Balancing Charger for 72V 20S 4P Battery Pack

[MegaWatt]

I'm starting to build a 72V battery pack for a MegaMoto Mini Bike I converted to electric. The pack will be built in 2 modules, each 36V 10s 4P and connected in series. I have a balancing charger however it is only capable of 6S. I'd like to know if any of the forum members are aware of a balancing charger capable of 10S. I may need to build one. I'm building the pack without a BMS to avoid the problems associated with them.

2 years ago I bought 12 - 36V battery packs that had defective BMS's. These were caught by Quality Control and sold without ever being put in service. Each pack has 40 LG INR 18650MJ1 batteries. To date I have salvaged 4 of these battery packs and all 160 batteries were in perfect condition. I've built 2 52V battery packs from those cells, on 1 the BMS has failed and the other is still working.

I've read many articles about problems with BMS's. As a retired electrical engineer, all of my work experience is in Transmission & Distribution however I have experience with large battery banks as backup power in sub-stations. I going to try building a 72V battery pack by removing the faulty BMS from two 36V packs and connect them in series.

[73Eldo]

Ain't cheap but its pretty versatile.

https://ebikes.ca/shop/electric-bicycle-parts/chargers/satiator-high-voltage-model-5a-max.html

[MegaWatt]

That's a nice charger however it doesn't have balancing capabilities, I would still need a BMS which is what I'm trying to avoid.

[AZguy]

I'm starting to build a 72V battery pack for a MegaMoto Mini Bike I converted to electric. The pack will be built in 2 modules, each 36V 10s 4P and connected in series. I have a balancing charger however it is only capable of 6S. I'd like to know if any of the forum members are aware of a balancing charger capable of 10S. I may need to build one.

Nearly all batteries for bicycle/scooter/light moto (or any other EV for that matter) have the electronics for balancing integrated into the battery (Battery Management System - BMS) so don't require a charger that can balance the individual cell groups in the battery

It's a safety thing - the BMS's that are integrated with the batteries also ensure that individual cell groups don't over-discharge etc.

Anyway would strongly advise any large Li-ion batteries to have integrated BMS's

[calfee20]

I'm starting to build a 72V battery pack for a MegaMoto Mini Bike I converted to electric. The pack will be built in 2 modules, each 36V 10s 4P and connected in series. I have a balancing charger however it is only capable of 6S. I'd like to know if any of the forum members are aware of a balancing charger capable of 10S. I may need to build one. I'm building the pack without a BMS to avoid the problems associated with them.

Here is a video about DIY battery no BMS.

https://www.youtube.com/watch?v=pljSZcEwc8Q&t=3s

You should be able to get a balancer from a drone hobby shop that was meant for lipo's. These things are all over Ebay.

https://www.ebay.com/itm/291596586816?epid=1048001833&hash=item43e482cf40:g:I94AAOSwjkZiDXTO&amdata=enc%3AAQAIAAAA0KpWZQqBXeM0fg2faIBY0foLkidnM1IXbrJyGnFXp9sBguJ7hpQerWb0WYgsng6X6IclPt19b4ZDEssmikPyUT4LM9LpPXJsG8jK9aLydNI0ZZhevgrjOKvtKNuxTjmLdm7Yt%2BYMXFFUDUwjQbBGf35HWx89Rrj1Dg6SZ41nvjCOy7yn0lZM8BvbxuAjF%2FYMCx3%2F4la4SzBEigC9UGj1NTjr7PYhG%2FCXl7NoStaWraVceO24w0uGGvAUPXXwMjKSxPZ46lccjSZaxfzaksSATX4%3D%7Ctkp%3ABk9SR7DC8-D_YQ

[MegaWatt]

calfee20, thanks for your reply. I added to my OP with more of an explanation of what I'm trying to build.
The video you posted by Shawn McCarty is excellent on explaining the problems with BMS's and the advantages of Balanced Charging.
The ICharger 1010+ shown in this video was discontinued about 4 years ago and there Out of Stock everywhere I've checked. I can't find another 10S capable balanced charger. I have a 6S and that is highest series charger the RC Industry seems to make.

I found another video by EV-Customs that describes how to build a Balancing Charger, so I think that's the direction I'm headed. That's going to be a project for next winter when I have plenty of spare time for soldering!

https://www.youtube.com/watch?v=ZLLQ9Br4GBI&list=PLdzZO1bNf8QtdUEFPRYTuCkrLxlaJ7KKc&index=41

[MegaWatt]

After a lot of searches and watching YouTube Videos, I finally found what I was looking for. I will still need to add a power supply but that won't be a problem

https://www.amazon.com/12String-Capacitor-Equalizer-Balancer-Equalization/dp/B096NN6H5V/ref=cm_cr_arp_d_product_top?ie=UTF8&th=1