Re: Battery charger for my 2V lead/acid glow plug battery

| Make the measurement under load, i.e. while charging. The voltage is | still 6.5 Volts?

... and if it is, it's pumping some serious power into that battery! (or the battery is dead.)

If you want to be sure, you could measure the current going into the battery while it's charging, but simply feeling the temperature of the battery after a few hours of chargning will probably do it -- if it's not hot, you're probably fine.

| When measure without load, it is normal that the output voltage rises | significantly.

Right. These Wal-Warts aren't very precise. Red made a nice writeup on them --

One thing to keep in mind -- when a lead acid battery is fully charged, it will release hydrogen as you keep charging it. For a little battery like this, it won't release enough to be dangerous, but it will slowly dry out your battery and kill it. So you need to stop the charging when it's full.

If your charger only delivered 2.45 volts to the cell you'd be fine, but if it's delivering up to 6 (though a resistor to limit current) it will happily keep charging.

Also, lead acid batteries slowly destroy themselves when left discharged.

So, what's my point? Keep that battery charged, but don't leave it on the charger for weeks at a time -- remove it after the number of hours specified. Lead acid batteries don't self-discharge very rapidly, so you don't need to keep charging it.

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And George, did you realize that your news reader is posting html copies of your posts? Might want to turn that off.