LG RESU16H DC coupled 350-450VDC Battery DIY copied

[Johnwilleliminatepge]

I personally installed a SolarEdge SE7600 Energy Hub inverter on my home.
I will install their interface #BI-NUSGN-01 and a storage battery(s) in the future.
SolarEdge requires a 350-450vdc DC coupled battery for this.
Not a 48vdc A/C coupled battery.
They recommend LG Chem RESU 350-450vdc DC coupled battery or their own
SolarEdge 10 KW DC coupled 350-450vdc battery (they partnered w/LG on this).
I'm now sure I won't DIY on this but save my money and buy one of these.
I want a MFGr guarantee on this.
Can any of you ET guys tell me how they build these higher voltage units.
I went through US Navy BEE school years ago so I understand the fundamentals.
I would like to know the details.
A step down transformer then step up?
I'm curious.
Give me a holler ET's
Thanks
John

 

[Hedges]

It is a 48V battery with boost converter.
Or this says 3x 48V in series, then boosted.

Any suggestions for adding capacity and backup power to my current SMA Sunny boy system

I am currently in the process of installing an SMA SunnyBoy 7.6 KW (Grid-Tie split phase 120/240v) system, with 30 Qcell 320 watt panels. I am awaiting my permit to finish install and to get the power company to reprogram my meter to read backwards. Right now I have 15 panels on my roof "testing...

diysolarforum.com

High voltage BMS suggestion

Hello guys, I am planing a HV storage system with around 80-120S configuration. The motivation to move to higher voltage than 48V is pure C-rate driven => optimize lifetime and overall efficiency. But of course the BMS selection at this configuration is quite rare. can someone recommend any...

diysolarforum.com

I would think the larger commercial ones are an actual high voltage battery. We've seen some surplus people bought, like 560VDC.

 

[Johnwilleliminatepge]

Hey Hedges thanks.
Very informative.
John

 

[Hedges]

If I made a DIY battery, I would consider the REC BMS, version that talks to Sunny Island.

REC Q BATTERY MANAGEMENT SYSTEM 16S – REC BMS

www.rec-bms.com

Their products can be cascaded, make a 128s battery if you wanted. Something in that range would be 400V.
I thought that might work for a large battery connected to Sunny Boy Storage. But the data sheet calls for max 40A short-circuit current.
It seems to be a modified GT PV inverter, using batteries instead and bidirectional. Maybe a really fast fuse would work.

https://files.sma.de/downloads/SBSXX-US-DS-en-20.pdf

I had considered the RESU (48V version), but went with AGM.
Some RESU-H (400V) and possibly some RESU have been recalled for fire.
It isn't LiFePO4, but a more flammable chemistry.
You'll probably want a UL listed ESS on your house, but safest chemistry as well would be good. And/or located a safe distance away.

 

[Ampster]

You might be able to get a DIY battery to work but my recollection from one LG Chem/Storedge integration that I observed was that a special interface card was required that talked between the HV battery and inverter. The point I am making is that you would need to understand the interface and what the inverter needs in order to make it work. High voltage batteries are built by all the EV conversion folks and managed by BMSs all the time. That is the simple part.

 

[Johnwilleliminatepge]

Thanks you guys.
I like the LifePo4 batteries from a safety standpoint.
Saw a guy named AveRage Joe on you-tube poking and prodding Lithium batteries.
He had a veritable fourth of July going on.
Amazing how volatile those lithium batteries are.
I will continue to learn about batteries and watch how they evolve before
I make a plan.
I will keep all your inputs handy.
Thanks
John