Many thanks for sharing this information.
I have a few questions for you.
Please contact me at : mongrenier@msn.com
Muller Industries - BMS for Valence U27-12XP
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I have a few questions for you.
Please contact me at : mongrenier@msn.com
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.
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.
bostonbuzz
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- Jan 13, 2020
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Seen this? BMS master for U27-12XP
https://www.thunderstruck-ev.com/valence-battery-bms.html
https://www.thunderstruck-ev.com/valence-battery-bms.html
Yes if you go back just a little bit you'll see I spoke in depth about it
Perrybuilds
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- Sep 30, 2019
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Thanks for sharing. I contacted them a couple weeks ago when I found the unit and requested some info. They seemed helpful and I ordered it.
Luckily I'm running my valence in parallel (12v) so I think I'll be okay... I wanted the muller unit, but not at that price point.
I'm hoping I can successfully use it with my victron hardware using the inputs for disconnect.
Here is a new version of the Arduino code which corrects visual discomfort of the gauge on the nextion screen.
Does anyone here know a way to activate multiple valence batteries simultaneously and without using an external BMS.
I'm looking for myself too. The first who finds does not gain the right to share. Have a good day .
Does anyone here know a way to activate multiple valence batteries simultaneously and without using an external BMS.
I'm looking for myself too. The first who finds does not gain the right to share. Have a good day .
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Yea I had a long talk with them too and discovered all the points you outlined above. They didn't sound like they were going to add the inter module balancing feature anytime soon, but on my follow-up call a day or so ago they told me they were adding more features to the BMS software. Since the inter module balancing is very important and it seems others might be requesting it, lets see what develops. I do like the fact it keeps the batteries internal BMS systems active which does the intra cell balancing. This at least lets me have my small setup keep the batteries internally balanced without having to have a PC permanently connected running the Valence diag software to accomplish this. Since I am only running at this time a 2 battery system, an inexpensive external battery balancer will keep the batteries balanced until Thunderstruck adds the inter module balancing feature.
cheezemanrich
New Member
The 12V resistors are not needed because when the batteries are connected in series the 4 internal balancing resistors will automatically engage on each cell. If all 4 cells are high, all 4 balancer resistors will be active. This is the same as in the Valence BMS control system.
Richard
you are incorrect. I tested with a thermal imaging camera. I activated the cell balancing board by the required communication with something and 5 volts supplied to the batteries internal board from external power supply. I pushed the cells over 4 volts each. As long as they remain balanced the resistors did not heat up. Unless thier balancer unit is somehow controlling the activation of the cell block resistor you shouldn't put them in series. It seems like it would be smart to use the cell block resistors in this way as well but valence does not have it programed that way. and honestly when I'm using the correct resistors for the job they have a hard time keeping up as it is. I would hate to rely on the cell block balancers which are actually smaller and in lesser numbers.
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cheezemanrich
New Member
There must be some differences in our setups or batteries/BMS firmware. I have 4x U27-12XP in series (48V system). As long as I treat my batteries well by not putting in or pulling out a huge amount of current (within specs) they stay very well balanced. The balancer internal to my batteries is always active, even without an external 5v. I verified this by opening the case and measuring the cells when nearing full charge when I didn't have the Valence SW yet. With the Valence SW, I can also see the balancing working properly. The only time I see a possible issue is when I over discharge the batteries which I don't do any more. I don't discharge below 20% as at about 15% the cells start to unbalance and at about 8% they get pretty far out of whack. I also set my charge controller to 55.6 and disable temp compensation. This keeps things in check and gets me to about 95% state of charge. My charge rate is only about 9A max on a really good day so this could also be a factor as it's a very low rate. Been running like this for about a year now without any problems.
Sounds like you need to do more testing to prove to yourself what's happening. Try these tests and let us know the results.
It's possible yours are working well because there already balanced well.
Checking cell voltage with a multimeter while having no laptop hooked up is the only way to see the voltage untampered. as soon as you hook up the laptop it activates the balancing board which only balances cell blocks between each other. With laptop not connected & while manually checking all cell voltages to make sure none go over 3.8 remove the side covers and try 58.4v. You'll want to do this in stages in starting from the voltage you have previously set and increasing by 0.3v at a time. With your finger monitor the tiny groups of resistors on the top left and bottom left of the board. If you don't feel any warmth and your voltage starts separating by more than .05 volts between cells You're not balancing.
Resistors on the top left are for cells. Resistors on the bottom left are for the entire battery.
Then do the experiments again with the laptop connected and you'll notice the higher voltage cells will cause the resistors to get warm. Slowly and safely raise the voltage to 13.9v per battery & then hold it there for quite a while while the resistor stay warm and I mean quite a while like as in days. Then raise the voltage to 14.1 volts (or up to 14.8v) per battery and hold it there until the resistors become cold this may take as much as 200 hours. And I mean actual hours don't count the night times when the solar is off. I have to warn you though with 4 in series you're going to realize that you're not series balancing and you'll end up noticing you are severely limited by the fullest battery and you won't be able to raise all the batteries high enough to complete the 200 hour balance. You need a proper u-BMS or 4 channel 12 volt battery balancer like I posted in one of the first three posts. Continuing like you are you're having a battery drift. The reason some of my batteries took 200 hours to balance is because they were allowed to go out of balance for many years. Now that I've balanced them I find them staying in balance much easier.
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I'm just getting started with solar and learning what I can so excuse the simple question. I have one of these U27-12xp batteries on my travel trailer being fed by a 100W panel (which I plan to expand).
The question is, am I OK using this single battery without the external BMS? What if I add a 2nd parallel? If I'm not, would that Thunderstruck BMS be sufficient for my needs?
Thank you for your advice.
The question is, am I OK using this single battery without the external BMS? What if I add a 2nd parallel? If I'm not, would that Thunderstruck BMS be sufficient for my needs?
Thank you for your advice.
Thank you! I do have a 30A charge controller. There also is a 1000W inverter. But I get what you're saying about the DC connected stuff. I've already camped 3 days without exhausting the battery (went down to 12.7V) and that was on cloudy days. I've also obtained a 2000w propane generator just in case solar doesn't give me enough recharge and plan to increase panels to 300W. Goal is to be able to dry camp for 5 days. Plan was to hit lots of music fests this year. F Covid... So this year it's more state parks instead and time to work out my energy system!
Heads up the propane refrigerator in my RV was computer controlled & the computer system took more power than a standard electric household refrigerator. I'd recommend putting a meter on everything so you know how much each thing takes so you can make the correct decisions for your system. I'd recommend 350 to 450 watts of panels per each U27-12XP.
