SOK disappointment. Am I expecting too much?

[Sam Cho TX]

Battery heating pad will only work when your system is connected to shorepower, with an active charger online, like a multiplus. One could mod it to come on when off grid, but with 9 amps or so, you get reduced usage. SFK has a setup like that.

If sensor are not working or suspect, it is easy enough to open it and stick it into ice water cup.

BMS all defective (not working as expected?), yes, that is obvious. Why do they have a new BMS V3. Why do all the dealers (a few openly admitted there is an issue). Even their competitors know about it. Come on, be honest, fix the guys BMS, send him new ones. Don't be cheap.

I have one concern regarding those who are using 24 or more volts system. There are things that must be done right. Be careful mixing voltages otherwise you will fry. Hopefully this isn't the case here.

I have the SFK v3 battery kit with the 150 BMS and the external switch with side heating pads. It works great. I just leave it on the green mode and on average I draw only 5-6 Ah for the entire day on cold days, most other days it never even runs so no amp draw. Its been that way for about 3 months now I think I'm going to turn it off now that the winter is pretty much over with in the south.


I'm glad I didn't order the 200 amp I never understood why they made heating only work on certain situations instead of allowing manual control.

I think the heating button is the way to go, add heating to any BMS you want. 150AMP is waaaayyy more than I need but strong enough to run a coffee pot.


I will post a build thread, I have a v4 kit on order with the 304 cells.

 

[Aly_Oops]

Grreat to hear all okay. I only have the SOK marine/bluetooth/heater unit. Which I bought to test before ordering 3 more. Had issue with balancing and not able to saturate the cell once. Total voltage would never go over 13.9. SOK eventually send me another BMS, I am assuming it the V3 that is currently in new stock of SOK. Easy to install and took a close look, should be no problem to install a third party BMS and balancer if needed.

With the new bms, balancing has improved from over 300 to 20mv, however, I still can not saturate the cell even once. However with long absorption time, the best total voltage I could get is 14.3 vdc.

The heating is the way this unit operates. I don't have the need, but I could add an overide switch to power the pad.

 

[brum]

14.3V is pretty good. Likely you have all cells above 3.5V and this means that they are kind of fully charged/saturated. Don't keep your battery at that voltage for a long time. Keeping LiFePo4 cells above 3.4V will degrade them faster from what I read.

 

[Aly_Oops]

Unfortunately with my SOK 206 I have, it never charges to 3.5. It won't allow me to saturate at least once. They have the parameter lock out, so can not put in correct parameters. All my other batteries, they hit 14.6 during absorption which means 3.65. If you can not saturate one time, then a reading of 3.4 or under 14.0 does not gurantee that it has reach SOC.

No, keeping cell at 3.4 will not degrade, it someone reading graphs only and making those conclusion. Even if that was the case, your Van or RV will rot before you use up the cycles. It just marketing BS. 3.5 to 3.6 is all okay. Also 2.6-27 is not an issue.

This SOK 206 is just now a kick around battery. We switch over to 3 x 300 and it behave exactly as expected and their app allow to view and make changes to match your setup and has smart BMS, communicates with my Victron System.

Sorry SOK, but until you fix and open up your app, I have warned all my clients and contact to stay away until it fixed.

 

[brum]

Just to be sure I'm getting it correctly - you want to saturate the battery just once to force 100% SOC calibration, right? And you don't want to keep them for a prolonged time (like months) at that voltage?