Ultrax Battery Rapid Voltage Drop

[Satdiver]

Has anyone experienced any "rapid voltage drop" with the Ultrax 6300mAh batteries?

Searching the forums I see there are quite a few positive posts on these batteries so I bought a "2 pack" from a seller on Amazon. Once they arrived, I charged them and my two stock batteries up on my Hitec X4 and took the H out to complete a construction progression flight for a client.

Finishing up my preflight checks, I inserted the first Ultrax and powered everything up. The first clue I had was that the battery had a slightly lower voltage (16.4v) than when it came off the charger at 16.8. It was a cold day so I noted it and planned to pay extra attention to it. I took off and brought the H up to about 6-8' of altitude as I usually do to check and make sure everything is good prior to starting the flight. I immediately noticed the battery voltage clicking down at a rapid pace and I started to land. Before I could even get it on the ground I had a low voltage warning (14.1v) and barely made it down. That flight was just at 32 seconds.

Thinking it was maybe just one bad battery, I inserted the other Ultrax. It was also at a slightly lower voltage than when it came off the charger. I took the H up to about 4' and the voltage started dropping! By the time I got it on the ground I had two low voltage warnings (14.3v) on a 46.5 second flight.

I finished the flight on my stock batteries and it was uneventful but this was a really odd experience.

To give the batteries a second chance, I charged them again when I got home, this time on the Yuneec stock charger. The flights were almost identical at 26.1 and 47.2 seconds.

Now I'm trying to work with the seller to replace the batteries with good ones. I hope that doesn't warrant a thread of it's own...

THanks,

Todd

 

[NorWiscPilot]

Has anyone experienced any "rapid voltage drop" with the Ultrax 6300mAh batteries?

Searching the forums I see there are quite a few positive posts on these batteries so I bought a "2 pack" from a seller on Amazon. Once they arrived, I charged them and my two stock batteries up on my Hitec X4 and took the H out to complete a construction progression flight for a client.

Finishing up my preflight checks, I inserted the first Ultrax and powered everything up. The first clue I had was that the battery had a slightly lower voltage (16.4v) than when it came off the charger at 16.8. It was a cold day so I noted it and planned to pay extra attention to it. I took off and brought the H up to about 6-8' of altitude as I usually do to check and make sure everything is good prior to starting the flight. I immediately noticed the battery voltage clicking down at a rapid pace and I started to land. Before I could even get it on the ground I had a low voltage warning (14.1v) and barely made it down. That flight was just at 32 seconds.

Thinking it was maybe just one bad battery, I inserted the other Ultrax. It was also at a slightly lower voltage than when it came off the charger. I took the H up to about 4' and the voltage started dropping! By the time I got it on the ground I had two low voltage warnings (14.3v) on a 46.5 second flight.

I finished the flight on my stock batteries and it was uneventful but this was a really odd experience.

To give the batteries a second chance, I charged them again when I got home, this time on the Yuneec stock charger. The flights were almost identical at 26.1 and 47.2 seconds.

Now I'm trying to work with the seller to replace the batteries with good ones. I hope that doesn't warrant a thread of it's own...

THanks,

Todd
View attachment 13140
View attachment 13141

Definitely an oddity no matter what brand.

I have had good experiences with my Ultrax. Hopefully the seller will pony up.

One might also consider going straight to the source... Gens Tatu I believe.

Good luck!

Jeff

 

[Satdiver]

Definitely an oddity no matter what brand.

I have had good experiences with my Ultrax. Hopefully the seller will pony up.

One might also consider going straight to the source... Gens Tatu I believe.

Good luck!

Jeff

Thanks Jeff. I have read so many good reviews of them and to have two exact failures was unnerving!

I almost didn't want to fly with my stock batteries for fear there was an issue with my H. I kept it at a low hover to make sure all was good before completing the flight.

I too hope the seller corrects this. Bought with Amazon Prime so I'll just return them for a refund if I have to.

Todd

 

[Steve Carr]

Most certainly there is a problem with the batteries and they should replace them without a problem.

 

[PatR]

Those batteries appear to indicate they had been deep discharged at some time and damaged the cells. Are you certain they were new or is there any evidence present to indicate they’ve been used prior to your purchase? The packaging would be the first thing I looked at. Battery in a fitted box, battery inside a bubble wrap envelope or sheet, instruction sheet for proper handling. GensAce, Tattu, and UltraX batteries are always packaged that way. They are also usually shipped at storage voltage.

The cell IR values will tell you what you need to know about condition. Any cell over 8m/ohms is concerning.

