Choosing a Charger and Power Supply

[dp106]

I';ve been looking for a new charger, ideally I want one that can charge 4 at once, 2 if it was a good one.  Flying a wing for FPV now I';ve started to have some bigger batteries so was a bit concerned over the power needed to charge these.

I already know the basics, ie to get the very best out of your batteries you should only charge at 1c. So for a 5800mah battery charging at 1C is 5.8a.  I also see on chargers they quote the power they can charge at, a common power seems to be 50w but you can go much higher if you';re willing to pay..

But how do you work out what power you are going to use to charge a given battery..?  Well there is a common formula Power(or Watts) = Volts X (Amps or current). So to charge my 5800mah 3s battery which when fully charged will be 12.6v we need  12.6 X 5.8 = 73 watts.  (Luckily my current charger is 80w but I';m still getting near the limit!)

For a more detailed (possibly clearer) explanation have a look at this excellent guide I found:  http://www.4-max.co.uk/pdf/charger-selection.pdf

I';m thinking about this charger: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=44532 with 100w and 10a per channel I should be covered for most charging requirements!  Just need to find a suitable power supply to to provide enough juice now :-S  The 540w one at hobbyking is on backorder 

[Cockney Boy]

I';ve recently gone down the route of the following

2 x HP 135 server PSU';s
1 x iCharger 306
1 x Buddy Paraboard V2

I can charge all my four 4500 4S batteries at the same time and all within an hour

Works a treat and using the 135 PSU';s meant I could have either a 12 or 24 (which gives you 1000w) option as the 306 can run upto 28 volts and each 135 is only £17. You';ll need to modify one to remove the ground

http://youtu.be/aVbk7cpOJuE

[dp106]

Just done a quick search and they look expensive..?? Wait think I was looking at brand new ones.

I was wondering if I could use a PC Power supply.  Randomly picked this one http://www.ebay.co.uk/itm/750W-ACE-PSUACE750BR-Single-Rail-1x120mm-Quiet-Fan-ATX-v2-3-PSU-/360881866966?_trksid=p2054897.l4275#ht_1769wt_1055 which is 750w and claims 37a so should be close to powerful enough to charge 4 batteries at a time?

[Cockney Boy]

You could try it

£17

Look at this on eBay:

http://pages.ebay.com/link/?nav=item.view&alt=web&id=360581075984

321632-001 HP ProLiant DL380 G4 DL385 G1 575W Hot-Plug Power Supply Unit ESP135


Sent from my iPad using Tapatalk HD

[Atlas]

Looking at that turnigy charger, dp106, and by your reckoning would you say that if it was given the full 18v input you could potentially charge 8 5000mah packs at once?
That is with 2 packs parallel charging on each port at 10amps between them?

Because if that';s the case that';s a bargain at £77!

[dp106]

Yes I think you could. You would have to charge below 1c though. Charging a 3s battery at 5a would use 63 watts so to do 2 you';d go over the 100 watt max.

[Atlas]

I';m using 6s packs, is the maths better in that case? or worse!

[dp106]

Much worse :-) You';re max voltage on a 6s is 25.2 I believe to charge that at 5 amps you need 5 X 25.2 = 126 watts.

[guest325]

No shortage of oomph with one of these!
http://www.giantshark.co.uk/product/170666/icharger-306b-6s-30a-1000w-balance-charger

[Atlas]

Right, think i';m there with this one now: To charge the 5000mah 6s packs in parallel at 1C then i';d need 252W per channel (assuming it was a multi output charger)

The 306B seems popular, and with a 1000W output, at 24V, presumably that would parallel charge 8 packs at once! Give or take a few watts.

For that to happen though, you';d need a 1000W supply too I assume.

[guest325]

For that to happen though, you';d need a 1000W supply too I assume.

Correct, and that';s where it can get expensive - server power supplies are good but you may need 2-3 of them to supply 1000W, that';s the only real problem with high capacity chargers!
You can get a single supply at a cost!!! http://www.newegg.com/Product/Product.aspx?Item=N82E16817151105
I use 2x Accucel 6';s and a Fusion elysium pro for my charging on a big server supply but I only use 3 or 4S 5000 mah max - mostly 2200';s that I occasionally run in parallel.
I use this when I only want to run the two A6';s

[Atlas]

Excellent, thank you guys, much appreciated.

It';s off to eBay land for me for some server PSU';s and a kilowatt charger! Suppose i';ll need some more LiPo';s too!