Doing preliminary research for a new system. 3x 6.5kV Multiplus and 2x JK BMS based 51,2V 300A 32kWh LiFePo batteries is at the heart of it.
We want a standard safety feature that is pretty much exactly what the Lynx Smart BMS NG does for Victron NG batteries (wish we could afford the NG batteries).
I know there is a workaround with using the older Lynx Smart BMS with 3d party batteries and that might also be an option.
Does anyone know if that is a supported function to bridge the battery coms to silence error messages to use that with 3d party batteries ?
We would probably prefer to have the cutoff per battery if possible and have a relay/contactor safely cut off and isolate an individual battery based on certain typical criteria such as issues in individual cells. Basically if something goes wrong, safely cut individual batteries off and notify. Maybe using Victron battery protectors, isolators or combiners that can handle this?
It would also need to be able to handle this under load with necessary preloading and arc prevention etc. Would be comfortable doing the logic for this in Node Red if needed.
So what is the recommended Victron gear and setup for doing something like this?
Helpful comments appreciated!
Could you elaborate more which safety features do you expect that are not working with JK BMS?
JK BMS have direct communication with GX. There is no need for Lynx BMS.
Check out Andi Offgrid Garage on YouTube for many details.
My stack of 4x PACE BMS handles “protection” a single battery/BMS level and reports to GX.
I can configure alarm and protect levels.
Alarm will notify GX.
Protect closes charge or discharge mosfetts.
If single batteries are in protect, the stack shows e.g. 1/4 batteries blocking charge in GX.
If you are looking für even more advanced pre-emptive features the “battery safety controller” might be an option for you as add-on.
Hello @BjoernK and thank you for your kind reply and the link to the DIY battery controller.
Will need to translate that as my German is not what it should be..
Some clarifications then:
I have been doing solar with Victron for some 10 years or so and am a frequent reader of Andy at The Off-Grid Garage and well aware of that it is not necessary to use anything other than the JK BMS in the batteries but as you know the SOC in the JK BMS and similar is often less than perfect so I definitely want the Victron BMS as a point of truth for SOC. I also want a second layer of security after the batteries if the JK BMS or a battery has a malfunction.
Trusting a 100 dollar BMS with it all does not seem appropriate and prudential to me if it is near humans or animals.
The Lynx Smart BMS can physically disconnect the batteries if needed so that is probably my first intention but have not read about anyone doing this with 3d party batteris. There are also devices like the iBMS and YamBMS that sits before the GX device and can throttle the charging or loads based on certain criteria like battery or BMS malfunction. Finally there are also devices from Victron that can disconnect individual batteries.
I guess I would like to hear from people who have also thought about this and how they have solved any additional security layers when you are not using Victron batteris that of course have some of this functionality already,
At least these alternatives:
Using a Lynx Smart BMS with 3d party batteries to disconnect via Node Red and certain criteria. Probably not supported by Victron but can be done.
Using Victron battery protect, isolators or combiners to be able to disconnect or isolate each battery based on Node Red or settings in the Victron devices
Using an BSC, iBMS or YamBMS to throttle at least the charge if needed.
Possible combinations of the above
other options?
This is partly a technical but also a security philosophy question and any helpful comments are appreciated.
@houser
I assume the Lynx Smart BMS (NG) works only with Victron LFP Batteries (NG).
This post states the same I read out of manuals:
A 3rd party solution would be the Battery Safety Controller which can use a Victron Smart Shunt to improve SOC calculation while using JK’s data like single cell voltages and temperature to manipulate CCL, CVL, DCL to throttle charge/discharge and an external relais to cut power.
I appreciate the tip about the BSC. It seems very interesting and may do what we want. Are you using one if I may ask?
The Lynx Smart BMS NG can not be used with third party batteries but the older Lynx Smart BMS for the older smart batteries can be used with a workaround according to some users. It gives you some advantages with precharge and the contactor.
OGPS
(Ed @ Off-Grid Power Systems - offgridps.com)
6
With all due respect, why not buy a more trustworthy battery in the first place? I don’t know where you are in the world, but check out Pytes. They have a V16 model that sounds like it would fit your need, is supported by both Victron and Pytes (see here: Battery Compatibility [Victron Energy]), and is very reliable from our experience. I understand wanting to save money, but you really do get what you pay for. The BMS is the single most important component in any battery yet is the first thing people want to scrimp on.
If you want to use the JK BMS, consider adding an iBMS with the SmartShunt add-on kit. This will solve your concern with inaccurate SoC readings on the JK.
