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BMS and active balancer recommendation

Darce

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Dec 4, 2020
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My batteries have shipped faster than I expected and tracking shows them here tomorrow. Now I'm scrambling to select a balancer and BMS. I was thinking of an Overkill Solar BMS 16s, 100a. For the active balancer I was looking at a Heltec. The cells are Eve 304's in 16s for 48v. I have a Midnite scc. I was hoping to go the route of skipping the top balancing and relying instead on the active balancer. Any advice is greatly appreciated.
 
I was hoping to go the route of skipping the top balancing and relying instead on the active balancer. Any advice is greatly appreciated.
Don’t skip top balancing.
Overkill BMS and Heltec balancer is good combo. I would turn off BMS balancing when Heltec installed.
 
I have Overkill BMS (4S) and Heltec. Charged in series to 3.4 vpc and all seemed close so it went direct to in service. No cells over voltage charging to 13.9 so i am OK with it balancing on its own.
 
Don’t skip top balancing.
Overkill BMS and Heltec balancer is good combo. I would turn off BMS balancing when Heltec installed.
I guess I'll have to see where the cells are at when they arrive. I have read threads that suggest it takes a little bit of time but that an active balancer will eventually bring everything together. Honestly I started looking into power supplies and chargers and hit my own personal overload lol. I just don't have time to sit and watch over the whole process. If there was a good charger you could recommend that was fully automatic once set up that would be different.

I just saw that the HEltec balancer is limited to 200aH batteries. Is there something more appropriate for the 304aH?
 
I found this 4A active balancer in a 2019 thread about top balancing, posted by a guy who said he was sick of top balancing new batteries on larger sets , while recommending this as an option: Has any one else tried this one out; any reference comments ? .... This looks like an Interesting Option to me:
NEEY 4A Smart Active Balancer 3S 4S 5S 6S 7S 8S 14S 16S 20S 21S 22S 24S Lifepo4 / Lipo/ LTO Battery Energy equalization
 
Have a Neey 4A active balancer waiting to be added to my 16S LiFePo4 OffGrid system that needs more than a passive balancer. My understanding is the original Neey units did not have the ability to switch off below a set cell voltage. The generation 3 now has this feature ( as of ? 6 months ago) that can be adjusted via the Bluetooth app. I am currently using the standalone Jikong 2A active balancer with balancing to come on when delta V is > than 20mV as it too has no setting to switch off below a set voltage ( unlike the combined Jikong BMS/ active balancer). When I mentioned to Andy from OffGrid Garage channel, that the gen 3 Neey was perhaps the go to add-on active balancer, he stated that the switch on/off mechanism was not ideal and could lead to a problem. I think this may have been covered in one of his videos, but I haven't clarified this issue yet. Certainly top balancing with an active balancer seems to be the preferred method, but there is a paucity of add on active balancers capable of this.
 
Have a Neey 4A active balancer waiting to be added to my 16S LiFePo4 OffGrid system that needs more than a passive balancer. My understanding is the original Neey units did not have the ability to switch off below a set cell voltage. The generation 3 now has this feature ( as of ? 6 months ago) that can be adjusted via the Bluetooth app. I am currently using the standalone Jikong 2A active balancer with balancing to come on when delta V is > than 20mV as it too has no setting to switch off below a set voltage ( unlike the combined Jikong BMS/ active balancer). When I mentioned to Andy from OffGrid Garage channel, that the gen 3 Neey was perhaps the go to add-on active balancer, he stated that the switch on/off mechanism was not ideal and could lead to a problem. I think this may have been covered in one of his videos, but I haven't clarified this issue yet. Certainly top balancing with an active balancer seems to be the preferred method, but there is a paucity of add on active balancers capable of this
Here is the youtube where Andy explains that the method the Neely 4A active balancer uses to switch on at say 3.4V is an average cell voltage (ie pack voltage / no of cells) not the first cell to get to 3.4V. He suggests that this may no be ideal in that cells may overshoot before balancing commences particularly if the start voltage is set higher and the pack is unbalanced.
 
Here is the youtube where Andy explains that the method the Neely 4A active balancer uses to switch on at say 3.4V is an average cell voltage (ie pack voltage / no of cells) not the first cell to get to 3.4V. He suggests that this may no be ideal in that cells may overshoot before balancing commences particularly if the start voltage is set higher and the pack is unbalanced.
great point!!

sampling average voltage will indeed result in delayed activation of the balancing.

proper implementation in my opinion is if ANY cell is over the threshold voltage value, begin balancing

thank you for mentioning this implementation detail
 
Came across this and shortly realized the discussion above was about the 3rd generation version. There is a 4th generation version now that is no longer sampling by averaging voltage but triggering on voltage of individual cell which is correct now.
 
All true, consumer pressure seemed to result in firmware/hardware upgrades. The 4th generation Neey 4A may possibly be the Duck's Nuts of add on active balancers for 8 -24S systems, though using current balancing amperage claims between different brands of active balancers may be misleading.
 
All true, consumer pressure seemed to result in firmware/hardware upgrades. The 4th generation Neey 4A may possibly be the Duck's Nuts of add on active balancers for 8 -24S systems, though using current balancing amperage claims between different brands of active balancers may be misleading.
FYI, Andy did do review of the 4th gen as well and said they implemented a lot of his feedback:
 
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