Charging Batteries
Table of Contents
Table of Contents
Chargers and Power Supplies (PSU)
TJinTech - How LiPo Chargers Work
TJinTech - The Charging Process
TJinTech - Chosing a Charger and Power Supply
TJinTech - Understanding Wattage in Relation to Charging
Charging Station
Chargers and Power Supplies (PSU)
In my opinion, chargers are very important if you are going to fly electric planes.
Without a charger (and power supply), you can't fly. And depending on the performance
of your charger, your flying time can be severely limited if you don't have
a suitable charging setup.
Here are some links with some very good information on Chargers, Power Supplies,
how they work and how to select a combination of the two that will work well for
you.
TJinTech - How LiPo Chargers Work
TJinTech - The Charging Process
TJinTech - Chosing a Charger and Power Supply
TJinTech - Understanding Wattage in Relation to Charging
After reading the material on the TJinTech website, I very much agree with what
Chris has to say.
I do believe in buying a power supply and charger to match your current and future
needs and doing that as early on as possible. If you are serious about flying electric,
it will save you time, frustration and money in the long run.
Now, not everyone can afford to buy the most powerful charger and matching power
supply, but as Chris mentions in his website, try to find something between the
cheapest and the most extravagant. Also, if you are only going to fly small electric
planes, you won't need a powerfull charger and you can probably get away with
connecting you charger to your car battery in which case you won't need a power
supply unless you want to charge at home.
Charging from your car battery has advantages such as being a cheaper alternative
and eliminating the need for a power supply, but it also has it drawbacks such as
slower charging and the possibility of draining your car battery.
As opposed to the advice given on the TJinTech site, I, unfortunately, did not
initially buy a charging setup that would suit my not-so-distant future needs. Well,
it kinda suited current needs, but not for long as my apetite for larger and larger
planes started to grow. I had bought a cheap and underpowered charger for my needs.
It was partly a question of cost, but mostly because I didn’t really know
what I was doing. Anyway, to make a long story short, I’ve ended up re-buying
chargers and power supplies.
Ok well this won’t be that short a story, but I think this is a good illustration
of what Chris was talking about. So here it goes...
I've bought lots of stuff from HobbyKing and for my charging needs, I started
with their Accucel 6 charger and a simple power supply. That worked well for a while,
until they came out with the Accucel 8. So I then bought two of those because by
then, I was flying a 26% Yak from Pilot-RC on 8s (2 x 4s). I thought I could charge
two 4s packs in series (1 flight pack) and that way I could charge 2 flight packs
(with 2 chargers) while flying another one. First I tried to power the chargers
from my car but quickly realised that wouldn't do when I drained my car battery
to the point I needed jumper cables. It could have been worse. I could have damaged
my car battery to the point of needing a replacement.
Anyway, I then graduated to using a converted PC power supply and a portable 1000
Watt Honda Generator to power the two chargers. And, I had to buy six(6) 4s batteries
to be able to fly back-to-back flights (2 flight packs charging and 1 flying). Well,
that was working pretty well until I shorted the balance plugs using my series connector.
Don’t panic. It wasn’t that bad but, at the time, I thought the cheaper
/ lower quality Accucel 8’s had failed me. Well, if you read Chris’
website, he has a section about parallel charging versus charging in series and
the pros and cons of each. He has a good diagram - if I recall - that shows how
you could short the balance plugs if you don’t plug them in the same order
as the mains. You have to be very careful with charging in series.
Well, I know that now but I was frustrated when I got the short circuit so I then
decided to buy a Hyperion charger - a EOS 0615i DUO3. Excellent charger but then
it outgrew my power supply if I tried to use the charger at full capacity. Upgrade
to 600W Meanwell power supplies. The good thing was that the Hyperion charger has
dual ports which eliminated the possibility of balance-plug shorts using a series
splitter.
