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Old Mar 01, 2011, 09:19 AM
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X2 for me
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Old Mar 01, 2011, 12:09 PM
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Steve,

That would be the correct way to wire it, but keep in mind that the power supplies are switching, and because they where not designed to run in series the oscillators are not sync'd up so the peak to peak voltage is effectively doubled. When you add a charger that has it's own switching dc to dc converter it's going to apply the load at it's own oscillator's frequency which given the sliding window affect can cause the power supply to overrun or underrun. When you add a second power supply set and charger you are doubling the oscillators in the system.

Running two in series for a single charger is not perfectly ideal, but has been shown to work very well in the real world because these power supplies are pretty hardy and because the chargers are not at all picky about perfectly clean DC because they have their own switching regulators to filter the output before applying a voltage on the battery.

When you start going down the road to four power supplies and two chargers you will without a doubt have really dirty DC, but that doesn't mean it won't work just fine. Only time and experimentation will tell.

Personally I wouldn't wire them like you have shown, I would dedicate one power supply to each charger.

Thanks,
schu
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Old Mar 01, 2011, 12:27 PM
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Could this perhaps be an example of out of syn oscillators.

http://www.rcgroups.com/forums/showp...postcount=1774
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Old Mar 01, 2011, 12:37 PM
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Yes, exactly.

schu
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Old Mar 01, 2011, 03:09 PM
One cell short of a Pack
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Good ole Smithsburg, MD
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Quote:
Originally Posted by akschu View Post
Steve,



Personally I wouldn't wire them like you have shown, I would dedicate one power supply to each charger.

Thanks,
schu
Understood; I will just quad them up when I have A123's to charge and just use one charger. I am just worried about the 47 Amps input when I use the PL8 @ 40 amps output, I'm sure the input to the charger is above 47 amps when output is maxed...

I wonder what running two PL8's on TWO quad banks would do when they are in expansion mode... I may get more efficiency if I run them @ 220v


Cheers,
Steve
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Last edited by steve1814; Mar 01, 2011 at 03:22 PM. Reason: Just finished a thought....
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Old Mar 01, 2011, 07:18 PM
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I don't know what they would do. That would be a question for FMA. I suspect it will work fine since in expansion mode they still act like two chargers, they just share config data with each other.

Also, the PL8 has a dc-dc converter. So it's more like watts in vs watts out minus losses. 3.6v * 8 * 40 = 1152 watts. If you add 10% overhead then you can basically charge at ~1000 watts which is still 35 amps, and that is only when the output voltage is 3.6s so in practice you can probably charge at the max 90% of the time on 8s and all of the time on 7s.

Lipo is different since the output voltage is higher, but you should still be able to charge a 6s pack at 40amps.

Basically the only time you will need more power supply then two 47 amp HP units is when you are above 6s lipo or 7s A123, and even then that is assuming max voltage.

So I wouldn't double the power supplies up when your only going to get a few minutes faster charge and only on the largest packs.
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Old Mar 01, 2011, 07:24 PM
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Then there are always 100 Amp. ones if using 220V ACl
http://www.rcgroups.com/forums/showp...97&postcount=1
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Old Mar 02, 2011, 11:58 AM
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I received the completed power supplies this weekend. I did a few quick tests with 6S 30A charging and they worked perfectly. Thanks schu!

Now all I need is a generator so that I can bring all of this power with me to the field...
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Old Mar 02, 2011, 01:11 PM
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Glad you like it!
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Old Mar 02, 2011, 01:53 PM
One cell short of a Pack
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Schu,

you going to do another run? I showed my PS to a few friends and now they want em..

Cheers,
Steve
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Old Mar 02, 2011, 01:57 PM
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Quote:
Originally Posted by ForceFedDSM View Post
schu,
I'm interested in a full kit with a y-power cable if you decide to do another run. Will any ESP135 series supply work or do I need a certain one? I found some DPS-600PB, are these the correct ones?
Quote:
Originally Posted by GReedTFD View Post
X2 for me

schu,
Are you planning on another run? Seems like there are a few of us interested. Are all ESP135 power supplies the same on the inside and compatible with your kit?
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Old Mar 02, 2011, 02:48 PM
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Not all ESP135 power supplies will work. You need a DPS-600PB. Yes, I'm going to order more parts today.

schu
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Old Mar 02, 2011, 03:42 PM
One cell short of a Pack
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Yes, I'm going to order more parts today.

schu
Cool, I'll let them know...
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Old Mar 03, 2011, 09:06 AM
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Quote:
Originally Posted by akschu View Post
Not all ESP135 power supplies will work. You need a DPS-600PB. Yes, I'm going to order more parts today.

schu
Cool, Thanks. Put me on the list for one full kit please
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Old Mar 03, 2011, 12:10 PM
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I'd like the full kit too. I'd like the y power cord too!
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Last edited by GReedTFD; Mar 03, 2011 at 08:12 PM.
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