Valence XP Super Thread

[Travis]

Interesting. The diagram for the 4 channel balancer linked by Sycamore showed the midpoints connected, and I've also seen it recommended in other places. Like in this Victron PDF for example:
https://www.victronenergy.com/upload/documents/Wiring-Unlimited-EN.pdf (p21)

I assumed connecting the midpoints would be ok, especially if there is a balancer connected. But I guess any minor difference in cable length and connector resistance could throw the whole thing out. The Valance batteries do have an extremely low internal resistance, which probably makes any cabling differences more significant.

So a balancer channel needed for every battery then. If using 2 of those 4 channel balancers for a 6 battery system, would you parallel 2 of the channels of each balancer?

the victron manual talks about connecting the midpoints on page 21 and 22. Which is exactly the way I had it connected and yes I did have the balancer connected as well. It ended up frying all 40khw of expensive AGM batteries. later I hook up the same configuration with the lithium batteries and measured the current at all points and discovered current moving very disproportionate. As soon as I disconnected the midpoints all strings have the same current. then I studed the diagram here in the victron manual and if you visualize the path of least resistance you can see how it would flow through one battery jump to the midpoint and then shoot down through the other batteries. so it's the resistance of the batteries isn't absolutely exactly the same this will occur. However disconnecting the midpoints causes batteries to work as sets together and if there resistance is different than they will deliver it slightly different current but they won't be disproportionate to each other in the series set.
At the time I was running a 24 volt setup. Eventually one of my AGM's shorted out one of its cells and it's voltage dropped but because it was paralleled to 9 other batteries it brought the voltage of those down with it. The charge controller for the lead acid setup didn't see individual cell voltage so even though half the battery Bank was refusing to rise to the correct voltage it didn't stop bringing the voltage up to the set point. So the voltage went into the other half that wasn't shorted out causing it to go way higher than it was supposed to which caused it to cook and short out as well then I ended up with 11 shorted out batteries and 9 that were severely undercharged followed by extra severely overcharged. It took about two months for it to catch my attention and by the time it did all the batteries were toast.
That was the second huge lead-acid loss that led me to lithium. I really wanted a battery management system that new the voltage of every single cell. Despite popular belief I think this is even vital with lead acid batteries but nobody creates such a system and most of the batteries don't even allow access to the cell. I dreamt of buying single cells for submarines like 2000 amp hour single cell lead acid batteries and putting them all in series and switching to a higher voltage setup that way I would have access to monitor each cell and if one ever shorted out it wouldn't screw with any of the others too badly. and if I had alarms and safety shut-off controls yada yada and eventually I thought you know what they're already doing all this with lithium I need to bite the bullet.

 

[Travis]

So the moral of my story is don't connect the midpoints and get a balancer for each series string. In a 6 battery 24 volt setup This could be accomplished with three of the two channel balancers or one of the 4 channel and one of the two channel combined.
I suppose another option would be to get two of the four channel balancers so they would actually overlap each other a little. that would enable it to more evenly distribute the power from the highest to the lowest but I think any method would work fine. As long as they're balanced to start out with and all your wire length and crimps have exactly the same resistance the lithium's don't require a whole lot of current in order to stay balanced especially compared to the lead batteries.

With the two channel / 24 volt balancer the center white wire goes to the midpoint and doubles as the negative input for One battery & the positive input from the other. as a side note you may want to know that on the 24-volt balancer that has indicator lights when the lights are completely off it's supposedly done balancing but if you measure the current it's actually still moving power from one to the other just at a rather insignificant rate.

 

[Peregrine]

Thanks, soon as I can I will order 2 more
these are a couple photos of it at this point

 

[Travis]

Thanks, soon as I can I will order 2 more
these are a couple photos of it at this point

NICE!!! I love the oversized wire and lugs. I can see by the proper wire routing you've done some reading. That's a serious amount of power stored in one tiny Place awesome!!

 

[Travis]

If you saw the part about the over under difference I don't think it'll matter with only three paralleled strings so you probably don't need to worry about it. It did add up though when I paralleled 50 batteries.

 

[Sycamore]

If you saw the part about the over under difference I don't think it'll matter with only three paralleled strings so you probably don't need to worry about it. It did add up though when I paralleled 50 batteries.

Hi Travis! Got a question: I have a 48 V system I'm setting up with the 20 Valence batteries. I will have 5 banks of 4. If I use 5 of the 48V balancer's, one on each bank shouldn't the fact that the 5 banks are terminating their 48v on a common neg/pos buss bar that the charger and inverter are on that all the banks will balance the 48V with each other?

