Battery Business

Michael Lione · Oct 18, 2017

I wasn't sure which of the FB Groups to approach so thought I'd give the Forum a shout out.

So far I have run four batteries through the recalibration process with seemingly good results. The new Battery Drain feature in Solex has been very helpful giving me motor cut off between 4-6%. Prior to their recalibration all four batteries would depleat in less than 5 minutes and so far two of the recalibrated batteries each flew 10 minutes to 25% remaining charge. I wasn't able to get out today but ran the second two batteries on the Battery Drain using MC props for an hour with Polar Pro light bars, Here, and GP attached which left them at a 30% charge so I'm reasonably confident they recalibrated successfully.

A couple of questions.

Am I correct that mAh is a measure of a battery's capacity and as a battery deteriorates (wears out) this value decreases?

Using the madhacker analyzer I see there are two places that display mAh. First directly below % of charge and again on the following screen below the 5200. The values listed are unequal but seem to come together at full charge. Why are the values different? Which one best indicates the actual capacity?

Understanding that a fresh battery is rated at 5200mAh is there a direct mathematical correlation between the 5200 rating and say a battery that is showing 4475mAh at a full charge?

SteveReno · Oct 18, 2017

Excellent questions!
If no one reply's with the answers soon, Then i would try "Solo Mod Club" Security Check Required

We may need Kelly to point us in the right direction.

Pedals2Paddles · Oct 18, 2017

Maximum capacity, as designed is 5200. The lesser one, which I believe is called absolute capacity in that gizmo, is the battery's actual calibrated capacity. Which as you'd expect, will reduce over time as the cells wear. The smart battery monitors MAH out and in to calculate that absolute capacity. Then the one that goes up and down with use and charging is the current state of charge.

Michael Lione · Oct 18, 2017

Pedals2Paddles said:
Maximum capacity, as designed is 5200. The lesser one, which I believe is called absolute capacity in that gizmo, is the battery's actual calibrated capacity. Which as you'd expect, will reduce over time as the cells wear. The smart battery monitors MAH out and in to calculate that absolute capacity. Then the one that goes up and down with use and charging is the current state of charge.

Thanks Matt! I did reply to a battery post on the Mod Club. In the process of compiling my response it kinda dawned on me that the two readouts might be related. Your explanation provides the how.

Vegasrobbi · Oct 18, 2017

Michael Lione said:
So far I have run four batteries through the recalibration process with seemingly good results.

Is this the recalibration process you refer too? If so what are guys using for balancing - or is that done by the Solo charger? I have a bunch of Solo batteries that are below 10 minutes flight time. Thanks

3DR Solo - Smart Battery Calibration

The Solo Smart Battery may need recalibration from time to time. The following write up details how execute a recalibration of the BMS.

Gently discharge the battery pack until it cuts off the first time (this is around 12V).
Allow the pack the relax for at least 5 hours. The pack’s voltage will climb above 12V during this process. DO NOT TRY TO DISCHARGE THE PACK AGAIN. Damage to the battery may result.
Charge the pack completely and leave it on the charger for 48 hours. The pack will relax, then do a balance cycle, then top off.
Let the pack sit for at least 2 hours off the charnger before using the pack.

This tutorial was written by the Solo EE team (Jeff Wurzbach and Philip Rowse).

Michael Lione · Oct 18, 2017

Vegasrobbi said:
Is this the recalibration process you refer too? If so what are guys using for balancing - or is that done by the Solo charger? I have a bunch of Solo batteries that are below 10 minutes flight time. Thanks

3DR Solo - Smart Battery Calibration

The Solo Smart Battery may need recalibration from time to time. The following write up details how execute a recalibration of the BMS.

Gently discharge the battery pack until it cuts off the first time (this is around 12V).

Allow the pack the relax for at least 5 hours. The pack’s voltage will climb above 12V during this process. DO NOT TRY TO DISCHARGE THE PACK AGAIN. Damage to the battery may result.

Charge the pack completely and leave it on the charger for 48 hours. The pack will relax, then do a balance cycle, then top off.

Let the pack sit for at least 2 hours off the charnger before using the pack.

This tutorial was written by the Solo EE team (Jeff Wurzbach and Philip Rowse).

Yes, but we aware that I'm far from the sharpest tack in the drawer but I assume that the waiting times incorporated in the procedure provides the necessary cell balancing you are referring to.

