I'm going to change MBMS to BBMS. What I'm really describing is a bank BMS that allows you to easily and effectively make use of a variety of drop-in solutions, each having their own BMS.
We paid less than $2 usd/ 12v ah
Matched and batched EVE 280ah 3.5v cells X 24 (8 makes a 24v @ 280ah batt)
A 200amp 24v JBD BMS and a 200 amp MRBF for each
Made 3 x totally independent batteries and, the boat will run on one - for the first few days we did just that as proof of concept
$3650 USD and that included delivery to the door China to Oz
Some assembly required
With a BBMS that's dead easy. Switch the battery offline and dial the BBMS down a bit. No rush to address.Right. I think most people do charge to full capacity regularly, so hopefully internal balancing works as designed.
In a parallel bank having an individual battery cut out in boundary cases - very low or very high SoC - may not be a problem as much as a cue that the battery is out of balance. Maybe you try to fix by cycling the battery a few times on the bench.
Mmm. Depends on scale. I have 3 300 ah drop ins, each with 200a BMS.Rather than a BBMS + drop ins, why not raw cells + BMS as Simi has done? I did the same at home and it's certainly the cheapest route. Plus you get full functionality.
Yeah, some of the instructions didn't translate well to Chinglish.Can you explain how the BMS hooks up? I can't make heads or tails of the description on Alibaba.
Rather than a BBMS + drop ins, why not raw cells + BMS as Simi has done? I did the same at home and it's certainly the cheapest route. Plus you get full functionality.
I guess I should share this to help with my perspective. The number 1 reason I am resistant to building my own battery + BMS is actually due to appearance. And no I dont mean appearance as in I think its ugly, but appearance susceptible to bias from a potential surveyor or Insurance company or possible future buyer.
I. There is an entire lagging subgroup right now of lithium haters and old school curmudgeons that spit venom at anything lithium as well as other groups that are very fearful of anything with the word lithium. We have all seen this in action and its very persistent.
I think the old adage "If you are explaining you are losing" when dealing with Insurance, Surveyors and potential buyers could be problematic.
.
But if a surveyor has to sign off on a homemade battery
Some people have no idea.
They need to do some research and try and keep up with the world or stop doing what they are doing
8 LFP cells joined by busbars and a BMS to monitor is as much a homemade battery as the 8 AGM joined with cables and lugs with a Victron battery monitor attached that we used to have
Right. And you're not in the USA, where if it's imperfect it's garbage.SIMI..you are preaching to the choir. But we still have to deal with these people in the mean time.
Sorry I was snarky. I felt like you were butting in. You weren't of course. I was just on a bit of a roll [emoji28]Catch up, man. Go back and start from the beginning.
Maybe you try to fix by cycling the battery a few times on the bench.
My thinking is not entirely original. Now that I think about it, my 2001 Prius and all following had 1.2v Nmh cells bundled into 7.2v modules. The BMS was attached to 14.4v pairs. This on a 230v battery.I have to think that BBMS exists somewhere in the RW.
Yeah, some of the instructions didn't translate well to Chinglish.
This pic from our supplier in China worked well
No words needed
You can see cell 6 gets a lot of wires
All done with 6mm heat shrink eye terminals
I guess I should share this to help with my perspective. The number 1 reason I am resistant to building my own battery + BMS is actually due to appearance. And no I dont mean appearance as in I think its ugly, but appearance susceptible to bias from a potential surveyor or Insurance company or possible future buyer. There is an entire lagging subgroup right now of lithium haters and old school curmudgeons that spit venom at anything lithium as well as other groups that are very fearful of anything with the word lithium. We have all seen this in action and its very persistent.
I think the old adage "If you are explaining you are losing" when dealing with Insurance, Surveyors and potential buyers could be problematic.
We really dont know what insurers will do over the coming years. I personally think they will be more apt to look for a manufactured battery assembly from a reputable manufacturer with all the certs. And then the surveyor sees something like the Epoch batteries and will just move on by.
But if a surveyor has to sign off on a homemade battery with balance wires and comm cables everywhere and then you tell him the BMS is this and that and I got the cells from China and then you just hook it all up and then program that.....
So this is my perspective of the middle ground. I dont want to pay Victron prices and I do want to install it myself. The appearance of a "typical" battery system might be worthwhile in key situations.
MoneybagsI couldn't agree more, and this is a big part of why I paid more for an engineered and manufactured battery system for the boat. For some questions the answer just needs to be a simple "Yes", not an explanation.
That model does up to 24 cellsSo it monitors voltage at each cell, up to 8 of them?
Mid pointAny cell temp monitoring?
Power distribution posts are illustrated.What's the thing in the upper left with big pos and neg cables? I think those are the loads?
.Is the battery disconnect a solid state switch inside the device? On yours, which I think is a different model, I see a contactor
Balancing is observed when the battery is nearing fullDoes it do balancing, and if so, when?
I couldn't agree more, and this is a big part of why I paid more for an engineered and manufactured battery system for the boat. For some questions the answer just needs to be a simple "Yes", not an explanation.