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Low Voltage Battery Scare

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I've read through several posts/articles/forums on how or why some Inspire 1 drone owners had crashed or fallen out of the sky. One common cause of crashing appeared to be sudden battery discharge. This has me paying closer attention to the batteries themselves.

The battery system is intelligent but it seems to have some faults. Lithium-Polymer batteries aren't perfect either and require some attention and proper charging cycles. I'm guessing that the mAH capacity readout is determined by the average voltage and current of each battery cell. I'm not aware of a means to measure capacity in a battery other than current and voltage calculations.

Somewhere in one of several Inspire 1 PDF manuals I'd read to "recalibrate" the battery cells by leaving the drone on until completely discharged and than fully recharge the battery. I did this with 3 of 4 batteries.

I was flying with the 4th battery that I did not fully discharge and recharge. It had been fully charged and the four charge indicator lights were illuminated. It has a total of 10 charging cycles on it. About 45 seconds after take-off, I ascended about 30-feet and suddenly the Inspire 1 landing gear came down followed by a verbal message on the iPad; "Battery Voltage Low". The drone than landed in it's immediate location.

The battery cells each indicated somewhere around 3.75V - 3.82V. Although a Li-Po cell is considered 3.7V, that's the low end of a Li-Po cell charge. 4.2V+ as I recall is near a full charge. Anyhow, that sudden emergency landing with a "fully-charged" battery had me freaked out. The "low voltage" message and emergency landing must be part of a newer firmware update. Perhaps partly due to the number of crashes from sudden battery discharge.

I installed a fully charged "recalibrated" battery on the next flight. I flew to about 35% capacity at low altitude. I left the drone on to view video from the tablet and watched as the battery percentage dropped. It finally hit 0%. It continually gave out audible"low battery" messages. It sat at 0% for over and hour. I haven't had a battery sit at 0% this long.

Since then, I've paid more attention to the battery voltage levels. The battery monitoring system seems to have some issues that need to be worked out.

Has anyone else had battery issues? How do you maintain your batteries?
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What are the percent restrictions you set in the settings?

The drone should do everything automatically when the batteries are low - return home / automatic landing.
This type of LiPo batteries used in the power supply of the drone does not imply a voltage cutoff at low discharge.

I have a low profile of responsibility and I do not follow the recommendations of battery manufacturers. I keep them always fully charged. I've never had a problem - on an airplane model, or on a drones .. Maybe I'm wrong, but the urge to start right away on the road for a flight does not give time to wait for the charge of all the batteries. It rarely happens when you can plan a trip for aerial surveys.
 
At 30% I recieve a warning. I don't recall the RTH percentage. I haven't changed the default setting. I'd just never heard or read of this low voltage condition. The battery is showing 2.5 bars just now. So either something else is at fault or the battery. I'm thinking the battery but I hadn't gotten time yet to look in to it.
 
I do not understand your settings....

Let me give you some tips (excuse me if you do not need them):
- Before starting, you must specify the point Home.
- Set the battery discharge percentage for automatic return to the Home and Auto Landing points. 15% of the discharge is enough for the drone to return to the point Home from a distance of 2 km and a height of 80 m. 3-5% is enough for a drone to make an auto landing from a height of 80 m.
- Never discharge batteries to 0%
- discharge all batteries to 3-5% and recharge them completely. For 20-30 flights of such a battery training is enough.
- the batteries can be discharged by turning on the drone motors of the house at idle without propellers.
- If you can plan your missions in advance, keep the batteries discharged to 10-30%.
- If your missions can be unexpected and fast, you can keep the batteries charged at all times. They themselves are discharged by 25% in 2-3 weeks and can be quickly charged.
- Make a checklist for flights and follow it unswervingly - this is the guarantee of your accident-free flights.
I do not claim the truth in my knowledge, the more experienced pilots can correct me if I'm mistaken in something.
I wish you successful flights!
 
I typically fly in different locations. The take off point becomes the default RTH, which is what I want.

I'm following the battery discharge directions per the Inspire 1 manual.
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This battery happened to be on it's 10th charge cycle. What I'm getting at is that the percentage indication is no longer accurate after so many partial discharge and recharge cycles. Completely discharging the battery or discharging below 5% must recalibrate the Intelligent Batteries onboard computer. This has been my understanding with some other battery operated Lio-Ion and Li-Po devices as well.
 
To clarify, the battery that decided to throw the drone in to "low voltage" emergency landing, had shown 90-95% at take-off. That was about 45 seconds of flight time.
 
I have old batteries (I bought a drone already flying from another men), according to the remaining percentage of the work capacity was 85 and 95% of the initial. While problems did not observe. Now I do not fly to Inspire more than a month - I wait for the spare parts after repair. The batteries show the remainder of 3 lights.
 
After the emergency landing I was in a bit of shock and didn't pay much attention to the remaining battery percentage. However, it's always good to read through the manually thoroughly because there are many things I am still learning about the Inspire 1. I try to be careful with a $1,500 toy [emoji3].
 
I understand you. Unfortunately, Inspire is not a toy, but a serious device that requires an appropriate approach and knowledge.
As for batteries - LiPo batteries have a certain character and their life - if one of the cells of the battery has disturbances in current output, the battery processor will be guided by it, which will affect the overall condition, but this can only be seen by the instruments and under load.

