Battery help please

[YakDout]

Originally Posted by FullFlavorPike

Test the charger with the multimeter?

Yep testing the output of the charger with voltmeter should work

[FullFlavorPike]

Originally Posted by YakDout

Yep testing the output of the charger with voltmeter should work

My thought is that perhaps the thing is only throwing 3.2V at 18mA or something. That would be an easy diagnosis.

I may be wrong about this, but isn't the "battery charged" indicator light just th product of some kind of diode responding to the current in the battery? When it meets a certain threshold, it shuts off power to the battery and flashes that green light.

Depending on how the charger is actually wired, there could be any number of ways in which it could fail to charge the battery, or provide a kind of false positive for reading the battery's state of charge.

My (admittedly inexpert) guess is that the easiest way to wire the charger would be that it responds to the battery's charge as compared to the current coming out of the charger. When the battery's charge is less than the charger's output, it charges, but if the charger's output is equal to or lesser than the battery's charge, it shuts down and flashes the CHARGED light. THe thing doesn't think, it just responds to the ratio of electrical forces between battery and charger. If the charger were outputting insufficient current, it would think the battery was charged, even if that were not the case.

[jorluivil]

If its 3 years old just save yourself the time and buy a new battery.

[bolocop]

Originally Posted by jorluivil

If its 3 years old just save yourself the time and buy a new battery.

Definitely thought of that, but I was worried about the charger too.

Thanks for the help, everyone!

[bolocop]

Thanks! I will give that a try when I get home! So if it's not reading anywhere near 6V, I need a new charger, right?

Originally Posted by FullFlavorPike

My thought is that perhaps the thing is only throwing 3.2V at 18mA or something. That would be an easy diagnosis.

I may be wrong about this, but isn't the "battery charged" indicator light just th product of some kind of diode responding to the current in the battery? When it meets a certain threshold, it shuts off power to the battery and flashes that green light.

Depending on how the charger is actually wired, there could be any number of ways in which it could fail to charge the battery, or provide a kind of false positive for reading the battery's state of charge.

My (admittedly inexpert) guess is that the easiest way to wire the charger would be that it responds to the battery's charge as compared to the current coming out of the charger. When the battery's charge is less than the charger's output, it charges, but if the charger's output is equal to or lesser than the battery's charge, it shuts down and flashes the CHARGED light. THe thing doesn't think, it just responds to the ratio of electrical forces between battery and charger. If the charger were outputting insufficient current, it would think the battery was charged, even if that were not the case.

[PescadorPete]

With no battery connected, charger reads about 6.8V. With a fully charged battery attached its about 6.5V. When I connect the pump, it drops to about 6.2V. I don't know what it would read with a discharged battery connected, I'll check next time I have to charge it up.

[bolocop]

The charger is reading 7.5V so the battery is toast. Like someone said,it's a 3 year old battery. Time to cut off the connector and buy an Amazon 6V 10amp/hr battery.

Thanks again for all your help!