[Ham-Computers] Parallel gelcel batteries

[Loren Moline WA7SKT]

Hello Robert,

I do agree with you in any critical power supply using batteries. If you 
parallel batteries and their voltage is different there would be a tendency 
to have current flow between batteries which is no good. Any large 
difference would cause current flow even when batteries werent being used 
til the voltages equalized. Then the weakest battery would drag it down.. 
One could but disconnects in all batteries to do a voltage check on each 
battery say once a month to prevent unforseen failure.

If its just a non critical supply then wont hurt a thing if a battery fails.


Loren




Loren Moline WA7SKT  CN86cx
Member: ARRL, Pacific Northwest VHF Society #151
2 Meter EME initials = 23
2 Meter EME with 4 X K1FO - 12's, IC-820H, and 380W from TE Systems 1452G



>From: WA5CAB at cs.com
>Reply-To: "Computers (or other) used for amateur radio, communications,  or 
>experimenting" <ham-computers at mailman.qth.net>
>To: ham-computers at mailman.qth.net
>Subject: Re: [Ham-Computers] Parallel gelcel batteries
>Date: Fri, 13 Aug 2004 03:07:58 EDT
>
>Goran,
>
>Seriesing cells is OK.  That is after all how all batteries are built.
>Paralleling batteries is to be avoided.  The weakest one will drag all of 
>the
>others down to its level.  If you isolate the individual batteries with 
>silicon
>diodes, you will lose about 5% of the available WH per diode (12 volt 
>system).
>No competent engineer would design such a system for either commercial or
>military use.
>
>Having said that, if you have a large quantity of the 8AH batteries 
>available
>at no cost, strap six of them together and use them.  When one fails and
>takes out the other five, throw the six away and start over with six new 
>ones.
>
>In a message dated 8/13/2004 1:26:40 AM Central Daylight Time, 
>ea8yu at arrl.net
>writes:
> > I would like to put six 12V 8Ah in parallel for power.
> > I am thinking of float charging them
> > and using a series resistor to limit the current from the
> > charger in case the batteries are flat.
> > Would this system work or do I have to isolate each battery
> > with diodes on the charge side and/or on the load side?
>
>Robert Downs - Houston
><http://www.wa5cab.com> (Web Store)
><wa5cab at cs.com> (Primary email)
><wa5cab at houston.rr.com> (Backup email)
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