[EVDL] BMS recommendations

[MacWrench via EV]

Hi All,

I've been lurking in the background for some time now,
occasionally responding since my background is that of a mechanic (auto
tech) with extensive experience in electrical and fuel injection systems.
I "retired" about 15 years back and went to work part time for Maine
Organic Farmers and Gardeners Association . MOFGA has
been supportive of my electrical interests and I have converted 2
cultivating tractors (lead acid batteries) and a Chev S-10 (prismatic
lithium cells 100 amp hour) to battery power. And built from scratch a
small, 2 tracked woods vehicle using a powered wheel chair drive system
(4, 7 cell lithium polimer packs in parallel with very basic bms). All
simple dc systems, functional for short trips and farm work.

2
years ago, MOFGA received a donation of a 1940's vintage tractor (Ford
9-N) that had been converted to battery power, again a simple dc
system.  Since that tractor was converted by a friend who, as a
mechanical engineer only made it functional enough to prove the point, it
was too rough and downright dangerous for general use. The family asked
specifically for me to "clean it up". For instance, it had 10, 12v
batteries in series charged by a grid charger consisting of 4 heavy diodes
screwed to a piece of board, 120ac in and 120dc out. Sorry I didn't take
some before pics.

I now have the tractor running on 8 LG Chem
16 cell packs configured to 120v, charging with an Elcon 5000 configured
by Elcon for that battery, and NO BMS. Scares the hell out of me knowing
how quickly that sort of battery can go into "thermal runaway" but again,
needed to prove the concept and get it into public use. I have spent 2
hours (all I could stand) on that machine running a bush hog with no
appreciable drop in battery voltage so I know it is capable of serious
work.

I have looked about for a BMS for this battery pack and
found the following  Is
this the best I can do for this battery pack? Could someone recommend a
better system? Mostly it needs to perform the basics, top balance cells,
monitor temp, provide LVC and HVC for the charger.

Thanks for
your comments and advice.

John
Unity ME
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[EVDL] Bms recommendations

[Steve Clunn via EV]

Mini BMS there's no longer making their BMS headboards or sell boards. I
looked on the eBay for BMS's and found one that could send information to
an Android phone about the cells voltage's along with voltage of whole pack
average voltage and current. They seem to be made for bicycles but they did
have a 30 cell model. They can be programmed for different cutoff voltages
and different amounts of cells. To control the shut-off when charging or
discharging they use a bank of mosfets so the amount of power these
transitions can handle is not up to what a car or a golf cart needs. I made
a little relay board that uses their control to turn the relay off and on
and have use them in a few battery packs for cars. They don't have a lot of
balancing capability I believe 60 milliamps is the rating of current. The
app for the telephone shows individual cell voltages and also data logs
each individual cell voltage along with the average voltage of the whole
pack and the charge discharge current. I bought mine from eBay for $100 and
then contacted the original supplier who says if I buy 10 I can get a
reduced price. I did a short YouTube video of one of these units hooked up
to some cells that I'm charging from my solar panels. There are a few other
videos on YouTube of this model but not a lot of information nor is there
much information from the company , xiaoxiang . They say nothing of the
data logging  capability . https://youtu.be/Yj7a1wzpQGQ if this doesn't
work you can just YouTube for my name Steve clunn. We have a few here now
and I'm going to order more could use some orders to help fatten up the
order if anyone is interested contact me offline from
www.Greenshedconversions.com  Steve Clunn
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