Valence XP Super Thread

Nainoa said:

Hi all, so I've bought the Thunderstruck VC1 and am going to be connecting it to two contactors to control high/low voltage cut off. I'm wondering if anyone has any ideas how to connect them in such a way as to not have them burn out the solar charge controller if the VC1 decides to disconnect them in full sun. I'll be charging using solar, the alternator from my van, and off of shore power.

Thanks!

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I'm wondering the same thing!

nrsmith83 said:

Yes, I have looked at it very closely. I have spoken with Thunderstruck as well. They wanted me to have the relay cut off connected at the controller positive outlet. This would fry my DCC50S when the relay opens the circuit because the panel and alternator would be disconnected from the battery. I am at a loss on how to make this thing work without such damage. I'm curious how others have done it.

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Why don't you just put the relay between the solar panels and the charge controller?

Your controller is lacking a remote switch...Switching off the panel will still let the alternator to take over charging. An option maybe is to simulate an overvoltage through the battery voltage sensor or an overtemp through the temperature sensor.
Then also, this relay should be a safety device. So it should be triggered only to protect batteries. So maybe it is safer to switch off battery and potentially damage the controller just to protect batteries. If settings are properly applied, there is no reason for this relay to disconnet under load.

nrsmith83 said:

Yes, I have looked at it very closely. I have spoken with Thunderstruck as well. They wanted me to have the relay cut off connected at the controller positive outlet. This would fry my DCC50S when the relay opens the circuit because the panel and alternator would be disconnected from the battery. I am at a loss on how to make this thing work without such damage. I'm curious how others have done it.

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Use two contactors -- one on each input -- that way when/if the circuit opens at high voltage it just disconnects the alternator and panels from your DCC50S.

Are you sure the DCC50S would get fried if you removed the battery? I'm pretty sure if you don't have a battery connected -- the charger turns off. Sure -- there might be damage if it happens instantaneously while it is trying to push 50A -- but I doubt it.

Anyways -- a third contactor on eBay is like $50 bucks -- just get one and be done with it.

Hi All,

Thanks for your feedback and ideas. I spent over an hour on the phone with Renogy yesterday. As WinnieVan noted, the alternator and solar panel charging capability of the DCC50S complicates things. The good news is that Renogy was able to confirm (hopefully correctly) that if the relay does disconnect the battery, the DCC50S will not be damaged. Thus, I can take the more simplified approach of disconnecting at the positive outlet of the DCC50S instead of the positive side of the panels and alternator.

I just noticed that my relay was damaged in shipment so I need to order a new one then give this all a go!

If possible, I would use 2 relays:
-one to disconnect charging on cell high voltage, more likely to happen at low charging current because end of charge
-one to disconnect load on cell low voltage, which will keep charging ability to restore asap battery capacity...

I just look at the VC1 manuel and it is how they advise to wire it...

ericgrand said:

If possible, I would use 2 relays:
-one to disconnect charging on cell high voltage, more likely to happen at low charging current because end of charge
-one to disconnect load on cell low voltage, which will keep charging ability to restore asap battery capacity...

I just look at the VC1 manuel and it is how they advise to wire it...

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I was racking my brain around this for a while when using the valence BMS. It controls 4 contactors but it's designed for electric vehicles that won't allow the Drive unit to be engaged (discharge)while the charger is plugged in. realizing though that this doesn't matter because the inverter will never take the battery down low enough to cause a cell to go under voltage with a balanced battery. also the charger will never bring the battery high enough for a single cell to go over voltage in a balanced battery.

Simple solution is to only use one of its contactor outputs and connect both relays to it. I know it's not perfectly ideal because then it won't allow the batteries to charge after a low voltage disconnect situation. it will require manual intervention like you'll have to be there to reboot the unit to get it charging again. But since this should never actually happen that is fine with me. It is good that it would force the user's attention because something is actually wrong at that point. If it gets disconnected something is definitely wrong. And the user should figure out which setting caused the disconnect and change the settings to avoid that condition.

With thunderstruck you should be able to use both contactors, charge and discharge simultaneously. but I don't know if it has independent controls of those contactors to disconnect only the discharger in a low voltage condition and only the charger in a high-voltage condition. Has anybody here actually simulated this in real life to see if it works? And if it does I would hope that it would have an audible alarm like the Valence bms does and I would hope it wouldn't stop ringing until it got your attention because at that point something is WRONG!