 

[AeroJ]

I had something similar with a Morpilot pack I ordered, but not as extreme as in your case. Mine starts at 16.7, drops to 15.0 within the first 20 seconds of flight, but then remains there for about 7 minutes before it drops any further ! Both my Yuneec packs drop hard to 15.6 or so but then discharge fairly evenly from there. It's a shame but we seem to play lucky dip with these 3rd party jobbies...

 

[DoomMeister]

This is the link to the official US distributor for the UltraX Rc hobby battery & uav battery & FPV lipo battery online shop - Gens ace and Tattu.

I have to agree that these batteries were either over charged or deeply discharged and sustained damage at some point. Can you measure and post the IR readings for each cell on both batteries?

 

[Satdiver]

Thanks for the replies gentlemen!

@Steve Carr I hope you are correct!

@PatR That was my first thought but the batteries arrived packaged as you mention. They appear to be brand new. Upon receipt, the first thing I did was check to see if they were at storage level and they were at ~15.2v each. The battery packaging was also nice and tight with no puffiness. I'm working on getting an IR measurement but do not believe my older Hitec x4 has that capability. I'll see if I can measure it another way- do you have any other tricks as how to do this? I'm very familiar with a volt/ohm meter but not with the connection points on these batteries.

@DoomMeister I will do that as soon as I'm able to get the IR readings determined.

Again, thank you all.

Todd

 

[Steve Carr]

I'll see if I can measure it another way- do you have any other tricks as how to do this? I'm very familiar with a volt/ohm meter but not with the connection points on these batteries.

If you don't have the right equipment to test it, don't bother. The indications you have are sufficient for replacement.

 

[OldHire]

Thanks for the replies gentlemen!

@Steve Carr I hope you are correct!

@PatR That was my first thought but the batteries arrived packaged as you mention. They appear to be brand new. Upon receipt, the first thing I did was check to see if they were at storage level and they were at ~15.2v each. The battery packaging was also nice and tight with no puffiness. I'm working on getting an IR measurement but do not believe my older Hitec x4 has that capability. I'll see if I can measure it another way- do you have any other tricks as how to do this? I'm very familiar with a volt/ohm meter but not with the connection points on these batteries.

@DoomMeister I will do that as soon as I'm able to get the IR readings determined.

Again, thank you all.

Todd

Satdiver,
I'm experiencing the same thing you are and am currently in contact with the seller, thru Amazon, and they asked for specifics and then stated they are going to have their "engineers" look at my information. I read on some blog that these batteries may need to be charged/discharged several times for them to begin acting correctly. Oddly enough yesterday was a good day to fly, so I thought I would test that theory and I re-charged my battery for the third time. It at first recorded a drop in voltage on my ST16 and then bounced back up to 16.1 volts and I flew it for over 11 minutes before the first warning in drop of voltage. I was deliberately letting my drone idle about a foot off the ground, in case of a total drop in battery volts and airspace. Didn't happen. But, the ST 16 only gave me one low battery warning. So, I landed and checked the voltage and the battery indicated 14.2 (Scary, never have or will do that again) and then it bounced up to 15.2 after I had removed it from the TH. Our weather is going to change again, so I don't think I'll be able to test it again for awhile but I plan on doing that. The battery seemed very strong, but I don't trust the rollercoaster voltage readings it has been giving me. Everything you mentioned ie' receiving , packaging, storage level was the same for me.
I'll be interested in the interest the seller has in replacing my battery as I don't have confidence in this particular purchase. However, I am pleased with the quick response I received from the seller and hope they follow through with a replacement. I'm sure we're not the only ones with this issue.

 

[Satdiver]

Satdiver,
I'm experiencing the same thing you are and am currently in contact with the seller, thru Amazon, and they asked for specifics and then stated they are going to have their "engineers" look at my information. I read on some blog that these batteries may need to be charged/discharged several times for them to begin acting correctly. Oddly enough yesterday was a good day to fly, so I thought I would test that theory and I re-charged my battery for the third time. It at first recorded a drop in voltage on my ST16 and then bounced back up to 16.1 volts and I flew it for over 11 minutes before the first warning in drop of voltage. I was deliberately letting my drone idle about a foot off the ground, in case of a total drop in battery volts and airspace. Didn't happen. But, the ST 16 only gave me one low battery warning. So, I landed and checked the voltage and the battery indicated 14.2 (Scary, never have or will do that again) and then it bounced up to 15.2 after I had removed it from the TH. Our weather is going to change again, so I don't think I'll be able to test it again for awhile but I plan on doing that. The battery seemed very strong, but I don't trust the rollercoaster voltage readings it has been giving me. Everything you mentioned ie' receiving , packaging, storage level was the same for me.
I'll be interested in the interest the seller has in replacing my battery as I don't have confidence in this particular purchase. However, I am pleased with the quick response I received from the seller and hope they follow through with a replacement. I'm sure we're not the only ones with this issue.

