Need help with replacing a lead-acid sealed battery with a Lithium Ion battery

AI Thread Summary
Replacing a 12v 5Ah lead-acid battery with a 14.8v 6600mAh lithium-ion battery may not work due to potential voltage compatibility issues with the motor's protection circuit. Users are cautioned against using the same charger for both battery types due to fire hazards. The lithium battery appears to run the motor briefly before failing, indicating possible current limiting or a dead battery issue. Measuring the terminal voltage during operation can help diagnose the problem, especially if it drops to zero. A smaller voltage battery may be a viable alternative if compatibility issues persist.
banglour
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What I am trying to do is replace my 12v 5Ah lead-acid battery with a 14.8v 6600mAh lithium ion battery. It powers a small fan belt. And for some reason I can't get the lithium battery to work. Can somebody tell me what I might be doing wrong, or if it will even work?
 

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#1: Do NOT charge the Lithium battery with the same charger used for the Lead-Acid battery! This is a potential fire and/or explosion hazard!

As for the problem you're having... assuming the Lithium battery is fully charged, it's possible that the motor has a protection circuit that doesn't like the higher voltage. What exactly happens when you connect the new battery? Does it run if you reconnect the lead-acid battery?
 
Yes I have a separate charger just for the Lithium battery.

The battery is fully charges and when I connect the lithium battery and turn the motor on it sounds like it actual runs, but just for a split second. Then nothing happens after that. When I connect the lead-acid back up the motor runs just fine. Why is that?
 
Sounds some form of protection circuit either in the battery pack or in the motor (or of course a dead battery).

Can you please measure the terminal voltage while you test it. If the terminal voltage drops markedly when the motor stops ("after a split second") then there is a problem with the battery. Either a dead battery or some built in current limiting.
 
After I start the motor the terminal voltage drops all the way to 00.0. I have a hard time believing that its a dead battery because its brand new. Would it work if I got a smaller Voltage battery?
 
Do you have any specifications on the battery pack. Does it have any built in over-current proctection?
 

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