Well, after a lot of laboring over how to best integrate the Valence batteries into my solar electric catamaran, I decided to go a different route.

Unfortunately the need for an external BMS, balancer, and relays was complicating the system I worked so hard to keep streamlined and simple. But the real deal killer was that my 24V bank is split between each of my hulls without any way to keep the interconnections between the two well protected from the elements.

In the end, I decided to have some batteries custom configured for me from a manufacturer in China. The replacement batteries while not quite as large in capacity, are smaller and lighter, and have an internal BMS will full protection, and the manufacturer was able to build/configure the batteries for me with a higher continuous discharge rating since my dual brushless motors are capable of pulling 100A.

I kept one of my Valence batteries and the Thunderstruck BMS and may install it as a house system in my Trimaran, but I’m not sure if I have room for a group 27 size battery and may switch to something smaller depending on how much solar I am able to integrate into its hard bimini top.

Alright I am back after working on my bus build for a couple of months. I want to make sure that I understand my battery bank and charge controller settings. I have 3 u27-12xps in parallel and a victron charge controller. There is a LFP preset that has absorption at 14.2v for 2 hours and float at 13.5V. From this forum I have gathered it might be better to set the absorption down to 13.9 or 14 to ensure un-balanced cells do not get over charged and to increase longevity of the batteries. I've been told that LFP batteries shouldn't have a float voltage so why is it included in the preset? Also this is a dumb question but even though the float voltage is lower (13.5V) it doesn't decrease the charge of the battery correct since it is drawing a very small current?

Basically assuming I balance my batteries (haven't been unbalanced so far) do you think that 13.9 absorption voltage for 2 hours and a 13.5V float voltage are good settings? I also have the option for adaptive absorption so if just a shallow discharge happens the time is decreased and vis-versa. I thought this might be good to decrease the absorption time in order to increase battery life but maybe it doesn't matter since the absorption voltage is set below the max?

mitchk1303 said:

Alright I am back after working on my bus build for a couple of months. I want to make sure that I understand my battery bank and charge controller settings. I have 3 u27-12xps in parallel and a victron charge controller. There is a LFP preset that has absorption at 14.2v for 2 hours and float at 13.5V. From this forum I have gathered it might be better to set the absorption down to 13.9 or 14 to ensure un-balanced cells do not get over charged and to increase longevity of the batteries. I've been told that LFP batteries shouldn't have a float voltage so why is it included in the preset? Also this is a dumb question but even though the float voltage is lower (13.5V) it doesn't decrease the charge of the battery correct since it is drawing a very small current?

Basically assuming I balance my batteries (haven't been unbalanced so far) do you think that 13.9 absorption voltage for 2 hours and a 13.5V float voltage are good settings? I also have the option for adaptive absorption so if just a shallow discharge happens the time is decreased and vis-versa. I thought this might be good to decrease the absorption time in order to increase battery life but maybe it doesn't matter since the absorption voltage is set below the max?

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If the battery makes it to 13.9 it's definitely full. It doesn't need to absorb there for any amount of time because pretty much anything over 13.7 is full if it's balanced. balancing starts kicking in a little bit around 13.6 and it's definitely in full swing near 13.8. the only reason you should bring your batteries up to 13.9 is for an occasional top balance and you could probably push up to 14.1 to 14.5 during the monthly equalization considering that your batteries are not having a problem staying balanced. You could use an equalization setting to do that once a month. The batteries naturally rest at 13.4 after they're done charging but it takes a lot of hours to drop down to 13.4. But if you only charge them to 13.5 they won't absorb much amperage and will take longer to charge. If I remember correctly, it's around 13.63 when the voltage starts to fly high fast signaling it's done charging. I would hope that smart lithium chargers could take advantage of this trait.

