Looking at SOK SK48V100-NCBT Base - Worth it to Pay Extra For Communication, 100A & UL Cert?

[AdvicetotheGraduate]

This will be a grid tied system and will have 32ct 455W panels running 14,560 watts. I have narrowed down my inverter choice to the EG4 18KPV and the Sol-Ark 15k. The difference between the EG4 18KPV and the Sol-Ark is $1,400. My preference is to go with the Sol-Ark.

I was originally planning on going with the EG4-LifePower4 30.72kWh rack for $8,103 ($263.77 per kWh) until I read a thread with lots of recommendations for SOK. I checked out Current Connected and found their base battery rack is $5,751 ($230.07 per kWh) which is a significant price delta of $2,352 in favor of the SOK.

I use an IotaWatt to monitor power consumption and I don't predict the 80amp limitation vs the SOK PRO will be an issue.

The UL cert does not really concern me as long as it does not represent a safety issue.

What I am concerned about is the lack of communication on the batteries. It is my understanding these batteries will not "talk" to the inverter, and so the battery information will not be accessible on the inverter. The SOK Base unit does have Bluetooth functionality so I would be able to monitor the batteries if needed.

My goal is a set it and forget it type of system, and if a battery that cannot communicate means that I will have to be constantly tinkering with the batteries, checking their status all the time and verifying they are balanced, etc, then the extra $2,352 would be worth it to me.

If the communication is just a nice to have bonus but not needed, then I would prefer to save the money and load up on more batteries.

Also, if the choice of inverter I mentioned above factors in I would appreciate a heads up (e.g. the Sol-Ark does great with batteries that do not communicate, etc)

Thanks ahead for any feedback.

 

[sunshine_eggo]

If the communication is just a nice to have bonus but not needed, then I would prefer to save the money and load up on more batteries.

It's 99% preference. Comms can enable a little more functionality if you want certain actions based on SoC.

If the batteries are in good shape, proper programming of the AiO parameters are all that's needed for hands-free, trouble-free operation.

@timselectric has a strong opinion on NOT using comms.

I LOVE the comms between my Batrium and my Victron system, but that's about remote monitoring, control and data logging. I tinker with it to no end, but that's because I'm obsessive about it. When I leave it alone, it's fine without me.

 

[timselectric]

Yup
Just personal preference

 

[AdvicetotheGraduate]

Without communication will the inverter know the state of charge of the batteries? For instance, if I want to use batteries at night then have grid power kick in at 30% state of charge, is that possible without comms?

 

[timselectric]

Without communication will the inverter know the state of charge of the batteries?

I wouldn't think so.

For instance, if I want to use batteries at night then have grid power kick in at 30% state of charge, is that possible without comms?

Would probably have to be set according to voltage instead of %.

 

[marionw]

Are you sure you can't have BMS communications between the Sol-Ark-15K. The Sol-Ark-15K (page 35) appears to have an RJ45 for BMS communications using either RS485 or CAN. The SOK batteries have an RS485A port that is specifically for BMS communications to an Inverter. Just need to make sure the Inverter can be set to use the Pylontech protocol.

Just double check both the Sol-Ark-15K Inverter and SOK battery manuals

 

[AdvicetotheGraduate]

I wouldn't think so.

Would probably have to be set according to voltage instead of %.

Thank you! I think I'll roll with the batteries with communication. I think the SOK without comms would be great for someone willing to tinker a bit more. I'm looking for an experience geared towards knuckle draggers such as myself.

 

[42OhmsPA]

@Kenny_ comms or no comms?
You've used both.

If the system is inspected one may want the UL for inspection reasons, I'd add batteries after the fact if that's the case.

Edit to add I've been running without comms, open loop, for over a year with 0 issues that weren't user induced.
I do have my BMS's communicating with Solar Assistant.

 

[zanydroid]

If it’s grid tie you need to do some or all of (1) be in a AHJ that doesn’t care about 9540 (2) install battery after pre PTO inspection (3) be aware of the different power consumption and export signature a battery will create (both in normal operation and when the config goes , this is a very complex and bleeding edge inverter), which could well be detectable by your POCO and lead to awkward questions and slap butthurt about (2).

If you want to be extra special you can install one battery to excuse your battery behavior signature. And then nautily add more. Still can give a different signature for 2 vs 1 battery but there are far fewer signature changes than for 1 vs 0 batteries.

 

[timselectric]

Same here. I've done it both ways.
I prefer to have my BMS (battery management system) only in charge of the battery.

 

[G00SE]

Sok also has UL cert batteries. Priced a bit more than their basic batteries but well worth the ability to replace your own internals.
I’m quite certain current connected has dabbled with sol-ark and sok comms at some point as well. Maybe they will chime in

 

[G00SE]

Without communication will the inverter know the state of charge of the batteries? For instance, if I want to use batteries at night then have grid power kick in at 30% state of charge, is that possible without comms?

It is with a smart shunt and solar assistant

 

[marionw]

The EG4-LifePower4 are great batteries (I have 6) but I suspect you will need an EG4 Communications Hub for closed loop comms between the batteries and the Sol-Ark-15K. The SOK batteries are the same as the Sungoldpower (SGP are clones, I have two) and they are also good batteries. Both can communicate with Solar Assistant as well. The SGP batteries use the Pylontech protocol on their RS485A port, the master would connect to the inverter using this port.

 

[AdvicetotheGraduate]

It is with a smart shunt and solar assistant

I am intrigued... the SOK Base does not have a communication port, so the smart shunt connects to the battery terminal which connects to the Raspberry Pi which connects to the Sola-Ark / EG4 18KPV?

Like this?
BATTERY ----> SMART SHUNT ---> RASPBERRY PI ----> INVERTER

 

[Kenny_]

@Kenny_ comms or no comms?
You've used both.

If the system is inspected one may want the UL for inspection reasons, I'd add batteries after the fact if that's the case.

Edit to add I've been running without comms, open loop, for over a year with 0 issues that weren't user induced.
I do have my BMS's communicating with Solar Assistant.

Yep... I had lots of strange issues running closed loop... But running smooth as silk open loop. Using Solar Assistant to report on batteries independent of the inverter Sungold 10k48
...

 

[G00SE]

I am intrigued... the SOK Base does not have a communication port, so the smart shunt connects to the battery terminal which connects to the Raspberry Pi which connects to the Sola-Ark / EG4 18KPV?

Like this?
BATTERY ----> SMART SHUNT ---> RASPBERRY PI ----> INVERTER

I don’t know that it could be done with the base batteries that lack the comm ports.

 

[timselectric]

If the 6kxp can receive mode change commands from Solar Assistant (I believe that it can). Then Solar Assistant can change the modes based on the SOC information from the shunt.
No battery connection required.

 

[marionw]

The latest Solar Assistant can also make scheduled changes to certain inverter operating parameters (you create the schedule).
BATTERY (entire stack)----> SMART SHUNT (current only)---> RASPBERRY PI <---> INVERTER

SA will not be able to monitor individual batteries which it can do whether you operate in closed or open loop as long as the batteries have communication ports

Personally I would not buy a battery that I could not connect to a computer. SOK (with communications port), SunGoldpower (SOK Clone) or EG4 Lifepower4 batteries come with software (or you download it) which allows you to to drill down into the battery to monitor individual cell voltages as well upgrade BMS firmware. Most also come with a longer warranty as well. For me this is a gamechanger since I am investing in something I hope will last 10 plus years. The ability to diagnose a possibly ailing battery for me is a necessity.

You will always have the option to run open or closed loop and I suspect you would try/experiment with both. A bit more investment but for me it was worth it.

Research, consider all options and go with what you feel will work for you