From: Glen Closson (glen@closson.com)
Date: Tue Apr 29 2003 - 17:23:53 PDT
One issue is that in a series circuit (the two 12V batteries in series) you
always have the same current flowing through each cell (Norton's current
law) if you are charging or discharging. So if you have different
chemistries, once battery will probably charge up faster than the other one,
so the first one may get over charged.
When you discharge the batteries (the most load they see is when cranking)
one battery may act like a limiting device for the "better" battery.
This also applies to mixing a new battery with an old one.
My guess is that is okay for the short term (emergency), but you will see
decreased total battery life and performance for the long term.
Regards,
Glen
-----Original Message-----
From: Military Vehicles Mailing List [mailto:mil-veh@mil-veh.org]On
Behalf Of Bruce Beattie
Sent: Tuesday, April 29, 2003 4:58 PM
To: Military Vehicles Mailing List
Subject: Re: [MV] Mixing batteries
Ok, I'll bite, Why would it make a difference if you use two different
chemistries?
As far as I know batteries don't talk to each other, so how on earth can
they
tell if the other battery is different.
The electrical load on each battery is going to depend on the application,
and in 24 volt settups
on CUCV's the loads and charging patterns are radicaly different from what I
can see. Not that I am
a guru about this sort of thing.
Bruce MVPA 23824
"Employee@MilVeh.com" wrote:
> If you are replacing older 6TL batteries with new 6TMF
> (or 6TLFP) batteries, it is desirable not to mix 6TL
> with 6TMF/6TLFP in the vehicle/equipment. The older
> 6TL cases are all green, including the top.
>
> The newer styles 6TLFP and 6TMF have black tops and a
> green case or brown case. The reason is that the
> chemistries are different. Bottom line: Its most
> desirable to have "black tops with black tops" and
> "green tops with green tops."
>
> If you need to know Army approved NSNs for other types
> of batteries, like those needed for communications and
> electronics, the Army CECOM-LRC website gives common
> use batteries, both commercial and MILSPEC styles, in
> their "Preferred Power Sources" listing.
>
> --- RKubu@aol.com wrote:
> > List,
> > I know there was a thread recently that covered
> > mixing batteries. I cannot locate the messages and
> > there is currently no list archive. Is it OK to mix
> > 6TLs and 6TMFs? The latter look identical to the
> > former and I was told they will work in a 5 ton.
> >
> > Thanks,
> > Bruce
> >
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