Muller Industries - BMS for Valence U27-12XP

I have zero affiliation with this company but they've been teasing a BMS for the Valence U27-12XP batteries and it's available for presale on their website for those, like me, who are wanting a clean BMS setup for the these batteries.

https://www.mullerindustriesusa.com/product/miusa-bmslv-battery-management-system/

I drove to Racine WI to pick up (4) of the U27-12XP batteries from them. At that time he told me they were coming out with an equalizer. A couple of months later I asked, and no reply. I see now that they have this, along with the $399 BMS from your link.
Please tell me if I am wrong, but I will be using the (4) batteries in series in a temp controlled environment, and with them having their own internal BMS, I am thinking that an equalizer will suffice. (Max of 40A charge rate for the pack, 20A typ.)

I have been eying these batteries for a while... but have a few of questions that the spec sheet does not provide clear answers to.

1) Does the internal BMS require the external BMS to operate?
2) Does the internal BMS have a over-voltage cut-off?
2) What is the self-discharge rate of the pack?

Like you guys, I am wondering how important the external BMS is... If I do 2 of these in series and set my charge voltage to a conservative number, would I be risking problems?

@ FilterGuy,
1) Not in parallel, but if using in series you need a minimum of an equalizer, per the guy that I bought the (4) batteries from.
2) No. A BMS would have relay/contacter outputs to disconnect in this case. What I have done is set the Midnight Solar Classic 150 to .4v below the max input voltage for a buffer, and, longevity. As far a low voltage disconnect, the inverter takes care of that. And, I do not need the high/low temp cutoff.
3) These Valence U27-XP's have the lowest internal resistance that I've seen; 5 mΩ. My U1-12XP and U1-12RT's will drift down after 6~12 months, but these, and the older 130Ah ones I have, stay rock steady.

Just FYI, Valence is now known as Lithiumwerks:
This link will talk about the internal protection they have, and the external BMS.

Be forewarned, unless you buy new from the factory, they have been known to ignore you. Buying a Valence BMS on eBay will leave you high and dry...I have two I'm using as paperweights!

Wow! Lots of good info. Thanks.

Jos. said:

1) Not in parallel, but if using in series you need a minimum of an equalizer, per the guy that I bought the (4) batteries from.

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Do you just treat each pack as a cell and use a 1 S equalizer between them?

Jos. said:

2) No. A BMS would have relay/contacter outputs to disconnect in this case. What I have done is set the Midnight Solar Classic 150 to .4v below the max input voltage for a buffer, and, longevity. As far a low voltage disconnect, the inverter takes care of that. And, I do not need the high/low temp cutoff.

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I can do the same on charge and discharge, but I do need the low temp cut-off. Would I need to manage low temp charge cut-off externally?

Jos. said:

3) These Valence U27-XP's have the lowest internal resistance that I've seen; 5 mΩ. My U1-12XP and U1-12RT's will drift down after 6~12 months, but these, and the older 130Ah ones I have, stay rock steady.

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The reason I am looking at these is that in my application they will sit unused in a mountain cabin over the winter and these are rated at -40C storage. When you say "drift down" does that mean they are totally discharged? When you say "Stay rock steady" does that mean no noticeable discharge? Does the ballencer you use draw much current?

Jos. said:

Buying a Valence BMS on eBay will leave you high and dry...I have two I'm using as paperweights!

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Good to know. Thanks!. Is that because they just don't work or you don't have the documentation needed to set them up?


Have you seen this video?

One more question: Have you been able to find the manual for these? I found it on one of the paid manual-library sites, but I have had really bad luck with those sites (I end up with Mal-ware when I use them).

1) I have not been using an equalizer, just running banks in parallel. That was with the (27) 139Ah black Valence batteries I bought in 2014. They started life in an electric bus, then as an UPS in a printing factory, then I repurposed them. I am looking at equalizers now because I want to run these (4) green 138Ah batteries in series for a project.
2) Low temp has to be done with a temp probe connected to the BMS, which is always external as far as I know. I have seen videos that Will has done on this. You may want to check his Youtube channel.
3) By drift I mean that the 40Ah RT's and XP's will get below 12v. The RT's are only 2c batteries, but have low voltage cut-off. Also, their LED's will go from GREEN to YELLOW during low voltage. The XP's are 3c batteries, but do not have the cut-off.
As for the U27-12XP, I forgot to take one (older, black, 130Ah) out of my RV when I put it in storage last winter. The Genasun GV-10 Lithium MPPT Charge Controller draws a true .12mA max standby, and luckily the roof solar panel was in a dark building, so it did not try to charge. The Polar Vortex hit -27°F, and I was worried. When I was able to pull it out of storage, the battery was just fine, 13.05V! An equalizer draws 5mA, and that would have been a problem. As for leaving them in your cabin, I wouldn't unless you have to. I can't predict degradation, or what hungry rodents might do.
4) You need documentation and software for the Valence BMS to work, and cables. I don't have such. I just joined this site today, but noticed there is someone playing with this...search "Valence".
5) Yes, I met Ben at the Midwest Renewable Energy Association Fair in Custer WI last June. His EV truck caught my eye with all that beautiful green in the bed...same number of Valences that I bought 5 years ago. It was through him that I got connected with Muller Industries.

So, that is all I know. I think all your answers may be on this site.

Here is a website that has the xp12 manual, diag software and pinout to build a usb com link. Have fun!

FilterGuy said:

One more question: Have you been able to find the manual for these? I found it on one of the paid manual-library sites, but I have had really bad luck with those sites (I end up with Mal-ware when I use them).

