Balancing The Pack [Battery Build #7]

[@chapulino1000]

Stuart, you are not the only one who, after putting the battery in gear, has had to do the TOP Balancing with what I call the Magical Crusader (I don't know if this translated makes sense in English,). Arm yourself with patience because charging at 6A is going to take a while and cover the battery well because it's very cold I don't want your new lithium candles to catch a cold. When you finish this part, I have no doubt that you will quickly see a way to use the data that give that inverter, make it a decent interface, hehehehe. Last, every day I feel happier and proud to be part of your Patreon for some time now. .

[@StuartPittaway]

Thanks chapulino

[@sjdtmv]

Thanks Stuart, if your feeling cold you can come to the land down under for a warmer break anytime, anyway try staying warm.

[@StuartPittaway]

Thanks Ross

[@muddy11111]

I gave up initial manual top balancing. I now fit a cheap active balance board and turn it on with MQTT at 0.1v below the max pack voltage. It save so much time.

[@StuartPittaway]

That's not a bad idea. Might consider that.

[@MiniLuv-1984]

That is my intention too, but flailing in the dark without hard data so your comment gives me hope! One question if I may, why not allow the balancer to run all the time? (I realise it is ineffective at any SOC less than 100% but I figure it wouldn't hurt running it all the time and overcomes having to connect/disconnect the active balancer).

[@sjdtmv]

That what I did for the last build, only took a couple of hours.

[@muddy11111]

​@@MiniLuv-1984 Running all the time simply wastes energy. Also if under heavy load cells will look out of balance due to differing internal resistances. You don't want to be trying to balance in this state. People worry too much about getting the perfect balance. It should run quite happily with a quick top balance once a month, unless you are completely draining the battery or have very poor cells. The active balancers have a pair of switch contacts with a soldered link across. Unsolder this and fit some sort of switch, relay or manual. Then just leave the balancer connected and turn on when required.

[@chapulino1000]

@@muddy11111 I have an active capacitor balancer as backup. The problem is that when it starts to balance, this generates reading peaks in the DIYBMS and therefore the protections are activated, reducing the charging amperage. could be used, temporarily disabling DIYBMS to make that balancing a bit faster and then disabling it and going back to DIYBMS. Specifically, I can activate it remotely with two Tasmota relays.

[@GarethJones-dk9yp]

Hi Stuart. Nice build. Top balancing these cells is an interesting topic. I've tried it a few ways. 1st time was the way you did it. Connect them all parallel and then use a bench top power supply. One 16s pack I help build with a friend was on charge for 5 weeks and even then it never dropped below 4amps. Gave up and connected in series and let the balancer do the rest. 2nd one I built just connected in series and let a 2A JK BMS balance them out but again took ages. I'm building another one atm and charging them all individually with multiple a bench top power supplies. Be interested to see how you get on. Initial top balance is a tricky one to do quickly and properly. I think patience is key. 😊

[@StuartPittaway]

I admit that I gave up too early before the cells were fully balanced. They are a lot better than they were though.

[@madsskov_dk]

Active balancing is rather popular. There’s a future version challenge for ya ;-) Colored min/max cell looks great. Good addition.

[@StuartPittaway]

I've just brought a basic active balancer, although blew up on first usage!!

[@nebulight]

I purchased a ZKETech electronic load tester and ran each cell through a full charge, discharge and recharge. This gave me a baseline capacity of each cell to make sure they were well matched. I only had a 1ah difference with my 310ah EVE cells which was good enough for me. If one of your cells is mismatched and lower capacity than the rest, then this problem won't go away. The reason I dropped the money on the ZKE tester was because it's a set the stages (charge, wait 10 min, discharge, wait 10 min, recharge) and let it run through a full charge, discharge, then charge again. All at 40 amps. I set it and walked away. The model I have is ZKETech EBC-A40L. It's got a usb port for programing and data logging. I tested all my cells immediately after getting them though it took over two weeks as I did one per day. This way if there was a problem cell I could return it to the supplier.

[@StuartPittaway]

I'll do some research on the ZKE looks good

[@PaulSturbo]

I'm in the same situation. 16s 280ah Lifepo4. 2 or 3 cells high and 2 cells low. Occasional top balancing over the last 6 months has made no difference. Still have usable 9-10 kWh so not too fussed. Interested in what could achieve with an active balancer.

[@StuartPittaway]

I may look at an active balancer. After manual balancing, I'm down to 8mV difference which I'm happy with, but time will tell.

[@gopikrishnayogarajah]

Hi Stuart , can you share details of the DC breaker and shunt trip you are using . Thanks

[@StuartPittaway]

I'm using PROJOY DC breakers - MCB's 80Amp

[@gopikrishnayogarajah]

@@StuartPittaway Thanks ..and the shunt trip ?

[@StuartPittaway]

@@gopikrishnayogarajah I've got a chnt one, although don't recommend, it's broken twice now. See if you can get a matching projoy one. Alternatively look at NOARC brand.

[@ndudman8]

Have you seen solarAssistant, running on a pi interfaces with most of those type of invertors I think. I've been very happy with it.

[@StuartPittaway]

Yes, I need to spend some time looking at that and also home assistant

[@ndudman8]

@@StuartPittaway SolarAssistant is paid, one time, but I'm very happy with it, and it can generate mqtt which can be picked up by homeassistant.

[@Danny-pp8xz]

Stuart is its posible u add a bit of code. That when a certain battery reaches a certain voltage u van control the relais to switch on/off so we van add a actieve balancer Saw this in Andy ofgrid garage review of the bms hè got.

[@StuartPittaway]

This could be done now with the relay rules - either at cell voltage level or at pack voltage level.

[@erikslagter3231]

I have 2 tesla modules and I kept having issues with it. After 2 hours connecting them to equalize, all probems resolved. Batteries are weird beast...lll

[@StuartPittaway]

Thanks for watching