400V system components

[billvon]

OK here's my pitch for a new product line that 1) I could really use and 2) that could make a fair amount of money for manufacturers.

Start making the charge controllers/inverters/BOS components for 400 volt systems.  There is little out there on the market like this right now, and there's a huge need.  Most EV batteries are still at the 400V level (most are 96s li-ion) and more and more of them are coming on to the market.  Companies like EV West are doing controllers to allow inverters to "talk to" the batteries over their CAN bus and close protection relays and whatnot, but as of now there's very little you can do with 400 volts.  Solaredge and SMA use 400 volt batteries but they're the only companies I know who do this, and they are not very "open" about their interfaces.

As EV's age out and get sold/junked/recycled there are going to be more and more used batteries on the market.  Being able to get a very used 40kwhr Leaf pack (effective capacity 25kwr) for $100, for example, would be a big deal to someone who is trying to go off grid, do net-zero or do utility backup.  It would also support the DR market.  And since EV sales are doubling every year, used battery availability will be doubling every year as well (with several years delay of course.)

For charge controllers a buck/boost topology would be ideal, but you could also just do a buck that works with system voltages up to 1000V.  600V system buck-only mean you have to maintain a voltage range between 420-600 volts or so, and that would severely restrict paneling options, since your string lengths would have to be dead on to hit the right voltage range.

[boB]

The coming 600V max input controllers should fit this requirement, don't you think ?

boB

[billvon]

Well, the Hawkes Bay flyer says "48 Volt battery only" and says the output will go from 40 to 65V, so I assume it won't go to 400V.  Can it really go to 400?

Or were you talking about another new product?

[boB]

Well, the Hawkes Bay flyer says "48 Volt battery only" and says the output will go from 40 to 65V, so I assume it won't go to 400V.  Can it really go to 400?

Or were you talking about another new product?

No, the Hawkes Bay and Barcelona are 48V battery, nominal

It would be nice to eventually do 380V DC battery though.

[GHOSTNH]

i agree with billvon we need 200 to 400 v dc input and output charge controller and 200 to 400 vdc input inverters. if you guy made such units you would make a killing in the market. huge demand out there

[boB]

Which batteries are you thinking of using ?

I know that LG has (or had) one and old EV batteries may also be an option...   

BTW, there was a problem (and recall ?) with the LG battery.  It was also considered very dangerous and required the buyer to go out of town for training just to buy one.  That was a couple of years ago though.

But wondering what you are thinking of...

boB

[billvon]

Which batteries are you thinking of using ?

Used EV batteries mainly.  There are going to be (literally) millions of them hitting the market in about five years.  For the most part they are 360V nominal, generally 96S.  A few are 192S and even fewer are 144S.

At Intersolar this year, inverters with this voltage range are starting to become available.  I saw perhaps a dozen (either existing or planned) that work in that range.  Sol-Ark has one for 208V 3 phase, and Solis has a few.

[boB]

400V DC  (or even AC)  can be dangerous !

I hope we don't see many DIY projects in these voltage ranges.

boB

[billvon]

400V DC  (or even AC)  can be dangerous !

Yep!  But people are DYIing with them now, and "real" installers have been working with the RESU high voltage batteries for quite some time.  As the market gets flooded with EV batteries, I think a lot of them will start looking at used EV batteries as a way to get cheap storage.

Edited to add -

Back in the lead acid days, people went from 12V to 48V pretty quickly, because 48V was still considered a safe voltage to work with.  (And it sorta kinda met the requirements for the IEC "extra low voltage" rating, and so was easier to work with on projects that needed standards approvals.)  Keeping it relatively touch safe was important because you can't turn off a lead acid battery.

That was still true when we were building LFP batteries from CALB cells.  You still had to keep that voltage low enough to work on while energized.  And even with insulated tools/gloves most people don't have the training or experience to work on live higher voltages.

But then server batteries came out - and you could turn them off.  And that was a big deal because you could now set up systems without ever touching a live conductor.  Set everything up, ohm it out, then throw the switches and power up the batteries.

And with EV batteries you have that to a much greater degree, because they shut down at the slightest excuse.  Tesla batteries will shut down if they see an HVIL fault, if they lose 12V power - even if the CAN bus stops sending data for more than 100ms or so.  So keeping them on is now the problem.

So the risk of electrocution has gone way down for DIYers lately, since they can set up a system and have it be completely de-energized until they are ready to test it.  There will, of course, always be a way to kill yourself.  But the availability of controlled-output batteries has made system set up an order of magnitude safer.