Rollingthunder

Hi All,

I'm trying to figure out how to field charge a pair of 3s Li-PO battery packs that are wired in series to power an Axi 4130/16 I'm thinking of getting for a Kadet Sr. My battery knowlege stops at carbon-zinc.

What I seem to be getting is that I'd dismantle the pack and charge them in parallel. Is this correct?
Or do I charge them seperately? I'd then need two chargers or a very long down time between flights.

I thought some where on this great web I'd find this spelled out. 'Li-Po's for Idiots' or some such thing.
My eye-balls are about to fall out, and I can't search no more.[>:] So.....

What I'm loosing in all this, is the connectors needed, the exact hook-ups, the charge rates for parallel, how to balance. best charger, and a whole lot more.

I just know a whole bunch of you out there have the answer to these and a whole lot more of my questions.

What I want to know is why haven't any of you ever put the answers out where I can find them....

Stalled in Toledo,

BoB

guver

My Feedback: (325)

If they are already in series, then they can be charged in series too. If your charger can't do 6S then to split them up is the good way.

They can be charged seperately or in parallel as long as they are seperate packs. They can be charged at twice the current in parallel.

I really think you got it, maybe needing a picture. This is helpfull link.
http://www.scriptasylum.com/rc_speed/_wiring_bec.html

mrasmm

if you want some more specific info, post the brand of batteries (or balance type and polarity), and the charger you are using.

otherwise guver has got it covered =)

jasonwang3a

Charge pair of 3S lipo packs in series or three 2S lipo packs with a 6S lipo charger is very useful, If the charger has built in cell blancer, the two 3S battery or three 2S battery will be fully charged and balanced sumultaneously, so the two 3S wil be discharged as one 6S battery, save money and easy to use. 6S lipo should be expensive. the other requirement for the charger is the output power must enought to fiinish the charge in a shortest time, if the charging time is 2 hours or above, the batter can be charged at 1C current one by one.

Rollingthunder

Hi Guver,

Nice link. I've got the set-up diagram, but the site is light on charging instructions.
The reason for my post is I read somewhere that LiPos could be charged in parallel. I've never heard of this. I can not find this set-up described anywhere. I've reviewed several on line charging manuals. No help there. I was trying to avoid buying a 6 or 8 cell charger. Not too many out there to choose from, and they tend to be pricey.

My LHS(2) both told be I needed either a 6 cell charger for series charge or a multi pack charger such as "Great Planes PolyCharge 4"
http://www3.towerhobbies.com/cgi-bin...?&I=LXKAU0&P=0
If this is the case so be it.

The batteries I was thinking of using were either-
1) 3 Cell 3000 mAh ULTRA Li-Poly 11.1 volt 20C
2) 3-cell, 3200mAh capacity Cellpro Revolution LiPo Battery Pack, rated 20C,
3) ElectriFly Power Series Lithium Polymer 3200mAh 11.1V 20C Balance Battery

I'm hoping to drive the Axi 4130/16 at 800-850 Watts for an 8 to 9 minute ride.
I don't know if I'm even in the ball park with theses selections.

At the price levels this project is headed, glow is looking more and more attractive.

Thanks for the feed back,

BoB

Set up diagram from web link.

guver

My Feedback: (325)

Since you are using them in series AND they are the same size and voltage batts then they will stay as equal in voltage good enough to hook them in parallel to charge. They can be charged in parallel as long as they are same voltage packs (they really don't need to be same size/capacity)

You'd be chargeing in effect a 3S x 6400 mah pack and can do it with a single output charger.

Rollingthunder

Guver,

Your last post was a real eye opener.
In parallel at 6.4 amps.... Ouch. []
I don't think there is a 4 cell charger out there, that'll put out 6.4 amps.

Well, it now on to plan B.
Except I don't have a plan B.

Thanks for the feed back,

Bob

Ps Where is LaGrange

guver

My Feedback: (325)

It's about 100 miles East of you.

I thought you had a pair 3S?

anyways that is 12 - 12.5 volts x 6.4 amps= 80 watts. The Triton2 and the Ice and 989 MRC will do the job.

even with 4S (16 x 6.4) it is 100+ watts and the Triton 2 will do it, but with slightly reduced rate, the Ice and 989 will do the full rate.