ULtra Compact 1800W charger + Eltek programming

Yep, many of us would love a Flatpack S 1800 or two but they are as rare as hens teeth it seems if you want one used or below cost.

If anyone has one - can you tell me if the Flatpack S uses the same connector at the rear as the 2000 HE rectifier.

Thanks
 
For fitting in the tank area of a Zero motorcycle for charging on the go. The 2000 HEs are too long to fit in the tank area :(
 
nice quad charger. on that page i read that they have that reverse current protection diode already built in..so it should work as long as one is in in the CC mode region as pointed out already... no further tweaking necessary. just setup one with a lower higher max voltage than the others, so it will be in CC mode. Like two with max voltage setup for 52.5V and one to 55V for 36s
 
okashira said:
Let's say you have 10 flatpacks in series programmed for 50v 30A
So, the whole string will go to 500V 30A.

If you limit one to 5A. Once that ONE flat pack sees 50V it will try to taper current. Only one, though.

Let's say battery is at 300V. All flat packs will provide 50V and 30A max except the one programmed for 5A. Just 6 flat packs can provide 300V and 30A.
Each supply will push 30A until it's individual 30A limit is reached, until 300V.

Once 300V and 30A is reached, that one "5A" flat pack will reach its current limit. But there are 9 other flatpacks setup for 30A and 50V. The other nine, ignoring the current limited one, can do 450V and 30A. So even if the limited power supply went to 0v, the other nine would force current through it.
So 6 PSU can do 300V 30A. The other 4 must have 30A going thru them per Kirchoff's current law. So... This supplys may end up with a negative voltage!

Thus, current limit must be applied to all PSU in series or bad things will happen!

Voltage limit can be applied so only some PSU to achieve desired limit ( ie 50+50+50+30 = 180)

Conclusion, current must be applied to all psu in series. On the other hand, voltage limit can be defined by all psu in series added.
B careful with this though. All it takes is for one PSU out of 10 to malfunction and produce higher then 50v and damage your battery without a BMS.

Total summary, use a well designed BMS! Lol.

As i said many times, the thumb rule for serie psu for charging is :
The only thing you need is to have ONE of the psu in serie that have enough voltage range to take all the delta V of the 0-100% battery SOC and that is also the psu with the lowest current limit ( in fact it only need to have let say 1 less amp than others)
 
I found this just now,
Eltek Flatpack 2 48/2000 HE 48V Power Supply
3 hours left though!!!!!
I hope if someone needs it here on E.S. they can scoop it up.
I also hope I did not frock up anyones chance here to scoop it up, as there is only 1 bid so far, so hopefully no one from E.S. is that 1 bidder.

Good Luck

http://www.ebay.ca/itm/Eltek-Flatpack-2-48-2000-HE-48V-Power-Supply/201687581629?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20141121090453%26meid%3Dd949afdfd7d94e6797f2d2667b2a62a8%26pid%3D100033%26rk%3D1%26rkt%3D1%26sd%3D201687581629
 
markz said:
I found this just now,
Eltek Flatpack 2 48/2000 HE 48V Power Supply
3 hours left though!!!!!
I hope if someone needs it here on E.S. they can scoop it up.
I also hope I did not frock up anyones chance here to scoop it up, as there is only 1 bid so far, so hopefully no one from E.S. is that 1 bidder.

Good Luck

http://www.ebay.ca/itm/Eltek-Flatpack-2-48-2000-HE-48V-Power-Supply/201687581629?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20141121090453%26meid%3Dd949afdfd7d94e6797f2d2667b2a62a8%26pid%3D100033%26rk%3D1%26rkt%3D1%26sd%3D201687581629

theres actually two of them from the same seller... Im watching them, but I dont plan on buying them yet. I have enough other projects going on... and something like 30 server supplies already. lol.
 
I too got a shit load of server PSU's for dirt cheap. I dont really know if I need them, but I got them for the price of a 7-11 coffee.



Not a bad deal actually.......
Winning bid:
US $58.00
Approximately C $76.27
[ 3 bids ]
Shipping:
US $72.98 (approx. C $95.97) UPS Worldwide Saver | See details
International items may be subject to customs processing and additional charges.
help icon for Shipping - opens a layer

Item location:
Berryville, Virginia, United States
 
Currently thinking to make a quick charger for my Zero DS.. But ran into some questions
I'm wondering how many amps are being pulled on the primary 230V (European) side when you put two of these Flatpacks in series and configured to max current and max voltage. The datasheet says 11.6Amps at full load, but how does this work when you put two of them in series? Since the output current stays the same when putting two in series.. I'm confused a bit here.

