Hello,
I've been in the hobby for over 12 years, but I'm about to take on my first electric plane project; a Todd's Models Attitude.
I'll be using a Mega Brushless 16/15/4 with the Astro 709 Gearbox and APC 12x6 Slowfly Prop.
I also would like to use TP 2100 3s LiPo's.

I see that Duralite has the TP 2100 3s LiPo's with the built in charge protection circuitry. I'm already using the Duralite Lithium Ion's with the charge protection circuitry on all my other planes for RX and TX and ignition batteries, so I'm liking this option.

Being new to this electric side of the hobby, I have some questions for you guys with experience:

1. I wonder how safe this charge protection circuitry makes the LiPo's?

2. What kind of charger will I need for the Duralite TP LiPo's and will I need to still take lots of precautions while charging them?

3. How long does it take to charge these batteries? If I want to do an afternoon of flying, how many battery packs will I need to own? I'd like to re-charge one battery while flying on another one.

Thanks in advance for your replies,

Jim

1. The CSC built into Duralite packs eliminates only the charging hazards of Lithium batteries. It will stop the charge in case of overvolting (using a 3-cell charge setting on a 2-cell pack) or cell imbalance. If the pack is internally damaged somehow there's still a chance of venting.

You still have to be very careful while discharging these packs; the discharge lead has no protection whatsoever. If you get a pack below 3V per cell you risk puffing the cells and ruining them. It's best to have a programmable ESC that allows you to change the low voltage cutoff to 3V per cell.

2. I personally recommend the AstroFlight 109 charger for charging all types of Lithium Polymer packs. It autodetects the number of cells in your pack and sets its charge voltage appropriately. No matter how safe and cautious you are about charging it's a good idea to charge in a fireplace or firesafe and never charge unattended. There are no "special" precautions here, just the usual stuff.

3. It should take about an hour to charge these packs at 1C. It's not recommended to charge them at a higher rate than that. You're going to have to measure amp draw to calculate how much flight time you'll get, but expect about 30 minutes total on a 5C discharge.


Please read this before doing anything.

Thanks Awakened,

I have read the "Ultimate Guide to Lithium Polymer Batteries"


I know going below 3v per cell will ruin them. I bought a Pheonix 25 esc and I believe I can program the cut-off on it.


You brought up another question in my mind. Why would I ever discharge these batteries? They don't have a memory, correct?

Thanks, Jim

I'm referring to in-flight discharge. The have no memory whatsoever and don't have to be topped off before flight.

O.K.
so you were just saying to be careful not to go under 3v per cell.

Thanks, Jim

You bet. This forum is on the cutting edge of lipo powered flight so you've come to the right place. Feel free to private message me if you have any other specific questions.