@OldHire

On one hand I'm sorry you're experiencing the same thing I am but on the other, I'm glad knowing I'm not the only one. Kinda thought I was going crazy having this happen to BOTH new batteries at the same time. Thought maybe I should buy a lottery ticket.....

As you can see in the screenshots I posted, the voltage level in mine bounced back up as well once i landed. I've put mine back on the charger for a third time to see how they act but I won't fly them again. Too close the first two times! I'm going to purchase a Tenergy battery checker so I can read the IR levels to see what is going on with them.

I did hear from the seller today that he has refunded me and if I'd like to purchase another set he has more. I'm not sure if he wants them returned or not. Now the dilemma is, do I purchase from this seller again or buy elsewhere? I really don't want to take the chance ending up with another set from the same lot.

Good luck with your seller, I hope it turns out in your favor!

Todd

 

[DoomMeister]

@OldHire

On one hand I'm sorry you're experiencing the same thing I am but on the other, I'm glad knowing I'm not the only one. Kinda thought I was going crazy having this happen to BOTH new batteries at the same time. Thought maybe I should buy a lottery ticket.....

As you can see in the screenshots I posted, the voltage level in mine bounced back up as well once i landed. I've put mine back on the charger for a third time to see how they act but I won't fly them again. Too close the first two times! I'm going to purchase a Tenergy battery checker so I can read the IR levels to see what is going on with them.

I did hear from the seller today that he has refunded me and if I'd like to purchase another set he has more. I'm not sure if he wants them returned or not. Now the dilemma is, do I purchase from this seller again or buy elsewhere? I really don't want to take the chance ending up with another set from the same lot.

Good luck with your seller, I hope it turns out in your favor!

Todd

Go right to genstattu.com or on Amazon filled by genstattu. I have a feeling the third party seller db??141 May be selling old stock. A battery should not have to go through several cycles to work properly.

It is a good idea getting a tool to measure the IR.

 

[PatR]

Regarding the return shipping of lithium polymer batteries that are behaving abnormally- do not ship them as they have become unstable. If a manufacturer wants them back, do your best to talk them out of it due to safety concerns but if they insist, YOU insist on a return mailer that assures THEY are the ones taking full responsibility for the shipment. You don't want to be the one assuring safe shipping state and accepting responsibility should they explode or catch fire in one of those brown trucks, a USPS delivery vehicle, or an airplane.

To assist understanding how a normally performing li-po works in the H, the following; At initial power up the full charge voltage will display, normally between 16.6v or 16.7v, depending on your battery. If left powered on but unarmed the initial voltage will remain stable for a considerable period of time. As soon as the motors are armed the displayed voltage will immediately decrease due to the current demand being placed on the battery. It may fall to ~15.8v or so after throttle up, indicating a load of 0.8A or so had been applied to the battery. As load increases voltage decreases. An action/reaction thing. That voltage will remain stable for a short period of time but cannot remain stable for long as the battery does not have an infinite supply of energy to maintain it. It's releasing energy, therefore it must deplete the voltage level with every second it is being drawn upon. The more throttle and speed desired the faster it will deplete the voltage. So seeing a sudden voltage drop when the motors are armed is completely normal. Seeing the voltage decrease a little more as climb throttle is applied is also normal because the current load was increased with the throttle command. Abnormal would be not experiencing a voltage drop, indicating there is something wrong with the volt meter.

After landing with the motors at idle the battery voltage will rise a couple tenths of a volt because the load on the battery has decreased. Disarming the motors usually allows the battery voltage to increase/bounce back ~4/10v,. After the battery has been given time to cool off the battery voltage will rise further. If you landed at 14.5v it would not be unusual to see the battery voltage had risen to ~15v or so after a half hour or so. Those that don't understand how this works can get themselves in trouble. Perhaps they landed with a battery voltage of 14.9 or 15v or so and check that battery a little later and see a voltage reading of 16V. They might think they still have a lot of flight time left in the battery, install it, and launch for a distant location. They probably won't get back because as soon as the motors armed that 16V suddenly dropped to 15.2V, and very shortly after being subjected to the load the battery will heat up and start increasing internal resistance, further reducing current available along with the voltage decrease associated with usage. So shortly after launch they get the first low voltage warning, with the second following very close behind it. Point being that 16V they saw when they checked the used battery was kind of a false reading. Sure, it was a true 16V but the remaining capacity was not sufficient to sustain it. It will be back to the previous landing voltage just a few seconds after launch. So unless you have a very good understanding of how li-po batteries work you should avoid re-using a partially used battery. Always launch a new flight with a fresh battery.

