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Re: (ET) Lead Acid Batteries
Short version - they probably need to be replaced, and in my experience
(multiple EVs on-road and off-road since the 1970s) you should replace
the pack in one shot. Then monitor the hell out of them to look for
infant mortality for the first few months or until warranty expired. I
loved the PakTrakr for that when it was available. Sadly, no more (but
I might still kludge one more together from parts for a future project -
I was a distributor for a few months. Same with the Battman, but then
couldn't get parts and very much oriented to 6-battery - e.g. golf-car -
systems.)
Anyway, for now, that probably means taking a meter to the individual
batteries before and after charging. Allow for uneven discharge if you
are using part-pack loads like the front and rear lifts or extra
lighting, but adjacent batteries under the same loads should be tracking
pretty closely. If not, best to find out before the warranty expires.
However, if you want to spend the time and energy seeing if you can
raise the dead, here are a few things I can suggest.
Have and use at least one quality charger that is matched to the module
voltage - e.g. 6-volts nominal, and preferably with a 'boost' setting.
I also like to have a load-tester, micro-flashlight, and cell-filler
funnel. (Because I have had a bunch of EVs and some interesting
batteries over the years, I have an eclectic bunch of chargers at my
disposal.)
Before charging. Open the cell caps on a battery. If the electrolyte
level is below the tops of the plates (usually bad news), add distilled
water just to the top of the plates - not more. Put the battery on
charge and watch the voltage (and if feasible, current). Once a good
charge voltage is reached - or you feel you have aged sufficiently
waiting - check the electrolyte level in the cells. If cell electrolyte
levels are still low (below fill line) top up to fill line with
distilled water, and charge some more. If you have not achieved a good
voltage on the battery at that point, it's likely scrap. If voltage is
good, try the load-tester on the battery. If the voltage sinks like a
stone, it's likely scrap. If it passes the load test, it could be worth
some additional charge-discharge cycles to see if capacity improves.
Repeat for each battery.
The 'desulphator' units really don't work on 'hard sulphation', which is
what you get if a conventional lead-acid battery sits a long time in a
discharged state (think a few months). Years is definitely hard
sulphation time scale.
But sometimes you get lucky. I have just finished trying to resurrect a
couple of 12-volt deep cycle batteries. One is basically OK, the other
has likely dropped a cell (shorted). They both carry current, and
voltage sag isn't bad under load. I put 10 cycles on each, and capacity
gain ended around 8-10 cycles. But, good enough to prove the rest of
the vintage e-bike is functional. Neither is showing enough capacity to
avoid replacement the next time this machine will see any real service.
(I used this to deliver chargers to the post office years ago - before
our community decided to redo the roads to be actively bicycle-hostile -
sigh). It would be suitable for taking someone or small loads around a
warehouse or similar.
I also used to test the electrolyte specific gravity per cell, but over
the years I have not found that provides much value (unless you know
electrolyte was lost and replaced with water or concentrated electrolyte).
I'm not a fan of the 'battery boilers' for a number of reasons, but
that's 'religious war' territory, so I won't expand on that on-list.
Darryl McMahon
On 2023-11-19 9:55 p.m., Frontier Yahoo Mail wrote:
I am looking for a bit of advice on my lead acid battery pack in my N/I EGT-150. The pack wasn't new when I
purchased them about 8-9 years ago. I know it should be time for them to go to the battery graveyard. This
tractor has been setting for a while due to the OEM F & R Contactors finally giving up. Since replacing those
I have been running the Pulse Tech desulfate charging system on each of the three 12 volt sub packs, (two deep
cycle six volts each). The Pulse Tech system will only work with twelve volts so you just parallel them and it
works great. One sub pack appears to be coming up as it is showing about 25% charge after 3-4 hours of
pulsing. The other two appear to be complexly dead and show as "bad battery" on the pulse
charger. As a test I thought I might try to put a surface charge in with my auto charger on each 12 volt
set and then see if the Pulse Tech would help them. On the fast charge one set appears to be taking a small
amount of charge whereas the other one did nothing. After reconnecting these two back on the Pulse Tech
they still won't begin to disulfate. I see liquid rejuvenator products advertised on eBay which claim to
work about 95% of the time on failed batteries.
I am wondering if anyone in Elec Trak land has tried this and what your results have
been. For the money it certainly would appear to be an economical if only short term
solution. Then again it may just be time to purchase new batteries. I noticed that the
lithium's are comparatively priced, however from what I am reading on this site it sounds
as though they are pretty finicky on the amount of discharge they are able to handle
without internal damage. Beyond my Pulse Tech desulfating charger I am still using
the EGT's on board "battery boiler" which has always done the job.
Any thoughts are most welcome.Autumn Train in NW Iowa
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Darryl McMahon
Freelance Project Manager (sustainable systems)
Do not mistake patience for weakness, nor action for strategy.
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