As an observation to the four batteries I ran through this process using the new Battery Drain Tool provided in Solex after an override RTH manual landing at approximately 6-8% I was able to run the batteries down to motor cut off. In all four of my calibrations I was not able to achieve the 12V charge described above. My starting voltages were very consistently in the 15.01-15.36v range with 4% battery charge and 1180-1301 mAh. All four batteries were giving me 3 minute flight times pre-calibration and 10+ minutes post calibration so I have to assume they were indeed candidates for the process.

I'll thrown this into the discussion as well. I have two unused batteries that were manufactured between 11/9 and 11/16 2015. Both show one cycle @ 5200/5200 and "Discharging"
Indicated Charge: 54%/15.43v/2826mAh and 56%/15.20v/2899mAh
Neither battery has been attached to my charger. Seems to prove out excellent shelf life capability.

SteveReno · Oct 18, 2017

I am also testing this "Smart Battery Reset" procedure.
Using Phillip's procedure & Kelly's Solex to drain the batteries.

I have a original battery from July 2015 & it's not giving more then 3 min. total flight time. I thought this will be a good candidate for this test.
Also, Did a perfectly good battery "4982mAh", just to see.

Finish taking both batteries off there chargers, letting them settle for 2 hours.
Too late to test now, hoping tomorrow will give us some good results?

Michael Lione · Oct 18, 2017

SteveReno said:
I am also testing this "Smart Battery Reset" procedure.
Using Phillip's procedure & Kelly's Solex to drain the batteries.

I have a original battery from July 2015 & it's not giving more then 3 min. total flight time. I thought this will be a good candidate for this test.
Also, Did a perfectly good battery "4982mAh", just to see.

Finish taking both batteries off there chargers, letting them settle for 2 hours.
Too late to test now, hoping tomorrow will give us some good results?

By time I got back to my batteries they got a 5 hr rest after the 48 hr charge. I was surprised that both of them were at 95/96% I assumed that the charger would keep them from discharging after the green light comes on. Apparently not the case.

RogueWarrior65 · Oct 21, 2017

I've got a battery that has the same behavior of running 3 minutes before it's done. I haven't had more than a dozen cycles on it. I tried the cycling/recalibrating procedure twice with no success. Sadly, there's a problem with Solex and a Galaxy Tab A or Tab S2 8-inch that prevents the cell voltages from being displayed so I don't really know what's going on. I can see in Solex that in hover, it's pulling 20 amps and the voltage is in the mid 14 range. If I run the motors on the ground, it pulls about 2 amps and runs for at least 2 hours before the voltage drops off.

I wish I knew what the battery BMS IC part number was so I could read the data sheet about this calibration thing.

Vegasrobbi · Oct 25, 2017

Vegasrobbi said:
Charge the pack completely and leave it on the charger for 48 hours. The pack will relax, then do a balance cycle, then top off.

Does anyone know how to do a balance cycle? If we had access to the individual cells this would be easy but from what I understand the charger is dumb and the balancing happens inside the battery through internal balance circuits? Are we suppose to charge for 48 hours, disconnect, then reconnect?

jimloss · Oct 25, 2017

Vegasrobbi said:
Does anyone know how to do a balance cycle? If we had access to the individual cells this would be easy but from what I understand the charger is dumb and the balancing happens inside the battery through internal balance circuits? Are we suppose to charge for 48 hours, disconnect, then reconnect?

Instructions are here:
3DR Solo - Smart Battery Calibration — Copter documentation

According to the instructions the "balancing" and "top off" would occur during the 48 hours on the charger. No reconnect needed.

Michael Lione · Oct 25, 2017

What jimloss said. After 48 "charge" cycle you let the battery "rest" for 2 hours which I believe allows the four individual cells a chance to balance out before reuse. My assumption is that the PH is reading each of the individual cell voltages and when one drops the RTL is initiated. This calibration process finds the weak cell(s) and presumably brings it up to par with the others.

Vegasrobbi · Oct 25, 2017

So this is interesting. I slowly discharged two (bad) batteries to 12 volts. I let them rest overnight then I plugged them into the chargers. Both batteries were blinking one light when I plugged them in. After about 20 minutes all the lights went dark on both batteries. In a normal charge it would take a couple hours for the lights to get to the end then shut off so something seems different. I'm going to leave them on charge for a couple days, take them off for 2 hours then top off. I'll report the results.

Michael Lione · Oct 25, 2017

First step in depleting the battery is to fly to RTL. Then I use the Battery Drain function recently built in to Solex. Great advantage using Solex is that each cell voltage is monitored in the process and a verbal announcement is made informing that the motor cutoff voltage was achieved. Criteria seems to be when the first cell hits 3v cutoff is called out. At this point I let the battery rest for the prescribed 5 hours before starting the 48 hour charge/relax/balancing cycle. This followed up with a 2 hour rest period. At this point the battery is ready for flight. My first post calibration flight is low and close in an open area with my RTL altitude set to 50'.