My logic says this when you do a quick and dirty calculation of two Eltek's in series:

Total voltage is (2x57) 114V and 40A gives a 4600W output power.

When I calculate this into a mains input Amp number: 4600W/230V gives 20A (losses excluded) So this will defenately blow the standard 16A fuse here. Also when I connect the onboard 1300W charger.

So, is this calculation right? In this case I need to make a kind of a switch so I can choose between a regular household 16A plug and a Menneks type2 socket..
 
Power is power.. if you're outputting 4kw to the batteries then you're certainly going to be drawing more than that from the wall. You are correct, you will need a way to turn down a series pair so you don't blow a 16a circuit. Fortunately exactly that is demonstrated in this very thread!

Anybody managed to purchase a Flatpack S for a reasonable sum yet?
 
Has anyone tried taking one of these apart yet?

If so.. what are the caps rated at? Has anyone modified the voltage divider feedback so it "lies" to the microcontroller? what other redundant safeties are there? a Zener setup I assume.. I am looking to squeak it up to 66.2v.
 
Ohbse said:
Anybody managed to purchase a Flatpack S for a reasonable sum yet?
have asked a few sellers on aliexpress and the cheapest was about 350USD for one PSU + shipping from china
 
Best price I've had is $341USD ea, at this stage I'm still not willing to spend ~$750 (including shipping/mods) for a charger when there's the slightly larger/heavier version for substantially less. Real shame because this seems like the absolute ideal solution for rapid, reliable charging for any pack within the voltage range!
 
Check out elkon dealers in your country. I phoned up a company and it was 200Eur locally here in Lithuania for the 1800 verion
 
elKON dealers?

200€ sounds great. would you mind to share a link?

thanks
 
Doctorbass said:
okashira said:
Let's say you have 10 flatpacks in series programmed for 50v 30A
So, the whole string will go to 500V 30A.

If you limit one to 5A. Once that ONE flat pack sees 50V it will try to taper current. Only one, though.

Let's say battery is at 300V. All flat packs will provide 50V and 30A max except the one programmed for 5A. Just 6 flat packs can provide 300V and 30A.
Each supply will push 30A until it's individual 30A limit is reached, until 300V.

Once 300V and 30A is reached, that one "5A" flat pack will reach its current limit. But there are 9 other flatpacks setup for 30A and 50V. The other nine, ignoring the current limited one, can do 450V and 30A. So even if the limited power supply went to 0v, the other nine would force current through it.
So 6 PSU can do 300V 30A. The other 4 must have 30A going thru them per Kirchoff's current law. So... This supplys may end up with a negative voltage!

Thus, current limit must be applied to all PSU in series or bad things will happen!

Voltage limit can be applied so only some PSU to achieve desired limit ( ie 50+50+50+30 = 180)

Conclusion, current must be applied to all psu in series. On the other hand, voltage limit can be defined by all psu in series added.
B careful with this though. All it takes is for one PSU out of 10 to malfunction and produce higher then 50v and damage your battery without a BMS.

Total summary, use a well designed BMS! Lol.

As i said many times, the thumb rule for serie psu for charging is :
The only thing you need is to have ONE of the psu in serie that have enough voltage range to take all the delta V of the 0-100% battery SOC and that is also the psu with the lowest current limit ( in fact it only need to have let say 1 less amp than others)

For a typical 400v system of 96s. this means you may need 4 "50V" flatpack's configured.

Min voltage of 96s: 240V
Max voltage: 403.2V
Difference: 163V.

So one flatpack is not enough. For a higher voltage system, one might need a way to ensure the flatpacks are all communicating in some way so they properly share voltage.
flatpacks might work great up to systems of 3s ~150V or so, but higher you risk funny things happening, unless you want to babysit them all.

At this level it's looking more like just using an 400V salvage EV charger setup (with a custom micro or even a CANBUS hack) makes more sense.
 
I think this guy figured it all out. Setting voltage and current. He's also active on this forum as Remmie1972:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=71139&start=75
Quite brillant how he kind of reverse engineerded all the code, communication etc of the flatpacks. All changes are done by can-bus communication, as I understood.
He's also active on the Zero motorcycles forum.
 
:lol:
 
Did any of you see the Little Box Challenge? The winner's inverter was 13.8 in^3 for 2kW. That's like 1/3 the size of the smallest FlatPack. Just shows what is possible...
 
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