Charging a battery before the automatic discharge happens

[Super Dave]

I stand corrected, but good info, just as well.
Thank you.

 

[With The Birds]

I stand corrected, but good info, just as well.
Thank you.

What you say is true and for your circumstances as depicted. That is if your flying every day or even every other day you are unlikely to notice the accelerated ageing that maintaining a pack at full rated terminal voltage will undoubtably cause. It can easily be close to 20% capacity loss over 12 months. That is fact- a well understood limitation of LiION chemistry. That and safety are almost certainly the intent of the battery management SOC developer incorporating the auto discharge feature.

I would be very reluctant to rely on your limited experience in suggesting to others that maintaining packs at storage level is good practice. Particularly those who fly less frequently. Aside from the benefit of extending service life and performance it is also well known that LiION cells are more susceptible to failure when fully charged. liPO fires are not fun. As infrequent as they might be the outcome can be disastrous.

 

[Geoff G]

Seems to me that these batteries are a good slave but a poor master!

After using Li-ion and Li-Po batteries for a long time in model helis, power thirsty video cameras (Red etc) and drones I can honestly say that the only serious damage I've ever incurred is by over-disharging them (total destruction or definite capacity reduction at least). You can't do that with a DJI drone.

Perhaps it suits DJI to keep charging and discharging batteries. I think that I read that these power packs have an automatic "end of life" number of cycles built into their firmware. If that's the case are DJI making sure that you need new batteries whether you fly or not!

My philosophy is simple - keep them charged all the time. I didn't get my drones to worry about loosing a few charging cycles, I bought them to be fully charged, ready to use, when I need them.

It's simple - whatever suits you, I think.

Does anyone have a link to actual tests on power packs maintained at low level vs. full charge?

 

[Not A Speck Of Cereal]

POLICE and FIRE: I think you just have to accept the fact that you will need at least a certain number of batteries charged to full / at the ready. That's the cost of the job and the departments should be footing that bill.

Many of us here that are following the discharge and store rules for longer periods are recreational users that want to extend the battery life has much as possible, because we can't afford to buy new batteries as often, but that's obviously not an emergency crew scenario.

I'm not LE anymore (and didn't have these fancy batteries when I was), but I can imagine that procedures could be created and followed for rotation of batteries, not for radios and such, but just for these aircraft. Number the batteries, keep 'x' number fully charged / topped off, rotate those that you do that with. Additionally, that procedure should have remote charging abilities at the ready. So, drive out to an incident location with 2 fully charged batteries, charging another 2-4 on the way there?

Also, could the design of these intelligent flight batteries be designed differently than the batteries for radios that are typically kept in a charging cradle 24/?

Just thoughts.

 

[solentlife]

Seems to me that these batteries are a good slave but a poor master!

After using Li-ion and Li-Po batteries for a long time in model helis, power thirsty video cameras (Red etc) and drones I can honestly say that the only serious damage I've ever incurred is by over-disharging them (total destruction or definite capacity reduction at least). You can't do that with a DJI drone.

Perhaps it suits DJI to keep charging and discharging batteries. I think that I read that these power packs have an automatic "end of life" number of cycles built into their firmware. If that's the case are DJI making sure that you need new batteries whether you fly or not!

My philosophy is simple - keep them charged all the time. I didn't get my drones to worry about loosing a few charging cycles, I bought them to be fully charged, ready to use, when I need them.

It's simple - whatever suits you, I think.

Does anyone have a link to actual tests on power packs maintained at low level vs. full charge?

There is a claim by some that the 200 Cycle limit then shuts down a DJI battery (P3 ... others I do not know). This is not actually correct ...

Why not ?

1. Life cycles are not each charge .. but in fact incremental in part. That is a 50% charge will be a half cycle.
2. When I questioned DJI Tech - I had varying answers - but finally was told that the battery can carry on PAST the 200 cycle mark if its physical condition is good.

Lets look at #1 .... considering that most people will be flying to about 30 - 40% and then charging from there .. it means that to accumulate 200 cycles could be well in excess of 300 charges ... how many times do you fly each week / month ? I fly approx 2x a week ... sometimes nothing for 2 - 3 weeks. But lets assume average 2x a week, That means 300 / 2 = 150 weeks ... nearly 3 years !!

As regards tests on storage vs full charge levels ... simple Google will pull up many sites such as Battery University as well as manufacturers pages advising storage charge. Given that DJi drones are only a small part of a much wider world of LiPo use - do you think that for example that the RC world is wrong to have invested in creating LiPo programmable chargers with Storage modes ... that DJI themselves gave us Auto Storage default ??

The funny thing is we post about not keeping the LiPo's fully charged - but DJI have already circumvented that practice by auto discharge routine.

As to flying heli's etc. - I am a model flyer of over 55yrs ... and I do not leave LiPo's fully charged - heli .. EDF .. 3D ... and various Multi-Rotors ... same as millions of other RC users.

 

[With The Birds]

Seems to me that these batteries are a good slave but a poor master!

After using Li-ion and Li-Po batteries for a long time in model helis, power thirsty video cameras (Red etc) and drones I can honestly say that the only serious damage I've ever incurred is by over-disharging them (total destruction or definite capacity reduction at least). You can't do that with a DJI drone.

Perhaps it suits DJI to keep charging and discharging batteries. I think that I read that these power packs have an automatic "end of life" number of cycles built into their firmware. If that's the case are DJI making sure that you need new batteries whether you fly or not!

My philosophy is simple - keep them charged all the time. I didn't get my drones to worry about loosing a few charging cycles, I bought them to be fully charged, ready to use, when I need them.

It's simple - whatever suits you, I think.

Does anyone have a link to actual tests on power packs maintained at low level vs. full charge?

Two things that are well established as limitations of LiION chemistry are that ageing (capacity loss principally) is accelerated by elevated temperature and cell voltage. This is evidenced by research and various papers authored by cell manufacturers and independent entities.

A good resource is battery university. The following table is from their website.

The cease to function at 200 cycles claim is a myth. It may be more or less. The battery SOC (manufactured by Texas Instruments) uses an algorithm to determine battery health (life percentage) which is determined by actual measurement of parameters while at rest, charging and in use. The life algorithm includes cell internal resistance (one of the best indications of cell health) and actual usable capacity in the cell health determination. The remaining % and time to empty fuel gauging parameters as depicted in the GO app are within 1% accuracy.