I have a Growatt ES 5000, that  was paired with a 48V 2.4 kw 50AH LifePO4 battery for about ten months. I upgraded to a 48V 5.09 kw LifePO4 and added some panels.

So, I was having a chat with this installer who asked why don't I have just add my previous battery(2.4 kw)to the system and this obviously piqued my interest. Is such a scenario possible? The batteries are both 15s with the same BMS(PACE).The other difference is that the 5.09 kw battery is using pin connectors, while the 2.4 kw battery uses 10mm nuts. This obviously poses a challenge on what kind of parallel cable to use, or can one be custom made for this purpose?

I have tried to look into the possibilities of such a set-up and getting conflicting information, some say it can be done while some say it should be completely avoided. Any insight on this possibility?

As long as packs are on the same voltage (15S, then 48v), no problem. Your installer either lacks basic training in his trade or just wants to sell you a battery ...

If both batteries use the same BMS, it's even better as you can set them up as slave & master then both can communicate with the inverter.

If electrical connectíon for both batteries is different, you could use busbars :

- 1 busbar for +, 1 busbar for -

- 3 points of connection for each busbar : inverter, battery1, battery2

You can buy an overpriced busbar (Victron for example) or DIY : a piece of pure copper large enough to accomodate 3 cable lugs and sized vs batteries cables. Typically 35mm2, then busbar = 3.5mm x 10mm x enough length to accomodate 3 lugs. Something like 100 mm ... Should cost you no more than 10 USD for 2 busbars of that size.

 

Even if batteries were of different voltage (15S/48v + 16S/51.2v), you could mix them : BMS of each batteries would stop accepting charge / discharge at individual cut-off anyway ... That might not be practical if one fully cycle their batteries as some BMS may shut down when battery reach cut-off but it's feasible ...

Edited November 18, 20232 yr by zivva

1 hour ago, zivva said:

As long as packs are on the same voltage (15S, then 48v), no problem. Your installer either lacks basic training in his trade or just wants to sell you a battery ...

If both batteries use the same BMS, it's even better as you can set them up as slave & master then both can communicate with the inverter.

If electrical connectíon for both batteries is different, you could use busbars :

- 1 busbar for +, 1 busbar for -

- 3 points of connection for each busbar : inverter, battery1, battery2

You can buy an overpriced busbar (Victron for example) or DIY : a piece of pure copper large enough to accomodate 3 cable lugs and sized vs batteries cables. Typically 35mm2, then busbar = 3.5mm x 10mm x enough length to accomodate 3 lugs. Something like 100 mm ... Should cost you no more than 10 USD for 2 busbars of that size.

I want to agree on this answer. Most manufacturers will indicate you cannot put their batteries in series. Although each has a BMS balancing cannot take place between cells in different batteries. BMS comms would be a major stumbling block for series. Above meant for 48V as I have no info on higher voltage systems. 

On the 12V drop in batteries series is allowed and adding a balancer is nearly if not a must. 

Please correct me if I have it wrong. 

It's parallel connection here, not series.

Manufacturers generally forbid the use of other batteries with theirs ... As they want to sell you their batteries 🥳

Still they have no way to tell if their battery has been used with another one ...

4 hours ago, Scorp007 said:

I want to agree on this answer. Most manufacturers will indicate you cannot put their batteries in series. Although each has a BMS balancing cannot take place between cells in different batteries. BMS comms would be a major stumbling block for series. Above meant for 48V as I have no info on higher voltage systems. 

On the 12V drop in batteries series is allowed and adding a balancer is nearly if not a must. 

Please correct me if I have it wrong. 

I know this post is not about series connection but you shouldn't run batteries in series that are not meant to be run in series.

On 2023/11/13 at 9:36 AM, JoeMobstarr28 said:

I have tried to look into the possibilities of such a set-up and getting conflicting information, some say it can be done while some say it should be completely avoided. Any insight on this possibility?

There should be no problem running different sized batteries in parallel as long they have the same cell chemistry and the same amount of cells make up the respective batteries. If both batteries are in decent shape, then they should divide the load between them, based on their capacities, so in your 2.4kWh and 5.09kWh scenario, lets assume you're drawing 3kW, then the smaller battery should supply just shy of 1kW and the larger one, just over 2kW, so percentage wise, they should split the load based on their respective capacities.

Now, if you are using BMS comms to the inverter, this is where a problem may come in. The 2 BMS' may not want to co-operate and this is where things could get weird. You could just use Voltage based battery settings on the inverter, but then SOC etc. would be iffy calculation and very far from accurate.

Edited November 18, 20232 yr by Kalahari Meerkat

12 minutes ago, Kalahari Meerkat said:

 

Now, if you are using BMS comms to the inverter, this is where a problem may come in. The 2 BMS' may not want to co-operate and this is where things could get weird. You could just use Voltage based battery settings on the inverter, but then SOC etc. would be iffy calculation and very far from accurate.

