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Old 04-07-2015, 02:25 PM   #1
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Questions?? How to match a DC power supply/Charger

I'm in the market for a new charger and I've exclusively used only AC chargers in the past.

I've been searching the market and like the specs provided by some DC chargers. But I have never had a power supply before, and I see there are many to choose from.

What specs do you have to line up? I'm a little overwhelmed by all the numbers.

For instance can a 300W charger run on a 250W power supply? Will you not be able to charge at the full amperage because of this? Or is it more important to line up amperages, such as the power supply puts out 15A but the charger can charge up to 20A?

Specifically I am looking at these two as my budget is about $150, $200 absolute max:

http://www.amain.com/rc-cars/junsi-i...n-206b/p195153

http://www.amain.com/rc-cars/protek-...k-8516/p263647



Then on a semi-related note:

Is DC really better than an AC charger?

Charging through 2 ports would be nice, but all the DC 2-port chargers seem to be priced too high for me including a power supply.

But I read somewhere that 2 ports on an AC charger doesn't charge that well. Any experience with this?


Lastly, before everyone starts dropping AC/DC chargers/power supplies I'll state my required specs:
-roughly $150 budget, $200 absolute max
-Charge at at least 10A (I use only 2 cell lipos, and I don't "juice" them up by charging at 40A)
-(not required spec) I would like the option to charge 2 packs at once (could sacrifice down to 8A charge rate if it is a more affordable option)
-(Do not need) Discharging capabilities

Any help/insight is appreciated, Thanks
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Old 04-07-2015, 02:55 PM   #2
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Watts are what really matters in the end.

volts X amps = watts. IF you want to charge a 2s lipo (8.4v) at 10amps you need a minimum output of 84 watts. (10amps X 8.4v = 84 watts) To included a safety margin you should really have about 100 watts of power available.

If you want to go with an AC/DC style dual port charger that can charge 2 packs at your 8 amp minimum you need to find one that is rated at least 75 watts per channel.

AC/DC chargers are normally limited to about 50 watts per channel because of the internal PS. You might be able to find one that suits your needs but I've never looked.
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Old 04-07-2015, 03:00 PM   #3
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Last edited by racer1812; 04-07-2015 at 03:31 PM. Reason: not relavent with the links he has..
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Old 04-07-2015, 03:17 PM   #4
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Unless you have a power supply to match the charger then it's a waste of money IMO. In fact you should go higher than the ratings of the charger in the PS due to the fact you will loose some power on the way to the charger.

My set-up is pretty close to what you have listed on A-main. I charge my 4400 Mah 2 cells in about 25-30 min @ 10 amps and 4 cell 5000 mah @ 10 amps around 35-40 min. I have plenty of batteries so the charger keeps up just fine.

If I was you I would use that PS (cant beat it for 35 bucks) and go down to the 106B+ $89.99. I have used the 106B+ for over 5 years and it works awesome.
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Old 04-07-2015, 04:09 PM   #5
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Thanks for all the help and quick responses so far! I'm feeling much more confident in what I need to look for now.

I've heard good things about iChargers, and the 106B seems like a good fit. However, I found this Hitec that would be comparable, but can charge up to 16A!
http://www.amain.com/rc-cars/hitec-x...c44215/p361364

I don't have any experience with Hitec products outside of their budget servos many years ago. Anyone have experience with Hitec chargers?

The Hitec has a ($100) power supply fitted for the charger ($180 bundle), but the protek i listed earlier has better specs, and is only $35... Don't see how you can beat that! (Its also identical to a different power source offered by Hitec).

The icharger and Protek are both rated for 250W, but the Hitec charger is only rated for 180W, so based off what was said above, the Hitec seems like a safer option. Then doing the calculations I would be able to safely charge all my 2s batteries at 16A if I wanted. I just have not heard much about their chargers, which is why I'm hesitant.

P.S. And as you originally mentioned Racer, I too like to stick to more name brand companies for my electronics. (Though I did try a Turnigy motor for a different class in a one-off race and it performed very well... But I'm always skeptical of cheaper made Chinese goods, especially when it comes to the ESC, radio, charger).
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Old 04-07-2015, 05:37 PM   #6
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Quote:
Originally Posted by mschumi101 View Post
Thanks for all the help and quick responses so far! I'm feeling much more confident in what I need to look for now.

I've heard good things about iChargers, and the 106B seems like a good fit. However, I found this Hitec that would be comparable, but can charge up to 16A!
http://www.amain.com/rc-cars/hitec-x...c44215/p361364

I don't have any experience with Hitec products outside of their budget servos many years ago. Anyone have experience with Hitec chargers?

