[ausev] Batteries not getting up to charging voltage?

[Roy Holder]

My Trojan J150 batteries are a little over 35 months and 700 cycles now.
After this last winter they seemed to loose a lot of storage. Through Dec
my daily use was about 40 amps with little or no low voltage issues.

 I have been experiencing similar voltage sag  issues as you, as well as
low charging voltage.  

As the flooded batteries get older the internal resistance increases,
diverting more of the input and output voltage and amps into heat production.

As they continue to age the internal resistance will increase to where the
charger will not turn off automatically, and you will need to closely
monitor your battery charger.

On the output side, they will continue to drop more voltage under load with
the increase internal resistance.  This will decrease both range and
eventually top speed that you can maintain.  

The batteries will also likely begin to self discharge as a noticable rate,
(for me) from a full charge to a half charge(or so) over a 3 day weekend.

Yesterday I made it to work and home on 1 charge, but the voltage was very
low by the time I got home.  I travel up and down north 183 often at 50+mph.

I switched today to charge fully at work too.(now 2 cycles a day on the
batteries instead of 1 a day)



At 02:56 PM 6/9/2009 -0500, you wrote:
>My batteries have been losing range for a while now...  i.e. The
>voltage sags more under high current load limiting my effective
>electric vehicle range.  However now I'm starting to see a new issue,
>which I presume is also related to my batteries being past their
>prime.  The batteries are not really getting up to the charging or
>acceptance voltage, so the PFC charger just keeps charging them all
>night.  This happens about once a month, that I get an unplanned
>equalization charge for my car.
>
>At 80F the US8VGC batteries that I have should be charging at 186V
>(2.583V * 72 cells as per http://www.usbattery.com/usb_faqs.html ).
>At the end of March, I dropped the charge voltage to 184V (the 90F
>charging voltage, since it was not reliably hitting 186V).  At the end
>of April I dropped it to 181V (the 100F charging voltage, since it was
>not hitting 184V).  Now at the end of May, it seems that my batteries
>will not get much above 175V.
>
>At first I thought it was temp or water issues (which it may have
>been), but I have been checking the water fairly often through this
>process.  I last refilled the water a month ago, and at the end of
>April the 18 batteries and 72 cells only needed 3 gallons of water
>(from the previous 6 weeks of car usage).  I actually have noticed
>that as the effective range of the vehicle has been dropping (so I
>charge it more often, and can not discharge the batteries as far) the
>water used by the batteries has decreased from the amount of water
>that I used to use in my batteries.  I spot checked a few batteries
>last weekend for their water and they seemed pretty high, and the
>batteries have always been very consistent in their water usage (from
>cell to cell, and battery to battery).  I'll be watering them again
>this coming weekend.
>
>Anyways, I guess my main question was if not getting up to the
>charging voltage was a known issue as batteries age.  Mine are at
>about 300 cycles now.  I was also curious what other signs would crop
>up as the batteries age further.
>
>
>-- 
>TTFN,
>Brian "Lasso" Lasseter
>
>"No Sane man will dance."   -Cicero (106-43 B.C.)
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