Gunner132

iTrader: (2)

can someone explain what parallel and series mean in batteries? What does it do to your cell count/mah? I want to hook my charger up to mutiple packs of the same rating, but i have no idea how to wire it or set up my charger.
So im asking:
-What are parallel and Series?
-how do u set up the connections to run parallel or series?

Please help me out. Thanks

Banshee8530

iTrader: (1)

Series is when individual cells are connected + to - like a 6-cell NiMH pack or flashlight and this creates a cummulative voltage increase with no change in capacity; i.e.- a Lipo cell has 3.7 volts... 3 cells in series (3S) is 3.7V x 3 cells= 11.1V per pack.

Parallel is when individual cells are connected + to +, - to - and this creates a cummulative capacity increase with no change in voltage; i.e.- 2 cells of 2500mAh capacity wired in parallel will be 3.7V and 2 x 2500mAh= 5000mAh capacity.

Lipo chargers are only concerned about "series" numbers so that the appropriate voltage is used in the various cut-offs the charger is programmed with. So a 2S pack will charge at the 7.4V setting, 3S at 11.1V, and so on. The Capacity is used to establish charging current. A 1C charge on a 5000mAh pack will be 5 Amps (5000 milliamps equals 5.0 Amps equals 1C, 3600mA equals 3.6 Amps equals 1C for a 3600mAh pack), a 2C charger would be 5.0 Amps x 2C= 10 Amps on a 5000mAh pack. Most battery manufacturers recommend a 1C charge, but some higher end batteries will acommodate as much as 2C which requires a pretty powerful charger on large capacity packs. Parallel cells do not change the settings on the charger, only the overall capacity.

Gunner132

iTrader: (2)

thats what i thought, so you charge multiple packs in series and it ends up being a larger cell count and same mah. Thanks!
One more question:
-how do u hook up multiple packs to a charger and charge them at the same time? I know you have to balance them like a larger pack, but do u just stick the balancers into the borad? do u need any more special connectors to enable you to do this? I get a little confused with the electric stuffs...

Banshee8530

iTrader: (1)

I have never tried charging more than one pack on a charger. The hold up is going to be the balancer. If your charger has internal balancing circuitry, I don't think you can pull it off. If you have a charger that requires a seperate balancer like Checkpoint, etc. then maybe you could just charge with a splitter and set the voltage to that of both packs ( they would have too match) and set current for cummulative capacity. Then Balance them seperately... That's the only way I would know how to do it. The other option is to get one the new Hitec X4 Chargers which has 4 independent charging curcuits for as many as four packs charging simultaniously... thats the best of my knowledge...

Dave H

Examples of parallel cables, you need both a charge and a balance type with the correct connectors for your stuff:

http://progressiverc.com/index.php?o...id=14&Itemid=1

http://epbuddy.com/index.php?main_pa...3uq8hevuq6u430

Or maybe an all in one deal:

http://epbuddy.com/index.php?main_page=index&cPath=15

Batteries must be the same voltage (cells in series, all 2S for example).

Set the charger to the same cell count/voltage. Add the capacities up for amperage. (Three 5000mAh lipos would need 15 amps for a 1C charge rate).

Much safer if you only parallel charge packs in good condition and of similar discharge state-similar starting voltage. Remember there are exponentially more ways to mess up with more connections, unused plugs need to be protected from shorts, etc.

Banshee8530

iTrader: (1)

I think charging two packs off of the same output is going to be a "Parallel" set-up not a "series" because you will be charging both packs off of the same +/- output. chances are you'll be charging below 1C to do this and I'm not sure you'll save much time unless you have 2 <5000mAh packs and a 10A capable charger. I'm not sure I'd attempt it.

Banshee8530

iTrader: (1)

NICE Dave H... I didn't know that stuff existed. Good job.

Banshee8530

iTrader: (1)

When you DO charge parallel like that, all of the number one cells are going to be averaged for voltage in the balancing read-out, so like Dave said, you'll need to be certain the packs are very close in voltage PER CELL otherwise you'll have problems.

i.e.- if you charge two packs, both #1 cell voltages will be averaged as well as both #2 cell voltages. So if one cell#1 is 3.86v and one is 3.8v you'll read 3.83v on the display and the charger won't know one cell is higher that the other... one pack might over-charge and one won't fully charge...

Gunner132

iTrader: (2)

I think charging in series would be easier because chargers support higher cells than amperage. but how do u hook multiple (of the same battery) into a series balance?

Dave H

The issue is the rush of current between the packs at different voltages when first connected. Once they are properly connected (including the parallel balance connections) they will quickly balance with each other and stay that way while charging. Assuming no issues with any of the many connections involved of course.

Series charging doesn’t benefit from the inherent balancing of a parallel connection. If there is any imbalance between packs the charging process will spend a lot of time balancing. Note getting the balance connectors to the correct pack in the series is very critical.

Not sure where to get premade series charge cables, but this site provides some info on the wiring involved. Check the 3rd section: Balance Connector.

http://scriptasylum.com/rc_speed/lipo.html

You can create schematics like this:

http://scriptasylum.com/rc_speed/_pi...s_wmain.gif~14

simplechamp

iTrader: (73)

Here's a little more detailed version of the tutorial for making a series charging setup. It was made by BrianG from RC-Monster forums, who is the creator/author of the ScriptAsylum RC Calculator site.

http://www.rc-monster.com/forum/showthread.php?t=9881

I use this method for charging my packs, since all my vehicles use a 2x2S lipo setup. I already had the main lead series adapter for running the vehicles, just needed to make the balance adapter. I find this method works very well for my needs because all my packs are bought and run in pairs, so their discharge states, capacity, age, etc. are always matched. If you plan on charging packs that are not so evenly matched the parallel method may be a better option.

Here is a pic of a 2x2S 5000mah setup ready to connect to the charger. As far as the charger is concerned, it's the same as a 4S 5000mah lipo (the circuit schematics would be identical). You can't see it, but on the adapter I have the 2S balance connectors marked + and - so I remember which pack to connect them to. Based on the connection of the main lead series adapter the upper pack is more positive and the lower pack more negative.

Gunner132

iTrader: (2)

this sorta explains some things.

http://www.youtube.com/watch?v=NczQwVTI2bY

im still confused on Once again... electric wiring stuff isnt my thing... Help?

Dave H

Basically what he’s saying is your charger needs to have enough power (amps and watts) to charge multiple packs to save much charging time.

What packs do you have? Are they used individually or in pairs? (+ on simplechamps’s post btw)
What charger do you have?

Gunner132

iTrader: (2)

Im running 2s 5000mah lipos and the icharger 208B (8s, 350w, 20a)

But i think i get it now. as long as my charger can handle the watts and amps needed to charge the packs, and the packs are all at about the same voltage per cell, i can charge in parallel with no problems. i just need to use (5a per battery for 5000mah = 5 x 7.4 = 37watts ---> 20a x 7.4v for 4 batteries = 148 watts) all of the amps my charger can push out to be able to charge at 1C for 4 2s 5000mah packs in parallel.

wingracer

iTrader: (24)

You will also need a power supply that can handle that much juice.