 

[Travis]

Hi Travis! Got a question: I have a 48 V system I'm setting up with the 20 Valence batteries. I will have 5 banks of 4. If I use 5 of the 48V balancer's, one on each bank shouldn't the fact that the 5 banks are terminating their 48v on a common neg/pos buss bar that the charger and inverter are on that all the banks will balance the 48V with each other?

Yes. Think of it like this you are basically creating five 48 volt batteries. So you would treat each 48 volt string as a single 48 volt battery. If you tie each 48 volt battery together in parallel then of course they'll each be forced to be the same voltage. Naturally you wouldn't want to connect them together unless they were the same voltage and state of charge. Because if one set was low the sets that were full would charge the low set at a dangerously fast speed as soon as you connected them together.
Make sure you put them all in parallel and do a complete top balance and make sure they're completely full and balanced before you separate them into their series strings for the 48 volt setup.

 

[Travis]

Hi Travis! Got a question: I have a 48 V system I'm setting up with the 20 Valence batteries. I will have 5 banks of 4. If I use 5 of the 48V balancer's, one on each bank shouldn't the fact that the 5 banks are terminating their 48v on a common neg/pos buss bar that the charger and inverter are on that all the banks will balance the 48V with each other?

On a side note with that many batteries you should seriously think about having a real valence U-BMS.

 

[Sycamore]

Hi Travis! Got a question: I have a 48 V system I'm setting up with the 20 Valence batteries. I will have 5 banks of 4. If I use 5 of the 48V balancer's, one on each bank shouldn't the fact that the 5 banks are terminating their 48v on a common neg/pos buss bar that the charger and inverter are on that all the banks will balance the 48V with each other?

On a side note with that many batteries you should seriously think about having a real valence U-BMS.

If I could actually find one that worked and had docs for setting up I would. Returned the Muller BMS for lack of support and docs for setup. Curently there is 20 banks of 24V as I haven't switched from the Outback 3524 to the LV5048 yet. All of the banks were the same when hooked up and I charge up to 27.2V daily

 

[Travis]

Hi Travis! Got a question: I have a 48 V system I'm setting up with the 20 Valence batteries. I will have 5 banks of 4. If I use 5 of the 48V balancer's, one on each bank shouldn't the fact that the 5 banks are terminating their 48v on a common neg/pos buss bar that the charger and inverter are on that all the banks will balance the 48V with each other?

If I could actually find one that worked and had docs for setting up I would. Returned the Muller BMS for lack of support and docs for setup. Curently there is 20 banks of 24V as I haven't switched from the Outback 3524 to the LV5048 yet. All of the banks were the same when hooked up and I charge up to 27.2V daily

So does anyone have a Muller unit actually working? You and one other person I know have (had) Muller units. And the other guy hasn't had time to hook it up yet. Like you I think he wants a step by step instruction. It's rather pretty simple if you look at the Muller PDF file it shows you what all the wires are for. You bring up a good point though that people getting BMS's from me might need an email with instructional links like for YouTube videos on how to hook it up.
My units will be plug-and-play though. I've got two different design ideas. The easier to connect idea requires it to be close to the batteries so pretty much you'll only need to pass the battery power through it and it will just simply work. The display will show the state of charge.
The other idea is instead of putting the contactors inside the project box I would give a length of wire connecting the contactor to the project box so the BMS box and the contactors could be a ways apart. And obviously you plug in the battery communication cable to the box as well. So it would be as simple as passing the battery power cable through the contactor and then giving the Box a ground wire from your batteries bank ground.
But then I thought some people do need an external contactor to disconnect the panels so that would have to be a length of wire to go to that contactor.

 

[seb303]

the victron manual talks about connecting the midpoints on page 21 and 22. Which is exactly the way I had it connected and yes I did have the balancer connected as well. It ended up frying all 40khw of expensive AGM batteries. later I hook up the same configuration with the lithium batteries and measured the current at all points and discovered current moving very disproportionate. As soon as I disconnected the midpoints all strings have the same current. then I studed the diagram here in the victron manual and if you visualize the path of least resistance you can see how it would flow through one battery jump to the midpoint and then shoot down through the other batteries. so it's the resistance of the batteries isn't absolutely exactly the same this will occur. However disconnecting the midpoints causes batteries to work as sets together and if there resistance is different than they will deliver it slightly different current but they won't be disproportionate to each other in the series set.
At the time I was running a 24 volt setup. Eventually one of my AGM's shorted out one of its cells and it's voltage dropped but because it was paralleled to 9 other batteries it brought the voltage of those down with it. The charge controller for the lead acid setup didn't see individual cell voltage so even though half the battery Bank was refusing to rise to the correct voltage it didn't stop bringing the voltage up to the set point. So the voltage went into the other half that wasn't shorted out causing it to go way higher than it was supposed to which caused it to cook and short out as well then I ended up with 11 shorted out batteries and 9 that were severely undercharged followed by extra severely overcharged. It took about two months for it to catch my attention and by the time it did all the batteries were toast.

