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High Voltage high current DC power supply

Posted: Apr 21 2019 5:02am
by Alexanderfoti
Hi all

I recently found this on Aliexpress

https://www.aliexpress.com/item/3000W-B ... 4c4dCR8x2L

its a 0-120V 0-30A power supply, It has trim pots on the front to adjust both. It seems to be a modified Huwaei R4850G, which is nominally rated at about 50v, so they have been making some heavy modifications internally.

So far, so good, some pictures:

Image Image Image Image
Image

I am using this to charge my 26S leaf pack to 107.9V. Seems to work well so far, comes with XT90 connectors on the back, which I change to anderson connectors.

I bought two, so plan to charge at 6kw ish.

As I am using this connected straight to the pack, If anybody has any idea on how to accurately set the output to 107.9 (or something slightly less eg between 107.5-107.9) without spending big money on a fluke 289, do let me know!

Many thanks.

Re: High Voltage high current DC power supply

Posted: Apr 21 2019 6:44am
by eee291
First: Nice charger!
Second: Too expensive for me :(
Third: Why a Fluke 289?
You can use some crappy Multimeter from eBay it'll do the job just fine, it's not like it'll be off by a huge margin or something especially when measuring DC.

Re: High Voltage high current DC power supply

Posted: Apr 21 2019 8:10am
by Alexanderfoti
Thank you. Its not too bad when you compare the alternatives for the power level I needed.

I also wanted something very small that would fit in the frame.

You say that, but a cheapo ebay meter on 600v dc range has an accuracy of 0.2% +- two counts, which means 100vdc could be 100.4vdc or 99.6vdc.... I think.

Re: High Voltage high current DC power supply

Posted: Apr 21 2019 10:39am
by john61ct
Just get an inexpensive one (not the cheapest) that can be calibrated, and borrow / rent a pricey Fluke to do so, near your target V.

Re: High Voltage high current DC power supply

Posted: Apr 21 2019 10:40am
by john61ct
Likely the output / adjustment circuitry will also drift

Re: High Voltage high current DC power supply

Posted: Apr 21 2019 10:46am
by Alexanderfoti
I'm looking at a bryman 867 which has a 500,000 count display!! So 5-4/5 digits with a 0.03% + 2d accuracy which should be more than sufficient. Not too cheap but not fluke money either.

Re: High Voltage high current DC power supply

Posted: Jun 24 2019 3:37am
by snejky
It can be iteresting to show modifications details. Because This PSU can be bought for $120 shipping included!

Re: High Voltage high current DC power supply

Posted: Jun 24 2019 3:39am
by Alexanderfoti
Everything is potted in the PSU, so I think it would be very difficult to reverse engineer without destroying it.

You could buy one to destroy but it would be expensive :)

Re: High Voltage high current DC power supply

Posted: Jun 25 2019 1:05pm
by snejky
I'd rather avoid it :roll:

Re: High Voltage high current DC power supply

Posted: Jun 25 2019 4:09pm
by leffex
I recommend the charger as well. I have it. Its pretty powerful. Just if you buy it, pay extra for shipping if you want it fast!

Re: High Voltage high current DC power supply

Posted: Jun 25 2019 4:42pm
by parabellum
Nice find.
Did someone try to run it on 120AC for <2000W out?
Original specs are 85-300AC <17A input, I wonder if any mode was done to the input /AC side by the seller.

Re: High Voltage high current DC power supply

Posted: Sep 06 2019 1:01pm
by Alexanderfoti
I would be suprised if it does the same thing at 120V ac, It will likely blow the internal fuse I would have thought.

Re: High Voltage high current DC power supply

Posted: Sep 06 2019 10:37pm
by Tony01
I haven’t found a 120ac plug that can handle charging at more than 1500W dc. Most times I just do 1000w. I’m using 3x 500w 24v 120ac psus which I once saw go up to 2200w but now I see it is overkill. Used only at home now as it’s too heavy to carry.

Re: High Voltage high current DC power supply

Posted: Sep 06 2019 11:02pm
by john61ct
There are modern 120V circuits rated at 20A, but most are 15A max.

And continuous draws should stay below 80% of rating, lower in an old house.

And that assumes no other loads on the circuit.

A big charge station area, worth getting the sparkie to out in at least one new 240V circuit, 50A or minimum 30A, as if for a large electric stove + clothes drier.