Since they rest at 13.4 if you're floating at 13.5 they'll remain at 100% unless you draw from them because your solar can't keep up with your load in the daytime. If the voltage gets down to 13.35 in the daytime I would hope that your charger would raise it up to 13.7 briefly just to make sure they're back to charged before dropping back to 13.5. that's only really necessary if you want them to remain at 100%. otherwise you could literally float them at 13.37 and they would stay above 95%. That's probably what most people should do unless they're battery bank is overly large then they could hold them at 13.3 instead. I hope I'm not confusing you LOL anyway I got to get back to work I'll check back again in a few days.

Travis said:

If the battery makes it to 13.9 it's definitely full. It doesn't need to absorb there for any amount of time because pretty much anything over 13.7 is full if it's balanced. balancing starts kicking in a little bit around 13.6 and it's definitely in full swing near 13.8. the only reason you should bring your batteries up to 13.9 is for an occasional top balance and you could probably push up to 14.1 to 14.5 during the monthly equalization considering that your batteries are not having a problem staying balanced. You could use an equalization setting to do that once a month. The batteries naturally rest at 13.4 after they're done charging but it takes a lot of hours to drop down to 13.4. But if you only charge them to 13.5 they won't absorb much amperage and will take longer to charge. If I remember correctly, it's around 13.63 when the voltage starts to fly high fast signaling it's done charging. I would hope that smart lithium chargers could take advantage of this trait.

Since they rest at 13.4 if you're floating at 13.5 they'll remain at 100% unless you draw from them because your solar can't keep up with your load in the daytime. If the voltage gets down to 13.35 in the daytime I would hope that your charger would raise it up to 13.7 briefly just to make sure they're back to charged before dropping back to 13.5. that's only really necessary if you want them to remain at 100%. otherwise you could literally float them at 13.37 and they would stay above 95%. That's probably what most people should do unless they're battery bank is overly large then they could hold them at 13.3 instead. I hope I'm not confusing you LOL anyway I got to get back to work I'll check back again in a few days.

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Ok I guess I was misunderstanding then. I thought you have your absorption voltage set at 14.07V? Or is that just the max voltage you will send to the battery? I think I am misunderstanding the absorption phase. Is the voltage you select for the absorption phase the voltage the battery will be brought up to or the voltage being sent to the battery (and the battery just reaches full, not necessarily that voltage)? The absorption phase should bring the voltage of the battery right to the float voltage (13.35V).

Either way do you think I should lower the absorption voltage to 13.7V or something lower then 13.9. I also don't understand the time factor with the absorption phase. But I'm assuming if I am reaching max capacity most days I probably want a low absorption time? I can turn on adaptive absorption so on shallow discharge days the absorption time is shorter.

It sounds like I should decrease my float voltage to 13.35 in order to preserve battery life? But basically if the battery is at 13.35 it is around 95 percent full correct?

Sorry I am so scattered. I feel pretty lost as I haven't ever dealt with this stuff but I think I am starting to get a small grasp on some subjects.

mitchk1303 said:

Ok I guess I was misunderstanding then. I thought you have your absorption voltage set at 14.07V? Or is that just the max voltage you will send to the battery? I think I am misunderstanding the absorption phase. Is the voltage you select for the absorption phase the voltage the battery will be brought up to or the voltage being sent to the battery (and the battery just reaches full, not necessarily that voltage)? The absorption phase should bring the voltage of the battery right to the float voltage (13.35V).

Either way do you think I should lower the absorption voltage to 13.7V or something lower then 13.9. I also don't understand the time factor with the absorption phase. But I'm assuming if I am reaching max capacity most days I probably want a low absorption time? I can turn on adaptive absorption so on shallow discharge days the absorption time is shorter.

It sounds like I should decrease my float voltage to 13.35 in order to preserve battery life? But basically if the battery is at 13.35 it is around 95 percent full correct?

Sorry I am so scattered. I feel pretty lost as I haven't ever dealt with this stuff but I think I am starting to get a small grasp on some subjects.

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You shouldn't lower your float voltage from the user manuals specifications unless you have more storage than you need. The thing with the absorption and float set points is the voltage will adjust battery degradation. With absorption there's no amount of time you need to stay at the voltage you choose. You simply have to reach that voltage and then you can immediately go down to float. The only time you stay in those upper voltages is during equalization

Alright I think I need to choose an absorption time with the victron charge controller but I will pick the shortest amount of time and just bump that time up to a longer amount when I want to equalize the bank.

