The 'What did you do in your workshop tonight?' thread

[Snoopy1]

This is what I belive is the correct temperature that are aloud for LiPo’s.
Operating Temperature
Charge: 50 to 11o degrees F
Discharge: 50 to 130 degrees F

 

[AKNick]

This is what I belive is the correct temperature that are aloud for LiPo’s.
Operating Temperature
Charge: 50 to 11o degrees F
Discharge: 50 to 130 degrees F

The key is in my words... "that cell"... the other side was barely even warm. So yeah, for some reason it has a buildup of internal resistance at that once cell leading to get that hot.

Thanks for those numbers too!

I've always had trouble determining the Charge rate for lipos... 1C??? can someone break this down in a few words for me please? I charge around 1.2-2.4A

 

[Jetpainter]

1C is charging at the same rate as the batteries capacity. So, 1C for a 2200mah battery is 2.2 amps, or 5 amps on a 5000mah battery and so forth.

 

[AKNick]

1C is charging at the same rate as the batteries capacity. So, 1C for a 2200mah battery is 2.2 amps, or 5 amps on a 5000mah battery and so forth.

Well said, thank you.

 

[Jetpainter]

Also most packs will tell you the recommended charge rate. I have some 5000mah batteries for my helicopters that can be charged at 3C, but I don't charge them that high, 2C on those is plenty fast for me. I can parallel charge 2 5000mah batteries in around 20 minutes at 2C. That's 10 amps per battery. My charger will do 4 at once at the rate, but I only do 2. Since we have power at most on the tables at our field, it makes life a lot easier. My LiPo receiver packs I charge at 1C.

 

[49dimes]

I have always wanted to know what value in Ohms each cell should have or "not go below" before condemning the cell. I got this meter and finally found how to check internal resistance but it only will do the first cell in the pack. You have to plug a same number of cells pack in to the voltage port and use the pin adapter plug that's plugged in to the main battery input. This is one of those 7in1 meters.
It is great at checking the balance state and voltage on each cell but I don't know about the internal resistance feature.
It read 80 mOhms for the 1st cell......The batteries shown I purchased in Dec 2015 and have about 25 cycles on each. I fly the QQ300 with them. They both are still "hard bricks" with not the first sign of swelling. I always store them between 50/60% charged. I have always figured the number of cycles I have put on a pack before considering replacing it. My safe cycle limit is 250 times on any brand Lipo.

 

[AKNick]

Also most packs will tell you the recommended charge rate. I have some 5000mah batteries for my helicopters that can be charged at 3C, but I don't charge them that high, 2C on those is plenty fast for me. I can parallel charge 2 5000mah batteries in around 20 minutes at 2C. That's 10 amps per battery. My charger will do 4 at once at the rate, but I only do 2. Since we have power at most on the tables at our field, it makes life a lot easier. My LiPo receiver packs I charge at 1C.

WOW. That's a lot of AMPS! I've never really fast charged a big lipo before. my 3700's and 4200's at about 2.4Amps. takes about 80min!

 

[BalsaDust]

Received a new short kit today. From mountain models for the Allegro RES glider. Really nice looking short kit for what it is. Laser cutting appears to be top quality. Just throwing it out there for everyone to go give the mountain models site a look over. The owner is trying to sell the buisness and if he can’t find a buyer he will be closing up shop. Might be worth it to see if there is anything you want before it’s gone.

 

[Snoopy1]

I have always wanted to know what value in Ohms each cell should have or "not go below" before condemning the cell. I got this meter and finally found how to check internal resistance but it only will do the first cell in the pack. You have to plug a same number of cells pack in to the voltage port and use the pin adapter plug that's plugged in to the main battery input. This is one of those 7in1 meters.
It is great at checking the balance state and voltage on each cell but I don't know about the internal resistance feature.
It read 80 mOhms for the 1st cell......The batteries shown I purchased in Dec 2015 and have about 25 cycles on each. I fly the QQ300 with them. They both are still "hard bricks" with not the first sign of swelling. I always store them between 50/60% charged. I have always figured the number of cycles I have put on a pack before considering replacing it. My safe cycle limit is 250 times on any brand Lipo.View attachment 100043 View attachment 100044 View attachment 100045

IR is a difficult thing to do and will change with the state of charge I made jig to do and it still difficult to do. Looking at what you are doing with the plug and wires you never get constant numbers to go by. I have charger that gives me the IR drop but it changes all the time while it is charging. From what I have found out the hard-way is to do it when the battery is at 3.85 volts it gives the same number 90% of the time. But if you are really interested FMA have just developed a IR meter I have been looking at it.
One Thing i do know is if you know the IR drop of your battery as complete unit you can calculate the C rating of the battery and the charge rate but I am still trying to figure that , if someone knows how to do that I would really appreciate how to do the math..

 

[Jetpainter]

http://www.usastore.revolectrix.com/Products_2/Accessories_2/REVO_IR_METER_2

This is Revo's new IR checker.