question

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marktj asked

Energy storage

I am looking to build a battery storage system to take avantage of cheaper electricity at night. I also want the ability to add solar later. Idealy I would like to begin with a simple system that charges at night and runs off batteries during the daytime. I have not purchased anything yet but I am looking at SOK 48v server batteries and a Multiplus 2 complete system with Cerbo GX for monitoring etc. I have spoken to a few installers and they all try to push me to their preferred solutions that always seem to put me into a system that someone else is controlling. My question is, am I on the right track? Is what I want possible and is my proposed choice of equipment the right way to go? I am a newbie so any help would be appreciated here, thanks.

Multiplus-IIMultiPlus Quattro Inverter Charger
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nickdb avatar image
nickdb answered ·

Batteries are the most important (and expensive) part of the system, it is vital it communicates well with the ecosystem.

If they don't, then you can end up with an unstable system.

This is the supported list:

https://www.victronenergy.com/live/battery_compatibility:start

3rd party can be used but you won't receive support.

These are all tried and tested and proven over many, many installs.

It is always advised to stick with what works well, especially if you are new to this.



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marktj answered ·

@nickdb Thanks for the advice I will look at batteries again, Pylontech were a strong contender and I did look at a few others on this list also.

I am more concerend with the correct choice of Victron hardware as there appear to be so many different ways to get to the same solution. My house is only 8-years old so all the wiring is very recent, we do get power outages here in Northumberland and I want to be able to go back to the grid automatically if the load is too great for the batteries or the SOC becomes too low.

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nickdb avatar image nickdb ♦ commented ·
You can do all of that with the native features of the inverters, both quattro and multi. You just need to pick the right size for your loads.

Never plan to run at 100% of the rating and ideally do some measurements with a clamp meter or such.

You would effectively run as a solar-less ess, leveraging schedules for charging.

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marktj avatar image marktj nickdb ♦ commented ·
Thank you for your advice, very much appreciated.
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Alexandra avatar image Alexandra ♦ marktj commented ·
@marktj

On the other hand with third party batteries and a BMV you can have a pretty stable decent ESS system.

The BNS and cell monitoring can be done locally with many BMS nowadays. And once they are stable don't usually need much attention.

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marktj avatar image marktj Alexandra ♦ commented ·

Thanks @Alexandra , SOK batteries do have a built-in BMS and say they are fully compatible with Victron systems but Victron dont mention SOK so I guess they are not recommended. If I were to decide to use SOK would I need to use the Victron BMS as well? I am only liking SOK because of their serviceability and build quality, Pylon are probably just as good as batteries.

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Alexandra avatar image Alexandra ♦ marktj commented ·
@marktj

We have plenty of systems running in the field with BMS that have no direct communication with the GX device with no issues. Some even strange long-name-no-can-say been running for years.

The ESS assistant works perfectly when you add just the BMV to the system and set it up correctly. As long as there is accurate SOC communicated to the system it will be stable.

The BMS is not necessary and only works with Victron batteries anyway.

At the end of the day it is up to you. The SOK looks like a solid battery I have never personally used them.

And before lithium there was lead acid with no comms that is where the BMV became a star.

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marktj avatar image marktj Alexandra ♦ commented ·
@Alexandra thanks for your time and reply. I will just delay slightly for (hopefully) the VAT to drop over the next week or so :-)
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