Lithium Charging Dilemma

[MsNomer]

Yesterday, MrNomer finished installing 2x100A SOK lithium batteries. SOK says to charge at 14.2 to 14.6V, 20-50A per battery.

When they first arrived, we charged them individually in the house with the NOCO g26000 AC charger. It took forever but we had no readout. Final voltage was 13.4, so we assumed they were not fully charged, but at least charged as equally as we could.

Charging in the van is with the NOCO on AC, Trimetric Solar Charger with 300W panels, and a 40A Renogy B2B.

Overnight I ran them down about 50A—I know that was the load I put on them.

Today, I can’t get them to charge.

Trimetric shows as much as 10A solar coming in under the shade, but <1A to the batteries.

NOCO specs say it should provide 26A at 14.2A for lithium, but it settles at 13.5V, 4.8A. That must be what happened in the house, too.

Renogy 40A charger won’t charge at all. It does not show a fault and appears to be trying to send the proper charge at 14.6V, but the 50A breaker is tripping and nothing goes into the batteries. Green light on, red light off.

My ignorant guess is that the BMS is not allowing charge, but it is unlikely that both are bad, so a bad setting somewhere?

Renogy is set with S1,2,3,4 DOWN and S5 UP.

Temperature Sensor was removed from the Trimetric Solar Charger. Relevant Trimetric settings are as follows:

P1 (Absorb Volts): 13.4
P2 (Charged Set Amps): 2% of Capacity
P3 (Battery Capacity): 200
P8 (Max Allowed Voltage): 14.6
P10 (Assumed efficiency factor) 99
P12 (Auto Reset SOC): OFF
P14 (Max Absorb Time): 0.5 hr
P15 (Max volts finish charge): 13.1
P16 (Float Voltage): 13.1
P20 (Overcharge %): OFF
P21 (Finish Stage Current Limit) OFF

Any insight would be greatly appreciated. I have also emailed SOK. We are supposed to leave on a trip tomorrow, but I’m afraid it will take a miracle at this point.

[booster]

Originally Posted by MsNomer

Yesterday, MrNomer finished installing 2x100A SOK lithium batteries. SOK says to charge at 14.2 to 14.6V, 20-50A per battery.

When they first arrived, we charged them individually in the house with the NOCO g26000 AC charger. It took forever but we had no readout. Final voltage was 13.4, so we assumed they were not fully charged, but at least charged as equally as we could.

Charging in the van is with the NOCO on AC, Trimetric Solar Charger with 300W panels, and a 40A Renogy B2B.

Overnight I ran them down about 50A—I know that was the load I put on them.

Today, I can’t get them to charge.

Trimetric shows as much as 10A solar coming in under the shade, but <1A to the batteries.

NOCO specs say it should provide 26A at 14.2A for lithium, but it settles at 13.5V, 4.8A. That must be what happened in the house, too.

Renogy 40A charger won’t charge at all. It does not show a fault and appears to be trying to send the proper charge at 14.6V, but the 50A breaker is tripping and nothing goes into the batteries. Green light on, red light off.

My ignorant guess is that the BMS is not allowing charge, but it is unlikely that both are bad, so a bad setting somewhere?

Renogy is set with S1,2,3,4 DOWN and S5 UP.

Temperature Sensor was removed from the Trimetric Solar Charger. Relevant Trimetric settings are as follows:

P1 (Absorb Volts): 13.4
P2 (Charged Set Amps): 2% of Capacity
P3 (Battery Capacity): 200
P8 (Max Allowed Voltage): 14.6
P10 (Assumed efficiency factor) 99
P12 (Auto Reset SOC): OFF
P14 (Max Absorb Time): 0.5 hr
P15 (Max volts finish charge): 13.1
P16 (Float Voltage): 13.1
P20 (Overcharge %): OFF
P21 (Finish Stage Current Limit) OFF

Any insight would be greatly appreciated. I have also emailed SOK. We are supposed to leave on a trip tomorrow, but I’m afraid it will take a miracle at this point.

It sounds as it the charger is not going to absorption stage but straight to float and at float very little charging as the batteries are that high already.


The Trimetric is set to absorb at only 13.4v so won't charge either.

[markopolo]

The Noco's 13.6V Supply Mode (power supply mode) should bring the BMS back online if it went offline due to under voltage.

Is the 50A breaker on the Renogy's input?

[MsNomer]

I changed P1 to 13.8. Ill find out tomorrow when the sun shines again.

Isn’t 13.6 itself under voltage?

[rowiebowie]

Originally Posted by MsNomer

Renogy is set with S1,2,3,4 DOWN and S5 UP.

Any insight would be greatly appreciated. I have also emailed SOK. We are supposed to leave on a trip tomorrow, but I’m afraid it will take a miracle at this point.

