Re: Max charging rate?

[Nawaz Qureshi <nqureshi@usbattery.com>]

Hi:

We recommend C/10 rate where C is the 20 Hr. capacity in Ah.
Higher rates are OK except you have to watch the temperature to avoid
thermal runaway. As the temperature rises, the Voltage drops (given a
constant current). If you charging with Voltage limit (like most chargers
have), the higher temperature will max. out the current resulting in fried
batteries. So, you can charge at high current rates (particularly the
initial charge)  if :
1. You limit your Voltage as Lee says, and
2. Do not the let the temperature rise above 130°F or so. If does, keep
dropping the current by 20% until the temperature stays in the desired
range.

Sincerely

Nawaz Qureshi

Lee Hart wrote:

> Mark wrote:
> > How can you determine the maximum charging rate of a particular
> > battery? Is it always some set formula, like the C/20 rate * 3.543,
> > or is it different for each battery?
>
> It's usually limited by the charger, not the battery. You can charge at
> just about any current you can discharge it at; that means 100's of amps
> are ok. The only caveat is to monitor charge voltage, and don't let it
> get too high. For lead-acid, charge at any current so long as the
> voltage does not exceed 2.4v per cell (14.4v for a 12v battery).
> --
> Lee A. Hart                Ring the bells that still can ring
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