Solark 15K and different batteries

[Kassi205]

I am having a 9KW system with a solark 15 k installed. I have 30kw of Eg4 V2 batteries being installed. I am considering adding more batteries and am told I should ad Homegrid batteries. Can you mix battery brands like that if they are both the same chemistry?

 

[timselectric]

Same type (chemistry) and nominal voltage, yes no problem.
As long as you don't need them to communicate.

 

[Nobodybusiness]

I am having a 9KW system with a solark 15 k installed. I have 30kw of Eg4 V2 batteries being installed. I am considering adding more batteries and am told I should ad Homegrid batteries. Can you mix battery brands like that if they are both the same chemistry?

The EG4 s are fine.
Why the Homegrid recommendation?

I would just add more Eg4s.

Yes you can run them together as long as it’s not closed Comms.

 

[Kassi205]

@Nobodybusiness, thank you for responding. I am a novice, so I hired a solar installer to do my job. The Solar installer is saying I should use the home grid but I already have the 30KW EG4 V2 ready to be installed so he suggested adding home grid instead of more EG4. Mine is the first job he is doing with EG4. I suspect he is just more comfortable with the Homegrid and may make more profit but they do look like something I could add new modules to myself without bothering with him later so I am curious now.

 

[chrisski]

I am having a 9KW system with a solark 15 k installed. I have 30kw of Eg4 V2 batteries being installed. I am considering adding more batteries and am told I should ad Homegrid batteries. Can you mix battery brands like that if they are both the same chemistry?

I would choose one battery whether or not you will be doing battery communication since it appears the 15k can communicate with a battery:

"The Sol-Ark 15K-2P-N inverter achieves battery communications through a single RJ-45 port labeled “Battery CANBus”. This port combines the Modbus andCAN bus pin configurations shown below. Both “Modbus RS485” and “Battery CANBus” ports are capable of Modbus communication."

When I look at the spec sheets both batteries are both close enough spec wise, but the price of the EG4 is less.

With no other differences I would not go with the Homegrid and use the EG4. What may change that is if the installer sells homegrid only and not EG4s. It will come to how well will after sales support be on a product he is not familiar with.

Mine is the first job he is doing with EG4.

I would be somewhat hesitant to be the test subject on a first install. Is there anyone that has installed or is qualified for this? I don't see qualified installers listed on the EG4 website, or any support listed for installers.

 

[42OhmsPA]

Might want to check this out.
Post in thread 'Solark tech support recommended not to use closed loop with EG4 battery. Newbie checking in.' https://diysolarforum.com/threads/s...battery-newbie-checking-in.84737/post-1130484

Edit to add, I'd run open loop on all of them.

 

[Nobodybusiness]

D

 

[2TrevorJ]

I've had a great experience with my HomeGrid setup but it's a 15-cell setup so it won't play well with 16-cell batteries (like most other server rack types).

I also wouldn't be too keen on dumping 30 kWh of storage that's already on site. Yeah, Homegrid's are great and are like PB&J with a Sol-Ark but that's one serious up-sell from the installer.

 

[timselectric]

So, the answer is no.
They are not the same nominal voltage.

 

[LydMekk]

This ^^.
Don't mix them.
I would stay with the EG4s and more of them if needed.
If issues with BMS comms, just run voltage on the Sol Ark. Works well.

 

[Carlos_Sol-Ark]

You should not mix the batteries. Any given battery bank should be made entirely of the same battery make and model. Just some of the problems I could think of with mixing them is charging voltages not being the same and the Sol-Ark can only accommodate for a single charging pattern. You will also likely run into issues where the different batteries have different internal resistances leading to uneven charge and discharge rates. It's best to commit to one type and stick with it.

 

[glandpuck]

I agree. Do not mix them. When I last read about Homegrid batteries warranty, there was something I think about having to have them either connected to the internet or have a USB dongle that records the charging and discharging everyday to be available for warranty evaluation. also, I think their rated discharge is down to like 20% SOC, not 10% SOC. But check out the warranty documentation carefully.

Here is the biggest concern that should make you not want to mix batteries:

THE SOL-ARK 15 K HAS A PLUG IN PORT FOR THE BATTERY COMM. A SINGLE PORT. BATTERIES OF A LIKE KIND ARE DAISEY CHAINED AND A MASTER IS DESIGNATED AND CONTROLS ALL CHARGING COMMUNICATION FOR ALL INDIVIDUAL UNITS TO ACT AS A GLOBAL SINGLE BATTERY.
PLUG IN THE BATTERY CABLES AND THE COMMUNICATION IS EASILY ESTABLISHED WITH TWO SOFTWARE MENU CHOICES.

