Running 48v inverter from my 24v battery bank - 1kw boost converter possible?

[Badger the solar]

So here’s the thing, I already have a 24v 15kw battery bank with dedicated 24v charge controllers with 24v grid tie inverters working well.
But I want to expand, and most systems now use a 48v battery pack.
I have a 2.5kw 48v inverter, but can’t use it with 24v. I’ve rigged up a very small 48v test battery and it works well.
The trouble is, I can’t use my large solar array as that’s all linked to 24v.

So I’m toying with a high wattage boost converter to go from 24-48v.
I know this will be very inefficient, but what matters is getting more current into the house grid from battery.

Has anyone done this? Will a converter just go up in smoke?
I’m loathed to have to build a second battery bank just to run the 48v inverter without having access to my 4kw of panels…

This is the sort of thing I’m looking at;

DC Boost Converter Step-up Power Supply Module 1500W 50A 12V~48V to 24V~70V UK | eBay

5, Input power: 1500W max. 4, Input current: 50A max. 11, The maximum input current should not exceed 50A and the power should not exceed 1500W. 17, output with load instructions: when input 12V (input current 50A, output 60V or less, output can carry about 550W load), when input 24V (input...

www.ebay.co.uk

Waterproof DC/DC Converter 24V Step Up to 48V, Boost Converter 20A 960W Voltage Regulator, DC‑DC Power Converter, for Automobiles, Electric Power, Coal Mines : Amazon.co.uk: Automotive

Waterproof DC/DC Converter 24V Step Up to 48V, Boost Converter 20A 960W Voltage Regulator, DC‑DC Power Converter, for Automobiles, Electric Power, Coal Mines : Amazon.co.uk: Automotive

www.amazon.co.uk

 

[sunshine_eggo]

Inefficiency aside, those are each current limited, so you'll get 1500W max out of the ebay unit and 1000W out of the amazon unit. They won't be able to handle any surge, and I wouldn't trust either to operate near their rated max without melting down. They might react very badly to any surge from charging the capacitors.

If it's for experimenting, sure. if it's for something upon which you plan to rely, nah.

 

[timselectric]

No
And don't put gasoline in a diesel vehicle, either.

 

[zanydroid]

Would something of a MeanWell quality step-up converter be ok?

Can the surge from capacitors be addressed with precharge procedure when system is first installed?

I don’t think it’s that different from chargeverter coupling of crappy generators onto a DC bus, that everyone is all over these days.

 

[Badger the solar]

Would something of a MeanWell quality step-up converter be ok?

Can the surge from capacitors be addressed with precharge procedure when system is first installed?

I don’t think it’s that different from chargeverter coupling of crappy generators onto a DC bus, that everyone is all over these days.

Thy look good units - I've sent an enquiry to them

 

[zanydroid]

Thy look good units - I've sent an enquiry to them

Many of them are configurable, voltage drop compensation, linkable in parallel with balancing control link, isolated, serial control bus, ...

UL listed too.

 

[Rednecktek]

Umm... just out of curiosity, what kind of inverter are you currently using? Would going to a couple Growatt 3kw 24v AIO's in parallel solve your issues?

 

[kundip]

So here’s the thing, I already have a 24v 15kw battery bank with dedicated 24v charge controllers with 24v grid tie inverters working well.
But I want to expand, and most systems now use a 48v battery pack.
I have a 2.5kw 48v inverter, but can’t use it with 24v. I’ve rigged up a very small 48v test battery and it works well.
The trouble is, I can’t use my large solar array as that’s all linked to 24v.

So I’m toying with a high wattage boost converter to go from 24-48v.
I know this will be very inefficient, but what matters is getting more current into the house grid from battery.

Has anyone done this? Will a converter just go up in smoke?
I’m loathed to have to build a second battery bank just to run the 48v inverter without having access to my 4kw of panels…

This is the sort of thing I’m looking at;

DC Boost Converter Step-up Power Supply Module 1500W 50A 12V~48V to 24V~70V UK | eBay

5, Input power: 1500W max. 4, Input current: 50A max. 11, The maximum input current should not exceed 50A and the power should not exceed 1500W. 17, output with load instructions: when input 12V (input current 50A, output 60V or less, output can carry about 550W load), when input 24V (input...

www.ebay.co.uk

Waterproof DC/DC Converter 24V Step Up to 48V, Boost Converter 20A 960W Voltage Regulator, DC‑DC Power Converter, for Automobiles, Electric Power, Coal Mines : Amazon.co.uk: Automotive

Waterproof DC/DC Converter 24V Step Up to 48V, Boost Converter 20A 960W Voltage Regulator, DC‑DC Power Converter, for Automobiles, Electric Power, Coal Mines : Amazon.co.uk: Automotive

www.amazon.co.uk

I am not a fan of boost converters on bigger draw devices as I find the adjustment fiddly. At $29 you are not going to get a good quality boost device IMO.
I would only use a 24V inverter myself mainly because moving away from a simple system to a more complex setup requires more devices & future monitoring.

 

[Badger the solar]

Umm... just out of curiosity, what kind of inverter are you currently using? Would going to a couple Growatt 3kw 24v AIO's in parallel solve your issues?

I think those are off grid - I need my system on grid. What I've got is a Goodwe BP 2500 which is a little unit that interfaces between a standard PV grid inverter and the solar panels themselves. It converts that PV power and splits it into a battery charge and the excess then feeds to grid tie inverter. At night the battery can kick in and turns the grid inverter effectively into a DC coupled storage inverter. It's capable of 2.5kw. But before I invest heavily into 48v (which would cost a LOT converting over all my existing batteries and charge controllers), I wanted to see if I could find a way of usefully converting that 24v to 48v so that the Goodwe could function on the battery packs I already have.

 

[Badger the solar]

I am not a fan of boost converters on bigger draw devices as I find the adjustment fiddly. At $29 you are not going to get a good quality boost device IMO.
I would only use a 24V inverter myself mainly because moving away from a simple system to a more complex setup requires more devices & future monitoring.

Yes, granted. Probably a piece of rubbish, but thought it was a good place to start. I'm kind of wondering if my dc coupled system would only work with the current available rather than trying to wrench every last bit of current that a standard grid inverter would do. I've currently got a tiny test battery pack, its probably only about 500wh, but I can limit the current (which I've set at the moment to just 10A). The unit I'm trying to power is a Goodwe BP2500.