 

[Satdiver]

Regarding the return shipping of lithium polymer batteries that are behaving abnormally- do not ship them as they have become unstable. If a manufacturer wants them back, do your best to talk them out of it due to safety concerns but if they insist, YOU insist on a return mailer that assures THEY are the ones taking full responsibility for the shipment. You don't want to be the one assuring safe shipping state and accepting responsibility should they explode or catch fire in one of those brown trucks, a USPS delivery vehicle, or an airplane.

To assist understanding how a normally performing li-po works in the H, the following; At initial power up the full charge voltage will display, normally between 16.6v or 16.7v, depending on your battery. If left powered on but unarmed the initial voltage will remain stable for a considerable period of time. As soon as the motors are armed the displayed voltage will immediately decrease due to the current demand being placed on the battery. It may fall to ~15.8v or so after throttle up, indicating a load of 0.8A or so had been applied to the battery. As load increases voltage decreases. An action/reaction thing. That voltage will remain stable for a short period of time but cannot remain stable for long as the battery does not have an infinite supply of energy to maintain it. It's releasing energy, therefore it must deplete the voltage level with every second it is being drawn upon. The more throttle and speed desired the faster it will deplete the voltage. So seeing a sudden voltage drop when the motors are armed is completely normal. Seeing the voltage decrease a little more as climb throttle is applied is also normal because the current load was increased with the throttle command. Abnormal would be not experiencing a voltage drop, indicating there is something wrong with the volt meter.

After landing with the motors at idle the battery voltage will rise a couple tenths of a volt because the load on the battery has decreased. Disarming the motors usually allows the battery voltage to increase/bounce back ~4/10v,. After the battery has been given time to cool off the battery voltage will rise further. If you landed at 14.5v it would not be unusual to see the battery voltage had risen to ~15v or so after a half hour or so. Those that don't understand how this works can get themselves in trouble. Perhaps they landed with a battery voltage of 14.9 or 15v or so and check that battery a little later and see a voltage reading of 16V. They might think they still have a lot of flight time left in the battery, install it, and launch for a distant location. They probably won't get back because as soon as the motors armed that 16V suddenly dropped to 15.2V, and very shortly after being subjected to the load the battery will heat up and start increasing internal resistance, further reducing current available along with the voltage decrease associated with usage. So shortly after launch they get the first low voltage warning, with the second following very close behind it. Point being that 16V they saw when they checked the used battery was kind of a false reading. Sure, it was a true 16V but the remaining capacity was not sufficient to sustain it. It will be back to the previous landing voltage just a few seconds after launch. So unless you have a very good understanding of how li-po batteries work you should avoid re-using a partially used battery. Always launch a new flight with a fresh battery.

Roger that PatR, I understand all points you made. Thanks again.

Todd

 

[DoomMeister]

@PatR that was a very good time lapse explanation of how the battery and voltage readings react during different phases of flight. It was simple, straightforward, and concise. While voltages will be different depending on the aircraft being flown, the same principle applies to all aircraft of this type.

Second nature to you and many others on this forum, but very necessary for those new to the hobby and aircraft to understand!

 

[Gomi]

Did you consider a fault with the charger or perhaps an incompatibility with the UltraXs? I have had no problems with my pair.

 

[OldHire]

Did you consider a fault with the charger or perhaps an incompatibility with the UltraXs? I have had no problems with my pair.

GM, Yes, I tried both ports of my DY 3 battery charger. Both registered the same. After charging I used my voltage tester and got the same reading. The ST16 also gave me the low voltages, when flying. I really like what I've read about this battery and will probably buy another. I think this is just a fluke of a battery in a mass produced product. At least I hope so. I'm working with them to resolve the issue and hope for a positive solution.

 

[Satdiver]

Did you consider a fault with the charger or perhaps an incompatibility with the UltraXs? I have had no problems with my pair.

@Gomi
In my original post I mention that I also used the same charger (Hitec x4) to charge both of my stock Yuneec batteries I flew that day. I also tried to charge the Ultrax batteries on the stock H charger with the same results.

Glad to hear you've had no problems with yours; I was not so lucky.

Todd

 

[brwatters]

Glad to have found this thread as I also had the exact issue with a pair I purchased and have since returned, with both batteries showing full charge I was barely able to get my H back on the ground before I was out of juice .. certainly not the experience I was looking for, either it's a large batch of bad batteries or you or I received the others return batteries

BRW

 

[Satdiver]

Glad to have found this thread as I also had the exact issue with a pair I purchased and have since returned, with both batteries showing full charge I was barely able to get my H back on the ground before I was out of juice .. certainly not the experience I was looking for, either it's a large batch of bad batteries or you or I received the others return batteries

BRW

@brwatters

Did you buy yours from a third party seller on Amazon also? Just curious because that's where i got mine. I believe that's where @OldHire bought his as well.

Thanks,
Todd