding rope grabs. THey allow you to move up and down
the rope easily, but grab the rope if you fall.
Ray Walters
I look forward to sharing some ideas on this topic.
cheers
Once you sign up, they start charging you, even for bogus leads. You never get
your money back, just credit (if you're lucky) to get more bogus leads.
Also, they waste a lot of your time with different sales reps calling you, but
never talking to each other, their internal communication is
Hi Drake;
I have kids, and I agree with you; an exposed ground rod would be a nasty thing
to land on.
I always had a fear of falling on one with my knee (ugh!), however, I have had
inspectors require 4 of ground rod above grade.
(most installs in New Mexico I see keep the connection above
I bought the Amprobe DGC-1000A. I paid around $1000, but I see they've gone up
a bit already. I can't necessarily recommend (or berate) the web biz I bought
it from, so I'm not going to give them a plug.
I'd just google: the make model #.
The Amprobe is very easy to use, but the 2 down sides
A couple of nice things about working on carports:
1) often the ceiling is exposed, making anchoring and finding rafters easy
2) If you did have a leak, its not quite as catastrophic.
Just because you get the wind loading and anchors right for the array, doesn't
mean the carport roof will still
, at 12:04 PM, Darryl Thayer wrote:
Hi
It can be used off grid, but you have to have two ground sources, so drive
two ground rods and measure the resistance you will get the sum of the two
resistsnces.
--- On Sun, 4/18/10, R Ray Walters r...@solarray.com wrote:
From: R Ray Walters r
I just recently bought a clamp on ground impedance tester. I found one system
that was less than an ohm, worst one was almost 800 ohms. Only a few were
below 25 ohms.
You're absolutely right: good lightning protection starts with a good ground.
The impedance tester takes the guess work out of
Marco;
Check out Citel, they make a line of DIN rail mountable units for DC voltages
up to 1000v. Prices are in the $100 to $200 range.
One at the combiner box, and one at the inverter, with ground rods at each
location should give reasonable coverage.
I like Polyphasor's stuff too, but it is
We've had the same experience with DC CFLs, about 50% return rate. They just
can't handle voltages below 12 v, so we quit carrying them.
After years of working on DC wiring, just go to AC. You could wire all the
lights on one circuit in 12 AWG. (instead of running 10 AWG or bigger, and then
Over the same amount of time a similar investment in PV would save even more
money.
R. Walters
r...@solarray.com
Solar Engineer
On Apr 8, 2010, at 4:28 PM, Bob-O Schultze wrote:
Guys,
Is it just me being dense or are none of you folks advocating for higher VD
looking at the savings over
Also consider that most people are figuring volt drop at a wire temperature of
167 deg F (75C). That's really hot, and most of the time the wire will be much
cooler, and therefore the volt drop will be less.
(use the fine print note #2, NEC table 8 to adjust down for cooler temperature)
be pretty silly to have a system shut down (ie lost production = lost
investment money) because of saving some money on wire.
Bill Hoffer PE
Sunergy Engineering Services PLLC
On Thu, Apr 8, 2010 at 11:41 PM, R Ray Walters r...@solarray.com wrote:
Over the same amount of time a similar
?
Todd
On Friday, April 9, 2010 10:46am, R Ray Walters r...@solarray.com said:
All our economic analysis is based on a 20 to 25 year life.
Safety first, but then good design is to spend the customer's money where it
does the most good.
No matter how big the wire, you will always
bit upfront is poor economy and as the
price of gird supplied power increases over the years, the waste and lost
revenue is even more acerbated.
Best, Bob-O
On Apr 6, 2010, at 6:04 PM, R Ray Walters wrote:
Just run the numbers sometime. Compare the cost difference of #6 vs. #4 wire
say
, Bob-O
On Apr 6, 2010, at 6:04 PM, R Ray Walters wrote:
Just run the numbers sometime. Compare the cost difference of #6 vs. #4 wire
say, and then look at how many more watts you're actually saving, then
multiply that additional wattage by the installed cost per watt.