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I'm currently working on an open source BMS that communicates with the board that's in the back of the XP batteries. I just got the data link between the battery and the BMS working today, so I expect to be making quick progress in the next few weeks. Here's a link to the thread: https://diysolarforum.com/threads/interfacing-with-valence-built-in-monitoring.2183/

t3chN0Mad said:

I'm currently working on an open source BMS that communicates with the board that's in the back of the XP batteries. I just got the data link between the battery and the BMS working today, so I expect to be making quick progress in the next few weeks. Here's a link to the thread: https://diysolarforum.com/threads/interfacing-with-valence-built-in-monitoring.2183/

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how are you progressing for comparison have you seen the muller industries bms and would you recommend it?

here is a link to the manual for the batteries.

benhenkel said:

how are you progressing for comparison have you seen the muller industries bms and would you recommend it?

here is a link to the manual for the batteries.

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You can check out the code repo at https://github.com/t3chN0Mad/OpenXPBMS

I haven't made a lot of progress since January, but I have plans to get back to work on it. Several others have also forked the repo and built upon it as well.

I have not had any experience with the muller industries bms; it costs more than what I paid for the battery, so it wasn't really an option for my use case.

Good morning all. I am new to the forum. I'm French and you're reading a Google translation. I have 20 U27 12XP batteries and the BMS LV. I would like to read all the batteries at the same time. I have the software to communicate with the bms. I need help because it doesn't work.

Nespadonc said:

Good morning all. I am new to the forum. I'm French and you're reading a Google translation. I have 20 U27 12XP batteries and the BMS LV. I would like to read all the batteries at the same time. I have the software to communicate with the bms. I need help because it doesn't work.

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Can you share the software with me? sSandersTravis@gmail.com I have a Tesla inverter requiring about 30 of these u27 batteries in series. I have the laptop software for communicating directly to the battery functioning properly but I don't have any software to communicate with the BMS.

t3chN0Mad said:

You can check out the code repo at https://github.com/t3chN0Mad/OpenXPBMS

I haven't made a lot of progress since January, but I have plans to get back to work on it. Several others have also forked the repo and built upon it as well.

I have not had any experience with the muller industries bms; it costs more than what I paid for the battery, so it wasn't really an option for my use case.

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Travis said:

Can you share the software with me? sSandersTravis@gmail.com I have a Tesla inverter requiring about 30 of these u27 batteries in series. I have the laptop software for communicating directly to the battery functioning properly but I don't have any software to communicate with the BMS.

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I sent the software. Tell me if you get a result.

Nespadonc said:

I sent the software. Tell me if you get a result.

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Can I get the software too. Let’s see how it goes. Gasolinenet@yahoo.com

I sent the software. Tell me if you get a result.

Nespadonc said:

I sent the software. Tell me if you get a result.

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Please can U send me the software.. thanks

Give an email address for sharing.

FYI, new product on market, a BMS for the Valence U27-12XP batteries Much less cost that Valence (hard to find) units, can program yourself easily. Tradeoffs, less overall features, but will probably handle 80% of users out there. https://www.thunderstruck-ev.com/valence-battery-bms.html

adambant said:

FYI, new product on market, a BMS for the Valence U27-12XP batteries Much less cost that Valence (hard to find) units, can program yourself easily. Tradeoffs, less overall features, but will probably handle 80% of users out there. https://www.thunderstruck-ev.com/valence-battery-bms.html

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Many thanks for sharing this information.
I have a few questions for you.
Please contact me at : mongrenier@msn.com

Hi,Here a gauge designed on arduino and nextion to display the SoC battery given by the U bms Valence in pin 2 connector 3.

adambant said:

FYI, new product on market, a BMS for the Valence U27-12XP batteries Much less cost that Valence (hard to find) units, can program yourself easily. Tradeoffs, less overall features, but will probably handle 80% of users out there. https://www.thunderstruck-ev.com/valence-battery-bms.html

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I gave them a call today and found out some details. This BMS is good for some minor things but the problem for anyone looking to put modules in series is that this bms will not command the modules 12V resistors to activate in order to keep series modules in balance with each other. It will open up communication to the batteries which will enable the batteries to balance their internal cell blocks to other internal cell blocks within the same module. And it will also control separate relays to disconnect the battery from the charger or from the load based on cell voltage for high voltage and low voltage protection. For a system with any modules in series this will end up causing imbalances and more and more voltage out of tolerance disconnects over time unless you also get an additional aftermarket module to module balancer. So this BMS will do good for anyone who gets an additional aftermarket module 2 module balencer and has 4 modules in series parallel at 24 volts or anyone who has four modules in series for a 48 volt system. If you have eight batteries (12v modules) or more it would be cost-effective to invest in the Mueller industries BMS.
That being said you should know that this BMS is literally fresh on the market and still has room for improvement. They are currently working on adding a can bus communication in addition to the rs-485 connector it's already utilizing to communicate to the batteries. I would not rule out an upgrade in the future enabling module to module balancing because that is absolutely vital for them to sell these in large numbers.

Nespadonc said:

I sent the software. Tell me if you get a result.

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I used the software you gave me to communicate to the BMS through a generic brand rs-485 USB adapter. I am able to read the values of the BMS. It appears I am able to flash the BMS with a different configuration but I have not tried it yet.
So far I am not able to communicate to the BMS using the can bus with the software. It appears that the reason I am not able to communicate through the can bus is because I am using a com Port USB adapter that is not a valance brand hardware.

Seen this? BMS master for U27-12XP
https://www.thunderstruck-ev.com/valence-battery-bms.html