10kWh LifePO4 DIY Battery Addition..... Here is my write up.

insular1 · 27-09-2023 10:30AM

Waiting for bits I have ordered to arrive and doing up diagrams and plans so I have everything clear in my head. Does this look ok for the wiring from battery to BMS to inverter?

Battery to Inverter JKBMS.jpg

gtsolar · 03-10-2023 01:26AM

Hello to everyone

I got a solis 6k hybrid with 16S DIY lifepo4 batteries and I am looking for a BMS

options so far:

JK BMS with 2A active balancer is the one that I like but how to run it with Solis? Can someone help with the esp-32 setup ?
Daly BMS i read that daly can provide firmware update and can support solis? to good to be true , what do you think? or to use ESP-32?
Seplos V3 OR V2 BMS that sounds plug and play with solis but no active balancer and I read always problems.

Any help will be apriciated 😀

insular1 · 03-10-2023 07:49AM

I think it was @unkel selling a rectifier a while back in the for sale thread. Got me thinking about maxing out the night rate charging if I change to a smart rate with short night rate window. Would there be any safety issues with hooking up a few thousand watt rectifier to the battery via a smart plug and just automate it to turn on at the start of the cheap night rate and off at the end? I assume once battery reaches the voltage of the rectifier (58v?) it can't push any more power into the battery? Is there a possibility of overcharging the battery or ruining a cell that's out of balance?

Was also thinking of using it to speed up top balancing if the cells arrive in a low SOC.

@unkel do you still have that rectifier available?

graememk · 03-10-2023 07:57AM

https://www.boards.ie/discussion/comment/121187606#Comment_121187606

Smart plug could be a bit wimpy, I'd be looking for a 20 amp one or similar.

If the socket and plug are good it should handle the 3kw fine.

The BMS will be able to cut the power incase of cell overvoltage, there is protection there.

munsterfan2 · 03-10-2023 09:32AM

https://www.boards.ie/discussion/comment/121187631#Comment_121187631

That's interesting, my solis will only charge at 3kw/h and with 3 hours @ 9c but the battery would take 14kw from 15% to 100%. Must have a look

unkel · 03-10-2023 09:54AM

https://www.boards.ie/discussion/comment/121187606#Comment_121187606

Yes still have it, PM me if interested. I have no use for it anymore as my battery is now 15S, so would be fully charged at 54.75V rather than 58.4V

unkel · 03-10-2023 10:11AM

https://www.boards.ie/discussion/comment/121187631#Comment_121187631

Yes. Crucial of course here is to connect the rectifier to the BMS, not directly to the battery terminals themselves!

graememk · 03-10-2023 10:17AM

https://www.boards.ie/discussion/comment/121188064#Comment_121188064

Yes, I'd also fuse it too.

Something like this

https://mpe-online.ie/shop/cables-distribution/busbar-to-connect-5-cip100200100-500-a/ could work nicely

Even a storage inverter would work if you could control it manually

unkel · 03-10-2023 10:20AM

Yes, fuse everything that connects to the battery. In the case of a JK BMS, you connect inverter or rectifier negative to the BMS and positive directly onto the battery positive (with fuse in between)

insular1 · 03-10-2023 10:27AM

If you see my diagram a few posts up, could positive be connected to the fuse holder and negative to the busbar to use the existing fuses or would be safer with its own fuse?

ddonq1412 · 03-10-2023 11:00AM

After reading last week JK BMS has a new version that has can support. Seplos v3 has an active that can be added to it. Its very new to market i have setup a few seplos v2 bms and ran into teething problems. after a few weeks it seem flawless. Seplos have a box to store all in that is nice looking. Dont know anything really about the daly bms.

graememk · 03-10-2023 12:35PM

https://www.boards.ie/discussion/comment/121188143#Comment_121188143

Yeah you can connect it as if it was another battery, quick doodle.

on_the_roots · 03-10-2023 02:06PM

I'm also interested in the Seplos Mason 280L DIY Kit but this is not clear to me which model of the BMS comes with that. From the assembly videos this is apparently the Type-B (separate board for comms and LEDs) but I'm not sure.

gtsolar · 03-10-2023 07:46PM

If you buy 2 seplos Mason kits = the value of 16S 280A batterry. So 15kw of extra battery or a good looking box?

I go for the 15kw battery.

Also is not working with Solis so good bye seplos. also you get passive balancer bms worthless that eats you the battery. Sorry no.

