New battery voltage

[btmurrell]

I recently bought four of these Li Time 12v 100ah trolling motor batteries. When I opened them, I charged each one to be sure they were fully charged. They arrived reading around 12v each. After charging two of the four were reading fully charged at about 13.3v each, but two of them after extended charging time will never charge past 12.7v. Since these four are going to be parallel buddies, I am concerned that two of them are runts.

Should I be concerned that two of them are not charging to the capacity of fhe other two? Does it warrant returrning the lesser two batteries while I'm still in my return window?

Thanks,
Brian

 

[DIYrich]

Return them. That is too much of a voltage differential to put in parallel.

 

[TomC4306]

I charged each one to be sure they were fully charged.

By what indication did you determine them to be fully charged?

After charging two of the four were reading fully charged at about 13.3v each

That is not fully charged.

after extended charging time

How much time with what charger/how many amps for how many hours?

 

[TomC4306]

Return them. That is too much of a voltage differential to put in parallel.

A bit premature, no?

 

[Ampster]

Should I be concerned that two of them are not charging to the capacity of fhe other two?

As others have asked, what voltage did you charge them to and what were the Amps when the voltage hit that charge voltage? At the top you should see voltage stay the same and the current decline. That is the only way to know if they were all charged to the same capacity. Also if you did not measure the voltage just befor the chafrging stopped, you should give each battery the same amount of time to settle and then measure the voltage when they have settled to about 3.3 volts per cell or 13.2 for the battery.

 

[btmurrell]

Thanks, all, for your timely responses and clarification requests. I am in pre-installation mode. This is my set-up. The only charger I have is my solar panels going thru my controller (details below). So, I was charging each one individually to top it off. I left each on the charge controller for a couple of days. After that period, each of them were not getting any more charge voltage. To be clear, my voltage measurents were with a multimeter when the batteries were disconnected from the charge controller.

By what indication did you determine them to be fully charged?

after each battery had two days of good sun each, one at a time, on my solar controller

[13.3v] That is not fully charged.

this was my reading after the batteries were removed from the charger and settled... I

How much time with what charger/how many amps for how many hours?

two full days under good sun, one battery at a time. Solar and charge controller specs below. Also attached is a screenshot of my Renogy DC Home app; shows 0.1A Battery Charging Amps at the end of this period, and while connected to charger, it's showing 14.4v.

what voltage did you charge them to and what were the Amps when the voltage hit that charge voltage?

While on charge controller, it always shows 14.4v, and at the end of two days .01A charging amps.

you should give each battery the same amount of time to settle and then measure the voltage when they have settled to about 3.3 volts per cell or 13.2 for the battery.

Yes, thanks. Don't have access to the cells, but yes, after settling, and disconnected, the four batteries are reading
- 13.3
- 13.3
- 12.78
- 12.87

So, with all that detail, does that give you experts enough info to help me determine if two of these batteries are deficient? Thanks A LOT!

## Solar
- 2 x Renogy 320W 24V Monocrystalline Solar Panels
- parallel = 24V 26.6A ==> 640W

## Charge Controller
- Renogy 60A 12V/24V/36V/48V DC Input MPPT Solar Charge Controller

## Batteries
- 4 x LiTime 12V 100Ah TM LiFePO4 Battery, Low-Temp Protection For Trolling Motors

 

[mikefitz]

It's possible the batteries with the lower voltage ,had, when under charge, reached a voltage where high cell volts exceeded the protection level and the BMS shut down the charge path. Applying a load of several amps may wake up the BMS.
Since you can, from the chargers display, observe charge surrent, this could have been seen whilst chargg.
Many low cost batteries have inbalanced cells and require a lower charge voltage, perhaps as low as 13.8 , to prevent BMS shutdown.

If the battery is in shutdown mode and loading does not 'wake it up' consider,

How to Wake Up a Sleeping LiFePO4 Battery - Footprint Hero

Learn how to wake up a sleeping LiFePO4 battery by jumping it with another battery. This easy method gets your lithium battery out of sleep mode.

footprinthero.com