Anyway... Yada yada yada to make a long story short... and now I have a 1344W
Cellpro Powerlab 8 from Revolectrix/FMA Direct powered by Meanwell 600W power supplies
in parrallel (3 of them for a total of 1800W PSU). So now, guess what? I’ve
outgrown my 1000W Honda generator! When will it stop?
Ok, maybe I’m crazy (ok I’m crazy) and this is an extreme example,
but I was laughing when I read Chris’ section on chargers and power supplies.
I did exactly what he described. I re-bought and re-bought... and... you guessed
it... re-bought.
Had I put some thought and done lots more reading, I probably would have started
with something like the Hyperion Charger, a proper power supply and a generator.
I would have saved myself lots of money and frustration!
The other thing I’ve learned is that being able to charge faster means that
you need to buy less batteries and still be able to fly as much as you want. It
allows you to fly more with less batteries.
For example, I have a 70” Extreme Flight Extra 300 EXP that I fly on Nano-tech
6s 5000mAh 45-90C batteries. I have two of them now, but I was flying that plane
with only one battery for a while. With just one battery, I could fly all day almost
back-to-back flights with only a few minutes in between flights. These Nano-tech
batteries have a charging rating of 8C (or maybe 10C?). Anyway, I charge them at
about 4C or 20A and they charges in about 11 to 13 minutes depending on how hard
I flew my previous flight. Actually, I can charge the battery to 90% to 95% in less
than 10 minutes. I can fly for about 8 minutes (10 minutes if the wind is low).
The battery is only a little warm when the plane comes down. When I only had one
battery, the first thing I would do after a flight was to pull the battery out of
the plane and let it cool for a couple minutes. Then I charged it and I would be
ready to fly again in less then 13 minutes. Now that I have two batteries, I can
literally fly back-to-back flights all day long - and that with only two flight
packs instead of three - and technically, I could do just fine with just one battery.
At $90 per battery (plus shipping), the potential savings of 2 batteries pretty
much pays for the charger! And, that doesn’t count any savings on batteries
for my other planes (that I fly on different packs).
So, IMHO, investing in a good charging setup may cost more up front, but you could
end up saving lots of money on batteries - especially in the long run.
Charging Station
As you’ve seen in my previous story about my charger experience, I’ve
got a heavy duty charging setup which includes:
- 1 Hyperion EOS 0615i Duo3 charger
- 1 Powerlab 8 Charger
- Various charging leads for each charger
- Various balance plug leads for each charger
- 4 Power Supplies - 3 for the Powerlag 8 and 1 for the Hyperion charger
- 4 AC power cords for the power supplies
- 1 AC power bar to plug the power supplies in
and then I also have a long AC extension cord to connect the whole thing to my
generator.
That’s a lot of individual components. After a while I started getting really
tired of putting all this together at the field and then dismantling the whole thing
before leaving. So, I built myself a charging station. Now all the components are
nicely mounted on a piece of plywood. Here is a picture of my charging station.
Notice it only has 2 power supplies. I haven't bothered putting all of them
on my charging station yet since I won't really get enough juice from my generator
until I go to a 2000 Watt generator or higher. Plus, for the size of plane I have
at the moment, I can charge even my largest batteries (6s1p 5000mAh) pretty quickly.
Now, I can easily carry the whole charging station from the handle on the toolbox
and all I have to do to set it up is plug the extension cord from the attached power
bar to my generator and voila! It’s that easy and convenient.
When I charge a battery, I place them in the toolbox. The wires from the chargers
are fed inside the toolbox through holes I cut just in front of the chargers. Once
the charge is started, I can close the lid of the toolbox and latch it for safety.
I also have a smoke detector that I keep in the toolbox just in case. You can never
be too safe.
Anyway, there are lots of different ways you can build your own charging station.
Let your imagination go wild. I’ve seen some built into a large case. Some
are kinda the same idea as the one pictured above, but using Lexan (Acrylic glass)
- it’s less flammable than the plywood that I used on mine. That may be my
next project - to replace the plywood.