How many 280A LiFePO4 cells can you put in series?

[1.21 Gigawatts]

I intended to build a 16s 280A LV battery, but finding it hard to find a 3 phase LV inverter in Australia. I have created a thread about the possibility of using a DC to DC converter to up the battery to high voltage https://diysolarforum.com/threads/connecting-48v-battery-to-high-voltage-hv-hybrid-inverter.51749/

But alternatively, maybe i have to just buy more cells and build around a 60s battery of 280A cells. Is there any electrical reason why that wouldn't work? Or would be a bad idea?

The other obstacle would be finding a HV BMS capable of 60s. Anyone know of BMS that would support 60s, (192volt).

 

[MaximusAnonus]

Yes, people do build these. Yes it works. It opens a whole can of worms tho and I'm not sure it's actually that much cheaper than 3 inverters connected together.

 

[Synopsis]

You can configure 3 48v victron inverters to make a 3 phase.

 

[1.21 Gigawatts]

You can configure 3 48v victron inverters to make a 3 phase.

Nice suggestion. Huge expense tho, and a lot of wall space i dont really have.

 

[1.21 Gigawatts]

Yes, people do build these. Yes it works. It opens a whole can of worms tho and I'm not sure it's actually that much cheaper than 3 inverters connected together.

Good to know it can be done. I didnt know if there would be a limt to the amount to current that can flow through all those batteries.

It might not be cheaper, but at least your getting more capacity for your money. would be about 53kw. Im hoping i can get away with a DC to DC boost converter, but i have to wait until some expert replies to that other thread.

 

[1.21 Gigawatts]

I just found this video of a guy using Batrium & Goodwe HV inverter to build a HV battery

 

[740GLE]

Nice suggestion. Huge expense tho, and a lot of wall space i dont really have.

So 3 inverters takes up a lot of space but 60 280 cells in series is perfectly fine?

 

[1.21 Gigawatts]

So 3 inverters takes up a lot of space but 60 280 cells in series is perfectly fine?

the shelving i have in my garage takes up most the wall (which is fine to put batteries on) but has only left space for a single inverter. Regulations here in Australia restrict which wall i can place an inverter on.

But also, If im to spend more $$$ id much rather it on capacity, than inverters. The market really needs a 3 phase LV hybrid inverter.

 

[Synopsis]

You'll find the Victron inverters have a very healthy peak over-rate so 3 x 3KvA's would likely be sufficient for most uses in a 3 phase environment. I don't actually reckon they're that expensive for what they are - I was one of the early adopters of MPP Solar transformerless inverters and within months had 2 returns - blown fets and all sorts of issues.

Had a 5KvA Multiplus now for around 7 years and just can't kill it.

Pay cheap, pay twice.

 

[Synopsis]

Additionally, working with a 200V DC batt would scare the living S**T out of me. You're getting up into seriously dangerous voltages there and need to employ extreme caution when working on such a bank.

 

[740GLE]

Additionally, working with a 200V DC batt would scare the living S**T out of me. You're getting up into seriously dangerous voltages there and need to employ extreme caution when working on such a bank.

Agreed flip flops and a shirt required.

 

[MaximusAnonus]

Good to know it can be done. I didnt know if there would be a limt to the amount to current that can flow through all those batteries.

It might not be cheaper, but at least your getting more capacity for your money. would be about 53kw. Im hoping i can get away with a DC to DC boost converter, but i have to wait until some expert replies to that other thread.

I'm at like 80-90kWh with packs of 280Ah EVE cells from Amy and I'm going the 48V route if only because it's an extremely common and still safe voltage range.

 

[MaximusAnonus]

You'll find the Victron inverters have a very healthy peak over-rate so 3 x 3KvA's would likely be sufficient for most uses in a 3 phase environment. I don't actually reckon they're that expensive for what they are - I was one of the early adopters of MPP Solar transformerless inverters and within months had 2 returns - blown fets and all sorts of issues.

Had a 5KvA Multiplus now for around 7 years and just can't kill it.

Pay cheap, pay twice.

Old MultiPluses? Yes. The new ones look like some aliexpress specials tho.

 

[1.21 Gigawatts]

I'm at like 80-90kWh with packs of 280Ah EVE cells from Amy and I'm going the 48V route if only because it's an extremely common and still safe voltage range.

Ok but how are you connecting them? Do you have 3 phase power? or single phase?

 

[MaximusAnonus]

Ok but how are you connecting them? Do you have 3 phase power? or single phase?

I have separate 16S banks connected in parallel. It's single phase. It was more cost effective to rewire my stuff into single phase (or simply get a VFD) than going thought the trouble of 3 phase setup (and still having to deal with spikes from motor starting up).
Plus I'm a BIG advocate of redundancy. Can't have any redundancy if you spend all your money on 3 inverters for 3 phase power.

TBH this all depends on why you are doing this. Me myself I'm a little bit of a shizo. I enjoy the idea of being able to run without problems completely offgrid even with parts of my system breaking down (no single point of failure here). But if you just want to save money then just buy some 3-phase HF inverter, size it properly get a rack mounted battery pack that can communicate with the inverter of your choice and be done with it.

 

[1.21 Gigawatts]

I have separate 16S banks connected in parallel. It's single phase. It was more cost effective to rewire my stuff into single phase (or simply get a VFD) than going thought the trouble of 3 phase setup (and still having to deal with spikes from motor starting up).
Plus I'm a BIG advocate of redundancy. Can't have any redundancy if you spend all your money on 3 inverters for 3 phase power.

TBH this all depends on why you are doing this. Me myself I'm a little bit of a shizo. I enjoy the idea of being able to run without problems completely offgrid even with parts of my system breaking down (no single point of failure here). But if you just want to save money then just buy some 3-phase HF inverter, size it properly get a rack mounted battery pack that can communicate with the inverter of your choice and be done with it.

I already have 3 phase power and 20kw pannels running on a NON hybrid grid connected inverter. I of course want to store some of my energy and power myself through the night, and still be up if the grid goes down. I also already have 16x 280ah cells & a BMS, but didnt realise it would be so hard to add 48v to a 3phase system.

 

[MaximusAnonus]

Expensive and there is few choices out there? Sure. But hard?
I don't really understand what issue do you have.

 

[1.21 Gigawatts]

Expensive and there is few choices out there? Sure. But hard?
I don't really understand what issue do you have.

The issue i have is trying to connect a LV battery to a 3 phase system. I cant fit 3x inverter on the wall. I need a single unit that supports 3 phase, low voltage and is approved for grid connect in Australia. I cant find any.

So that leaves building a HV battery, but i needed ask see if putting say 64 x 280A cells in series would be an issue. Apparently not (tho dangerous). So now i just need to rob a bank, buy more cells, and find a BMS that can support such a setup. Looks like a batrium WatchMonCORE + 4x CellMate-K9 should do the job? Tho open other other options. Then i got to get that talking to a 3phase HV hybrid inverter like a GW-GW10KL-ET.

Really wish i could just get the 16x 280A cells i already have connected to my system.