The Hitec has a ($100) power supply fitted for the charger ($180 bundle), but the protek i listed earlier has better specs, and is only $35... Don't see how you can beat that! (Its also identical to a different power source offered by Hitec).

The icharger and Protek are both rated for 250W, but the Hitec charger is only rated for 180W, so based off what was said above, the Hitec seems like a safer option. Then doing the calculations I would be able to safely charge all my 2s batteries at 16A if I wanted. I just have not heard much about their chargers, which is why I'm hesitant.

P.S. And as you originally mentioned Racer, I too like to stick to more name brand companies for my electronics. (Though I did try a Turnigy motor for a different class in a one-off race and it performed very well... But I'm always skeptical of cheaper made Chinese goods, especially when it comes to the ESC, radio, charger).
lets be clear. how many cells are you charging?


2s @17amp = 142 watts
3s @17amp = 214 watts
4s @17amp = 286 watts


so there you go. If you are only doing 2s charging, then that 250 watt power supply should be fine. Personally I use a converted power supply that costs be about 35-40 and is capable of 900 watts
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Old 04-07-2015, 05:42 PM   #7
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keep this in mind on the icharger

Maximum Charge Power Capacity: 300W @ Input voltage > 18V

it will be less wattage at 14v, but probably still all you need for 20amp 2s charging
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Old 04-07-2015, 08:36 PM   #8
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Quote:
Originally Posted by Wildcat1971 View Post
lets be clear. how many cells are you charging?


2s @17amp = 142 watts
3s @17amp = 214 watts
4s @17amp = 286 watts


so there you go. If you are only doing 2s charging, then that 250 watt power supply should be fine. Personally I use a converted power supply that costs be about 35-40 and is capable of 900 watts
I will be primarily charging 2s batteries as I only have 1/10 race vehicles for now. Possibly in the future (after I graduate) I would pick up ebuggy or a basher, but I could get by with 2s in series or just buy a new charger all together as I'll have a real job!
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Old 04-07-2015, 08:47 PM   #9
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If you have soldering skills, old 12v server power supplies are great for running battery chargers. I converted my own out of an old Dell PowerEdge 2600. It puts out 60 amps at up to 730watts. I have some connections so I got it for free from a company that was replacing their old server. Just had to carry it to a recycling center for them. I run two chargers off it charging 2S at 25 amps on one and 10 amps on the other and it can still handle a whole lot more. You can also find them already converted on eBay and some handle up to 1000 watts. However, they are all 12 volt.
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Old 04-07-2015, 08:53 PM   #10
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Here you go. I just saw this while noodling around here.

FS: Used SkyRC 20amp charger w/Power supply
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Old 04-07-2015, 09:03 PM   #11
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Quote:
Originally Posted by beemerfan View Post
If you have soldering skills, old 12v server power supplies are great for running battery chargers. I converted my own out of an old Dell PowerEdge 2600. It puts out 60 amps at up to 730watts. I have some connections so I got it for free from a company that was replacing their old server. Just had to carry it to a recycling center for them. I run two chargers off it charging 2S at 25 amps on one and 10 amps on the other and it can still handle a whole lot more. You can also find them already converted on eBay and some handle up to 1000 watts. However, they are all 12 volt.
Whats the disadvantage of a power supply being only 12V if it can still put out 1000W?

And that is an intriguing idea using a computer power supply, I have near 10 years experience soldering motor/battery wires down to circuit boards! Shouldn't be too hard...
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Old 04-08-2015, 01:35 AM   #12
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With 1000w you do keep some extra power for powering tire and/or motor heaters, your audio, a 2nd charger, lights, tire truer, 12v dremel (Proxxon), 12v solder iron etc.
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Old 04-08-2015, 06:34 AM   #13
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Quote:
Originally Posted by mschumi101 View Post
Whats the disadvantage of a power supply being only 12V if it can still put out 1000W?

And that is an intriguing idea using a computer power supply, I have near 10 years experience soldering motor/battery wires down to circuit boards! Shouldn't be too hard...
some chargers put out less power at 12v. that is why I copy/pasted that from the icharger ad. the icharge 406b is like a 1000 watt charger, but at 12v it is a 500watt charger.
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Old 04-08-2015, 06:35 AM   #14
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If you want to convert a single dps1200, here is the guide for a 24v conversion, you just do one power supply

http://www.rchelination.com/setting-...-power-supply/
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Old 04-08-2015, 09:02 AM   #15
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Okay, reading this thread made it more confusing for me than before.
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