• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

Show idea... "Parallel lipo charging".

#1
How to parallel charge. Explain the theory of how it works. How to do it safe. As filler you could show us some of the set ups you guys use to charge batteries. I imagine you guys charge a lot of batteries. From what I am reading on the subject it's a safe way to cut down on charge time as long as you follow some basic rules.

I can imagine what type of mad scientist setup David has put together. Fifty 2000mah batteries in parallel at 100 amps! :cool:

frets
 

vk2dxn

Senior Member
#2
Mate that is a terribly dangerous idea. You should never parallel charge lipos as you run the risk of over charging individual cells.
Over charged cells = unhappy battery
And unhappy battery = extremely hot smokey stuff that smells lots
 
#3
Mate that is a terribly dangerous idea. You should never parallel charge lipos as you run the risk of over charging individual cells.
Over charged cells = unhappy battery
And unhappy battery = extremely hot smokey stuff that smells lots
Hey, thanks for your reply. From all the research I have done over the past week or so I think parallel charging is completely safe as long as you follow some basic rules. Perhaps you are confused and thinking about "series" charging batteries. Series charging can in fact be dangerous, but from what I have read parallel is completely safe and a lot of people do it. (just search youtube or google and you will find them)

If you think about it the lipo batteries them selves are set up in parallel as well. For example. If you take apart a 3 cell lipo battery you will find that there are actually 6 individual cells inside. What the manufacturer does is that they parallel the cells together to get the larger capacity. Your charger only see's three cells even though there are actually six cells inside the battery. So it is the same concept. If you parallel six "3 cell 2000mah" batteries together your charger only sees them as one "3 cell 12000mah" battery. As long as you have a quality balance charger and you make sure that all the batteries you are connecting together in parallel have the same voltage you should be fine. You will of course also need a beefy power supply that can enable your charger to push the high amps needed.

This is exactly why I thought this would be a great subject for the Flite Test show. I am sure they would be able to explain all this stuff much better than I can. :)

frets
 

vk2dxn

Senior Member
#4
I will take your word for it, personally I will stick to charging individual batteries. My concern with parallel charging is that how can you regulate charge evenly between the batteries. What I mean by that is if battery A is already at 4.2v per cell and battery B is still taking charge then how do you regulate that? External balance regulator?
Can you post a link for me to have a read up on this please
 

vk2dxn

Senior Member
#5
Oh btw I forgot to say that series charging cells is ok in fact I work with large battery banks used for scada backup control of high voltage switch gear. Our banks consist of up to 56 cells in series to provide 120v nominal voltage and charged in series configuration.
 

xuzme720

Dedicated foam bender
Mentor
#6
I think since people DO charge multiple Lipos at once, it's still a great show topic. Show the dangers and possible pitfalls and how to do it safely and cheaply. I for one would be very interested in see that...
 

MrGravey

Senior Member
#9
I have boards built to parallel charge some of my smaller packs. It can be great, but it can be a pain as well. Mostly the batteries have to be really close in voltage, and if for some reason they aren't (different flight times, or different kinds of flying) then parallel charging can't be used. Some people will hook up to discharge a pack to a voltage to match, but that adds another step instead of just charging. If you rely on this kind of charging to keep your packs full in the field it is easy to think you can charge 10 packs at a time and end up having to charge them one at a time anyway.

These is also the concern of total watts to the charging port. Most charges that will charge 4 batteries at a time basically have 4 50 watt charges in them. Add a power supply with enough power and you can charge 4 2200 mah 3S packs at 2C and not much more (it would be a fraction of a volt more and I don't think that really matters). So, if you want to charge 8 2200 mah 3S packs you could charge 2 of them at 1C on 1 port, or split them up and charge them at 2C each and not have to worry about following any additional rules like making sure they are close together in voltage. The timing is the same (or close to it) and less equipment is required. If you have a much high watt rating on your charger it might be worth it, but I really haven't seen too many reasonably priced charges with more output than that.

Basically this is great for very small packs. I charge 6 210 mah 2S packs for my UMX Beast on one port at 1C. These batteries aren't rated for a higher charge rate, and each pack needs less than 2 watts of the 50 each port is ok putting out. In this case the time saving is worth the trouble. The law of diminishing returns plays a large role here.