Yes, more safety can't hurt (especially the fail-safe, or nearly fail-safe
kind). I would highly recommend going with a well known and reliable BMS
system though, and not try and design your own. There are hundreds available
on the market already (DIY versions and marketed versions).
Did you
e a lot of heat
in
the wrong place.
Peri
-- Original Message --
From: "jkenny23 via EV"
To: ev@lists.evdl.org
Cc: "jkenny23"
Sent: 19-Apr-20 6:16:39 PM
Subject: Re: [EVDL] custom battery
>Well you shouldn't need to use the disconnects; but yes, those
amperage
&g
wrong place.
>
> Peri
>
> -- Original Message --
> From: "jkenny23 via EV"
> To: ev@lists.evdl.org
> Cc: "jkenny23"
> Sent: 19-Apr-20 6:16:39 PM
> Subject: Re: [EVDL] custom battery
>
> >Well you shouldn't need to use the disconnects;
, if something goes wrong, there'll be a lot of heat in
the wrong place.
Peri
-- Original Message --
From: "jkenny23 via EV"
To: ev@lists.evdl.org
Cc: "jkenny23"
Sent: 19-Apr-20 6:16:39 PM
Subject: Re: [EVDL] custom battery
Well you shouldn't need to use the disconn
Well you shouldn't need to use the disconnects; but yes, those amperage
levels are used commonly in EVs of course. EV West has pretty good prices
for stuff like this (service disconnect, rated for max current your system
would see):
Peri Hartman via EV wrote:
Thanks for responding.
Yep. about 1 min discharge - load can vary a bit. I can use pretty much
any voltage, but the lower the voltage, the higher the current and I'll
need huge cables and disconnects. The higher the voltage, the more cells
and cell monitors I need,
--
From: "jkenny23 via EV"
To: ev@lists.evdl.org
Cc: "jkenny23"
Sent: 18-Apr-20 6:06:08 PM
Subject: Re: [EVDL] custom battery
You got me stumped. What application do you need only 85WH at 6.6kW for?
That's a discharge period of 46 seconds if I have my math right...
Do y
You got me stumped. What application do you need only 85WH at 6.6kW for?
That's a discharge period of 46 seconds if I have my math right...
Do you truly need 240VDC for this application also? What about using the
first stage of a 6.6kW 240VAC inverter, which would produce a high voltage,
high
continuous current ? (Bear in mind the
discharge time will be short and there will be ample cooling off between
uses.)
Peri
-- Original Message --
From: "Cor van de Water"
To: "Peri Hartman" ; "Electric Vehicle Discussion
List"
Sent: 13-Apr-20 10:59:58
Peri Hartman via EV wrote:
Ok, I did a little bit of research. Anyone care to double check this ?
Looks correct (at a casual glance).
I'll say right now that 100 caps at $40 is a non starter :)
Yes. It's possible, but not cheap. :-)
The cheapest solution is probably an ICE and generator.
zel
-Original Message-
From: EV On Behalf Of Jan Steinman via EV
Sent: Wednesday, April 15, 2020 11:03 PM
To: ev@lists.evdl.org
Cc: Jan Steinman
Subject: Re: [EVDL] custom battery
I think the answer is really quite simple — and very expensive: capacitors!
I have a fence charger that char
Yes, so in practice I probably could only get about 70-80% of the energy
out, I presume. And then I need to step up the voltage. Complicated.
Peri
-- Original Message --
From: "Jay Summet via EV"
To: ev@lists.evdl.org
Cc: "Jay Summet"
Sent: 16-Apr-20 8:12:16 A
The other issue with Capacitors is that the voltage goes down quickly,
and to get all the energy out you need to be able to make use of the
widely varying voltage range.
Jay
On 4/16/20 11:00 AM, Peri Hartman via EV wrote:
Ok, I did a little bit of research. Anyone care to double check this ?
Ok, I did a little bit of research. Anyone care to double check this ?
Here's one for $42 at unit quantity. 1200F, max voltage 2.7V
https://www.digikey.com/product-detail/en/tecate-group/TPLH-2R7-1200SL60X74/2085-TPLH-2R7-1200SL60X74-ND/9930298
Energy is
E = 1/2 CV^2
where E is joules.
I'm looking at supercaps. I appreciate that a few people have suggested
this, though I don't know yet whether it could be done economically.
