Debate on Lipos. To balance or not?
03-26-2014 | 05:43 AM
#51
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not being a tech on batteries. I have used nicad;s and nimh batt's for years and with proper maintance and a log for each bat/pac have never lost a bird, But electrics and lipo are a new thing for me and still trying to get it stright before I waist a bundle of $$$ so my question still is, why do the lipo batteries checkers that on the market do not use a load when used.
Cheers Bob T
Cheers Bob T
03-26-2014 | 06:03 AM
#52
Moderator
My Feedback: (1)
not being a tech on batteries. I have used nicad;s and nimh batt's for years and with proper maintance and a log for each bat/pac have never lost a bird, But electrics and lipo are a new thing for me and still trying to get it stright before I waist a bundle of $$$ so my question still is, why do the lipo batteries checkers that on the market do not use a load when used.
Cheers Bob T
Cheers Bob T
A partially discharged nicad or nimh battery can show 1.2v per cell with no load, and then suddenly drop to 1.0 volts when a load is applied.
lipos and LiFe's don't do that. so adding a load to a lipo battery checker won't do anything.
03-26-2014 | 07:41 AM
#53
mostly because of the battery chemistry, lipos (unlike NiCads and NiMh's) do not typically drop voltage when a load is applied.
A partially discharged nicad or nimh battery can show 1.2v per cell with no load, and then suddenly drop to 1.0 volts when a load is applied.
lipos and LiFe's don't do that. so adding a load to a lipo battery checker won't do anything.
A partially discharged nicad or nimh battery can show 1.2v per cell with no load, and then suddenly drop to 1.0 volts when a load is applied.
lipos and LiFe's don't do that. so adding a load to a lipo battery checker won't do anything.
LiPos and LIFE - ANY battery chemistry will drop voltage as load is applied.
How you do it however, is different -
First these chemistries have a relatively flat discharge curve
Secondly -tho the curve is flatter- it drops like a rock at the end of the capacity-
Using the old dinky loads which were common on NIMH/ NICAD charges is simply a worthless test.
When 2.4 radios came on the scene, a number of users blamed failures on the rx - real issue was typically, voltage depressions.
If you elect to use LiPo / Life - get a charger which will balance charge these and also learn to read accumulated time of a flight and then recharge the packs to see how much capacity is used PER TYPICAL FLIGHT.
Finally get a meter designed to be placed between battery and rx and read no load voltage vs the load of your radio system as shown by stirring the stick fully for a couple of minutes .
If you se a voltage which drops more than ONE volt each time you cycle -
you have a battery pack which isn't up to the job.
Either the battery is too small (not enough capacity) not high enough C rating (low discharge capability)
Or both.
Also the test will reveal a servo overload or wires which won't carry the load .
03-26-2014 | 07:45 AM
#54
Moderator
My Feedback: (1)
Not eggzactly-
LiPos and LIFE - ANY battery chemistry will drop voltage as load is applied.
How you do it however, is different -
First these chemistries have a relatively flat discharge curve
Secondly -tho the curve is flatter- it drops like a rock at the end of the capacity-
Using the old dinky loads which were common on NIMH/ NICAD charges is simply a worthless test.
When 2.4 radios came on the scene, a number of users blamed failures on the rx - real issue was typically, voltage depressions.
If you elect to use LiPo / Life - get a charger which will balance charge these and also learn to read accumulated time of a flight and then recharge the packs to see how much capacity is used PER TYPICAL FLIGHT.
Finally get a meter designed to be placed between battery and rx and read no load voltage vs the load of your radio system as shown by stirring the stick fully for a couple of minutes .
If you se a voltage which drops more than ONE volt each time you cycle -
you have a battery pack which isn't up to the job.
Either the battery is too small (not enough capacity) not high enough C rating (low discharge capability)
Or both.
Also the test will reveal a servo overload or wires which won't carry the load .
LiPos and LIFE - ANY battery chemistry will drop voltage as load is applied.
How you do it however, is different -
First these chemistries have a relatively flat discharge curve
Secondly -tho the curve is flatter- it drops like a rock at the end of the capacity-
Using the old dinky loads which were common on NIMH/ NICAD charges is simply a worthless test.
When 2.4 radios came on the scene, a number of users blamed failures on the rx - real issue was typically, voltage depressions.
If you elect to use LiPo / Life - get a charger which will balance charge these and also learn to read accumulated time of a flight and then recharge the packs to see how much capacity is used PER TYPICAL FLIGHT.
Finally get a meter designed to be placed between battery and rx and read no load voltage vs the load of your radio system as shown by stirring the stick fully for a couple of minutes .
If you se a voltage which drops more than ONE volt each time you cycle -
you have a battery pack which isn't up to the job.
Either the battery is too small (not enough capacity) not high enough C rating (low discharge capability)
Or both.
Also the test will reveal a servo overload or wires which won't carry the load .
I stand corrected. I KNEW somebody would call out my cartoon diagram logic.
thanks for the explanation rmh!
03-26-2014 | 08:28 PM
#57
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From: Oklahoma City, OK
I have been flying electric since 1985, built my own Ni-Cd packs with balanced cells. Entered into the Li-Po world about 10 years ago. My ASTRO Charger didn't have "Balance" plugs and the Battery Packs didn't have Balance Plugs either. I built more and More Electric, Bigger an Bigger models and then came the "Brushless" age.
New batteries had those extra leads that didn't plug into anything, not on my charger anyway. Then, one day, without warning, while Charging a New 4s Li Po, it started smoking, I pulled the Charge plug apart and the Battery burst into FIRE. I threw it outside and it landed in the driveway, still burning until there was not much left but the wires.
Two weeks later another (used) Li Po caught fire while charging. Out it went into the driveway. (Now I have two (2) Burned Black spots in front of my garage. The Local Hobby Shop would not replace the New Burned up battery, he said it caught fire because I wasn't using the Balance Plug during charging. A new Charger (Actually 3 New chargers over time) and almost 5 years have gone by, and I haven't burned up any more batteries. I do put them in a big Clay Flower Pot with a Clay cover while charging, just to be on the safe side. I can afford Batteries and Chargers, But I Can't afford another House.
Just my 2 cents,
Ken AMA 1528
New batteries had those extra leads that didn't plug into anything, not on my charger anyway. Then, one day, without warning, while Charging a New 4s Li Po, it started smoking, I pulled the Charge plug apart and the Battery burst into FIRE. I threw it outside and it landed in the driveway, still burning until there was not much left but the wires.
Two weeks later another (used) Li Po caught fire while charging. Out it went into the driveway. (Now I have two (2) Burned Black spots in front of my garage. The Local Hobby Shop would not replace the New Burned up battery, he said it caught fire because I wasn't using the Balance Plug during charging. A new Charger (Actually 3 New chargers over time) and almost 5 years have gone by, and I haven't burned up any more batteries. I do put them in a big Clay Flower Pot with a Clay cover while charging, just to be on the safe side. I can afford Batteries and Chargers, But I Can't afford another House.
Just my 2 cents,
Ken AMA 1528
