Charge parameters for Outback flex 80 to LiFePo4 batteries

Hi,
I have two Outback Flex 80 charge controlers and I just purchased (4) LiFePo4 24v 170ah batteries from Big battery. I am having a difficult time finding information regarding the best charge setting. I have reached out to Outback and to Big battery but each company is sending me to the other for how to program the charge controler. Does anyone out there have experience in programing for the configuration?
Thanks

This is 100% the responsibility of the battery supplier to let you know the charge parameters for their batteries.

I can tell you what i use for my LiFePO4 setup, but it may not suit your batteries.

toms said:

This is 100% the responsibility of the battery supplier to let you know the charge parameters for their batteries.

I can tell you what i use for my LiFePO4 setup, but it may not suit your batteries.

Click to expand...

Yes, the battery supplier did provide this information, however they were unable to answer a couple questions I had. I want to preface this with "I can be clueless sometimes" Big battery recommends a bulk voltage of 29.2 and a float voltage of 29.2 but they also say that no float is needed. so my first question is why program a float voltage at all if it's not needed? and the second question is regarding adjusting the charge voltage to give me the longest battery life. I've been told that a lower charge voltage will extend the battery life but I don't know what that ideal voltage is.

thanks

In the MidNite world which is designed by the same crew as the Outback we set the bulk voltage to the battery manufacturers specs, set the absorb the same and adsorb time to 5 minutes or the minimum time allowed, and the float to 2-3 volts less than bulk so float will not come on, And equilize off. This workaround is used because both the Outback and MidNite designs were pre lithium designs and as such they have no defined lithium type. If you go to the battery select menu you will find “user defined battery” , That is the heading under which you need to set these settings........but the battery manufacturers specs are the key values .

Bottom line, Lithium only needs the bulk charge mode, by setting the values low you will inhibit the absorb, and float stages which lithium does not need or like.

check out this midnite article for more info on lithium charge profiles:

http://www.midniteftp.com/support/kb/faq.php?cid=1

AllanR said:

Yes, the battery supplier did provide this information, however they were unable to answer a couple questions I had. I want to preface this with "I can be clueless sometimes" Big battery recommends a bulk voltage of 29.2 and a float voltage of 29.2 but they also say that no float is needed. so my first question is why program a float voltage at all if it's not needed? and the second question is regarding adjusting the charge voltage to give me the longest battery life. I've been told that a lower charge voltage will extend the battery life but I don't know what that ideal voltage is.

thanks

Click to expand...

Only when the BMS could communicate with inverter,then the inverter will charge/discharge the LFP as its rule,constant current-constant voltage.Otherwise,the lifepo4 battery is same as lead acid battery without communication,the setting could be bulk charge at 28.8V,float voltage at 27.6v.If the conformity of cells are not good,then the parameters should be decreased a little.

Some controllers do not allow no adsorb or no float so what i suggested is a work around to no valid lithium settings.

These settings will make a 3 or 4 stage charger more closely mimic a cc/cv source that is better for lithium