Peri
-- Original Message --
From: "Jan Steinman via EV"
To: ev@lists.evdl.org
Cc: "Jan Steinman"
Sent: 15-Apr-20 11:03:27 P
I think the answer is really quite simple — and very expensive: capacitors!
I have a fence charger that charges/discharges six joules every second or so.
I have studio strobe lights that can charge/discharge nearly 5,000 joules in
under ten seconds.
Other than the magnitude of energy that is
https://www.lipobattery.us/high-c-rating-li-poly-battery-50c-2/
On Wednesday, April 15, 2020, 2:28:44 PM CDT, jkenny23 via EV
wrote:
Let's keep the discussion in the context of the original ask too. A 50C(!!)
battery is a very different beast than a laptop or a cell phone that
Let's keep the discussion in the context of the original ask too. A 50C(!!)
battery is a very different beast than a laptop or a cell phone that
discharges over the period of a few hours. Honestly, I think this is a
rather bad idea. Even high performance EVs don't slam batteries that hard.
Here's
cle Discussion List"
> Cc: "paul dove"
> Sent: 14-Apr-20 12:35:14 PM
> Subject: Re: [EVDL] custom battery
>
>> There are literally hundreds of products out there using these batteries.
>> It is rare to see a fire caused by one. I have computers, phones, tools
On 14 Apr 2020 at 19:35, paul dove via EV wrote:
> I have computers, phones, tools cars etc. none have ever blown up or
> caught on fire.
Market researchers have a saying: "The plural of anecdote is not data."
In other words, when estimating how likely an unfortunate incident is to
happen,
c: "paul dove"
Sent: 14-Apr-20 12:35:14 PM
Subject: Re: [EVDL] custom battery
There are literally hundreds of products out there using these batteries.
It is rare to see a fire caused by one. I have computers, phones, tools cars
etc. none have ever blown up or caught on fire.
On
There are literally hundreads of products out there using these batteries.
It is rare to see a fire caused by one. I have computers, phones, tools cars
etc. none have ever blown up or caught on fire.
On Tuesday, April 14, 2020, 1:36:12 PM CDT, Lee Hart via EV
wrote:
I agree with
On 04/14/2020 11:35, Lee Hart via EV wrote:
For years I worked for Robertshaw and Honeywell designing furnace
controls. A furnace control has to be DAMN fool proof, or it could
(for example) open the gas valve without lighting the burner, fill the
house with gas, and THEN light it. So the
I agree with Bill. The battery itself can be built with today's
technology. It's the BMS that's going to give you trouble.
As Bill said, the pack will be used until it breaks. And *when* it
breaks, it could easily start a fire that leads to a disaster. It's
really hard to design things that
-- Original Message --
From: "Lawrence Winiarski"
To: "Electric Vehicle Discussion List" ; "Peri
Hartman"
Sent: 13-Apr-20 10:22:34 PM
Subject: Re: [EVDL] custom battery
Isn't 60c or 100C common in Radio Control stuff now? Lots of
solutions there.
O
Peri,
That is 50C discharge, not impossible but also not trivial.
The good old A123 cells could do this.
The cylindrical cells are almost 10Wh and can discharge at metal melting
speeds.
I have a bunch of them here, in case you are interested.
Cor.
On Mon, Apr 13, 2020, 9:33 PM Peri Hartman via EV
On 4/14/2020 4:51 PM, Peri Hartman via EV wrote:
Nominally 240. But it really can be anything and I can convert it to
what I need.
Peri
Cells <
You can get about one third of the specific energy (~8000 W/kg) from
ordinary A123 26650 cordless tool cells.
You can get over
;Alan Arrison via EV"
To: ev@lists.evdl.org
Cc: "Alan Arrison"
Sent: 13-Apr-20 9:48:53 PM
Subject: Re: [EVDL] custom battery
>That sounds like almost super-capacitor territory. What voltage is needed?
>
>Designing and implementing a BMS is something even EE's
Nominally 240. But it really can be anything and I can convert it to
what I need.
Peri
-- Original Message --
From: "Alan Arrison via EV"
To: ev@lists.evdl.org
Cc: "Alan Arrison"
Sent: 13-Apr-20 9:48:53 PM
Subject: Re: [EVDL] custom battery
That sounds like al
That sounds like almost super-capacitor territory. What voltage is needed?
Designing and implementing a BMS is something even EE's have trouble with.
However, if the voltage is low enough, it makes it much easier.
Al
On 4/14/2020 12:33 AM, Peri Hartman via EV wrote:
Hi,
I need a battery
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