I'm more lost with the float voltage now. The valence data sheet calls out 13.8v to 14.6v. But I thought in your previous reply you said that they like a float of 13.5v and I should set it at 13.35. Once again maybe I'm confusing the float voltage being applied to the batteries vs the float voltage that the batteries are actually at. So I should set my charge controller at 13.8v float voltage but while the batteries are in float they themselves will measure somewhere around 13.5v when at 100 percent.

I think I am confused with the solar charger applied voltages vs the battery voltages. I don't think the victron allows me to set battery voltage levels for the float and absorption. Instead it allows me to set what voltages will be applied to the battery during the float and absorption stages. Maybe I'm completely off. Sorry that I'm taking a while to get this stuff.

If anyone has expertise in the quality of used Valence U27 XPs, I posted the diagnostics for mine here and am looking for feedback:

Looks like Mueller Industries may have tapped out?

Website went dark.

If anyone has interest in a non-working low voltage BMS (Chinese valence version) PM me.

I did a search and haven't been able to find any fix. I made a new Post about the issue I'm having.
Could you help?

So I plan to run two U27-XPs in parallel with a Xantrex Freedom 2000 controller/inverter. How much benefit will I get from using the Thunderstruck BMS with this setup verses not? The Xantrex controller/inverter will give me high/low temp and voltage protection, but would not balance the cells. The BMS would balance the cells. Is this an issue if using in paralell?

For the cells balancing only you can use the Valence software, or the open source arduino bms project linked in this thread too.

Hi - I'm a noob here - but I have a question about XP batteries Vs. LifePo 280Ah 4s 12V setup. I'm working on a van build and I need to support a load like 1800W at 12v. That's around 150A with headroom like 200A.

option 1: EVE LifePo 280Ah 4s 12v battery with 250A Daly BMS
option 2: 138Ah Valence XP batteries x 2 (= 276Ah) with thunderstruck BMS

Thoughts on the pros and cons of the Valence option? will it support this type of load?

Thanks, C

Corbury said:

Hi - I'm a noob here - but I have a question about XP batteries Vs. LifePo 280Ah 4s 12V setup. I'm working on a van build and I need to support a load like 1800W at 12v. That's around 150A with headroom like 200A.

option 1: EVE LifePo 280Ah 4s 12v battery with 250A Daly BMS
option 2: 138Ah Valence XP batteries x 2 (= 276Ah) with thunderstruck BMS

Thoughts on the pros and cons of the Valence option? will it support this type of load?

Thanks, C

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The most I have done was 2000W from 4 valence batteries that handled it nicely. Maybe somebody else here has experience with such a small system. What's the cost comparison between your 2 options?

I have a set of 7 battery in my EV, connected in serie. Discharge rate are going up to 250 A, and batteries have logged a 332A peak. THey seems to hold well. So I suspect 150A continuous are not a problem...
And keep in mind batteries are usually around 13.4V, so it is 134A, just around 1C rate.

ericgrand said:

I have a set of 7 battery in my EV, connected in serie. Discharge rate are going up to 250 A, and batteries have logged a 332A peak. THey seems to hold well. So I suspect 150A continuous are not a problem...
And keep in mind batteries are usually around 13.4V, so it is 134A, just around 1C rate.

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It's not the voltage that determines the C rate. It's the amp hour rating. Their 138amp hours. Or maybe a bit less because of the degradation so by chance 134 is about right.

marin said:

For the cells balancing only you can use the Valence software, or the open source arduino bms project linked in this thread too.

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The Thunderstruck activates balancing just not between modules so if you are running 12v the thunderstruck does everything you need, besides monitoring ... It uses putty and is garbage on that front.

My batteries blink green every 5 seconds with the Thunderstruck vc1 plugged so it wakes them up .

Travis said:

It's not the voltage that determines the C rate. It's the amp hour rating. Their 138amp hours. Or maybe a bit less because of the degradation so by chance 134 is about right.

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I was calculating the amp following the 1800W asked by Corbury. 1800W at 12V gives 150A but if you consider battery is more around 13.4 rather than 12V, it lower the AMP around 134A.
Having 2 in parallel will gives a C/2 charge on the battery which is no problem.