hlb14

iTrader: (28)

im looking for some helpful info on a power supply for the 720i, i want to be able to charge 5s packs FAST, thanks in advance

oldsprintfan

iTrader: (11)

I use my 720i to charge my 5200 2S packs at 1.5C or at 7.8 amps. It takes less than 30 minutes to charge my packs at that rate after a hard 5 minute run with a Novak Velociti 5.5R motor. I don't see ever using anywhere near the 20A charge capacity (250w max) of the 720i. I use a Ripmax 13.8V 20A power supply with no problems. It seems like I could charge at quite a bit higher rate if I wanted. Any good clean 13.8V/20A power supply should work for you Hope this helps.

Frank

JAM MaxAmps

20 amps is fine for 2S packs but to get the full power from the 720i to charge 5S packs you'll need at least a 30 amp or better power supply. With larger packs the 20 amp PS won't have enough to maintain a full charge rate.

Jason

hlb14

iTrader: (28)

So a car battery would work for 1c charging, but if i wanted to charge at 2c or greater i would need a pretty good power supply??

oldsprintfan

iTrader: (11)

Jason, just for my own understanding with regard to my 720i. The maximum charge rate for the 720i according to the specs is 20A, regardless of whether a 1s or 5s pack is being charged. From your reply I think you are saying that trying to charge a pack at 20A with a PS only capable of producing only 20A would be asking too much from the PS. I don't anticipate ever needing to charge anything at 20A but just trying to learn as much as I can about the whole Lipo charging business.

Thanks, Frank

JAM MaxAmps

A car battery will work fine for 1C charge rates but even at a 1C charge rate a 20 amp power supply will still struggle to do a 1C charge rate on larger packs such as a 5S.


yes the larger the cell count and capacity the bigger the PS needed. So to get the max out of the 720i you'll need a 30 amp unit or better.

Jason

oldsprintfan

iTrader: (11)

Thank You Jason.

DragonFireSG

Hmm... for a relatively cheap (US$80-100), high current supply look on ebay for a HP J4839A single-railed switching power supply. It is used for enterprise network switches, and throws out 24V at 23A. It has an integral 92mm cooling fan and is built for 24x7x365 operation.

A 14 pin molex connector provides power out. This can be built by trimming down a 20 pin ATX male connector commonly used for PC power supplies. You will want to replace the power leads with thicker cables though since I have my doubts as to whether a few thin cables can handle that much current.

Pin outs are

|+24|+24|GND|---|---|GND|+24|
|+24|GND|GND|---|---|GND|+24|

with the power supply label up, and the output connector on the lower left side of the case The 4 "---" pins are used for signalling and are left untouched.

I suggest you test outputs with a multimeter yourself before making / connecting the harness to prevent a short. Shorting out 500W is NO fun.

Using one now with my EOS0615i Duo3.

DF

JAM MaxAmps

That's a waste of money. I bought an IBM server supply off e-bay 2 yrs ago that does 30 amps at 560 watts for 20 Bucks. If your going to spend 80 to 100 bucks you might as well spend a bit more and get a PS that will do what the DUO needs to get full power.

Jason

DragonFireSG

Nice find that . They do say however that the high end Hyperions need at least 15V for optimal performance. Any truth to that? Afaik standard server supplies throw out only 12V tops unless you get one from their enterprise blade enclosures.

DF

JAM MaxAmps

There's a a way to trick the charger. I can do two 6S 5000's at the same time with no issues at 5 amps each and the PS keeps right up.

Jason

dnrcustoms

Hmm, I'd like to hear a little more about tricking my 720i into charging two 5s 5000mah at the same time. "safely"!! What ps are you using?

JAM MaxAmps

That's easy buy another 720i and network them together to charge two packs. It's the way they were designed to work.

Jason

DraftDriver

iTrader: (14)

I run 2, 720i on a Checkpoint dual 25A power supply to charge two, 5200mah 24c batteries. The batteries are charged at 9amps a piece with the balancer attached, with a potentiometer that allows a change in voltage but keep it at 12v where it could go up to 14v. The chargers operation independent of each other.

Also, if there was a problem with charger/ps configuration how would we know? Do the chargers have some sort of alert? Is the power supply I'm running now adequate to run the two chargers? ( My intial thought was keep the amps below or near 20 and I'd be all set to charge to charge the 5200 batteries. Though I'm running at 12v aren't we really worried about the total watts being drawn from the entire set up?)

Lastly, what power supply(s) does Hyperion use to bench test the 720i chargers? I would assume they would use what racers use for compatibility reasons and practicality.

JAM MaxAmps

If your power supply isn't giving enough power for the chargers you'll see a lower charge rate. If it's really underpowered you'll get an input voltage error. As for what Hyperion uses to test with it's likely an industrial power supply of sorts. This is a company that started in the RC plane side of the hobby so I highly doubt they are using a power supply that a racer would be using.

Jason