Something is draining my pack

ereams65

Solar Addict
Joined
Feb 10, 2021
Messages
282
Ok, is it my AIMs converter/charger or the Daly 150a BMS w/fan discharging my cells? It has to be one of the two. I’m currently building 2 golf carts; one 36v standard and the other a 48v limo style, 6 pass. The latter cart (48v) I’ve had fabricating to do and paintwork so the battery pack I built has not been cycling at all. The cart hasn’t even been connected to the battery, it’s just been sitting in place. It’s probably been a month to 6 weeks since I even looked at the battery, but this morning I had the nagging feeling it was time. The pack has discharged down to 2.9v per cell, very evenly I might add. But, that means one of those two is draining the pack. Im suspicious of the BMS because I had another 48v pack using LGChem bag cells with a non-smart Daly that ballooned on me all accordion style. I blamed that on moisture, but now im not so sure. Any thoughts?
 

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Bubba1

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Feb 6, 2021
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284
I put a switch between my aims charger and battery. On some review someone mentioned it has a parasitic draw. If you have a DC clamp meter it would be easy to check.
 

ereams65

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Feb 10, 2021
Messages
282
I put a switch between my aims charger and battery. On some review someone mentioned it has a parasitic draw. If you have a DC clamp meter it would be easy to check.
Good point on the meter. I’ll confirm it with that once I’m charged back up. How did you wire your switch? A marine type on/off?
 

Bubba1

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Feb 6, 2021
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Yes a marine off 1 or 2 or both. I use the number 2 so I can charge other batteries. With the same charger. I have a 12v system.
 

A.Justice

Swears he didn't start that fire.
Joined
Sep 12, 2020
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If you do add a switch as @Bubba1 suggested, make sure you have a resistor to pre-charge the inverter when you reconnect. Disconnecting and reconnecting an inverter can cause a lot of damage if the capacitors aren't precharged.

I have a main battery disconnect between my BMS and battery, so I can mechanically shut off ALL of the loads if needed. It's great for long-term storage.
 
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