SOK LiFePO4 Battery Possible Failure

[DT6]

HI - We purchased two SOK 100Ah Lithium batteries late last year and used them in our 21C which has the newer Victron controllers (nice improvement over our 19 which had the GoPower setup). We have used these off and on since January and they worked great until a few weeks ago.

As we all know the weather had been really hot, and I ran the MaxxFan one night. I woke up around 4AM to a blinking blue Victron read-out in the trailer with the batteries going down to below 10 percent. I shut off the MaxxFan and the next day the batteries seemed to charge back fine.

We were hooked up to shore power for over a week after that, but on the way home from Banff we tried to use the batteries without a hookup at a Harvest Host stop and the Victron readout showed power was below 50 percent, even though we had it plugged into the truck while towing all day (not to mention the two 180W solar panels). We requested an electrical hookup and or hosts were very generous so we had power that night. But the next night same issue, but no way to get any power. I ran the generator to charge it up to 65 percent, but our CPAP machines stopped working at 430AM. Normally, even running both machines all night does not draw the batteries down more than 35 to 40 percent and that is without being careful.

That was the last night we used the trailer (this past Wednesday night) and when we got home Thursday, the batteries were at 100 percent. So our experience does not seem to be consistent from day to day.

I've initiated a conversation with SOK, but I feel like I'm starting to get the run-around. I know some other have SOK batteries, but the issues is likely something generic and not brand specific? I"m not sure. Any thoughts/suggestions are much appreciated. BTW - I'm good at sawing, hacking, installing stuff, but I'm a goof when it comes to electricity (hence my major switch from Engineering to Mathematics), so think "crayons" if you can offer any suggestions on how/what to check. Thanks!

[CE Vogel]

The first thing to check is the tightness of all your battery wiring, at the batteries, current monitor, and the fuse panel. If all connections are good, charge the batteries to 100% and disconnect all battery wiring at both batteries. Let them sit overnight or longer, then check their voltage with a meter. If one is down, it may be a bad battery. It is unlikely both batteries have failed simultaneously, but a bad battery will draw down a good battery when they are wired together.

[DT6]

I forgot to mention that I did check the battery connections, but I will need to go over the other wiring so great idea. They are at 100 percent now, so I'll disconnect them this afternoon and see what happens. The batteries are also connected to Bluetooth so I can get individual readings from them, and I'm just good enough with a volt-meter to check the voltages.

[Ron in BC]

Originally Posted by DT6

I've initiated a conversation with SOK, but I feel like I'm starting to get the run-around.

If you want to know what a run-around is try dealing with Renogy. They'll string you along until you give up.

Good luck on your trouble shooting. Isolating components is good advice.

Ron

[oldwave]

There have been a few issues with the bms with SOks
Very few
Did you buy them from Current Connectioned
?
SOK direct is a 7 year warranty
Current Connectied adds 3 years

[DT6]

I disconnected the batteries and was surprised. I connected to the Bluetooth in each battery and found them to be 43% and 41% charged, respectively. This, despite the Victron readout that said 100%. I can only assume the Victron was reading the solar panels?

BTW - when I disconnected them this afternoon, they had been hooked up to the solar panels for two and a half days of mostly sun. Certainly enough to have easily charged them back to 100% previously. Something seems very wrong if they are only at about 40%.

I purchased this pair directly from SOK.

Still waiting to hear back from SOK. I hesitate sending them screen shots of the new Bluetooth readings as every time I send a new email it seems to start the process all over again as they act like they never got a prior email from you. However, I'll certainly keep everyone posted on how well they eventually do in coming to a solution.

[alanmalk]

Originally Posted by DT6

...

BTW - when I disconnected them this afternoon, they had been hooked up to the solar panels for two and a half days of mostly sun. Certainly enough to have easily charged them back to 100% previously. Something seems very wrong if they are only at about 40%.
...

One easy test to help narrow down the possible points of failure: Reconnect the batteries and go back to charging with solar. After a couple of hours (at that rather substantial 360 watts) use your newly refined multimeter skills to measure the voltage at the battery posts. It ought to be very close to the recommended charging voltage.

