Parasites

Gary in NJ

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I have an SAE battery connector which allows for convenient charging and maintaining. It also allows me to plug in a Battery Tender 12v to 5v DC to DC USB adapter. I accidentally left this little contraption attached to my bike, and in a matter of a few weeks it drained my battery. While it’s an insignificant draw, over time it adds up on a little 18aH lithium battery. A parasite loss.

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But that’s not really the purpose of this post.

I attached my battery tender to charge the battery and I got a flashing orange light. That means that the battery isn’t attached or present. I knew that wasn’t the case, but checked anyway. All was good.

I’ve often read that you can destroy a lithium battery if it is too deeply discharged, and I assumed that happened here. And then I thought about it.

Modern LiFePO4 batteries use micro circuits to protect the battery from over and under charge conditions. The Battery Tender is also smart enough to know if there is an open circuit or reversed polarity and will keep the unit from functioning if it’s checklist isn’t complete.

I started to think that the battery tender wouldn’t kick-off a charge cycle because the battery itself would not allow itself to be detected. So I broke out my trusty old-school 14.5V battery charger. When I plugged it in the amp gauge pegged at 15a which told me the battery hadn’t failed, and within seconds the amperage began to drop - which meant the battery had less resistance so it was taking the charge. Within a minute I was down to 7 amps, so I unplugged the analog charger and plugged in the battery tender. It immediately saw the battery and began a normal charge.

This is all a long way of saying that a micro processor based charger can be fooled by the protection circuit in the battery itself. My battery wasn’t fully drained, but reached the allowed discharge threshold. The battery tender was unable to recognize this condition and initiate a charge. The battery needed a boost to turn off its self protection function.
 
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Motogiro

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This is really good info! Thank you Gary!
I was feeling a little itchy at first...
 

TownsendsFJR1300

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Kinda related, I have two C-TEC Mus 4.3 chargers.

One's used for the bike (mounted on the wall) and the other
out at my boat lift (to charge the boat battery).

Hurricane Ian put the charger under about 2' of SALT WATER for several hours...
Several days later while cleaning lift motors/controls, I tried the charger which I figured was toast.

Surprisingly, it fired up and works fine!

And it doesn't draw anything when left plugged in with no power to it...


.
 

Motogiro

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Kinda related, I have two C-TEC Mus 4.3 chargers.

One's used for the bike (mounted on the wall) and the other
out at my boat lift (to charge the boat battery).

Hurricane Ian put the charger under about 2' of SALT WATER for several hours...
Several days later while cleaning lift motors/controls, I tried the charger which I figured was toast.

Surprisingly, it fired up and works fine!

And it doesn't draw anything when left plugged in with no power to it...


.
Did you rinsed it with fresh water?
 

TownsendsFJR1300

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Did you rinsed it with fresh water?

Both electric lift motors, control boxes and charger were hosed down with fresh water.
The charger is sealed up tight and I don't believe salt water or fresh water got into it...
(Too busy to take it apart yet)...

Both lift motors and control box were saved (after the flush, air blow out, liquid wrench blown inside, outed motor bearings lubed).
 
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