But, with the time and money spent to make up for the deficiencies in the JK BMS, maybe just buy something better in the first place? There are other batteries on the 3rd party list you can look at, too.
Good luck!
1 Like
OGPS
(Ed @ Off-Grid Power Systems - offgridps.com)
7
It does, and we have used them to cover up deficiencies in other “budget” BMS’s. But, at nearly $1,000USD…..see my comment above
Pytes seem nice but proprietary and looks overpriced to me and you probably know you can get the best LiFePo cells for really decent pricing these days. It is all Chinese cells in all those batteries anyway and you get more than three times the storage with equal quality cells. And yes, we are looking at iBMS, as mentioned earlier in th thread for the reasons you mention. The potential weakness in any battery is often the BMS so that is what I am looking for advice on here,
..and to answer your second post, We will 100% want a Victron shunt or BMS regardless so the added cost from the simpler shunt to the Lynx Smart BMS seems reasonable to also get some added security with the precharge and the contactor. Do you happen o know if you can access the contactor via the Victron nodes in Node Red?
I guess I am in the semi-DIY camp, trusting Victron with all the important stuff but unable to afford their batteries, so getting the best LifePo cells in a more affordable casing,
Thanks for the pictures and the BSC tip. It looks interesting. Is it in production? Do you have link for pricing somewhere?
OGPS
(Ed @ Off-Grid Power Systems - offgridps.com)
11
Yes, the Pytes BMS is proprietary. It’s also higher quality. Let me know when you get the code to the JK BMS firmware and can submit patches yourself . It’s also proprietary and problematic, which is why the iBMS exists. Don’t get me wrong, I have several batteries in the shop that I have built over the years, with the most recent ones using the JK PB series of BMS’s. I’m well aware of the good and bad. I did the math on making new ones and then supplimenting them with additional doo-dads to make them more reliable and decided it wasn’t worth the cost. BUT, that’s because I’m super busy and don’t have time to tinker as much as I’d like these days. Sometimes, plug–n-play is very worth it.
That said, if you have the time and can handle a little downtime on the system then the up front savings could very well be worth it in the end!
You seem to have been around the block with all this. Me too, but only off-grid until now.
It will be fun if it works, and I am hoping for a few months of tinkering and then silent running,
One can dream
Not expecting to modify the code for the JK BMS. I am expecting to replace it with something better when/if needed as the price is what it is.
Yes plug and play is worth it, if there is such a thing, ever. Not sure there is
Would have bought the NG batteries for that very reason if we could afford it.
OGPS
(Ed @ Off-Grid Power Systems - offgridps.com)
13
That’s one way to describe me being an old man. lol But yes, I have built my own batteries long before I ever purchased commercial LFP batteries. That was before something like the JK BMS with CANbus was available and there weren’t all these Chinese battery boxes with JK PB BMS’s available like we have now. There is absolutely nothing wrong with homebrew batteries so long as your expectations align with reality. The number one cause of stress is misaligned expectations. That’s true for interpersonal relationships (i.e. marriage) and DIY batteries
In my opinion, if you end up with four, six, or more JK BMS’s then it’s probably worth the DIY and additions such as the iBMS w/ SmartShunt. But for two batteries? Meh, that comes down to a time vs money question and differs for everyone.
Old-ish man here too
My expectations are reasonable in my own opinion.
A first version of this system should be up and running in about two months, so I will try to post back somehow, but they “kill” the threads here after some time of silence so we shall see how that goes.
And the combo of Lynx Smart BMS and iBMS or similar might be within our means as it stands, unless new info emerges..
@houser
Another high quality alternative is Batrium:
Check out Jens Rehpoehler “Meine Energiewende” on YouTube. He personally uses a combination of all BMS mentioned in this thread with appr 240kWh a Frankenstein stack of batteries and provide experience on his channel.
He is a consultant and installer for Victron and also offers DIY battery build workshops.
In addition pls find a link to Jens’s channel with a videos about 128kWh GobelPower batteries. I have 4 of them.
Will study the Batrium link, looks good!
Yes, we have looked at NKON. Very reasonable indeed. At the moment we are also looking at various Chinese brands with premium cells and JK BMS like Yixiang and the like. Pricing is hard to beat, but we shall see, but the whole venture becomes rather pointless without enough kWh…
, I’m indeed using the translation methods you mention much of the time..
Based in Scandinavia ATM.
Gobel is one of the Chinese brands we are looking at, similar to Yixiang, who does 32kWh Eve MB56 16S packs at very decent prices..
