Feedback on Third Owner Valence U27-12XP Quality

[brooke_heaton]

Hi everyone. I'm a recent lurker working on a solar setup for an A-Frame camper. I plan to have a large battery bank for dry-docking. I purchased two Valence U27 XP's off eBay. Taking a risk, I assumed they had moderate use but the price was the best I've seen in a while so I snapped them up. I set up the diagnostics on both and ran tests on them and the results are below. One has 51 cycles and the other has 28. The only thing that concerns me is that one battery shows an "Exceed Discharge Limit Count" of 1, but I'm not sure that is a big deal or would affect the battery life. Are there any warning signs in the diagnostics below? I'd greatly appreciate any feedback.

 

[snoobler]

483967Wh Discharge:
483967Wh/(12.8V*144Ah) = 263 "cycles"

478771 Wh Discharge:
478771Wh/(12.8V*144Ah) = 260 "cycles"

That means the batteries have delivered the energy equivalent of being discharged 262 and 260 cycles, respectively. Given that the cycle count is lower, I suspect it has been subjected to many shallow cycles, which may be good for life.

I would interpret the "Exceed Discharge limit count" as the number of times the BMS had to intervene and stop a discharge.

The 0% SoC on the first battery is a concern as that's not correct, but it will probably calibrate the next time significant current is placed on the battery.

Given those number, and my interpretation of their meaning, I would expect that those batteries have a lot of life left in them UNLESS they were stored at 100% SoC for extended periods of time in warm temperatures.

It would be worth your while to procure a battery tester and see how they perform:

Battery Capacity Testers

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www.mobile-solarpower.com

If you can monitor the cell voltages in the batteries during discharge, that would be good as well.

 

[brooke_heaton]

Thanks for the feedback @snoobler! I will grab that Capacity Tester and give it a go. I may post questions on using them here if that's okay. Looks like these batteries should have decent life left! I should note that these are 138AH so perhaps that lowers the discharge count a bit.

 

[brooke_heaton]

Side note: I plan to wire these in parallel to a 12V Inverter/Controller. I understand that I'd need to use the external BMS for temp/voltage monitoring and automatic shutoff, is that correct? I plan to use this BMS: https://www.thunderstruck-ev.com/valence-battery-bms.html

I may also add a Victron Battery Protect, but am not sure if this is 100% necessary and if I'd need it on both the load and charge sides of the system. https://www.victronenergy.com/battery_protect/smart-battery-protect

 

[snoobler]

138Ah would only change the count by a few percent, so no worries.

Ask away anywhere you like. Just don't ask the same question in different threads (cross posting).

I don't know Valence all that well, but that BMS looks like a good option.

A Battery Protect should only go on the discharge side to 12V loads. It should not be used to disconnect from an inverter or charge controller. The BMS should take care of that for you.

 

[brooke_heaton]

138Ah would only change the count by a few percent, so no worries.

Ask away anywhere you like. Just don't ask the same question in different threads (cross posting).

I don't know Valence all that well, but that BMS looks like a good option.

A Battery Protect should only go on the discharge side to 12V loads. It should not be used to disconnect from an inverter or charge controller. The BMS should take care of that for you.

Thanks for the help. I'll only go with the Protect on the load side. Thanks!

 

[snoobler]

And just to confirm, "load" means things powered directly by 12V, not the inverter.

Honestly, with the built-in BMS and the add-on you're using, I doubt it's necessary.

 

[brooke_heaton]

Gotcha. Yes, by 'load', I would be referring to a 12V Fuse Block, though I do plan to use a Controller/Inverter with these batteries. The documentation on using the Victron protect is a bit confusing but I had the impression that if I had it on the 12V load side, that might give some peace of mind. There would also be a load on the inverter side as well, but I'm hoping my Inverter/Controller will also provide low voltage protection.

 

[Gazoo]

I was going to suggest you ask in the Valence XP Super thread but I see you have posted there and referred to this thread.

 

[Travis]

Gotcha. Yes, by 'load', I would be referring to a 12V Fuse Block, though I do plan to use a Controller/Inverter with these batteries. The documentation on using the Victron protect is a bit confusing but I had the impression that if I had it on the 12V load side, that might give some peace of mind. There would also be a load on the inverter side as well, but I'm hoping my Inverter/Controller will also provide low voltage protection.

There's no need for the victron battery protect. The thunderstruck will disconnect the batteries to protect them from undervoltage based on cell Voltage level. The victron can't do that at all it only looks at the total voltage.

 

[Travis]

If you test them accurately you will see that they will easily hold over 90% of the original rated Capacity. The state of charge will Suddenly jump to 100 When fully charged but only when balancing is complete.

 

[Travis]

I've sorted/ tested through hundreds of these batteries. I am very impressed buy their performance and I am sure you will be to.