Question #1 about batteries

[Gerald Hix]

Have you done a video on batteries? I have a vehicle that I don’t drive much. Today I went out to check on it and no lights and no indication of starting. I pulled my meter out and checked the battery. It read 2 volts. So I got online to see what was needed to charge it back up. Looks like a regular battery charger will not charge it that low. This battery is a yellow top Optima battery. According what the people at Optima say this battery is not bad. I have not attempted to do anything yet, just getting information. Have you had to pull a battery back from being that far drained?

Topic

[Richard Kirshy]

Optima yellow top are a AGM ( Absorbed Glass Mat ) designed deep cycle battery unlike a standard flooded lead acid cell type.
The reason your charger will not work on it is because of the low voltage.
These batteries like to be charged slow with low current.
Your charger may have microprocessors that collect information from the battery and adjust the current and voltage accordingly.
If the battery voltage is too low the charger will not start.
A work around is to jumper a known good battery to it and raise the voltage, then the charger sees it as a good battery and will begin charging

[Billy]

Chargers available from the auto parts store come with a deep cycle mode.

[Gerald Hix]

This may take a few times to do this. I tried to hook up another jumper type battery used for emergency usage. It drained that battery down fairly quickly. There was still not enough to start the vehicle. May have to do it several times charging the emergency battery in order to get a high enough charge on this drained battery to get a battery charger on it so it can charge.

[Richard Kirshy]

You might try using a “dumb” charger to just bring the battery voltage up enough to use a proper AGM charger.

[Author]

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