Very simply, once
I agree that we don't want to create the code first, and try and develop the
product after. On the other hand, if a DC AFI can be developed that could stop
some of the problems I've seen breakers not help, I'm installing them, and
pushing for code requirements.
AC GFIs were gimmicky too at
This is interesting, because once again the normal electrical protection
systems assume an almost infinite current supply to work properly, which is
obviously not true for many solar applications.
I've seen sustained series arcs that were current limited by the load, and
therefore lower than
:03 AM MDT
To: Ray Walters r...@solarray.com
Cc: Andy O'Reilly a...@positiveenergysolar.com
Subject: Re: [RE-wrenches] Outback Grid Problems
Ray – I appreciate all the comments and recommendations relative to the grid
voltage parameters. However, in my opinion, there is no data to support
Thanks very much Steve;
I still have 2 questions: does the temp sensor control all voltage set points
or just absorption and float voltage?
2) I'm still a little confused about the absorption time, and refloat, rebulk
features. for instance, what is the difference between refloat and rebulk?
to the cost of a combiner
box.
Kent Osterberg
Blue Mountain Solar, Inc.
R Ray Walters wrote:
And just to be clear, when using these 100% duty rated breakers, you only
have to oversize the cable by 125%, not 156%.
Also, as William mentioned, even correctly sized wiring can have
...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of R Ray Walters
Sent: Monday, April 05, 2010 12:13 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Fwd: Outback Grid Problems
Thanks very much Steve;
I still have 2 questions: does the temp sensor control all
And just to be clear, when using these 100% duty rated breakers, you only have
to oversize the cable by 125%, not 156%.
Also, as William mentioned, even correctly sized wiring can have problems; we
just recently had a short circuit that caused quite some damage in a junction
box, and the
I've oft wondered why we didn't use this time tested automotive wiring method
more in PV; especially at higher voltages.
An energized roof is a happy roof as they say.
You go Solar Guru.
R. Walters
r...@solarray.com
Solar Engineer
On Apr 1, 2010, at 10:53 AM, Jason Szumlanski wrote:
I am
the battery banks to make sure
there isn't a dead cell the OBs are trying to charge. BB1 one day, BB2 the
next so on.
Sent via BlackBerry by ATT
-Original Message-
From: R Ray Walters r...@solarray.com
Date: Tue, 30 Mar 2010 10:42:58
To: RE-wrenchesre-wrenches@lists.re-wrenches.org
discussing with OutBack.
Good luck,
Randy Brooks
Brooks Solar, Inc.
Solar Power for People
140 Columbia View
Chelan, WA 98816
509-682-9646
ra...@brookssolar.com
www.BrooksSolar.com
On Mar 31, 2010, at 10:48 AM, R Ray Walters wrote:
Ventilated, but small enclosure. Definitely
outage during the night and the batteries need charged.
--
Sunny Regards,
Kirpal Khalsa
NABCEP Certified Solar PV Installer
Renewable Energy Systems
www.oregonsolarworks.com
541-218-0201 m
541-592-3958 o
On Tue, Mar 30, 2010 at 2:11 PM, R Ray Walters r...@solarray.com wrote:
HI
the battery banks to make
sure there isn't a dead cell the OBs are trying to charge. BB1 one day,
BB2 the next so on.
Sent via BlackBerry by ATT
-Original Message-
From: R Ray Walters r...@solarray.com
Date: Tue, 30 Mar 2010 10:42:58
To: RE-wrenchesre-wrenches@lists.re-wrenches.org
We currently have a Grid Tie system with a pair of Outback inverters that are
regularly dropping out of sell mode, and letting the arrays spend all day
charging the battery bank.
It seems to do this several times a week, and the customer is losing
substantial production, and gassing the
of connection?
Brian Teitelbaum
AEE Solar
-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of R Ray Walters
Sent: Tuesday, March 30, 2010 9:43 AM
To: RE-wrenches
Subject: [RE-wrenches] Outback Grid
...@solarray.com
Solar Engineer
Begin forwarded message:
From: Roger L. Johnson rogerjohn...@itltd.com
Date: March 30, 2010 2:06:42 PM MDT
To: Ray Walters r...@solarray.com
Subject: Re: [RE-wrenches] Outback Grid Problems
Ray – I have been selling solidly at approx. 2 kW since about 1100 hours
Can't say whether the AFCIs will work with the mod sine (I'd guess not) but I
do know that even a pair of Outbacks (in parallel) will not supply enough
current for an AFCI to actually trip in a fault situation.