He said both batteries have pace bms's so they should work fine together.

19 minutes ago, Kalahari Meerkat said:

problem may come in

 

6 minutes ago, Tinbum said:

should work fine together

 

Sorry guys I missed the 48V and misread the 2.4kWh as 24V. 

Need new specs. 

May be someone can help. Since yesterday all text on the forum is very small. Running in Chrome. What can I do? 

 

Edited November 18, 20232 yr by Scorp007

9 minutes ago, Tinbum said:

He said both batteries have pace bms's so they should work fine together.

Let me clarify, I'm saying it may not work, you're not guaranteeing it will work, since quite a few scenarios have been mentioned, where people added a battery or two, to an existing set, but the BMS firmware versions were different, even though it was the same battery model and capacity, but since the firmware versions were different, they did not play nicely together until firmware versions were the same. Now this may not be the case with these batteries, but since they are of different capacities, I rather stick to my thinking that they may give him trouble in BMS comms mode, but then Voltage mode would still work and should be fine as well.

2 minutes ago, Scorp007 said:

May be someone can help. Since yesterday all text on the forum is very small. What can I do? 

Ctrl + scrolling wheel in my case zooms in or out, depending on the scroll wheel direction...

Just now, Kalahari Meerkat said:

Ctrl + scrolling wheel in my case zooms in or out, depending on the scroll wheel direction...

No Cntl on a cell? I have changed it under settings but it makes no difference.

2 minutes ago, Kalahari Meerkat said:

Ctrl + scrolling wheel in my case zooms in or out, depending on the scroll wheel direction...

Ctrl + to zoom in and Ctrl- to zoom out

1 minute ago, Scorp007 said:

No Cntl on a cell? I have changed it under settings but it makes no difference.

Using a cell phone, jy's seker gepik in die bol? Well, for us older fogies, met die brille en die pille, there may be a font size option setting under the control panel / display setting, that's Android, can't remember the rotten Apples settings anymore...

16 minutes ago, Kalahari Meerkat said:

Well, for us older fogies, met die brille en die pille

So true I simply cannot do any of this on my phone 🤪
I watched a guy film a video on his phone and then proceed to do hectic editing of that video also on his phone, no freaking idea how these yougsters do this s$#%%

🤣

And just a note I have been in IT my whole life...

15 minutes ago, WannabeSolarSparky said:

And just a note I have been in IT my whole life...

Since '87 to '08 also in IT, now I just get so cheesed off that I can't see properly anymore. Cell, phone, time for a good old fashioned GSM style only phone, none of this touchscreen sh*t that I can't see enough, except if I have a magnifying glass handy... give me a PC and a half way decent display >24" and I'm sort of ok, but even the laptop these days is becoming a problem and going back to 800x600 display on a 14" ain't on the cards, need more display real estate...

I don't know whether you ever saw/used Ventura Publisher on the PC pre Windows/DOS days, they used GEM graphical interface and they had this thing scrolling left and right up and down, smoothly, so it gave you a *LARGE* display area, but due to the monitors limitation, you would have to, by moving the mouse to the edge, where you wanted to go to, scroll that way and your effective display area was huge. This would be useful nowadays, must have a look, maybe something like this exists for X...

What is most annoying is think for us without a choice. Just bought a Samsung micro card this week. Guess what. Samsung decided to supply it with all the folders for a Android phone. Even every folder for Android. No mention was made about this. I prefer to get it clean. My be getting too old now. 

As can be seen. Only the reply will adjust text size as per setting of text in the browser. 

2 minutes ago, Scorp007 said:

What is most annoying is think for us without a choice. Just bought a Samsung micro card this week. Guess what. Samsung decided to supply it with all the folders for a Android phone. Even every folder for Android. No mention was made about this. I prefer to get it clean. My be getting too old now. 

As can be seen. Only the reply will adjust text size as per setting of text in the browser. 

The moment the reply is posted... Bang back to find the hidden treasure to read any word. 😉😉

3 minutes ago, Scorp007 said:

As can be seen. Only the reply will adjust text size as per setting of text in the browser. 

Okay, Settings -> Accessibility -> Visibility enhancements -> Display mode - choose - Large display...

time to turf the cellphone and get a tablet instead 🙂

Just now, Kalahari Meerkat said:

Okay, Settings -> Accessibility -> Visibility enhancements -> Display mode - choose - Large display...

time to turf the cellphone and get a tablet instead 🙂

As I indicated I did use it and set to 175% but it only helps while typing the msg. Once posted it is back to small. 

I find the problem only on this forum. Using the same browser no change on other forums. 

17 minutes ago, Scorp007 said:

I find the problem only on this forum. Using the same browser no change on other forums. 

I have not noticed anything different here with the browser on my PC, not sure whether any changes were made, @Energy-Jason have any changes been made to the web server that would cause @Scorp007's font size issues on his Android device?