I would have thought that where the current flows has more to do with the battery voltage rather than the internal resistance, and batteries in parallel will naturally keep their voltages in sync (assuming external wiring is balanced). If it works to run batteries in parallel to increase the current, I don't see why these parallel units can't then be put in series with each other. Which is effectively the same as tying the mid-points of series strings.

But perhaps this gets less true for larger setups with very many batteries. Certainly the risk of damaging many batteries because 1 battery goes bad is increased when connecting the midpoints. Although of course monitoring of individual battery (or better individual cell) voltages would mitigate this risk.

I note that the Valence XP manual (p46) does not tie together the midpoints for series/parallel combinations. But then there is no need to because of the way the inter-battery balancing is done with the XPs.

That was the second huge lead-acid loss that led me to lithium. I really wanted a battery management system that new the voltage of every single cell. Despite popular belief I think this is even vital with lead acid batteries but nobody creates such a system and most of the batteries don't even allow access to the cell. I dreamt of buying single cells for submarines like 2000 amp hour single cell lead acid batteries and putting them all in series and switching to a higher voltage setup that way I would have access to monitor each cell and if one ever shorted out it wouldn't screw with any of the others too badly. and if I had alarms and safety shut-off controls yada yada and eventually I thought you know what they're already doing all this with lithium I need to bite the bullet.

Yes, I absolutely agree with you there. Multi-cell batteries without internal monitoring of the cells voltages just don't seem a good idea for large battery banks. In fact that Victron "Wiring Unlimited" PDF says this on p17, suggesting to use 2V batteries for larger lead acid battery banks.

And then of course this naturally leads us to lithium with proper BMS

 

[Travis]

I would have thought that where the current flows has more to do with the battery voltage rather than the internal resistance, and batteries in parallel will naturally keep their voltages in sync (assuming external wiring is balanced). If it works to run batteries in parallel to increase the current, I don't see why these parallel units can't then be put in series with each other. Which is effectively the same as tying the mid-points of series strings.

But perhaps this gets less true for larger setups with very many batteries. Certainly the risk of damaging many batteries because 1 battery goes bad is increased when connecting the midpoints. Although of course monitoring of individual battery (or better individual cell) voltages would mitigate this risk.

I note that the Valence XP manual (p46) does not tie together the midpoints for series/parallel combinations. But then there is no need to because of the way the inter-battery balancing is done with the XPs.



Yes, I absolutely agree with you there. Multi-cell batteries without internal monitoring of the cells voltages just don't seem a good idea for large battery banks. In fact that Victron "Wiring Unlimited" PDF says this on p17, suggesting to use 2V batteries for larger lead acid battery banks.

And then of course this naturally leads us to lithium with proper BMS

you're right about it being voltage dependent. But the resistance determines the voltage under load so batteries with different resistance will pass different amounts of power and if the midpoints are tied 1 battery with a different resistance now affects the entire banks current flow instead of only the one in series with it.

 

[seb303]

Here are some photos of the final build of my Arduino BMS, fitted in the van. I'm quite pleased that I managed to squeeze all the electrics under the front passenger seats: 2x U27-12XP batteries, charge controller, battery protect, fuse box, inverter, RCDs, etc.

The BMS code can be found here, complete with schematic, stripboard layout, etc.

GitHub - seb303/Arduino-XP-BMS: A BMS for Valence XP batteries, designed to run on Arduino or similar hardware.

A BMS for Valence XP batteries, designed to run on Arduino or similar hardware. - seb303/Arduino-XP-BMS

github.com

 

[Sycamore]

So does anyone have a Muller unit actually working? You and one other person I know have (had) Muller units. And the other guy hasn't had time to hook it up yet. Like you I think he wants a step by step instruction. It's rather pretty simple if you look at the Muller PDF file it shows you what all the wires are for. You bring up a good point though that people getting BMS's from me might need an email with instructional links like for YouTube videos on how to hook it up.
My units will be plug-and-play though. I've got two different design ideas. The easier to connect idea requires it to be close to the batteries so pretty much you'll only need to pass the battery power through it and it will just simply work. The display will show the state of charge.
The other idea is instead of putting the contactors inside the project box I would give a length of wire connecting the contactor to the project box so the BMS box and the contactors could be a ways apart. And obviously you plug in the battery communication cable to the box as well. So it would be as simple as passing the battery power cable through the contactor and then giving the Box a ground wire from your batteries bank ground.
But then I thought some people do need an external contactor to disconnect the panels so that would have to be a length of wire to go to that contactor.

