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Battery charging

#1
Hi guys just picked up a zippy 3s Lipo.
ZIPPY Compact 2200mAh 3S 25C Lipo Pack
Just wondering what he best way to charge it is on my charger, have a core rc charger, just unsure on what settings to charge it in for best performance and life.
Cheers
 

DamoRC

Well-known member
Mentor
#3
I recommend charging it it 2.2 amps under the Lipo Charge settings menu.
Yep. Typically, safe practice is to charge at 1C which in your case is 2.2 amps.

A couple of other points to note.

Conventional wisdom is to store you batteries at ~50% charge and don't store fully charged for longer than 24 hours.

If you want to maintain the life of the battery, don't just focus on the charging side, you can do a lot more damage to the battery on the usage side. Make sure that when you are flying you use a timer so that you don't discharge the battery more than 80% or let the cell voltages drop below 3.65 - 3.7 volts.

My experience is that as a beginner, once in the air you want to stay there as long as possible leading to overly discharged batteries. In the long run it is better value to buy 2 batteries and fly them conservatively than squeeze another minute flying time out of one battery.

DamoRC
 

sprzout

Knower of useless information
Mentor
#5
I tend to fly my batteries to 3.8v/cell, which allows me time to fly, goof around, and then go, "Ok, time to come down," and if I have to wait 30 sec. or 1 min. more because someone's slow to clear the runway or there's a crash that has to be cleared, I can circle and come around again while they're clearing. It's just one of those safety factors I've built in, and something that the club instructors have suggested time and again. It's come in handy a couple of times, so that I'm not going, "Guys, if you don't clear the runway SOON, I'm going to have a dead stick electric crashing in the middle of the runway!"
 
#6
Thanks for the help guys, much appreciated, already have a battery alarm setup for 3.5v in my buggy so that will find its way into that, just wasn’t sure on the charge procedure
 

PsyBorg

Fly Angry
Mentor
#7
BALANCE charging is best. Normal charging lipos can tend to cells getting unbalanced and that's not good for them. It may take a slightly longer time but is best for the batteries.

Most chargers have two programs. Straight charge where you connect the main battery leads and charge which will bring the voltage up total pack voltages selected regardless of each cells voltages. So if you had a 3s pack which cells were 3.6, 3.8, and 3.5 the charger would charge them to the 12.6 total but the cell voltages could end up at 4.2, 4.4, and 4.0. more so over time as the packs internal resistance changes.

The other is balanced charging where the balance connector is also used so a program can read each cell and bring them up equally and stop at 4.2 volts as each cell reaches max charge. If field charging to get back in the air faster its not bad to normal charge but regularly check the cells and keep them balanced as possible. Variation between cells of .02 or more can become problematic.

Finally most chargers have a storage charge setting that will balance the cells to 3.82 (for one of mine) the other one stops at 3.8 even. Don't confuse the store at 50% to mean 50% total voltage of the pack its safe operational range is 3 - 4.2 v per cell.
 

sprzout

Knower of useless information
Mentor
#8
Also, keep in mind that sometimes, balance chargers will read off by 0.01-0.02, depending on brand. I have a Hitec charge checker that reads as 0.01 off from when my Hitec RDX charger is connected to the battery. My dad's Turnigy battery checker will show as 0.02-0.03 off from what my Hitec charger and checker will show. You ideally want the cells to be equal, but sometimes it just doesn't happen where they're perfectly equal.

Where it should concern you is, say, if you have a 3S battery and you check it, and it shows that the battery has 2 cells that are 4.19 and one cell that is 3.92, even after balance charging. I've got one like that which I have been using for bench testing servos and motor spin, and have been slowly just discharging it in preparation for disposal. Once it's dead, I'll take it down to my local Home Depot (which actually shows as a disposal location for lipo batteries, along with the local Lowes!) and offload it onto them.