Now, if reading a recommended charging voltage, turn off (or disconnect) the solar and turn off any lights or other loads. Then use the Victron to measure the current leaving the batteries - if any. If the Victron can't be used in that manner then try the multimeter on its Amp setting if it goes to 10 Amps. Note that if there is a current drain greater than the maximum of the meter then its internal fuse will blow - requiring a reading of the owners manual and a trip to the hardware or auto store for a replacement fuse. Make the amp measurement between a battery post and the wires connected to it. (Sometimes the - post has fewer wires to disconnect.)

What you will have learned: If the solar charging voltage is 2 or 3 volts lower than the recommended charging voltage (commonly 14.4.- 14.7) than the problem is not the batteries. If there is current drain when none is expected then the problem is not the batteries. But you should have a good idea where to look for the next clues.

[oldwave]

Current connected has excellent recommendations for the charge settings for theses batteries. Also the Bluetooth accuracy of the bms is suspect unless you drain the batteries completely and charge to 100 percent
Twice. I ignore the Bluetooth charge and rely on the victron shunt for state of charge.
I also charge with a multiplus that gives very granular control of the charge algorithm. Most other charges have fixed charge cycles, the progressive dynamics ones have a two stage lithium cycle. It’s possible the charger is not balancing the cells because it’s not charging long enough. Check your solar charge settings ?
https://www.currentconnected.com/pro...solar-battery/
Scroll down to the settings for charging

[John in Santa Cruz]

Originally Posted by oldwave

... Most other charges have fixed charge cycles, the progressive dynamics ones have a two stage lithium cycle. It’s possible the charger is not balancing the cells because it’s not charging long enough. Check your solar charge settings ?
https://www.currentconnected.com/pro...solar-battery/
Scroll down to the settings for charging

AFAIK, the PD4655L series is just one phase in lithium mode, it outputs a steady 14.6V once the current drops below about 50A.

60 minutes at 14.2-14.6V once the current has dropped to near zero should be plenty of time for the internal BMS equalization cycles to complete.

[Perry Butler]

Originally Posted by DT6

I disconnected the batteries and was surprised. I connected to the Bluetooth in each battery and found them to be 43% and 41% charged, respectively. This, despite the Victron readout that said 100%. I can only assume the Victron was reading the solar panels?

BTW - when I disconnected them this afternoon, they had been hooked up to the solar panels for two and a half days of mostly sun. Certainly enough to have easily charged them back to 100% previously. Something seems very wrong if they are only at about 40%.

I purchased this pair directly from SOK.

We have two 100 ah SOK batteries purchased last January. Our BMS was totally wonky concerning SOC and CAlC Capacity. It said one battery had 46 ah's of CALC Capacity and the other 284 CALC Capacity. What does each of your batteries read for CALC Capacity?

In early July, we received two new BMS boards for our batteries, I installed them and now my CALC Capacity says 105 ah's for one battery and 106 ah's for the other, so now our SOK SOC is roughly the same as our Victron BMV-712 shunts SOC.

The previous boards did not read CALC Capacity correctly so the SOC was never accurate. Again, what CALC Capacity does your app display for each battery?

This has been a huge problem for SOK! Go to SOK's facebook page and read about endless users with the same problem. If you bought them late last year you need to get a new BMS for each battery! SOK will send them to you free, but you have to install them. It's quite easy and there is a Youtube video to help you change them out.

Exchanging the BMS will help correct half your problem. I'm guessing you also have a loose wire, failed battery, or other failed item.

Enjoy,

Perry

[John in Santa Cruz]

FWIW, I have a pair of the original metal case 206AH SOKs, bought from Current Connected, without the bluetooth or heater, and I've had ZERO issues.

[Perry Butler]

Originally Posted by John in Santa Cruz

FWIW, I have a pair of the original metal case 206AH SOKs, bought from Current Connected, without the bluetooth or heater, and I've had ZERO issues.

