General battery charging question for NiMH and Lead-Acid powered LED lights for third world applications

Hi there, I have a smattering of random small LED lighting solutions from various countries, with either lead-acid batteries or NiMH batteries inside. They all seem to have some sort of charging circuitry (over voltage protection, etc.)

I'd like to measure the charging time of these LED lights (I have AC adapters). Can I just monitor the current going into the light from the AC adapter, or will this likely not reflect the battery state? I've read that I have to monitor the battery voltage instead?

Thanks

Reply to
jwodin
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Hello,

Generally spoken, current that goes into the battery does not reflect the charge state. How de current decays versus time depends on the type of charger.

Some simple low current chargers do not even stop (as they don't have a timer or other charge termination control) and distroy the battery in the end.

A good measure can be: determine the capacity of the battery. Discharge the batteries completely and monitor the current that goes into the battery. Integral of current versus time is a good measure. A good website on batteries and chargers:

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click on technical resources.

Best regards,

Wim PA3DJS don't forget to remove abc when using pm

Reply to
Wimpie

That's true for NiMH. Lead acid current tapers off at the end of charge.

Reply to
Raveninghorde

Monitoring the current won't tell you what you want to know. Charging time will depend on three variables: the size of the battery, the degree to which it is discharged when you start, and the charger design. You need information on all three.

Ed

Reply to
ehsjr

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