Hi Travis
The Muller pdf was ok but not clear enough to be sure I wouldn't toast $8K of batteries like one guy did from what I heard. Your BMS would communicate with EACH battery via their cables and keep it all balanced? My Inverters and chargers are all programmable so not worried about disconnects etc., but I suppose a fail safe contractor from the panels and one to disconnect the power lead from the inverters wouldn't hurt. Thought I saw your phone number earlier?

 

[Travis]

Hi Travis
The Muller pdf was ok but not clear enough to be sure I wouldn't toast $8K of batteries like one guy did from what I heard. Your BMS would communicate with EACH battery via their cables and keep it all balanced? My Inverters and chargers are all programmable so not worried about disconnects etc., but I suppose a fail safe contractor from the panels and one to disconnect the power lead from the inverters wouldn't hurt. Thought I saw your phone number earlier?

I don't know if my numbers in this thread or not but I pm it to you.

 

[wind28k]

Hello Travis
This a great thread thanks for all your work and all the other contributors.
I am trying to connect my laptop to 4 U27 XP batteries. I have read the first 4-5 pages and have done all the windows fixes. I believe my cable set up is good. I am using the adapter recommended wiring checks out. I have even put an O-scope on the end connector and can see the signal. After all this I am getting the com port check message and no batteries found when I search. Has anyone found this problem and a work around?

 

[Travis]

Hello Travis
This a great thread thanks for all your work and all the other contributors.
I am trying to connect my laptop to 4 U27 XP batteries. I have read the first 4-5 pages and have done all the windows fixes. I believe my cable set up is good. I am using the adapter recommended wiring checks out. I have even put an O-scope on the end connector and can see the signal. After all this I am getting the com port check message and no batteries found when I search. Has anyone found this problem and a work around?

Possibly a dot NET framework issue. Check out post 228. https://diysolarforum.com/threads/valence-xp-super-thread.5683/post-129530

 

[wind28k]

Possibly a dot NET framework issue. Check out post 228. https://diysolarforum.com/threads/valence-xp-super-thread.5683/post-129530

Travis thanks for pointing out that post. It did the trick. I had the connector wired with A B straight through just needed to swap the white and green. Working great now. I am sure I will be back to learn more about charging and balancing.

 

[jeremyjeremy]

Got my Thunderstruck BMS set up and plugged it in. I don't have the batteries connected yet aside from the BMS cables. The BMS immediately activate the internal BMS's on both batteries and started balancing. Here's what the cells looked like when I ran the command every 10-15 minutes. Now time to get the Valance software running.

>show cells
showing cells
Module | cell 1 | cell 2 | cell 3 | cell 4
------------------------------------------------
     1 |  3.295 |  3.297 |  3.289 |  3.291
     2 |  3.340 |  3.341 |  3.338 |  3.339

>show cells
showing cells
Module | cell 1 | cell 2 | cell 3 | cell 4
------------------------------------------------
     1 |  3.296 |  3.297 |  3.289 |  3.290
     2 |  3.340 |  3.340 |  3.339 |  3.339

>show cells
showing cells
Module | cell 1 | cell 2 | cell 3 | cell 4
------------------------------------------------
     1 |  3.295 |  3.297 |  3.289 |  3.290
     2 |  3.339 |  3.340 |  3.340 |  3.339

>show cells
showing cells
Module | cell 1 | cell 2 | cell 3 | cell 4
------------------------------------------------
     1 |  3.294 |  3.297 |  3.289 |  3.291
     2 |  3.339 |  3.340 |  3.339 |  3.339

 

[Alexfrood]

Travis thanks for pointing out that post. It did the trick. I had the connector wired with A B straight through just needed to swap the white and green. Working great now. I am sure I will be back to learn more about charging and balancing.

seems this is common issue, some of the RS-485 adapters Pin layout diagram use A+/B- and the Valence diagram uses A-/B+

I had the same issue

HOW TO: USED Valence U27-12XP Lithium batteries. Repair, Communication & Software issues

 

[seb303]

seems this is common issue, some of the RS-485 adapters Pin layout diagram use A+/B- and the Valence diagram uses A-/B+

I had the same issue

HOW TO: USED Valence U27-12XP Lithium batteries. Repair, Communication & Software issues

Technically the RS485 spec is A-/B+ (= logic 1), but common RS485 chips such as the MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 have it the other way round in their datasheets, hence why many adapter boards are labelled the other way round.