Since you don't have bluetooth you don't understand the frustration of spending over $1,000 for 200 ah's and having one battery say you have a SOC of 0% and another saying your 90% full when they really are 60% full.

Today everyone is getting bluetooth and then were told just forget reading your SOC on SOK's app. Many didn't have or want to spend money on a Victron shunt to see the actual SOC of the battery, another frustration for them (we left the 712 in our previous trailer, but know its worth and installed another on our new trailer).

For those who purchased before May (?), when bluetooth version 8 was released, either have to look at a defective SOC reading or just never use the bluetooth we paid money for. Since it appears SOK had 7 previous versions of bluetooth that didn't work properly there are a lot of owners who were frustrated at their batteries. Just go to the SOK facebook page and for the past few months owner after owner complained about the wonky SOC reading. Easily more that 100 posts from frustrated users and that's just the owners who actually belong to the SOK Facebook group.

If you don't live near the dealer you purchased your batteries from (in our case Current Connected in Henderson, NV) you had to remove the top of the battery, disconnect the wires, replace the bluetooth, and reinstall, while worrying that you won't short the battery. Plus you have to take your battery to a 0% SOC twice, where the BMS shuts the battery down, to get the battery's readings to be correct.

So far, after 7 weeks our CALC Capacity has stayed where it belongs. OTOH, it's nice to see the voltage for each cell and slowly see the cells balance. This is a handy reading to see if you are starting to have a failed battery.

Since lithium is so new the jury is still out on the actual long-term reliability of lithium batteries in users hands. After 7 years our friends just replaced their Lifeline AGM leaded batteries not because they failed, but because he had the discretionary money to do so. If I would have done my due diligence, I would have stuck with SiO2 leaded batteries. YMMV.

Food for thought,

Perry

[Perry Butler]

Originally Posted by DT6

but our CPAP machines stopped working at 430AM. Normally, even running both machines all night does not draw the batteries down more than 35 to 40 percent and that is without being careful.

Are you running your CPAP on 120v with your inverter, or running a 12v from the larger 12v plug (cigarette lighter).

Reading about CPAP's in camper on other forums, we found out running Terry's CPAP (she just got her CPAP in May) on our inverter we were down 30-40 amps in the morning. We then bought a 12v unit power unit and found out (using our 712 shunt) it only used 20 amps at night, even with humidity running. We don't need our inverter on when we're sleeping anyway.

Food for thought,

Perry

[DT6]

I have plans to install a direct DC connection to the CPAPs, and we even ordered the wiring stubs for that purpose. However it is something I planned to put off until January when we take our 2-months in the southwest. So currently running on the inverter, but we only run the air on the CPAP not the air warming/humidifier. When we had our 19 we just had the 225Ah lead acid Interstates and they always worked without issue, although we ran them down probably 40 to 50 percent each night, but we were not being careful and were running the humidifier on one of the CPAPs (which we no longer do).

The SOKs also have the built-in heater and shutoff which was my main reason for purchasing these. We live in Oregon near Salem and while it gets below freezing sometimes in the winter, however it is usually not prolonged, so I don't see the need to remove the batteries for the winter, but maybe I should??

I was pretty excited to get these installed late last year and I tracked their performance (albeit through he Victron readouts as I felt the bluetooth on the batteries was redundant and not important to check). After tracking the power consumption for several days I figured we could get at least two, possibly three nights out of the batteries assuming we had no solar and no generator to recharge.

I'm going to go back and run the other tests recommended by Alan and others. When I checked the battery terminals with a multimeter yesterday, they showed about 13.41V and 13.3V respectively.

Finally, this could not have come at a better time (read sarcasm here) as I'm having knee replacement surgery this coming Tuesday (Argh!). So if I don't get it figured out today or Monday, it may be several weeks or a month or two before I can get back in there. I will keep everyone posted on any meaningful responses from SOK. So far they just keep asking for screen shots of the bluetooth readout from the batteries.

[alanmalk]

Originally Posted by DT6

... When I checked the battery terminals with a multimeter yesterday, they showed about 13.41V and 13.3V respectively.
...

We need to know a bit more than just individual voltages.

