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RVing message boards => Tech Talk => Solar => Topic started by: winslow on February 09, 2018, 02:47:14 PM

Title: Your Experience with LiFePO4 Deep Cycle Batteries?
Post by: winslow on February 09, 2018, 02:47:14 PM
We are thinking of going with 2 to 4 of these to replace our 8 155-amp hour VMax Tank AGMs:
https://battlebornbatteries.com/shop/12v-lifepo4-deep-cycle-battery/

 I am not concerned about battery bank sizing, I have that under control, but I am interested in anyone's experiences charging these with an MPPT controller (It's a Midnight Solar Classic 150). Any experience charging and discharging these batteries, and any pointers to their best treatment would be terrific.

Here's a quick link to the charge controller, too:
http://www.midnitesolar.com/productPhoto.php?product_ID=256&productCatName=Charge%20Controllers%20-%20Classics&productCat_ID=21&sortOrder=1&act=p

Moderators - can you move this to the solar Child Board if that's more appropriate, please? Sorry for the small screw-up!

Thanks in advance!

Title: Re: Your Experience with LiFePO4 Deep Cycle Batteries?
Post by: AStravelers on February 19, 2018, 08:57:45 AM
Make sure you can program the charge voltage to the batteries so voltage stays below 14.2V.  I prefer 14.0V so I don't over charge the Lithium.  Also keep your float voltage down around 13.6-13.8V. 

Lithium prefers not to be charged to 100%, 93%-95% is best so keep that in mind.

I have a Morningstar Tristar MPPT-60 and On really bright sunny days I will turn off the controller so I am not sitting there with 14.0 volts and a few amps over charging my batteries. 

I bought the 400AH lithium battery kit from Starlight Solar in Jan 2016 and it has worked very well for us.   Here is a link to more info:  http://www.lithiumrvbattery.com/Lithium_RV_Battery/GBS_100AH_Cells.html (http://www.lithiumrvbattery.com/Lithium_RV_Battery/GBS_100AH_Cells.html)

I also have 650watts of solar in 2 large solar panels, wired in parallel, feeding the MPPT controller with about 36V.
Title: Re: Your Experience with LiFePO4 Deep Cycle Batteries?
Post by: Gizmo on February 19, 2018, 06:48:11 PM
Contact the manufacturer and ask them what the charging parameters are for their batteries.  We have recently purchased 3-Battle Born LiFePO4 batteries, I contacted Battle Born and they require 14.4V absorption, 13.6 for float and 30 minutes of absorption time charge per battery.  If you have a different brand they may have different parameters so check with them.  If you set your controller settings per the manufacturer's parameters you will not overcharge the batteries, so no concern there. Likely you will not want to equalize for these batteries and you will not need temperature compensation as generally a good idea for lead acid and AGM batteries.
Title: Re: Your Experience with LiFePO4 Deep Cycle Batteries?
Post by: Frank B on February 19, 2018, 11:05:36 PM
Some good information in this current thread:

http://www.rvforum.net/SMF_forum/index.php/topic,109633.0.html

IIUC, the batteries you are considering have internal overcharge protection.