HOWEVER, SOL-ARK ADVISES THAT YOU ALSO SET THE MANUAL PARAMETERS FOR CHARGING AND DISCHARGINGTHE BATTERIES AND CUT OFFS IN CASE OF A COMMUNICATIONS FAILURE TO THE BATTERIES.

IF YOU PLUG IN THE EG4, HOW ARE YOU GOING TO MANUALLY SET PARAMETERS FOR THE EG4 BACKUPS AND THEN HOW DO YOU SET ANY PARAMETERS FOR THE HOMEGRID. THERE WOULD BE NO SECOND BATTERY TYPE MANUAL OPTION. SO ITS A BIG NO. ONE OR THE OTHER.

 

[teal95]

My original build had a rack of EG4 LL. Once inspection was done and the supervision (I did most of the install with him keeping an eye on me) left I added another rack. Not really that difficult.

 

[DIYrich]

I have EndurEnergy batteries in communication with the Sol-Ark 15k.
I also added a DIY battery with JK BMS with no communications.

System works fine. The DIY is along for the ride. The Comms limits battery charging/discharging to the EndurEnergy Batteries, but way over the 275 amp limit of the battery connection, so not an issue.

 

[2TrevorJ]

When I last read about Homegrid batteries warranty, there was something I think about having to have them either connected to the internet or have a USB dongle that records the charging and discharging everyday to be available for warranty evaluation. also, I think their rated discharge is down to like 20% SOC, not 10% SOC. But check out the warranty documentation carefully.

Homegrid's warranty is here:

HomeGrid

HomeGrid Website

www.homegridenergy.com

Hasn't changed since Apr-2023. No SOC limitations and no requirement for internet (the individual slabs internally record throughput energy over time for warranty purposes).

My battery setup isn't online and I discharge it regularly down as low as 5% SOC...the few times I've interacted with support they were cool with it.

About the only thing concerning is the 45*C top end limit. Yes...that is about when you should start worrying but you are likely to get there in a hot garage in the south in the summer. It's not that uncommon. Outside mounting would be even more problematic.

 

[Kassi205]

I would choose one battery whether or not you will be doing battery communication since it appears the 15k can communicate with a battery:

"The Sol-Ark 15K-2P-N inverter achieves battery communications through a single RJ-45 port labeled “Battery CANBus”. This port combines the Modbus andCAN bus pin configurations shown below. Both “Modbus RS485” and “Battery CANBus” ports are capable of Modbus communication."

When I look at the spec sheets both batteries are both close enough spec wise, but the price of the EG4 is less.

With no other differences I would not go with the Homegrid and use the EG4. What may change that is if the installer sells homegrid only and not EG4s. It will come to how well will after sales support be on a product he is not familiar with.

I would be somewhat hesitant to be the test subject on a first install. Is there anyone that has installed or is qualified for this? I don't see qualified installers listed on the EG4 website, or any support listed for installers.

I figured it would be better to have the solar installers put in the batteries with a licensed electrician than for me to do it. I just could get 30kwh with EG4 for the same price that 10kH would cost with Homegrid.

 

[chrisski]

figured it would be better to have the solar installers put in the batteries with a licensed electrician than for me to do it. I just could get 30kwh with EG4 for the same price that 10kH would cost with Homegrid.

Going with an installer and what he is used to is certainly a logical choice.

What bothers me is that he recommended a different battery that was 15S. A 15S battery is NOT compatible with 16S batteries you already purchased. Having a 15S battery is very unusual and an installer should know this and that this would be incompatible with most lithium batteries on the market.

I'm a little unclear if he recommended combining the batteries or not. If he did, I would really, really want a different installer and drop the one you have.

Whether or not you do use those EG4 batteries you already have is a tough choice. Instead of buying cells from China and making a battery myself, I opted to get a battery the installer regularly installed. Even when I expanded the battery pack, there was more of a temptation to build from Chinese Cells especially because no inspections are involved, but I went with the same type of batteries installed before.

 

[glandpuck]

I have EndurEnergy batteries in communication with the Sol-Ark 15k.
I also added a DIY battery with JK BMS with no communications.

System works fine. The DIY is along for the ride. The Comms limits battery charging/discharging to the EndurEnergy Batteries, but way over the 275 amp limit of the battery connection, so not an issue.

Very nice experiment. But not in places like California where fire codes and permits are the norm for battery installation.

 

[DIYrich]

Very nice experiment. But not in places like California where fire codes and permits are the norm for battery installation.

My comment was more in response to mixing batteries on the 15k, and not DIY additional battery when you need UL9540.