Since you gave us 2 different voltages I think it is safe to assume that the batteries were disconnected from each other.

Were they also disconnected from the system - meaning, not being charged or discharged? If that is true then both 13.4 and 13.3 are fine - probably close to 100% of full charge. But that said, with lithium it is very difficult to estimate percent of charge from voltage alone, so that is just an educated guess.

[DT6]

Yes, I disconnected the batteries yesterday, then checked the voltages. I've got a LiFePO4 capable charger that I use to recharge my 40Ah lithium battery that I use to run my astronomy gear. I'm going to bring one of them inside and hook it up to the charger and see what that does.

Still getting the slow-roll from SOK. Got an email today asking if the batteries were hooked up to solar (which I already stated they were), and they also asked the capacity of the solar (again I already provided this). I'm not at the point yet where I wish we had spend the Extra $$$$ for BattleBorn, but getting there.

[DGLP]

Originally Posted by DT6

I have plans to install a direct DC connection to the CPAPs, and we even ordered the wiring stubs for that purpose. However it is something I planned to put off until January when we take our 2-months in the southwest. So currently running on the inverter, but we only run the air on the CPAP not the air warming/humidifier. When we had our 19 we just had the 225Ah lead acid Interstates and they always worked without issue, although we ran them down probably 40 to 50 percent each night, but we were not being careful and were running the humidifier on one of the CPAPs (which we no longer do).

The SOKs also have the built-in heater and shutoff which was my main reason for purchasing these. We live in Oregon near Salem and while it gets below freezing sometimes in the winter, however it is usually not prolonged, so I don't see the need to remove the batteries for the winter, but maybe I should??

I was pretty excited to get these installed late last year and I tracked their performance (albeit through he Victron readouts as I felt the bluetooth on the batteries was redundant and not important to check). After tracking the power consumption for several days I figured we could get at least two, possibly three nights out of the batteries assuming we had no solar and no generator to recharge.

I'm going to go back and run the other tests recommended by Alan and others. When I checked the battery terminals with a multimeter yesterday, they showed about 13.41V and 13.3V respectively.

Finally, this could not have come at a better time (read sarcasm here) as I'm having knee replacement surgery this coming Tuesday (Argh!). So if I don't get it figured out today or Monday, it may be several weeks or a month or two before I can get back in there. I will keep everyone posted on any meaningful responses from SOK. So far they just keep asking for screen shots of the bluetooth readout from the batteries.

Have you considered a portable battery to use as a backup for the CPAP?

Good luck with the knee replacement! I'm planning to have mine done next spring.

[Mike G]

Originally Posted by DT6

Still getting the slow-roll from SOK. Got an email today asking if the batteries were hooked up to solar (which I already stated they were), and they also asked the capacity of the solar (again I already provided this).

One is not encouraged about a company's technical prowess when one is faced with their apparent lack of reading comprehension skills! Best wishes getting this resolved, and for a great surgery outcome.

[alanmalk]

Originally Posted by DT6

Yes, I disconnected the batteries yesterday, then checked the voltages. I've got a LiFePO4 capable charger that I use to recharge my 40Ah lithium battery that I use to run my astronomy gear. I'm going to bring one of them inside and hook it up to the charger and see what that does.
...

Using an amp meter (the amp position on the multimeter if it is high enough) can provide useful information.

For example, I set my charger to 10 Amps and keep a casual eye on it. When the current drops from 10 to 0.1 or so, then I know the charge is finished. If it took 4 hours then the charging replaced 40 Amp-Hours.

All this jumble of numbers should be taken care of by your Victron - assuming of course that everything is working as it should. Possibly not - in your case.

[John in Santa Cruz]

Originally Posted by alanmalk

Using an amp meter (the amp position on the multimeter if it is high enough) can provide useful information.
...

most multimeters handle a MAXIMUM of 10 amps, and have an internal fast blow fuse if that's exceeded. I generally avoid using this mode, and when I do need it, I have to be very careful with it. In particular be sure to switch it OUT of Amps mode the moment you are done, and move the + lead back to the normal + input port.