Used Valence u27-12xp

[Jermorrell]

I am looking to get two Used Valence U27-12XP battery’s. I plan on hooking them together to run a 12v trolling motor in my boat for a month or so then move them to the rv for the summer. I saw on one of the sites selling them say “Onboard bms will not function without additional circuitry that we do not have but ask about the TSM BMS specific for Valence batteries! LED present that shows status. “ on one of the YouTube videos I watched it looked like Will just connected the battery’s together and used them.my question is will I really need the bms? Also is there a cheeped charger you can refer that I would only use a half dozen times or so a year.
Thanks for the help.

 

[Justin Laureltec]

I am looking to get two Used Valence U27-12XP battery’s. I plan on hooking them together to run a 12v trolling motor in my boat for a month or so then move them to the rv for the summer. I saw on one of the sites selling them say “Onboard bms will not function without additional circuitry that we do not have but ask about the TSM BMS specific for Valence batteries! LED present that shows status. “ on one of the YouTube videos I watched it looked like Will just connected the battery’s together and used them.my question is will I really need the bms? Also is there a cheeped charger you can refer that I would only use a half dozen times or so a year.
Thanks for the help.

In at least several of Will's YouTube videos he actually has the Valence RT series, which do have an onboard BMS and are truly drop-ins; the XP series that you reference does not have an onboard BMS, so is not a drop-in LFP battery.
There are lots of ways, using 3rd-party hardware, to "emulate" a BMS for these batteries (just search "Valence" on this site and you'll uncover a wealth of information) but, bottom line: you should never run an LFP bank without some kind of BMS, which will manage cell balancing, HV/LV cutouts, charge/discharge rates, and HT/LT cutouts. It's not that you can't just hook the thing up and go... but the odds of irreparably damaging it -or the connected components- by doing so are extremely high.
Even as used and relatively cheap LFP batteries go, they're not so cheap that most people can afford to buy a bunch to keep replacing them when they burn theirs out... In the end it's up to you what risk you feel comfortable taking, but I strongly advise against ever running any LFP (or any chemistry other than Pb for that matter) without a good BMS on the system to make sure you don't destroy your battery investment and/or other connected components.

 

[CROF2B]

Look in the section on the forum called
Second Life Lithium Batteries https://diysolarforum.com/forums/second-life-lithium-batteries.24/
all the Valence stuff is there.

 

[Kamhuss]

In at least several of Will's YouTube videos he actually has the Valence RT series, which do have an onboard BMS and are truly drop-ins; the XP series that you reference does not have an onboard BMS, so is not a drop-in LFP battery.
There are lots of ways, using 3rd-party hardware, to "emulate" a BMS for these batteries (just search "Valence" on this site and you'll uncover a wealth of information) but, bottom line: you should never run an LFP bank without some kind of BMS, which will manage cell balancing, HV/LV cutouts, charge/discharge rates, and HT/LT cutouts. It's not that you can't just hook the thing up and go... but the odds of irreparably damaging it -or the connected components- by doing so are extremely high.
Even as used and relatively cheap LFP batteries go, they're not so cheap that most people can afford to buy a bunch to keep replacing them when they burn theirs out... In the end it's up to you what risk you feel comfortable taking, but I strongly advise against ever running any LFP (or any chemistry other than Pb for that matter) without a good BMS on the system to make sure you don't destroy your battery investment and/or other connected components.

I bought 4 from a guy in New York for $325 a piece with cables

 

[Sabre36]

Please be careful with used Valence batteries. We had a client bring us some used 138Ah Valence U27-12XP batteries that only tested at 91- 94 +/- Ah. The bigger problem however was the zipper-like discharge curve on one of the batteries, a battery that could only deliver 94.79Ah under a 10A constant-current load.

When we contacted Valence we were told to tell the customer to stop using the batteries immediately. They suspected some internal cell-weld failures were causing the zipper-like discharge graph.