So how can we make JK-BMS work with Solis through an esp-32? any guide step by step?

ddonq1412 · 03-10-2023 09:20PM

Has anyone got capacity tester I could buy or borrow a few days. Before I do the china route

ddonq1412 · 03-10-2023 09:51PM

Seplos mason boxes that come from seplos directly will be V3 BMS everyone else will be v2.

poker--addict · 03-10-2023 10:05PM

https://www.boards.ie/discussion/comment/121187903#Comment_121187903

Mine was topping out at 2.2kw per hour but between solis doing an update remotely and messing with settings I eventually got it pumping power in a lot faster. Will check rate of charge tomorrow but fairly sure it's faster than 3, possibly 4.

gtsolar · 04-10-2023 12:14AM

https://www.boards.ie/discussion/comment/121191555#Comment_121191555

Yes and the price of V3 is $150 extra and still have old technology with passive balancing burning your batteries energy.

Worthless.

Big Lar · 04-10-2023 06:19AM

You can add the JK BMS as a lead acid battery and just monitor it with home assistant which I am currently doing at the minute https://github.com/fl4p/batmon-ha

Or use this project https://github.com/Uksa007/esphome-jk-bms-can so that you can use can bus to emulate a battery, its on my agenda to do this and I have all the bits and bobs but not a priority at the moment as the lead acid battery works.

on_the_roots · 04-10-2023 08:59AM

https://www.boards.ie/discussion/comment/121190757#Comment_121190757

Let me know where you can get 16x 280Ah battery cells delivered to your door in Ireland for about €1.4k, I'm very interested :D

Solis inverters do work with Seplos BMS. Just need to set battery type AoBo on inverter and CAN to Sofar in the BMS.

The Mason kits are the way to go for those without an attic space and the batteries will have to be installed in a visible place (utility room or so).

https://www.boards.ie/discussion/comment/121191790#Comment_121191790

Seplos released a new firmware that does active balancing on V3.

However I totally agree that this is just too much workaround for something that should work straightaway. Solis is probably the most popular inverter brand on the global market and Seplos is still crawling on compatibility and basic features like the actual balancing (the update above was released just a few days ago).

on_the_roots · 04-10-2023 10:19AM

Is ~5m of AWG4 cable length ok between the Inverter and battery pack? (current can reach up to 100A).

How much would be the drop in voltage?

gtsolar · 04-10-2023 11:02AM

https://www.boards.ie/discussion/comment/121192352#Comment_121192352

Alibaba you can get 16S 280A FOR $1500 delivered. not so hard so if i pay for 2 seplos empty boxes i better buy 16s battery instead.

Selpos release the new firmwork v3 but it doesn't change your hardware so it is still doing passive balancing. google to see the difference between active and passive balancing of the BMS.

Daly said that their new BMS Home storage has 1A active balancer and can work with CANBUS Pylontech's so does this means will work with Solis ?

Thank you

irishchris · 04-10-2023 11:06AM

Why not just add a neey balancer to your setup. 4a active balancer for a very reasonable price and will work independent of your bms and at a higher balancing amperage than most bms with balancers

https://www.boards.ie/discussion/comment/121192833#Comment_121192833

unkel · 04-10-2023 11:06AM

https://www.boards.ie/discussion/comment/121192674#Comment_121192674

No! Cable between inverter and battery should be as short as possible, try get it under 2m

on_the_roots · 04-10-2023 11:24AM

https://www.boards.ie/discussion/comment/121192857#Comment_121192857

My inverter is in the utility room and I just don't want to allocate even more space for a battery there =/

unkel · 04-10-2023 11:32AM

https://www.boards.ie/discussion/comment/121192931#Comment_121192931

Well if needs must...But you will suffer significant heat losses. That said, heat losses in winter isn't the end of the world as long as they happen in a heated part of your house.

on_the_roots · 04-10-2023 11:44AM

https://www.boards.ie/discussion/comment/121192965#Comment_121192965

Maybe not that bad though, due to the stupid limitation of 15min on the Solis inverter @100A

on_the_roots · 04-10-2023 11:45AM

Speaking of which, does anyone know what happens if I set the max current to say 90A? Is it going to derate to ~70A after 15min anyways?

unkel · 04-10-2023 01:23PM

https://www.boards.ie/discussion/comment/121193006#Comment_121193006

From what I've seen from other users, yeah, goes back to about 60A after 15 minutes but for some people it's a bit better, depending on the (custom) firmware if you have logged the issue with Solis. Personally I would demand either a warranty replacement of an inverter that can output 100A continuous as per the spec, or a full refund.

graememk · 04-10-2023 02:54PM

https://www.boards.ie/discussion/comment/121193560#Comment_121193560

More Like 70ish amps it drops to (bms says 68!)

10kWh LifePO4 DIY Battery Addition..... Here is my write up.

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