Re: (ET) Battery Question

["Travis Creswell" <ozsolar ipa net>]

Although it's a good idea, Solar Charge controllers aren't designed to
regulate the voltage in-between batteries (or banks) of different 
voltages. 
A battery can deliver far more amps than a solar charge controller can
safely "control".  A starting battery is capable of over 2000 amps, a big
solar charge controller is 40 amps and it costs several hundred dollars. 
I'm
afraid that using a Solar Charge Controller to regulate a battery used as
charging source for another battery could have disastrous results.

The flooded Trojan batteries are excellent deep cycle batteries for the
money but they are not what you want to be using.  I assume you are talking
about their deep cycle batteries (T-105's and similar models).  They are 
not
designed for starting thus probably will be damaged by the high amp draw 
and
have a very short life if asked to do so repeatedly.  The Trojans also 
won't
hold up to lots of G's either.  The reason they are such good deep cycle
batteries is because of the high lead content of the plates which also 
makes
them pretty soft and more easily damaged than starting batteries.

The most obvious and easiest solution to me is a higher capacity battery
charger.  If that is not the route you want to go my next suggestion would
be two "4D" or "4DLT" class batteries in parallel.  The 4DLT is a little
smaller than the 4D.  4D's are standard in big trucks and tractors.  They
are pretty heavy at somewhere around 80 lbs but have about twice the
capacity of the standard size starting battery so should easily last the
whole race day, especially if he is able to do some charging in-between
races.  Another suggestion is to take 2 sets fully charged batteries of
whatever style then swap out the discharged set for the charged halfway
through the event. 

Just my .02.  My trade is independent power systems thus I am quite 
familiar
with batteries.

Travis Creswell
E-15, charged by solar



>Subject: Re: (ET) Battery Question
>Date: Tue, Jul 16, 2002, 10:10 PM
>

>
>Then choose batteries etc to maintain the voltage, with enough
>capacity.  For example, a solar charge controller powered by
>2 8-volt deep cycles, charging a small 12v battery at say 14.2v.
>Ignition runs off the 12v (nominal), 'always' charging at 14.2v.
>Choose the solar controller power rating to be at least 50% over
>the peak current draw of the ignition.  A small gel cell could
>be the12v battery, located very close to the ignition system
>(for least voltage drop), and the larger 8v batteries can be
>conveniently placed.

>----- Original Message -----
>From: "Pestka, Dennis J" <Dennis Pestka TycoHealthcare com>
>To: "'Elec-Trak Email Discussion List'" <elec-trak cosmos phy tufts edu>
>Sent: Tuesday, July 16, 2002 3:10 PM
>Subject: (ET) Battery Question
>
>
>> This isn't really a tractor question, but here goes.
>>
>> A fellow I work with races super stock dragsters on the weekends.
>> He presently runs a no alternator system with (2) 12 volt Optima Blue 
>> top
>> batteries in parallel.
>> When he races a lot and gets all the way to the finals, he notices his
>> batteries getting pretty weak and may not be getting the high voltage
>needed
>> for optimal spark.
>> He charges in between races, but has very little time.
>> He would like to upgrade and is considering several options.
>>
>> Staying at 12 volt with (2) 12 volt Optima yellow tops in parallel.
>>
>> Staying at 12 volt with (2) Trojan 6 volts or (1) 12 volt.
>>
>> Using a higher voltage combinations, say 2 Trojans, (1) 6 volt, (1) 8 
>> volt
>> in series for 14 volts.
>> Even higher voltage with (2) Trojan 8 volts in series for 16 volts.
>>
>> He is now adding 80 pounds of ballast to get to the minimum racing 
>> weight,
>> so the extra weight of the Trojans should not be a problem.
>>
>>
>> I know they would have a higher amp hour rating and last longer, but 
>> would
>> the Trojans be able to deliver the amperage needed during the race 
>> versus
>> the Optimas ?
>>
>> Would the G forces be a problem with the Trojan floodeds versus the
>Optimas
>> ?
>>
>> Any opinions ?
>>
>>
>> Thanks;
>> Dennis
>