15s balance charging - three 5s chargers in series

[Samd]

Well I've been pondering this. I've seen some folks using a 1010i charger to charge 10s as two 5s packs in series.

I have a custom aluminium frame dual with 15s internal (3x5s2p). I've been breaking it down and charging each 5s in parallel. But I'm wondering if i can't use three outputs from something like the Turnigy 4x6s charger and charge each 5s section at the same time without breaking the links between packs.
http://www.hobbyking.com/hobbyking/store/__27891__Turnigy_4x6S_400W_Lithium_Polymer_Battery_Charger_AU_Warehouse_.html

Or maybe use three seperate chargers with a common DC power source.

Sure I could get a 60V meanwell, tweak the voltage and current for 63V but I'd still need to get into the bike occasionally and balance it. I'm time poor and want a simple solution. And I want to charge 18s sometime soon, so this would be better than setting up a different meanwell for that...

What do people reckon? Would appreciate any insight.

 

[major]

I am not sure about the charger you reference, but I found that my BC168's are not isolated from the power supply so I cannot use 2 of them to charge my 12S pack when the power supplies have a common ground. If the negatives on the separate charge ports on the Turnigy unit are common, you'll have a short circuit across one battery if you leave them series connected. Check it out or put fuses in the charge leads before you connect them for the first time.

Ref: http://endless-sphere.com/forums/viewtopic.php?f=14&t=57165&p=852760&hilit=thunder+1220#p852760

 

[Samd]

Yeah that does make sense. Good point about isolation from the power supply across the different ports.

I'm guessing from the above that it'd be possible - albeit probably impractical - to run three chargers in series from three stand alone SLA power sources.

 

[dnmun]

once you have them balanced why not just bulk charge them with a BMS to watch them to make sure one doesn't go too high. you can find 80A continuous/120 surge D131 lipo BMSs for about $56-60 plus air freight.

you could even balance them initially with the BMS but if you don't wanna charge to full voltage then you can bulk charge to lower voltage, but just use the BMS for protection.

 

[TheBeastie]

I believe one way to go or at least the way I thought about doing it is to use the latest 9s/ 9channel bc168 style charger and have your battery pack with a simple switch to split in half. Do keyword searches for UNA9 balance charger on eBay or aliexpress etc.
http://www.ebay.com.au/itm/UNRC-R-c-RC-Plane-Car-UNA9-Plus-9S-LiPo-Li-polymer-300W-Battery-Balance-Charger-/360732877603?pt=AU_Toys_Hobbies_Radio_Controlled_Vehicles&hash=item53fd5ae323&_uhb=1

Then on the second charger have it receive its power via a step down transformer of about 500w, since PSUs accept 110v or 240 you can use any one of your choosing.
http://www.ebay.com.au/bhp/240v-110v-step-down-transformer#ht_3554wt_1132

Then you have up to a 18s that can be charged in one go. This is what I have read anyway, I believe ozsplinter said he used a setup of this nature at one time.

 

[Samd]

Might split the packs with links like Kepler used on his bomber. Doubles as an anti theft key.


http://static.electricbike.com/wp-content/uploads/2012/07/ec52.jpg

 

[999zip999]

My 48v lifepo4 ping charges to 61volts. Then a bms. Some others charge to 58.6v.

 

[TheBeastie]

Actually in my last post with the voltage step down transformer you shouldn't need to split your pack. I guess I stuck two suggestions in one there.