Maintaining aging Inspire 1

[Ralph thompson]

I have scanned the forum & not found a satisfactory conclusion on battery life. I have a 2015 I1P v1 & 2017 I1P v2, 10 batteries including the 3 yr old originals with between 80 & 100 cycles. The Battery Life is registering close to 80% on some. I deep cycle all batteries after 15 to 20 cycles using the Phantom Angel. They all look good, charge to 100% & no bulging or cracks. I quite often get a big drain on one cell, occasionally a low voltage warning according to the Healthy Drones database. My question is when is it prudent to retire a battery? Is 80% battery life time for retirement? I’d rather buy a couple of new batteries than risk the drone shutting down when I do a quick maneuver.

 

[Florida Drone Supply]

Ultimately it is up to the pilot to decide the comfort level of older batteries. At 80%, I would say you still have a lot of cycles left. DJI's warranty states 6 months or 200 cycles, cycle wise you are half way there. If you get a lot of warnings in the go app then go ahead and retire the battery. Healthy drones/airdata parameters are quite sensitive and are a good guide to battery health.

 

[Ralph thompson]

Thanks, appreciate experienced feedback. It seems as though one has to be a LIPO battery expert or a soothsayer to decide what is safe.
If I check all uses of say a relatively low use battery, #8 (TB47, manufactured Jul 2016), 40 charge cycles and battery life 90%, it seems to get a lot if minor, sometimes major errors in cell #1, a few to zero errors in the other cells. It also uses high amps occasionally, a couple of "above 23.6 amps". In Nov 2017, cell 1 had 4 major deviations (0.123v to .129v). So according to HD, under Batteries/Trends/Deviations, one must "monitor this battery closely". It feels like we need the third person in the cockpit like to old long haul B747, DC8's, etc. where the FE spent his life staring at the engine dials.
Healthy drones/airdata provides lots of data and I certainly appreciate the great job they've done. The database is really valuable. But I find its not always easy to interpret the significance of all the info. Ideally, it would be nice to have CAUTION and NO FLY flags against any doubtful batteries.
All this to say, I'm just trying to be supper cautious. Any thoughts on how you "monitor this battery closely".

 

[Florida Drone Supply]

Thanks, appreciate experienced feedback. It seems as though one has to be a LIPO battery expert or a soothsayer to decide what is safe.
If I check all uses of say a relatively low use battery, #8 (TB47, manufactured Jul 2016), 40 charge cycles and battery life 90%, it seems to get a lot if minor, sometimes major errors in cell #1, a few to zero errors in the other cells. It also uses high amps occasionally, a couple of "above 23.6 amps". In Nov 2017, cell 1 had 4 major deviations (0.123v to .129v). So according to HD, under Batteries/Trends/Deviations, one must "monitor this battery closely". It feels like we need the third person in the cockpit like to old long haul B747, DC8's, etc. where the FE spent his life staring at the engine dials.
Healthy drones/airdata provides lots of data and I certainly appreciate the great job they've done. The database is really valuable. But I find its not always easy to interpret the significance of all the info. Ideally, it would be nice to have CAUTION and NO FLY flags against any doubtful batteries.
All this to say, I'm just trying to be supper cautious. Any thoughts on how you "monitor this battery closely".

I personally have AirData info going back to November of 2015. I just scrolled thru some battery data from my Inspire 1 and saw only minor deviations but many of them. Your mentioned a major deviation was .006 of a volt, that does not appear to be excessive.

You are the third person in the cockpit! If you are trying to be super cautious, create a standard for yourself and limit your batteries to 2 years or 90 cycles and retire them or some practical timeframe that helps you with your flying comfort. There is nothing wrong with retiring equipment before it fails and will give you great peace of mind. Manned aircraft have been doing this for a long long time.

Airdata/HD is also covering their butt by creating sensitive warnings and as I said earlier it is only a guide. We are glad that you take battery maintenance seriously and wish more people felt the way you do.

 

[Ralph thompson]

Sorry I didn’t write clearly, just to clear, the actual voltage deviation was between .123 & .129v (ie the average deviation was around 0.126v), that is significant.

