Battery Life Issues

Joined
Feb 7, 2015
Messages
34
Reaction score
2
I have seen many posters comment that they are finding their batteries are becoming unreliable after 30 or 40 flights. This does not seem to make a lot of sense since according to most Li-on manufacturers the batteries should be good for ~200 cycles or so. I found this interesting article on Li-On batteries and maintaining them on this site: http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
the article indicates that even after 100 cycles the batteries should have near 85% of their original capacity.
It is definitely worth a read and hopefully someone out there can figure out why these very expensive battery packs don't seem to hold up like they should?
Thanks for any replies!
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
 
I have seen many posters comment that they are finding their batteries are becoming unreliable after 30 or 40 flights. This does not seem to make a lot of sense since according to most Li-on manufacturers the batteries should be good for ~200 cycles or so. I found this interesting article on Li-On batteries and maintaining them on this site: http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
the article indicates that even after 100 cycles the batteries should have near 85% of their original capacity.
It is definitely worth a read and hopefully someone out there can figure out why these very expensive battery packs don't seem to hold up like they should?
Thanks for any replies!
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries



The 'smart' system is supposed to protect them from the know abuse issues such as over-charge, over-discharge, improper balancing, etc. so what then would cause this?...

...low quality and while monitoring voltage during charging, do not appear to be charged correctly by the 'smart' system (i.e.CC/CV).
 
Last edited:
Because they are low quality and do not appear to be charged correctly by the 'smart' system.
Well they certainly aren't "low priced" - not from DJI anyway. It will be interesting to see if anyone who has bought the LimeFuel batteries reports better luck with battery life!
I wonder if that charger that does 4 batteries at a time properly charges the batteries - if you read the article it indicates that the charging rate DOES affect battery life - the DJI charger seems to charge them fairly fast - wonder if that could be part of the cause??
Thanks for the reply!
 
Also, I don't know that most people understand how to properly care for their batteries. It seems many people believe the batteries will care for themselves.

Here's a good article about RC batteries (not DJI specific though):
http://www.rchelicopterfun.com/rc-lipo-batteries.html
 
Well they certainly aren't "low priced" - not from DJI anyway. It will be interesting to see if anyone who has bought the LimeFuel batteries reports better luck with battery life!
I wonder if that charger that does 4 batteries at a time properly charges the batteries - if you read the article it indicates that the charging rate DOES affect battery life - the DJI charger seems to charge them fairly fast - wonder if that could be part of the cause??
Thanks for the reply!


I edited since your quote/post.

LiPos should follow a 'constant current, then 'constant voltage' charging profile, CC/CV.

Charging at 1C should produce an approximate one hour charging cycle.

The first 40 or so minutes the battery is fed constant current equal to it's capacity or C rating. So for a P2 will call that 5.2 amps. Once the battery reaches 12.6 the charger then begins the CV phase by slowly lowering the current to maintain the 12.6volts until it reaches about 1/10 or so of the C rating. This usually takes about 40% of total charge time ending after about 1 hour.

If you monitor the P2 batt. voltage during charging it is a slow ramp-up to 12.6 volts at which time the charger shuts-off. This is not CC/CV.

Because the DJI P2 charger can only deliver 4 amps (probably less due to losses) it take more than an hour to charge a 5.2C, amp, battery.
 
I edited since your quote/post.

LiPos should follow a 'constant current, then 'constant voltage' charging profile, CC/CV.

Charging at 1C should produce an approximate one hour charging cycle.

The first 40 or so minutes the battery is fed constant current equal to it's capacity or C rating. So for a P2 will call that 5.2 amps. Once the battery reaches 12.6 the charger then begins the CV phase by slowly lowering the current to maintain the 12.6volts until it reaches about 1/10 or so of the C rating. This usually takes about 40% of total charge time ending after about 1 hour.

If you monitor the P2 batt. voltage during charging it is a slow ramp-up to 12.6 volts at which time the charger shuts-off. This is not CC/CV.

Because the DJI P2 charger can only deliver 4 amps (probably less due to losses) it take more than an hour to charge a 5.2C, amp, battery.
Agreed - it takes somewhere around 80-90 minutes to charge a battery that has been depleted to around 10% of capacity. Well if the issue is a dual problem - battery quality/charger quality then I will have to keep looking for better batteries and a better charger obviously - can't afford to replace batteries after 30 or 40 flights - it's already a fairly expensive hobby as it is!
Thanks for the info!
 
N017RW, are you suggesting it would be best to use a 3rd party battery charger? If so, can you recommend any?
 
N017RW, are you suggesting it would be best to use a 3rd party battery charger? If so, can you recommend any?


No because you can't 'get past' the smart system. With the possible exception of a higher current supply to reduce time but I don't know how the smart system would handle that.

I'm concerned over the apparent (my observations only) charge cycle not being CC/CV.
 
I seem to remember reading that one should limit their battery use to 30% to get longer battery life...any truth or logic to that?
 
I seem to remember reading that one should limit their battery use to 30% to get longer battery life...any truth or logic to that?


Just a few years ago when flying CP Helis, the rule of thumb was 80% discharge max and never below 3.3v per cell under load. Doubt much has changed.

Although the P3 is touting a 4S 15.2 when currently most all other 4S packs are rated at 14.8v so there may be a new rule for those types.
 

Recent Posts

Members online

No members online now.

Forum statistics

Threads
143,519
Messages
1,471,091
Members
105,494
Latest member
tgbest
Want to Remove this Ad? Simply login or create a free account