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Re: (ET) Batteries
- Subject: Re: (ET) Batteries
- From: "David Roden (Akron OH USA)" <roden ald net>
- Date: Mon, 29 Apr 2002 14:43:21 -0400
- In-reply-to: <F154LbtbS8oLhWTjvuD00003ea0@hotmail.com>
- Sender: owner-elec-trak cosmos phy tufts edu
If you're measuring an SG of 2.2, either you're reading your hydrometer
incorrectly or it's inaccurate. Typical SG range is 1.1 to 1.3. A fully
charged
battery should measure 1.28 or so when new, perhaps 1.25 or so after a few
years. The declining SG with age is an (but not the only) indicator of
declining capacity.
Your big voltage sag when you apply a load indicated high internal
resistance. This is characteristic of discharged batteries. Are you sure
the
ET charger is putting out enough voltage to charge them fully?
Assuming that it is, don't junk the batteries yet. Give them a chance.
Here's
something you can try.
Make sure the electrolyte level is above the plates, then give them a full
charge (charge for 8-12 hours). Discharge them with a light load, just
until
they seem a bit weak. Charge again. Repeat this a dozen or more times
(unused batteries lose capacity and need to be "exercised").
Then, give them a long, slow equalization charge. The ET charger is a bit
brutal for this purpose, but if you don't have anything else it will have
to do.
Keep them bubbling gently for a day or two, or until the voltage (measured
carefully and accurately with a digital multimeter while on charge) has
pretty
well stopped rising.
Follow this with more cycling as above to exercise them.
This regimen has roughly the same effect as the high-priced "desulfators."
If
the batteries have enough capacity after this to mow the lawn, great.
Otherwise, it's probably time for new ones.
I have been satisfied with batteries from Trojan and US Battery (also sold
under the "Interstate Workaholic" brand). In my experience, difference in
maintenance and use will account for most the difference in life between
these two brands. I have been less satisfied with Exide, though some
people
do like them. I have no experience with GNB but haven't heard much good
about them.
Sam's Club and other generic sources buy from whomever bids lowest, and
often the bid depends on how close the supplier is to the store or
warehouse.
Thus the Sam's Clubs in California might have different batteries from
the
Sam's Clubs in Ohio. You might get US or Trojan, but you're just as
likely to
get somebody else's.
If you're getting quotes over $55, call another dealer. Check with the
local
golf course (or the people who maintain their cars) and ask where they get
their batteries. Drop in on them and make friends; they may be able to
set
you up with a good price. Something in the $40-45 range is very good.
Around $50 is decent. After my first bunch (I also run on-road EVs), I've
never paid more than $55 each.
Hand-selected used batteries from a golf car dealer or golf course can be
a
good choice for people who don't need the maximum range. These are
usually available for $10-20 each.
Hope this helps.
David Roden
Akron OH USA