AFCIs are designed to stop a 70 amp or higher arc, while the Outbacks only
surge to
This brings up a related question, that I can't seem to find an NEC answer to:
How do we calculate the available fault current, for picking our AIC rating?
I used to always throw 20,000 amps AIC rating fuses and breakers for large
battery banks, but on grid, it seems we would have to know things
85367
Retail Store Shipping Address:
2998 Shari Ave.
Yuma, Az 85365
- Original Message -
From: R Ray Walters r...@solarray.com
To: RE-wrenches re-wrenches@lists.re-wrenches.org
Sent: Wednesday, March 24, 2010 10:51 PM
Subject: Re: [RE-wrenches] PV excellent battery charger
On Mar 25, 2010, at 5:55 AM, Warren Lauzon wrote:
Actually, PV is not a particularly excellent battery charger,
What is better than a properly sized array with the latest controllers?
Everything else mentioned can be done by any decent AC battery charger.
True, but at great expense. The
MPPT doesn't really do that much for the battery, it just makes the PV modules
more effective.
The real magic is:
A) the 3 stage charging (compared to traditional single stage AC chargers)
B) Temperature compensation
C) PWM that helps pulse off sulfation
D) Slower charge rates let batteries
That's why we never bought the crimping tools. We just order the ready made
cables with each job. We have surprisingly little waste of cable. I worked out
the difference in cost ,and it was going to take us decades to pay for the
crimper. Until they settle on a connector, I'm just going to
We have a couple out in the field. A bit of hassle to upgrade the firmware at
first, but Apollo was very helpful, and sent us a free interface to do the
update.
I'm sure that's all cleared up for current versions, by now.
Now a couple of years later, we've had zero trouble, and we are running
Both ideas are simple and make good sense. I think listing the number of years
certified is a strong reason I'd renew actually, otherwise what's the
difference between someone who has been certified for 6 years vs. 6 months?
R. Walters
r...@solarray.com
Solar Engineer
On Mar 14, 2010, at
I almost never run rebar, but we do always cut a tab of metal on the pole (with
a torch) and bend it out to grab into the concrete.
This was an idea gleaned years ago from of all places: the Wrenches list.
R. Walters
r...@solarray.com
Solar Engineer
On Mar 13, 2010, at 11:15 AM, Allan
First, I agree with you, that a 48 v system can run a single string of smaller
batteries.
Usually 48 v systems are running larger battery banks already.
As far as undersizing the jumpers that carry less current, a 2/0 cable has a
free air rating of 300 amps (table 310.17 for THHN at room temp).
the best Ahr for the dollar.
Last 3 to 10 years.
R. Walters
r...@solarray.com
Solar Engineer
On Feb 22, 2010, at 9:25 PM, toddc...@finestplanet.com wrote:
What is a golf cart battery?
Todd
On Monday, February 22, 2010 12:53pm, R Ray Walters r...@solarray.com
said
Sounds like:
A) the batteries are getting old, and are not paralleled properly.
B) The desulphators aren't that great. I have some pics of one that completely
short circuited, melted, and caught on fire. I would never put those in, myself.
C) I no longer recommend monthly EQing, but I think its a
Consider a pair of MX 60s instead of the MX(oops).FM80. We had customer
complaints about the fan noise on the 80, and went to pairs of 60s.
120 amps total is worth it for future modules. Those amps go fast at 24 vdc.
Redundancy is a 3rd valuable asset.
R. Walters
r...@solarray.com
Solar
I think it depends on the original sale. If the sales person set up the system
proposal to take advantage of tax credits, and established a 2 phase, multiyear
build out, the sales person definitely deserves full credit.
That additional planning took more time, saved the customer more money, got
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