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Discussion Starter #1
Re: [EVDL] How low of a charging current is too low?

Lee Hart wrote:
> Chuck Hursch wrote:
>> Why does charging batteries at low current reduce their life?
>
> I think high charging current tends to decrease the size of the crystals
> that form (improving their surface area), and increases the mixing and
> diffusion rates of the sulfuric acid back into the electrolyte.
>
> But I think Nawaz monitors this list. Maybe he (or other battery
> experts) can provide more definitive data.

I am currently charging my 120 v pack (20 6v batteries) with a 10 amp
charger. The 6v batteries are 105 reserve minute batteries (I estimate
around 205 AH?) in series. My only other option is a 17 amp 240v
charger. Is my 120v 10amp charger not providing enough current to keep
the batteries healthy?

[I'm mostly charging the pack when it is only 15 to 30% discharged...]

Jay

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Discussion Starter #2
Re: [EVDL] How low of a charging current is too low?

Other than some AGM batteries (Hawkers?) I haven't heard of any problems
with low charging current. That is, if you equalize them every month or so
with a good high voltage (which may require a higher current to achieve) to
stir up the electrolyte. I have heard more issues with too high of charging
current than too low... but most of my experience is also much larger (AH
capacity) deep cycle batteries than EV's are using, where even 100 amps of
charging may still only be C/20 on some of the larger banks.

Z

Jay Summet <[email protected]> wrote:

>
>
> Lee Hart wrote:
> > Chuck Hursch wrote:
> >> Why does charging batteries at low current reduce their life?
> >
> > I think high charging current tends to decrease the size of the crystals
> > that form (improving their surface area), and increases the mixing and
> > diffusion rates of the sulfuric acid back into the electrolyte.
> >
> > But I think Nawaz monitors this list. Maybe he (or other battery
> > experts) can provide more definitive data.
>
> I am currently charging my 120 v pack (20 6v batteries) with a 10 amp
> charger. The 6v batteries are 105 reserve minute batteries (I estimate
> around 205 AH?) in series. My only other option is a 17 amp 240v
> charger. Is my 120v 10amp charger not providing enough current to keep
> the batteries healthy?
>
> [I'm mostly charging the pack when it is only 15 to 30% discharged...]
>
> Jay
>
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Discussion Starter #3
Re: [EVDL] How low of a charging current is too low?

>> I am currently charging my 120 v pack (20 6v batteries) with a 10 amp
>> charger. The 6v batteries are 105 reserve minute batteries (I estimate
>> around 205 AH?) in series. My only other option is a 17 amp 240v
>> charger. Is my 120v 10amp charger not providing enough current to keep
>> the batteries healthy?
>>
>> [I'm mostly charging the pack when it is only 15 to 30% discharged...]
>
> How's your battery life turning out Jay?
>

Well, I'm on charge # 10 now....so I'll let you know in (hopefully) 3-5
years.... My only two options (without buying another charger) is 10amp
and 17amp, but the 10amp charger is more convenient. I'll hope that the
charging current is less important than the SOC and keep charging my
batteries once a day.

Jay

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