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High power battery chargers (10KW+)

Posted: Sat Dec 24, 2011 7:16 pm
by jjmouris
Anybody have any good links for the above?

Looking for something that would improve on the below 8KW charger;

http://www.evassemble.com/index.php?mai ... ucts_id=27

In theory i would like to charge a 100 series Lifepo4 pack at around 17.5KW. I suppose i could use two of those 8KW charges to get 16KW but there must be something bigger out there?

Thanks for any and all help on this.

Joe

Re: High power battery chargers (10KW+)

Posted: Sun Dec 25, 2011 4:36 am
by retepsnikrep
Make you own out of series stacked 50A 45-55V 3kw server power supplies which you can get on e-bay pretty cheap.
Six would give you around 18kw and 270-330V capability.

Hack one supply so that the voltage pot or power on command can be controlled by your BMS and add a solid state relays so the whole array can also be turned off by your BMS etc.

That's what i did years ago I only used two in my setup though for a 6kw £100 charger

http://www.ebay.co.uk/itm/HP-253232-001 ... 53eaa357ce

http://www.ebay.co.uk/itm/HP-406424-001 ... 53eaa464fe

6 of the above with some interconnection work would give you 18kw :shock:

With a pic in control of the power relays you could also stagger the switch on sequence so your supply does not see the huge startup load surge.

Re: High power battery chargers (10KW+)

Posted: Sun Dec 25, 2011 1:36 pm
by jjmouris
Hi, thanks for your reply.

As i understand it, those 48V power supplies just change 220V AC into 48V DC. I don't fully understand how you would wire them in to get a 288V DC supply but i guess you are saying that by slightly changing the output voltage i can controll the charging current?

I'm pritty good with understanding electronics but i am not capable of making a controll board from scratch that would run the above componants without some help. If you say you have done this, is there any information available for me to digest?

:)

Re: High power battery chargers (10KW+)

Posted: Tue Dec 27, 2011 2:14 pm
by GregsGarage
As long as the DC output is isolated from the AC input then you connect the outputs in series to increase the voltage. It's the same thing you do when you connect your cells in series to get a higher voltage. The key is that the supplies must be isolated, in practice it is hard to get non-isolated supplies, but some are out there.

Re: High power battery chargers (10KW+)

Posted: Tue Dec 27, 2011 5:31 pm
by retepsnikrep
jjmouris wrote:I'm pritty good with understanding electronics but i am not capable of making a controll board from scratch that would run the above componants without some help. If you say you have done this, is there any information available for me to digest?

:)


I have nothing written down I suggest do some googling for hacking meanwell power supplies as there is a hug thread on the endless sphere forum which discuses lots of techniques. Basically you bridge or parallel the voltage control pot in one of the supplies and use this variable voltage to control the overall current. You may also be able to increase the V adjustment range for the pot by changing it's value entirely. You can also do the same on the variable current pot on some supplies.

As far as the slow start up is concerned a pic with six outputs controlling six transistors which in turn control six solid state relays, turning them on in sequence at one second intervals would spare your mains supply the huge switch on load.

I have seen some connection data on those supplies posted somewhere so you will need to find that or get a manual/datasheet at the very least.

Stacking these big power supplies is the only realistic way of getting a cheap high power isolated charger unless you want to try just putting a full wave bridge rectifier and huge smoothing capacitors on the mains for a very dirty and dangerous non isolated charger that will do 300v or so. :shock: Again you could control/shut this off with a triac control module. Bit like a giant dimmer switch knob!! The power of this would be limited only by your mains supply and the rectifier/triac/caps capability. A lot depends on how well you pack is isolated from the vehicle chasis when charging.

Re: High power battery chargers (10KW+)

Posted: Fri Dec 30, 2011 12:11 pm
by PHEV
These guys are making a 10KW programmable charger. They sell either PCB and parts list, full kits ready to assemble, or finished chargers.
http://www.emotorwerks.com/cgi-bin/VMcharger.pl

Steve