I'm not an electrical engineer and I didn't stay at a Holiday Inn Express last
night, but both EVs we own have PowerCheq equalizers installed. There is
substantial activity regarding these equalizers on the Xebra Yahoo group and
recently some traffic on the Sparrow/NMG group. Sean of GPEV sells the product
and apparently can arrange quantity purchases at a discount.
He is of the opinion that using these (and by extension, other) equalizers,
your pack life will be extended three-fold.
I can personally attest to one advantage of using these (and by extension,
other) equalizers. We had three batteries fail about a year into using the
vehicle. (user abuse) At the time, no monitoring device and no equalizers
installed. I'd been told that one cannot put new batteries into an old pack,
especially Deka Dominators. I installed a PakTrakr and a full rack of
PowerCheqs along with the three (of six) new batteries. Two years later,
perhaps longer, all batteries maintain the same level of charge and discharge.
My second EV has a double pack, series/parallel and after almost a year, these
batteries are happily level and balanced.
I recognize how expensive the PowerCheqs are, but if you are unlucky in finding
a homespun method, the investment will pay itself back in a year, I think.
I've paid as low as two hundred american dollars for the Deka and as high as
three hundred. These are 98ah 8G31 batteries, seventy two pounds each and I
want to make my money stretch the distance.
Deka Dominators dislike intensely the AGM charge algorithms and will die
prematurely if charged with that profile. Expect an early death with a flooded
charge algorithm as well. Having equalizers installed means your charger will
be more effective at the end of the sequence and less likely to cook the pack.
Long life and happy miles!
From: Michael Clark michaeljaycl...@gmail.com
To: listserv@floridaeaa.org
Sent: Friday, April 3, 2009 9:03:42 AM
Subject: [FLEAA] battery equalizer
Submitted by Michael Clark for Matt Krump
Got a question for the electrical engineers out there. I'm replacing the
battery pack in the Cherokee with some new Deka Dominator Gel batteries.
12V each, #26 for a total of 312 nominal volts. They were shown to work
well for years on the Geo Force with 13 - 15 batteries each without
equalization. I don't trust a series string of 26 to stay equalized. My
plan is to make a simple shunt with a 600W 15 volt zener diode in series
with a light bulb or two as an indicator and load. Lee Hart has used a
similar design using two 5W 6.8V zeners in series with a bulb or two. I
think he uses two diodes to split up heat production and sink it to two
battery terminals. His shunt is designed for AGM batteries. I looked up
Hawker odesey charging voltage and the recomended max is 14.7V.
My reasoning for a slight difference in design is that the gel batteries
that I will be using have a recommended maximum charge voltage of 15.5V
roughly at 90 degrees F. For a charger I am using a Manzanita Micro charger
that operates at a fixed user-adjustible amperage with variable voltage
until a user adjustible voltage limit is reached. Then an adjustible timer
begins running while the amperage is decreased and voltage is maintained.
I've thought about using commercially available regulators, but they are all
$45 per battery or more and with 26 batteries, that is just too much for
now.
Any thoughts anyone?
Matt Kramp
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