24v vs 48v inverter

[CaptMichel]

"Is there anyone having experience with the 24v Eg4 in series and parallel ?

I presently own a 24v dc converter magnum 4kw split phase 120/240
I am planning to replace my wet cell batteries with Eg4 24v-200ah
So all 24v in parallel and done.
But,
Eventually I will need to update my system to 8kw and to do this with magnum is complicated and costly
Need to purchase another magnum 4kw $1,750 approx
then many items at a cost of $1.5k minimum to connect them both together to achieve 8kw
So all this consider should I sale the magnum ?
Start from scratch and get a 48v inverter and the 48v Eg4
If S/P is a bad idea for the Eg4 then it's a no brainer

Also any recommendation for the batteries or inverter are welcome...
thanks

 

[Don B. Cilly]

Well, if you want to achieve 8kW, it's probably because you plan to use some 4-5 often enough, right?
24V is a bit "skimpy" for that. You should really go 48.
-

 

[schmism]

I'm happy with my 3kw Growatts (I have 2) which can be paralleled to up to 6 units. (and true 240v split phase). 6units supporting 18kw @ 48v and 6 MPPT SCC supporting 4kw PV each. 24kw PV total

At about $750 each its a simple choice for me. you could buy an extra unit and put it on the shelf as backup incase china quality bites you and you'd still be ahead money wise.

my vote, sell the old dinosaur tech and move on.

 

[timselectric]

I would never recommend putting batteries with BMS's in series. If you need 48v, buy 48v.

 

[timselectric]

Also a big fan of Growatt. You can't beat what you get for the money.

 

[rhino]

I would never recommend putting batteries with BMS's in series. If you need 48v, buy 48v.

This^. If one of the 24V batteries in series for a 48V system trips its BMS then you now have a 24V battery system connected to your 48V system.

 

[timselectric]

This^. If one of the 24V batteries in series for a 48V system trips its BMS then you now have a 24V battery system connected to your 48V system.

Actually, you have zero power.
The reason why you shouldn't put them in series is because the BMS's balance their cells individually. So, the batteries get out of sync with each other. Which requires regular maintenance. (Disconnecting and charging individually periodically)

 

[rmaddy]

Actually, you have zero power.
The reason why you shouldn't put them in series is because the BMS's balance their cells individually. So, the batteries get out of sync with each other. Which requires regular maintenance. (Disconnecting and charging individually periodically)

For what it's worth, as a single data point, I've had two 12V LiFePO₄ batteries in series running loads 24/7 for the past 10 months and both batteries are still perfectly balanced. So far no maintenance has been needed. The key is to take extra steps to properly balance them together before connecting them in series. I think people that have issues are not balancing them together properly first. There's more to it than just fully charging each one.

Having said that, I went with two 12V for a 24V system because at the time there were virtually no 24V LiFePO₄ options.

 

[time2roll]

So, the batteries get out of sync with each other. Which requires regular maintenance. (Disconnecting and charging individually periodically)

There is a balancer to automatically take care of this too.

 

[robby]

"Is there anyone having experience with the 24v Eg4 in series and parallel ?

I presently own a 24v dc converter magnum 4kw split phase 120/240
I am planning to replace my wet cell batteries with Eg4 24v-200ah
So all 24v in parallel and done.
But,
Eventually I will need to update my system to 8kw and to do this with magnum is complicated and costly
Need to purchase another magnum 4kw $1,750 approx
then many items at a cost of $1.5k minimum to connect them both together to achieve 8kw
So all this consider should I sale the magnum ?
Start from scratch and get a 48v inverter and the 48v Eg4
If S/P is a bad idea for the Eg4 then it's a no brainer

Also any recommendation for the batteries or inverter are welcome...
thanks

I would get an MPP LV6048 and some 48V SOK rack mount batteries.
I would also look at Wills affiliate link for Watts247 for the Inverter and his SOK link for the batteries.
It will save you some cash and MPP and SOK have a pretty good reputation.

 

[toms]

Actually, you have zero power.
The reason why you shouldn't put them in series is because the BMS's balance their cells individually. So, the batteries get out of sync with each other. Which requires regular maintenance. (Disconnecting and charging individually periodically)

I’ve seen as many balancing issues with seperate batteries in parallel as i’ve seen with batteries in series (essentially they have the same balancing issues).

Ideally you wouldn’t do either, but if you setup your system with the access to individually charge each seperate battery at its nominal voltage you can make it work.

 

[timselectric]

Of course, there are always ways to deal with any balancing issues. I just prefer not to have to.
Starting right, is always my choice.

 

[HRTKD]

I’ve seen as many balancing issues with seperate batteries in parallel as i’ve seen with batteries in series (essentially they have the same balancing issues).

Ideally you wouldn’t do either, but if you setup your system with the access to individually charge each seperate battery at its nominal voltage you can make it work.

Balancing parallel batteries can be handled in how the batteries are wired. Series, you're kind of stuck and at the mercy of the BMS.

Of course, there are always ways to deal with any balancing issues. I just prefer not to have to.
Starting right, is always my choice.

Agreed. If you need 24v or 48v then build an actual 24v or 48v battery.

I have two 4s batteries paralleled in a 12 volt system. If I lost my mind and decided to switch to a 24 volt system I would take those eight cells and go 8s, even though it meant the purchase of a new BMS.

 

[CaptMichel]

I would get an MPP LV6048 and some 48V SOK rack mount batteries.
I would also look at Wills affiliate link for Watts247 for the Inverter and his SOK link for the batteries.
It will save you some cash and MPP and SOK have a pretty good reputation.

Thanks for the advice appreciated