used Valence LiFePo 4

[somewhereinusa]

I have 4, Valence U27-12XP 12 volt 138Ah batteries wired in parallel. They are used and I got the internal BMS talking to my computer yesterday. All 16 cells are within .006 volts of each other. Total charge of each module (4 cells) is 99.6%. It also shows total cycles of each module mine are 117,142,165, and 195. Not bad for a projected 3000 cycle life. Lots of info available that I haven't deciphered yet.

Crappy picture of one of the modules.

[farok]

Nice! If we ever go full-time, I'd be looking very closely at this. Right now my charger doesn't support Lithium, so it's more than just a simple battery swap. Awesome, though!

Chris

[john61ct]

The Valence system looks better than most.

The secondhand units seem to be sold with lots of lifespan still in them, test out at decent results

but are selling for 80%+ what I'd want to pay for brand new.

Personally I'm not buying secondhand cells for more than 25-30% of the new price, just too risky.

[mrpincher]

Great to hear these stats. Where are these batteries manufactured? Is there any info on that?


Mike

[somewhereinusa]

Originally Posted by john61ct

but are selling for 80%+ what I'd want to pay for brand new.

I paid less than 25%

[john61ct]

Originally Posted by mrpincher

Great to hear these stats. Where are these batteries manufactured? Is there any info on that?


Mike

I think at least assembled in Europe? A123, Valence and Super B are now all part of Lithium Werks.

Dutch, but I believe all the factories are China of course.

[JohnnyG]

Hello,

I am looking very closely to installing these same used Valence batteries but am getting confused on if the internal BMS will function stand alone. Can you offer any guidance on how you were able to establish the BMS communication and if without such communication are you still getting low/high voltage and temperature protection from the internal BMS without external connection or monitoring? Many Thanks!

[somewhereinusa]

Link to manual and software as well as instructions on how to make the cable here. valencefiles

The internal BMS will handle cell balancing. It will not protect, I don't think but don't know for sure, against high/low voltage or temperature.

I have almost completed, should be less than two weeks, a system using overall bank temps and voltages to turn on heat, compartment fan and complete disconnect. It will also turn on/off the solar controller. It also has a data logger to log readings and also, I hope, log readings at the time any relay is triggered.

Hardware is done, I think, and since I'm really crappy at coding I have hired someone to do that for me based on what I think is needed.

[JohnnyG]

Thanks for the info and link to the other site! Still need to find an answer to the temp and voltage cuttoffs working if the internal battery BMS is not connected to the aggregator/or PC.

[stephaniempepper]

What size solar system are you going with? We are researching the same Battery. Any update?

[somewhereinusa]

Originally Posted by stephaniempepper

What size solar system are you going with? We are researching the same Battery. Any update?

System is pretty much done. 1500 watts of solar.

[stephaniempepper]

Do you have the external BMS? We are trying to get our BMV-712 to communicate correctly - seems the rs485 I built is reading a different SOC than what our BMV-712 is. Curious what you did for the BMS! Appreciate any help in advance!!

[somewhereinusa]

You have to tell the 712 what your SOC is, after that mine pretty much agree with what the Valence internal readings say. Don't remember exactly but it is in the 712 documentation.

[cadillackid]

you sometimes have to tweak the settings on the 712. I watch mine and then when I hook my shore charger up when i see it get to the magic .05C charge rate in terms of amperage I look to see if im at or near 100%, using the phone app makes it nice to change the settings on it.. ive got it pretty good now in regards to SOC for my batteries.. the default settings definitely werent correct for my 2 AGM batteries.



-Christopher