I have a similar 200A lithium battery bank and the same charger. My Renogy 40A DC-DC came with instructions that were not very clear as to DIP switch settings. So at the time of my install, I spoke with Tyler in Renogy support. He stated the following:

S1 UP with 2, 3, 4, DOWN and S5 UP.

It has been working fine for two years and my settings were also confirmed in a Long Long Honeymoon install video on youtube (that I can't currently locate by searching).

As far as charging, I once ran my lithiums down to 10 volts and the inverter
/charger would not charge from either shore or generator. However, when I started the engine and switched on my Renogy 40A DC-DC the battery began to charge. After 20-30 minutes, the battery voltage was up to the point where I could finish charging on shore power.

[booster]

Originally Posted by MsNomer

I changed P1 to 13.8. Ill find out tomorrow when the sun shines again.

Isn’t 13.6 itself under voltage?

It depends on who you listen to, I think. The trend is to leave some "head room" at knee in the charge current, usually by voltage control. Where that point is will be a bit different for everyone who looks at, it appears. IIRC 13.8v will give you something like 95% SOC on lithium which if correct would probably be a good place to be. One on the home lithium builders here will know for certain, I think.

[eric1514]

Also, ON is down, OFF is up.

[MsNomer]

rowiebowie, your setting is for 14.4V. Mine is for 14.6V.

I read where someone got up-down backward, so I made sure I got that part right.

Another data point. I know voltage is a very poor indication of SOC, but these batteries are sitting at 13.4-5V. Load is parasitic 0.4A. The only chart I have, which is not specific to SOK, says 13.4 is 90% at rest and 99% under load. The one certain datapoint I have is that I pulled 50A out of them last night. I have not replaced it, so they should be about 75% SOC and that's what the meter says they are.

[markopolo]

I've watched several charge cycles with per cell monitoring and observed that higher voltage charging like 14.6V = greater chance of cell imbalance at the top and greater likelihood of one cell going over voltage and temporarily shutting down the BMS.

The 13.6V Power Supply setting I mentioned earlier was just to supply a steady output to bring a BMS back online if it went offline due to being undervoltage. Lots of chargers don't work if they don't sense a battery in the circuit. Power Supply mode avoids that.

I tested 13.6V, 13.8V & 14.4V here: https://www.classbforum.com/forums/f...tml#post120842

13.6V does charge lithium but much slower (too slow IMO).

S1 & S2 Up (Off) S3 & S4 Down (On) and S5 Up (Off) = 14.0V Lithium setting on the Renogy is all that's likely needed.

New lithium batteries can have a bit more capacity than advertised. Here's SOK cycle testing from another forum: SOK battery SK12V100-0915 life cycle curve-1.pdf Looks like 104Ah at the beginning on that battery.

[MsNomer]

All is well. Tomorrow, we leave this furnace for more favorable climes.

Solar was two bad parameter settings on the Trimetric. SOK had me change P1 to 14.6 and P16 to 13.5. It appears to work fine now.

Renogy had two issues. First, a bad breaker was replaced on the output wire. Second, Ummmmm, MsNomer discovered that MrNomer had not connected the Renogy to the shunt.

All's well that ends well. The Renogy charged the batteries in short order and we are good to go.

Thanks, everybody, for your support.

[Frankshay]

Originally Posted by MsNomer

The one certain datapoint I have is that I pulled 50A out of them last night.

I'm not trying to be pedantic but do you mean 50 Ah (amp-hours)? I'm only mentioning this because lots of people confuse amps and amp-hours and it can cause misunderstandings when discussing situations such as yours.

[booster]

Originally Posted by Frankshay

I'm not trying to be pedantic but do you mean 50 Ah (amp-hours)? I'm only mentioning this because lots of people confuse amps and amp-hours and it can cause misunderstandings when discussing situations such as yours.

That has been endemic here and on many RV sites for quite a while, and it is very confusing sometimes. I think a lot of it started with the battery sellers putting down the cranking amps of their battery labeled "amps" in the specs where shoppers would expect it to amp hours of capacity to make the batteries look better. Roadtrek was kind of famous for that as it was listed in the specs for new vans so lots of people were fooled thinking they had a 400 amp hour battery when it was only 185 amp hours when comparison shopping, especially since Roadtrek had 400ah lithium battery packs on other products.


Even people that know better have started using amps and amp hours interchangeably so very disappointing to me.

[MsNomer]

Sorry 'bout that. I know better.

Update: MrNomer says it's like a kid with strict parents going off to summer camp. These new batteries just work. Who cares if the charge is 80%, 60%, 40%, whatever? When you actually get to use the available solar instead of the batteries only sipping and wasting the rest, even rainy days and smoke haze give us almost enough juice to maintain, and a little driving takes care of the rest. The system doesn’t even seem to care that we have added a 22qt freezer.

When we get home after the present 5-week trip, we will add a third 100Ah battery because we can—the lithium’s are that much smaller than the AGM’s. This will give us more elbow room for extended bad weather.