jonyjoe303
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- Joined
- May 18, 2017
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I had problems with my 4s20p 110ah lifepo4 battery pack not getting a full charge due to the BMS always tripping early due to one cell always reaching 3.65 volts while the other 3 cells where at 3.40 volts, this has been going on for 6 months. When the BMS tripped, the solar charge controller would surge (voltage would go over 15 volts) resulting in damaging anything connected to the battery , mainly burning out my swampcooler fans. About 5 of them in the past 6 months.
I installed an overvoltage relay to try and control the surge but it wasn't fast enough to prevent the damage.
Fast forward to last week finally got a 4s balancer, this unit will balance at a constant 6 amps and (will peak at 10 amps). The balancers on many of the BMS are in the 60 milliamp range which are next to useless for balancing a low ah battery let alone a 110 ah lifepo4. Also these built-in balancers don't start balancing until the cell reaches 3.60 volts (which is nearly full for lifepo4 3.65 is full). At 6 amp balancing you can charge at 24 amps and the balancer will keep up with that rate of charge. For comparison my 14 amp balance charger will drop to less than 1 amp of charge current once the battery starts going out of balance.
I been testing it all week and like its performance. It is always on and balancing while connected, will balance while charging/discharging. With this balancer I can just let the overvoltage relay set for 14.4 volts disconnect the solar panel when that voltage is reached. 14.6 volts is when the battery is fully charge but setting at that voltage is too risky because it will trip the BMS, 14.4 volts is close enough and a voltage I never reached except when connected to a balance charger. To get that close with a solar controller is a major achievement.
These balancers is mainly for those with DIY lithium battery packs. It will work on li-ion,lifepo4 and there is no limit (recommended 50 to 1000 ah), you just add more balance modules as needed. They are interconnected and they work by bleeding from the hi-cell and transferring to the low-cell instead of wasting the excess voltage as heat. They do make a high frequency noise while working which is all the time. But you need to be next to them to hear it. If you DIY your own battery pack you won't have any problem installing or using this balancer. You just connect it and it works in the background. Just disconnect it if you wont be using the battery pack, it is always running and using power.
I paid 80 dollars plus 10 dollar shipping for my 4s balancer. I bought from electriccarpartscompany but also available from overseas sellers. Expensive but worth it if you got a lifepo4 with balance problems.
I installed an overvoltage relay to try and control the surge but it wasn't fast enough to prevent the damage.
Fast forward to last week finally got a 4s balancer, this unit will balance at a constant 6 amps and (will peak at 10 amps). The balancers on many of the BMS are in the 60 milliamp range which are next to useless for balancing a low ah battery let alone a 110 ah lifepo4. Also these built-in balancers don't start balancing until the cell reaches 3.60 volts (which is nearly full for lifepo4 3.65 is full). At 6 amp balancing you can charge at 24 amps and the balancer will keep up with that rate of charge. For comparison my 14 amp balance charger will drop to less than 1 amp of charge current once the battery starts going out of balance.
I been testing it all week and like its performance. It is always on and balancing while connected, will balance while charging/discharging. With this balancer I can just let the overvoltage relay set for 14.4 volts disconnect the solar panel when that voltage is reached. 14.6 volts is when the battery is fully charge but setting at that voltage is too risky because it will trip the BMS, 14.4 volts is close enough and a voltage I never reached except when connected to a balance charger. To get that close with a solar controller is a major achievement.
These balancers is mainly for those with DIY lithium battery packs. It will work on li-ion,lifepo4 and there is no limit (recommended 50 to 1000 ah), you just add more balance modules as needed. They are interconnected and they work by bleeding from the hi-cell and transferring to the low-cell instead of wasting the excess voltage as heat. They do make a high frequency noise while working which is all the time. But you need to be next to them to hear it. If you DIY your own battery pack you won't have any problem installing or using this balancer. You just connect it and it works in the background. Just disconnect it if you wont be using the battery pack, it is always running and using power.
I paid 80 dollars plus 10 dollar shipping for my 4s balancer. I bought from electriccarpartscompany but also available from overseas sellers. Expensive but worth it if you got a lifepo4 with balance problems.