Charge rate up to 40%

[Don Bradner]

Batteries don't "attempt to pull" any particular charge rate. The charger
regulates the current, and internal resistance then dictates the voltage. As the
charge continues, the voltage will always rise if the current is above trickle
levels, as the resistance increases but the charger continues to put out the
amps.

It doesn't matter if your battery bank is 200AH, 400AH, or 1200AH, 75 or 100 amp
chargers are equally capable of raising the voltage to 14.x; it just takes
longer at 75 amps. The fact that a 1200AH bank can be bulk-charged at 300 amps
without harm does not mean that 75 amps will be unable to charge it, nor will 75
amps only produce a surface charge if maintained long enough (hours, in this
case) to bring the voltage all the way up.

If the charger is constant output, the batteries would eventually reach a
resistance/voltage where they would literally boil. A charger should instead
begin to reduce the current such that voltage remains constant during the
acceptance stage.

On 2/24/2008 at 1:32 AM joewalton2003 wrote:

>It is my understanding that the batteries will dictate how much
>amperage they draw. In other words, if your batteries are down and
>they attempt to pull 150 amps from a 100 amp charger, two things will
>happen. First, you will overload your charging system. Second, you
>will shorten your battery life by allowing your batteries to accept a
>surface charge. Deep Cycle batteries need a deep charge to retain
>their capacity. There is excellent information on this subject at
>David Smead's website, - amplepower.com.
>
>
>Joe
>91 PT40
>Arizona
>--- In WanderlodgeForum@yahoogroups.com, "Troy Tikalsky"
> wrote:
>>
>> Should the 12 volt accessories that are also using voltage during
>this time be considered?
>>
>> Troy
>>
>>
>> ----- Original Message -----
>> From: Don Bradner
>> To: WanderlodgeForum@yahoogroups.com
>> Sent: Saturday, February 23, 2008 9:37 AM
>> Subject: Re: [WanderlodgeForum] Re: Charge rate up to 40%
>>
>>
>> On 2/23/2008 at 6:43 AM Gregory OConnor wrote:
>>
>> >Are you saying 200 amp would charge your example in in 4 1/2
>hours?
>>
>> Probably more like 3 to 3-1/2 hours. The first 100AH would flood
>into the batteries in about 1/2 hour, and then the rate would start
>dropping, but it would still be putting it in way faster than a 75 or
>100-amp charger for quite awhile. In the comparisons we were doing,
>75 to 100 is not a huge increase. 100 to 200 is huge.
>>
>> >your bulk charge numbers agree with Ross. maybe there is charger
>> >technology out there that could top off the batteries quicker??
>>
>> I don't believe there is any way you can push juice into a
>battery at maximum amps while constraining voltage. If there is, that
>would be fast, but it defies the nature of a lead-acid battery.
>>
>> >Or it may be cause to get a honda 2000watt minigenset for
>balance of
>> >charge??
>>
>> I've certainly thought of it, and might consider it if I was a
>year-round boondocker like some people I know. For us it is about 40-
>60 nights per year, and not worth the aggravation.
>>
>
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