I can not fully spend all my knowledge and knowledge of the community and producers - you will have to learn and seek knowledge more independently.
I can recommend a Russian forum and a thread on batteries. If you do not speak Russian, open it through Google Chrome and automatically translate it.
Here is a link to the forum thread - Электрика - моторы, регуляторы, аккумуляторы (Inspire1) - Inspire1
I also advise you to turn to a repair shop where you can test your batteries
 
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For dji batteries for the i1. If it gets below 3 volts on any cell it will shut the battery off during flight. It’s happened to me as many others on here and abroad. Do not, I repeat, do not go by percentages left. They are a basic guide to follow that is more than half of the time very inaccurate. The thing you need to watch is voltage. Do not put any trust what so ever in percentage left, if you do one day your bird will drop to the ground. DJI’s smart batteries are actually pretty dumb. They would rather save your 200 dollar battery and see your drone fall to the earth than save the drone and damage your battery. WATCH VOLTAGE. If your cells show 3.4 volts you better land then. If at 3.5 you better think about looking for a place to land real quick without using major stick movements. 3.6 you are ok for a bit and try not to use major stick movements (full stick in any direction) .With the battery off you can hold down the power button for 5 to 6 seconds and the leds will light up telling you the health of the battery. I deep cycle batteries every 15 cycles or less if you want the percentage that is left in it to be anywhere near somewhat close. Deep cycle just like you did leaving it on till the drone shuts itself off, then fully charge. Once it says it’s charged remove it from the charger, turn the battery on and stick it back on the charger until it says it is fully charged again.
 
What he said ^^^^^^ :)

I have said it so many times on this forum until I’m blue in the face.
Battery percentage readings are totally useless and nothing more than an estimation based some flakey algorithms. DJI ‘smart’ batteries were invented to try and weed out the idiot gene but they fall short on so many facets.
Battery/Cell voltage is absolute and should be monitored rather than % number.
Use the search and there are already threads on this that I have contributed to and explained the logic.
 
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What those two said above v v v v v v v - makes sure you let the freshly discharged battery sit for about 30 minutes or so before trying to recharge it.
 
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Thanks. So I guess I'm not crazy. So I'll be watching the cell voltages from now in. If one cell has much less output, what should the overall voltage be? I thought I'd seen 23ish volts. What's the low and high overall voltage to watch for?
 
Thanks. So I guess I'm not crazy. So I'll be watching the cell voltages from now in. If one cell has much less output, what should the overall voltage be? I thought I'd seen 23ish volts. What's the low and high overall voltage to watch for?
I wouldn’t watch over all voltage for the battery. Set your c1 or c2 button to display the battery screen or just tap on the battery icon on the screen. You will 98 percent of the time have one or more cells that will fall lower than the rest. Those are the cells you need to keep an eye on the most because they if any will be the cells to make your battery shut down during flight. Especially if the battery has sat for a number of days before use and or if the cycle count is high on the battery.
 
I’ve noticed that my I1P older batteries >60 cycles & >2 years old, regularly show low voltage <20v under high demand (Autopilot initially climbs to altitude very aggressively). Battery life at 89% & initial voltage between 98% to 100%. Would these be considered at the end of their life & dangerous to use?
 
I’ve noticed that my I1P older batteries >60 cycles & >2 years old, regularly show low voltage <20v under high demand (Autopilot initially climbs to altitude very aggressively). Battery life at 89% & initial voltage between 98% to 100%. Would these be considered at the end of their life & dangerous to use?
Have you discharged them as shown in the image I shared above from the manual?
 
I probably would not fly with that battery if you experience any quick discharging. Try multiple discharge/recharge cycles to balance out the parallel cells. I have more of an understanding about ni-cad and lead batteries. I have built multi-cell Lithium-Polymer battery packs both in series and parallel but as far as life expectancy I haven't any idea. I am uncertain why or how these type of batteries cells fail or the rate of complete cell failure.

I'd bought several cheap Chinese import Li-Po cells and it has been "hit or miss" on the number of life cycles. Some last half a dozen charges till the voltage output begins to decline at a "full charge" and others are still holding 4.2v - 4.4v. This may also be dependent on the charger itself inaffectively sensing the batteries state of charge. But how these batteries are charged (individually/parallel) is important.

From all of the battery issues I've been reading about with the Inspire 1, many of these were a sudden loss of output - as if there was a voltage imbalance between two cells in parallel (6 in-series on Inspire 1 = 12 cells). I would hope that DJI engineered the "Intelligent Battery" to balance charge each parallel cell individually rather than charging two parallel cells as one.

Charging each pair of parallel cells as a single cell may create a voltage imbalance. So one parallel cell could have a much lower state of charge than the other and report a full state of charge between the two to the computer system via the voltage output. I am guessing a complete discharge is required every so often to re-balance the voltage between parallel cells.

This is an interesting arcticle on RC Li-Po batteries: Parallel LiPo Charging – The Faster & Safer Way To Charge?

The publisher of this article wrote, "The general rule I follow is no more than a 0.1 volt maximum difference between cells of packs I hook together in parallel." This statement makes a whole lot of sense to me. Worth a read.
 

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