Twin Ogrphy 260ah batteries voltage mismatched and dropping after initial charge?

[Wanderingon]

I recently picked up 2 Ogrphy LAF12260 LifePo4 260AH batteries from Amazon. Both arrived in good condition at 13.16 volts. I used a NOCO Genius 10 (Li) to charge both batteries in the house (room temp).
Voltage test #1:
Battery #1 charged to a max of 13.67 volts after 20 hours, then left in float mode for another 12 hours. After 24hr rest the voltage showed 13.46, and remained at that voltage for 8 days before dropping to 13.45volts.
Battery #2 charged to a max of 13.63 volts in 14 hours, then left in float for another 18 hours (same amount of time on the charger). After 24hr rest, the voltage showed 13.48, dropped to 13.41within 3 days, and down to 13.40 volts 2 days later.
Voltage test #2:
Battery #1 re-charged to 13.93 volts and went to float after 20 mins. After 24 hr rest the voltage showed 13.55, and held for 2 days dropping to 13.54 volts for the next 5 days (end of test)
Battery #2 recharged to 14.22 volts and went to float after 20 mins. After 24 hr rest, the voltage showed 14.12, and after 24hours showed 14.05volts.
Over the next 3 days it consistently dropped to 13.99 volts; held at 13.98volts for 2 days, then dropped down to 13.96 volts the last 2 days.

I've placed no load on either battery yet.
Based on this info, does Battery #2 have serious issues like a bad BMS, or shorted cells? Or, do I need to do some load tests or something?
I already reached out to Ogrphy, and they said they would be responsible to send a new replacement. Quote, "We have noticed your problem and it is the first time we meet this kind of problem from our customers. The full charge should be 13.5v-13.8v".

Any insight would be greatly appreciated! Thanks

 

[Substrate]

Generally, a fully charged LFP is left to rest for awhile will be *near* 13.4v

I think you are ok, but perhaps looking for problems.

The problem may be that you are using such a dinky amount of current, that the Noco might be timeing out (I'd have to check the specs on mine). This is seen by you recharging and reaching a higher voltage, basically resetting a safety timer.

In other words, you are charging at a .04C rate that is just below what would be considered the *minimum* for an efficient charge of .05C. What I'm saying is to save your time and sanity, is to use a bigger charger. 20A LFP chargers are not that hard to find.

Consider this: even if you upgraded to a 20ah charger, and depleted one battery, it would take you THIRTEEN hours to recharge more or less.

Note that the Noco does not float, (in li mode), so there's that. At the very least, you've given the batts time to catch runners and balance with such small current, but spent a LOT of time in the upper end of charging getting there.

So go ahead and cycle those batts first, but truthfully, you are on the hook for a larger charger upgrade, especially if you are thinking of charging these in parallel! The Noco 10A is just too small to do a proper job on that large a capacity, either singly or in parallel if you are thinking of doing that.

Essentially like trying to recharge your car battery from your phone-charger.

 

[Wanderingon]

Thank-you, Substrate! I'm new to the lithium world and appreciate your input.

I've got a 25a LFP charger coming. I'll run some load on them and charge them again... see what I come up with. You're right about "looking for problems"... been listening to all the negatives out there...

These are going into a truck camper which I've set up with the Renogy 40a dc/dc charger and also has a 60a built-in convertor. Solar is next. Trying to do this in a controlled environment as the rig is in process of being assembled and it's been snowing a lot. I was being cheap about buying another charging device!

Thanks again for the info.