Will a 10 Amp power supply be able to handle 2 chargers

[NSDie]

The title says it all. If I do the math, say, if I charge my batteries at 4 amp for each charger, does it mean that it will draw 8 amps off the power supply and therefore a 10 amp power supply should do the job find.

I would appreciate any input or real life experience from this fine community here.

[_JP_]

should easily do it, but 8amps is 80% of the power so may start to run hotter?

I use a 20amp and pull 10amps no problem (2x5amps)

[NSDie]

Before I invest some money into a new bigger power supply, I know very keen to know if anyone here actually runs a 10 amp or thereabouts for 2 chargers no problem.......

Obviously, I own a 10 amp power supply now. Just don't see a need to go bigger if it's absolutely not necessary.

[mark christopher]

Originally Posted by NSDie

Before I invest some money into a new bigger power supply, I know very keen to know if anyone here actually runs a 10 amp or thereabouts for 2 chargers no problem.......

Obviously, I own a 10 amp power supply now. Just don't see a need to go bigger if it's absolutely not necessary.

er if you have the power supply

1/ why not try it to see if it works
2/ buy another 10 amp psu

what make of psu is it? if its one of the cheap small ones id say no

[matthew413]

My little 10amp psu can't power two chargers at 4 amps each, it can just about cope with 3.5 and 4. On of the chargers does have 3 quite vicious fans though, which doesn't help.

[tony6187]

i run a 14 amp lrp power supply and it can handle 2 chargers no problem.doesnt seem to get 2 hot

[Gnarly Old Dog]

I've got a Nosram 10A power supply and it fails to run 2 chargers - even if the charge rate is set to be a total less than 10A.
It seems that the start up (In-rush) current when you a switch the 2nd charger on causes the PSU to dip and the first charger (an LRP Pulsar 2 Comp) trips out at that point sensing an input failure.

Didn't bother after than - I now run one from the PSU and one currently from a 12v until I can afford a new 14A or 24A PSU.

Hope this helps

[sparrow.2]

Depending on the quality of your power supply you might have trouble with false peaks if the chargers pull power in pulses. Even if your power supply is rated @ 10Amps and works fine at 8 amps or so with a single charger it might well have trouble with two set at 8 amps total.

Try it out but keep an eye on the peak point and see whether the cells are taking the same amount of mah as with a single charger on the PSU.

You could also try with a large capacitor with a charging circuit like the ones used for car stereos but that alone would probably cost more than a second PSU

[NSDie]

Looks like I need a new PSU. Thanks for the info guys!

[ashleyb4]

I have a 10a psu with a 12 amp peak i can run 2 chargers at 5 amps.

A

[sparrow.2]

Originally Posted by NSDie

Looks like I need a new PSU. Thanks for the info guys!

Try it out first though, you might get away with it

[VintageRacer]

Originally Posted by Gnarly Old Dog

I've got a Nosram 10A power supply and it fails to run 2 chargers - even if the charge rate is set to be a total less than 10A.
It seems that the start up (In-rush) current when you a switch the 2nd charger on causes the PSU to dip and the first charger (an LRP Pulsar 2 Comp) trips out at that point sensing an input failure.

Would this be avoidable by starting charging at a lower current and building it up slowly? I have a Nosram stealth which can adjust the charge current "on the fly" I believe the Pulsar can to the same.

[super__dan]

Theorectically if it is 10A @ 12V then it should easily cover 2*5A chargers @ say 7.2 - 9.1V.
However, i've got a current meter on my PSU and the difference in power draw (and hence efficiency) between two of my chargers is MASSIVE. My Pulsar is very efficient and draws about 3.8A @ 13.8V(what power suppley gives out), but the Novak is something like 5.4A @13.8V, which means it's something like 50% efficient Which explains why the fan is always on when charging.

Conclusion, first try it!

Secondly, buy one of these, amazing value for money.

http://www.modelsport.co.uk/index.ph...n&ItemID=23410

[dev]

As super_dan says it depends on the charger design, switch-mode chargers are much more efficient than linear ones. Best bet is test each charger's current draw.

See http://en.wikipedia.org/wiki/Switched-mode_power_supply for an excellent comparison between switch-mode and linear designs.

Generally if your charger can charge more than 8 cells (or about 3S lipo) from 12V (ie it can put out more voltage than its input voltage) then it is a switch-mode design and roughly your peak charger input current would be ( 9.5V x 4A ) / 12V = 3.16A (assuming it was 100% efficient, which it won't be, probably more like 80%, so maybe 3.9A max), where the max battery voltage for the cells is about 9.5V, the charge current is 4A and the charger is running from a 12V supply. Note that this means as you increase the output voltage the input current goes up, so as your battery peaks the current peaks.
I believe all the Pro-Peak chargers (Constellation, Prodigy, Elite) are switch-mode, as is the Much More silent charger, obviously the pulsar ones are and many others will be.

Linear designs, instead of switching the power, dissipate the excess voltage as heat, so if you are charging at 4A, your cells are at 7.2V and your PSU is at 12V the charger is dropping (12V - 7.2V) = 4.8V across itself, the current through the charger is the same as through the batteries, so the power (heat) in the charger in this case is 19.2W, hence why it needs fans to keep it cool! On top of that charge current you have the current to run the LCD, fans, microcontroller and all the other bits in the charger, meaning the overall current is more than your charge current. Note that unlike the switch-mode chargers the current drawn over the charge cycle will be pretty much constant.
A Muchmore Ctx-cell master platinum (the one with the loud fans) charging at 5.5A draws about 6.5A, but they are big fans and a fancy screen!
Chargers like the Pro-Trak and many others are linear; normally they have the cooling fans running most, if not all of the time, to keep the heat down.

I have a 12A supply that runs two switch-mode chargers, charging at 5.5A, without any problems.

If both your chargers were linear then it might be too close to the limit of the psu at 10A, if at least one of them is a switch-mode design then it should be okay.

[This reply has become way more complicated that I ever intended...]

[NSDie]

thanks dev. Just the information I need!