Here are some typical stats through the various steps-
Before Launch- 100% 16.74v 4472mAh avg cell voltage 4.17 (27 cycles)
After Low Battery RTL- 5% 15.38v 209mAh avg cell voltage 3.85v
(Note: In the flying run down of this battery it did three successive RTLs. 1st @ <1:00m/68% 2nd@ 3:12m/32% and 3rd @ 2:16m/10% Except for the last RTL I suspect the RTL was triggered by a low cell not total volts or charge.)
After Solex Drain- 0% 12.01v 0mAh cell voltages- 3.23/3.06/3.25/3.18
After 5hr Rest- 0% 14.06v 0mAh cell voltages- 3.50/3.46/3.55/3.52

When I hooked up to the charger one LED was flashing on the battery. After approx 10 minutes the second LED began flashing. I got full charge in approximately 3 hours with all LEDs out and green LED on the charger.

Here are the stats after the 48 hr charge and 2hr post charge cycle-
After 48hr Charge- 98% 16.68v 4886mAh cell voltages- 4.17/4.17/4.17/4.17
After 2hr Rest- 98% 16.68v 4863mAh cell voltages- 4.17/4.16/4.17/4.17

Too windy and cold today. (Funny in a few months I'll kill for a 50 degree day to get out a fly) I'll add the final installment to this post as to how the battery performs.

Vegasrobbi · Oct 31, 2017

So good and bad. I took two batteries that I thought were toast for the test. I ran them both down to 12% then let them sit overnight. I charged them for 2 days then took them off the charger. A few hours later I connected them back to the charger; it took about an hour to top them off; I think this was part of the balance cycle.

I flew both batteries today, to my surprise battery 1 went about 13 minutes which is more than double the time prior to the procedure. Battery 2 unfortunately depleted in less than 3 minutes, same as before. Maybe battery 2 is too far gone but I'm going to try again.

Chernabog · Nov 5, 2017

Michael Lione said:
First step in depleting the battery is to fly to RTL. Then I use the Battery Drain function recently built in to Solex. Great advantage using Solex is that each cell voltage is monitored in the process and a verbal announcement is made informing that the motor cutoff voltage was achieved. Criteria seems to be when the first cell hits 3v cutoff is called out. .

Hi Michael,

Where is this battery drain function within Solex? Had a look about in the application but cant seem to see it or find any other info on it on the web, so if you could point me to any documentation/forum posts on it that would be good, as I would like to try an recalibrate one of my batteries.

The issue I have one of my batteries is that it seems to suddenly increase is mAh used near the end of the flight despite the aircraft not doing anything too taxing ... the below image shows an example (red is Volts being used, green is total current used), aircraft was just manouvering slowly when the failsafe kicked in, which was maybe 30 seconds after the 25% battery remaing warning flaged upon the controller.

Thanks.

John Githens · Nov 10, 2017

For some situations, comments in the "dead battery fix?" thread may be relevant to this thread.

Ray Mongelli · Nov 14, 2017

All has been perfect until 2 weeks ago. I have many batteries that fly for only a few minutes. Some will RTL, then the pack voltage will jump back up to 80-90% and resume flight. Sometimes it'll spike a few times. I would guess there is an issue with an individual cell.

Decided to try this procedure. Draining the battery in Solex currently.

I'm not getting individual cell voltage in Solex. It only shows the full pack voltage and %. Anyone have a clue why?

John Githens · Nov 15, 2017

John Githens said:
For some situations, comments in the "dead battery fix?" thread may be relevant to this thread.

A general heads up (or maybe heads down) to thread readers:

During a flight, did the display on your Solo Controller flash back and forth from 100% to a lower percentage? I suspect (but have not verified) that this condition is related to a Smart Battery being, shall we say, internally confused. And this may be why some of my recent missions returned sooner than expected due to "low battery".

However it could be as simple as dirty contacts on a sensing pin on the battery's connector or the Solo's battery connector. I have not been out to fly any of the three batteries that I "recovered" recently, so I can't offer more suspicions.

makokoy · Nov 27, 2017

Hi all. I'm not anglophone, so i Try to understand what you wrote, and I'm not sure I understand everything.
I use solex to try to climb close to 12V, but I'm now at 8% and voltage at 15,51V. Ai can't see the voltage of each cell.
Could you tell me if I did something wrong or if I have to continue the discharge ?
Thanks