400 volt charge controller?

Started by billvon, May 27, 2022, 11:33:44 AM

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billvon

Does anyone out there know of any 400 volt charge controllers?  (Used to charge systems with 400V batteries)  Pika had one, but since Generac bought them I think they have discontinued them.

boB

Since the transistors (FETs) used to make inverters and charge controllers come in certain voltages, you probably won't find a controller rated at 400V maximum.  There are very few 300V FETs but more 250V rated FETs available.

The next step up from 250/300 V is either 600V or 650V FETs.

So, you will see MPPT charge controllers and grid tie inverters conservatively rated below 600V, like, 500V and 550V.

Rating at 400V like Pika did is sort of the same as Solar Edge did and just picking a intermediate voltage.  Even a PV system that has, say, a 500V Voc will have a max power point voltage of around 80% of that or somewhere around 400V.

You might actually check Solar Edge for products in this range.

I believe a newer "standard" is 380V or 400V for telecom and may be a good reason to choose around 400 volt operating area.

boB
K7IQ 🌛  He/She/Me

billvon

OK thanks.

Yeah, a Solaredge system might work well if we could figure out what it wanted to hear from the battery's BMS. 

billvon

Quote from: boB on May 27, 2022, 12:06:33 PMYou might actually check Solar Edge for products in this range.
Did some more research and found out a few interesting things about Solaredge.

1) Normally when the system is used with a 240VAC single phase system the DC system voltage (oresent at the inverter input) is 400 volts.  As far as I can tell, when a StorEdge is used, that voltage is fed directly to the battery (no additional conversion.)  That would imply that the voltage is allowed to droop when the battery is at low states of charge, then finally limits at 400 volts when close to full charge.  That makes sense since there is working feedback to the optimizers to control the system voltage.

2) When used with a 480V system the system switches over to an 800 volt DC bus.  That makes sense since the peak voltage you need to generate to drive a 480V AC line is 679 volts.  So at 800 volts you can live with a buck conversion topology alone.

boB


Thanks for the info...

Yep, 800V in means just a buck converter needed.

Simple !  😁

K7IQ 🌛  He/She/Me

billvon

Hold the presses!  After a few weeks of searcing I found ONE controller that can handle 400 volt batteries that's not via Alibaba or some similar sketchy channel.  It's here:

https://energetechsolar.com/solar-charge-controller-mppt-96v-120v-192v-216v-384v

It's called a 384V charge controller but it will handle 288 to 480 volt battery voltage.  You have to feed it a very high voltage and there's not much wiggle room, since minimum voltage is around 570V and max is 850V.  But at least there's one out there.

So MidNite - show them how it's done!

qrper

#6
Since there appears to be a high voltage charge controller, what the off grid people need now is a high (input ) voltage dc to ac inverter. An inverter that can use second life Tesla batteries directly. Although 48V dc has become the off grid standard, after you hit 5kW, those pesky I squared times R voltage losses,  even with 0000 cables, will bite you in the butt.

A 10kW inverter loaded for max would draw under 30A with a 350V supply. For most installations, 8 gauge wire would be more than enough.

mike, wb8vge
System one: 7kWp w/ Trina 250 W panels @90 Vdc. Classic 150 to 16-6 V U.S batteries. Trace 5548 sine wave inverter.
System two: 6kWp grid tie with solaredge inverter.
System three: Midnite Brat, two 120 W Astropower modules, 100 Ah battery. Runs the LED streetlight in the back yard.

billvon

>An inverter that can use second life Tesla batteries directly.

Yep, that's ideal.  In the meantime there are a large variety of Meanwell isolated power supplies that can convert 400VDC to 12, 24 or 48VDC.  So the interim solution is a (small) 12 to 48 volt battery with a standard inverter/charger, fed by such a power supply from a 400V battery.

The availability of fairly cheap, very large used EV batteries is going to be a significant change when looking at the design of independent and net-zero power systems.  A week of backup will no longer be out of the question.

littleharbor2

12 Suntech 175's
   Classic 200
   Bogart Tri Metric
   Trace SW 4024 (brand new, sort of, first energized Feb. 2015)
  460 Ah. 24 volt LiFePo4  Battery bank

boB

K7IQ 🌛  He/She/Me

littleharbor2

Oddly they're listed as 384 vdc inverters.
12 Suntech 175's
   Classic 200
   Bogart Tri Metric
   Trace SW 4024 (brand new, sort of, first energized Feb. 2015)
  460 Ah. 24 volt LiFePo4  Battery bank

boB

K7IQ 🌛  He/She/Me