 

[Alexfrood]

Technically the RS485 spec is A-/B+ (= logic 1), but common RS485 chips such as the MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487 have it the other way round in their datasheets, hence why many adapter boards are labelled the other way round.

Fair enough, I guess it becomes a common oversight of people ( like me ) reading the A and B and not the plus and minus

 

[Solgato]

Looks like there’s been some cool new developments on here since I last checked in.

Still trying to get settled in to my new place which unfortunately means I have to continue to put off the fabrication of my new solar bimini top for my catamaran. My Valence batteries and Thunderstruck BMS have just been sitting in storage, however I was thinking I might like to at least get the batteries installed so I can use the boat a few times while it is still Summery.

With my current FLA bank, I am running two 12V in series for 24V. The bank is normally charged by two Victron Solar Charger Controllers in parallel with back-up onboard individual 4A NOCO AC chargers installed on each battery.

Since my Solar has been off the boat, I’ve been using the onboard NOCO chargers to keep my FLA bank healthy and topped off.

If I swap out my FLA’s for the pair of Valences I bought, could I use something like NOCO’s Lithium 5A chargers in the same way -one 12V Charger on each individual battery -just until I can get the new top built, the solar reinstalled, and my chargers configured for the Valence Batteries along with the Thunderstruck BMS for balancing and over charge protection?

NOCO states the chargers are to be used with LIPO batteries with onboard BMS’s, I assume to protect the batteries from over charging. However I figure their LiPO “charge mode” is probably set with the typical safe ranges you would find on a low current charger. Provided of course my cells are balanced and I don’t deplete my batteries badly during an outing, I would think this should get me by until I get around to building a more permanent self sustained higher power solar charging system.

 

[Travis]

Looks like there’s been some cool new developments on here since I last checked in.

Still trying to get settled in to my new place which unfortunately means I have to continue to put off the fabrication of my new solar bimini top for my catamaran. My Valence batteries and Thunderstruck BMS have just been sitting in storage, however I was thinking I might like to at least get the batteries installed so I can use the boat a few times while it is still Summery.

With my current FLA bank, I am running two 12V in series for 24V. The bank is normally charged by two Victron Solar Charger Controllers in parallel with back-up onboard individual 4A NOCO AC chargers installed on each battery.

Since my Solar has been off the boat, I’ve been using the onboard NOCO chargers to keep my FLA bank healthy and topped off.

If I swap out my FLA’s for the pair of Valences I bought, could I use something like NOCO’s Lithium 5A chargers in the same way -one 12V Charger on each individual battery -just until I can get the new top built, the solar reinstalled, and my chargers configured for the Valence Batteries along with the Thunderstruck BMS for balancing and over charge protection?

NOCO states the chargers are to be used with LIPO batteries with onboard BMS’s, I assume to protect the batteries from over charging. However I figure their LiPO “charge mode” is probably set with the typical safe ranges you would find on a low current charger. Provided of course my cells are balanced and I don’t deplete my batteries badly during an outing, I would think this should get me by until I get around to building a more permanent self sustained higher power solar charging system.

Yes your assumptions are correct. Did you get your batteries from me? if yes and you're the guy that got his batteries from me for his catamaran in Hawaii then I've already balanced them so you can proceed without worry but you'll want to connect the laptop for cell balancing during charging because if your charger has a lithium iron setting it will get the voltage up high enough to invoke top balancing for a small amount of time before dropping the voltage to float.

 

[floridianman27]

The black circles on the side of the u27-12xp reveal screws. You can remove the side cover and you'll have access to the individual wires going to the cell blocks so you could actually hook up a traditional cell balancer like a Batrium or many other far cheaper than Batrium choices. But if you have more than a few batteries that would be a hell of a lot of wires and I'd recommend getting the actual BMS designed for these.

Photo courtesy of http://cogito44.free.fr/technologie.html#wa-anchor-jrc1z2om1dqjuxl91c

The black circles on the side of the u27-12xp reveal screws. You can remove the side cover and you'll have access to the individual wires going to the cell blocks so you could actually hook up a traditional cell balancer like a Batrium or many other far cheaper than Batrium choices. But if you have more than a few batteries that would be a hell of a lot of wires and I'd recommend getting the actual BMS designed for these.

Photo courtesy of http://cogito44.free.fr/technologie.html#wa-anchor-jrc1z2om1dqjuxl91c

Hey Travis, are you saying i could pop off the side panel to access the cell balancer and add in the OVERKILL BMS to these Valence batteries? or is it best to use the Valence BMS?