From: Michael J. Hill (wild800@pacbell.net)
Date: Sat Feb 23 2002 - 10:14:59 PST
Ed and List,
That is true.....
Mike Hill EMT-1
Kilo Golf Six Foxtrot Julia India
M1009
M105A2
(wanting a cool shop phone)
Ed Kirkley wrote:
>
> Jeff,
>
> I understand the wording of your message and in that setup I tend to agree.
> On the other hand in a two 12 volt battery system with two alternators that
> each provide power to one battery, (such as my CUCV), I wouldn't think that
> this would apply?
>
> Best Regards,
>
> Ed Kirkley KG4OUJ
> 1984 M1009
> M103 Trailer
> ----- Original Message -----
> From: <TacticalTruck@aol.com>
> To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
> Sent: Saturday, February 23, 2002 09:08
> Subject: Re: [MV] CHEAP (er) 24 to 12 volt converters, if you care
>
> >
> > In a message dated 2/22/02 10:56:38 AM, amnon@deltaforce.net writes:
> >
> > >This may be a stupid question, but why can't one just run wires from one
> > >battery to get 12V?
> >
> > Let me quote from "Battery Equalizer Application Notes" by Mark Endres,
> > Project Engineer Sure Power Industries, Inc.
> > "The 24V system normally consists of two-12V batteries connected in
> > series, with a 24V alternator providing power. It seems the most logical
> > place to to obtain 12V power is the junction between the two batteries.
> > However, a problem arises if the system is constructed in this fashion.
> > "Consider the situation when the engine is off (alternator is not
> > generating), and 12V power is used. Load current comes only from the 12V
> "low
> > side or A" battery, none of which is being furnished by the top or "high
> side
> > or B" battery. After a time, the 12V loads will discharge the "A" battery
> > while leaving the "B" battery charged up. Since the "B" battery has not
> been
> > discharged it will not need any electrical current to recharge it;
> however,
> > the "A" battery will.
> > "When the engine is started and the alternator furnishes current to
> the
> > load and to charge the "A" battery. All the current now flows throught the
> > "B" battery, since it is in series with the load and "A" battery.
> > "When this happens, a condition exists where the "B" battery
> overcharges
> > because it does not need recharging, and the "A" battery does not get the
> > charge it requires. Charging current for the "A" battery is impeded by the
> > already charged "B" battery and reduced by the amount of current that
> flows
> > to the load. Even if there were no load at this point, the same problem
> would
> > exist due to the imbalance of the battery charges.
> > "When operating the system in this manner, the life of the batteries
> is
> > dramatically shortened. The "A" battery fails prematurely because lead
> > sulfite builds up on the battery plates, reducing the capacity. The "B"
> > battery fails when its electrolyte "gasses" and evaporates and damage
> occurs
> > to its plates and separators in the dry battery cells as a result of ov
> > ercharging. Failure time can be as short as a few weeks for heavy 12V
> loads.
> > "If there is no 12V load, a 24V system with a two battery "stack" can
> > operate well without an equalizer. However, the batteries must be of the
> same
> > type and age. Without a battery equalizer, current draw from one battery
> and
> > not the other will cause an imbalance. This imbalance accumulates over
> time.
> > Because the effects of the imbalance are cumulative, battery degradation
> > occurs even with very small loads, such as a radio, clock or small lamp"
> > The paper goes on to describe how their converter/equalizer works and
> the
> > benefits of their system. Again, I have some new surplus 25 amp units for
> > sale for $150.
> > Jeff
> > TacticalTruck.com
> >
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>
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