 

[The Editor]

Sorry I didn’t write clearly, just to clear, the actual voltage deviation was between .123 & .129v (ie the average deviation was around 0.126v), that is significant.

No it isn't.
That's the problem with these so called fancy apps. They throw up 'warnings' that shouldn't be warnings at all and fill people with fear of impending doom.
Cell fluctuations of less than 200mV under load are perfectly acceptable and in some cases normal for lithium polymer chemistry.

With regards to when is a good time to retire a pack - only you can answer that one.
If it still flies ok, balances and recharges fine then keep using it.
I tend to retire mine when I consider the flight time is not really of any great use to me - say 6-8 minutes.

You will find that packs that are nearing their end of useful life will dip voltage far more under load (climb outs) and you will get fed up with having to come into land and swap batteries before it will suddenly drop out of the sky.
Just be sensible about what you feel is performing adequately and what you feel needs to be retired. There is no magic formula as to if and when......

 

[Ceeps]

I’m only getting 10 mins for for tb47 landing on 30%. I was wondering if I should get some tb48 but the price in the uk for an extra 6 mins don’t seem worth it

 

[MrTVR]

Whilst I don’t have my I1 now I did build up a total of 14 TB47s before I purchased some TB48s and remember wishing I had started to purchased TB48s sooner.

Whilst you only get a few more minutes, these extra minutes are a significant increase in the useable flight time making old TB48s so much more useable for a given (high) number of charge cycles.

 

[Ceeps]

Whilst I don’t have my I1 now I did build up a total of 14 TB47s before I purchased some TB48s and remember wishing I had started to purchased TB48s sooner.

Whilst you only get a few more minutes, these extra minutes are a significant increase in the useable flight time making old TB48s so much more useable for a given (high) number of charge cycles.

Thanks very much for your advice I just found 3 nearly new with only 5 cycles each for £80 each. How often do I need to top them up if I store them over the winter? I know they say charge them up to two lights but when would I top them up and how many days discharge is best?

 

[Ceeps]

Sorry for all the questions

 

[MrTVR]

I have always left the default 10 day discharge setting, checked the batteries at least once every 4 weeks and recharged on the occasional time that I havn’t flown for more than two months.

As i fly commercially I am flying most of the time, even in winter. My only experience of longer periods without flight came when I started flying the Inspire 2 as my main drone and the Inspire 1 just became a backup.

Interestingly, the Inspire 2 flight times don’t seem to be dropping off with battery age like the Inspire 1 did. I have some sets (they are flown in pairs) with over well 100 charge cycles on and I don’t notice any significant drop in flight time.

 

[slim.slamma]

the Inspire 2 flight times don’t seem to be dropping off with battery age like the Inspire 1 did.

Best batteries DJI ever made!

 

[Ceeps]

I have always left the default 10 day discharge setting, checked the batteries at least once every 4 weeks and recharged on the occasional time that I havn’t flown for more than two months.

As i fly commercially I am flying most of the time, even in winter. My only experience of longer periods without flight came when I started flying the Inspire 2 as my main drone and the Inspire 1 just became a backup.

Interestingly, the Inspire 2 flight times don’t seem to be dropping off with battery age like the Inspire 1 did. I have some sets (they are flown in pairs) with over well 100 charge cycles on and I don’t notice any significant drop in flight time.

Thanks for your advice. I am located in uk and have just set up a drone company and looking to get work. So it’s all a learning curve I got my i1p a p4p and a Mavic Air so got alot to learn ha

 

[Ceeps]

Would you fully charge them after a month. Or just back up to two lights?

 

[MrTVR]

I generally give them a full charge after about two months of non use to ensure that the cells are rebalanced properly.

 

[Ceeps]

Thank you

 

[Sunscreen]

Cell fluctuations of less than 200mV under load are perfectly acceptable and in some cases normal for lithium polymer chemistry.

With regards to when is a good time to retire a pack - only you can answer that one.
If it still flies ok, balances and recharges fine then keep using it.
I tend to retire mine when I consider the flight time is not really of any great use to me - say 6-8 minutes.

Excellent insight Editor. Thank you