Author Topic: Battery voltage drops suddenly  (Read 239 times)


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Battery voltage drops suddenly
« on: July 27, 2019, 08:06:39 PM »
Why do 1 of my 2 6v batteries connected in series in a rechargeable fan fail within days? One battery drops to 2 volts within one minute when load is turned on, and then very slowly goes back to 6v once load is turned off. This problem starts in 10 days after replacement with new batteries. Only one battery fails.


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Re: Battery voltage drops suddenly
« Reply #1 on: July 27, 2019, 09:15:37 PM »
What kind of batteries are you talking about ? What is the load of the fan , age of batteries, etc ?  How deep are you discharging the batteries from full ?
Were the batteries fully charged after you got them ? How often are you charging them ?   Also it can take a few cycles to on lead acid batteries to get them to full capacity .
There are so many factors that need to be considered so that is why I ask all the questions. 
If flooded lead acid batteries they may need equalize since one or more cells may be low.

system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie