Hello, I just got into fpv so I have much to learn.

I use two different lipo batteries 4s and 5s.

1. When I charge my batteries both 4s and 5s using my isdt D2 200w I set the full charge to be 4.2v/cell, then wait for the charger to beep once all cells reach 4.2v - is this right?

2. When I charge I also set my C rating like this. 1300Mah = 1.3C and 1550mah = 1.5C - is this right?

3. In case I wont fly for more than one week I set my charger to storage and 3.85v/cell and C rating to 0.5C and wait for my charger to either drain or charge the battery to 3.85v/cell - is this right?

4. When I fly I have set my OSD to show cell voltage, and I always land when I reach 3.7-3.8v/cell - is this right?


Sorry if this things seems obvious but I just wanted to double check. I get a bit confused when the battery labels says that full charge is 3.8v/cell and then I read that the real full charge is 4.2v

Not that I would be a lipo expert, but here's my opinion:

1. I'm not familiar with the specific charger, but I suppose you use a balance charging mode since you can set a voltage per cell. Then it's correct to set the voltage per cell to be 4.2 volts. Just please also keep in mind that lipos can be dangerous and it's a very very very good idea to charge them in a safe, fire-proof place and keep an eye on them while charging (watch for temperature increase, puffing, smell, etc.), never leaving them unattended.

2. I suppose you meant to write 1300mAh = 1.3A and 1550mAh = 1.5A - I suppose you are setting the amps on your charger. In that case it's correct, because you're charging them at 1C that way - that is considered the safe value.

3. That is correct. Again not sure about the 0.5C, did you mean 0.5A?

4. Landing in around 3.7-3.8V per cell is the safe value. You can go a bit lower, the lipos can handle it, but usually going lower than 3.5V per cell is not recommended if you want to make sure your lipos will live a long and happy life.

And about the battery labels: what you read there is a "nominal voltage" of the battery, not the "full charge" voltage. Full charge for lipos is in fact 4.2V per cell. You can google around what the "nominal voltage" is, I'll just leave a quick link here: https://bixmart.3dcartstores.com/Nominal..._54-1.html

(26-Sep-2018, 10:33 AM)izzy26 Wrote: Not that I would be a lipo expert, but here's my opinion:

1. I'm not familiar with the specific charger, but I suppose you use a balance charging mode since you can set a voltage per cell. Then it's correct to set the voltage per cell to be 4.2 volts. Just please also keep in mind that lipos can be dangerous and it's a very very very good idea to charge them in a safe, fire-proof place and keep an eye on them while charging (watch for temperature increase, puffing, smell, etc.), never leaving them unattended.

2. I suppose you meant to write 1300mAh = 1.3A and 1550mAh = 1.5A - I suppose you are setting the amps on your charger. In that case it's correct, because you're charging them at 1C that way - that is considered the safe value.

3. That is correct. Again not sure about the 0.5C, did you mean 0.5A?

4. Landing in around 3.7-3.8V per cell is the safe value. You can go a bit lower, the lipos can handle it, but usually going lower than 3.5V per cell is not recommended if you want to make sure your lipos will live a long and happy life.

And about the battery labels: what you read there is a "nominal voltage" of the battery, not the "full charge" voltage. Full charge for lipos is in fact 4.2V per cell. You can google around what the "nominal voltage" is, I'll just leave a quick link here: https://bixmart.3dcartstores.com/Nominal..._54-1.html

Thanks for the help izzy26!
Yea A not C, my bad!

Then I will keep charing my lipos to 4.2v : I wasnt sure if it would matter if the battery was a 4s or a 5s.

Yea I use a balance charger where I need to hook up both cables, the charger also display each cells voltage.
I try to charge my batteries in my garage since there is a stone floor and I always store my lipos in a lipo battery case inside my closed fireplace just in case.

1. Isdt in balance mode will charge the lipo using fast charge then refine the balance. So first beep means fast charge is done, second beep means balance charge is done completed. 4.2v per cell is full charge for regular lipo.

2. Already answered

3. 3.7-3.85v is what is recommended. As for discharge, you can discharge at the lipo rated discharge. I usually use a light bulb or run motors. Final discharge with ISDT. Otherwise a fully charge lipo discharging with ISDT takes forever.

4. I land when it is about 3.4V for more than 4 secs. When the lipo recovers, it is usually 3.7ish

" I also set my C rating like this. 1300Mah = 1.3C and 1550mah = 1.5C ".....
it is the best to use about 0.5C charge rate. 1C is ok too because most of batteries used for copters are 10C discharge rate
In this case 1300mAh is ok to charge with 1300mA=1.3A current

(26-Sep-2018, 02:30 PM)kivo123 Wrote:  I will keep charing my lipos to 4.2v

Actually there is no other way, unless you cobbled that charger yourself from a few resisors and rectifier....
Just let the charger charge untill it gives indication of charge completion. And I presume this is Li battery charger...