Ok, had a total loss of airframe last weekend. I must have misinterpreted in my research. I set my low voltage warning to 7v on my er9x modified FS-TH9x with led backlight. I'm assuming my error was in using alkaline batteries as my controller died at 7.5 volts. Of course it was while my aircraft was airborne, which resulted in a less than desireable ending. Right now I'm using 2300 mah nimh rechargeables. What should I set my voltage alarm to? I currently bumped it to 9.5 volts to be safe.
Also, is there a generic charger I can use for the charging port on the side of the controller?
I feel like a complete putz. Everyone was impressed with my controller...now they question it...but I'm sure it was my fault.
Voltage Cutoff
Re: Voltage Cutoff
Ouch, too bad...
But yeah, sounds like you overlooked part of the info. 7v would be for a 2s lipo battery.
8 nimh about 9-9.5v, alkalines probably 9.5-10v or so.
Sent via mobile
But yeah, sounds like you overlooked part of the info. 7v would be for a 2s lipo battery.
8 nimh about 9-9.5v, alkalines probably 9.5-10v or so.
Sent via mobile
Re: Voltage Cutoff
8 cells at a total voltage of 7.0 volts is 0.875 volts per cell.
So the cells are absolutely empty.
The bigger problem will be, that the capacity of the single cells will not be absolutely identical.
That means, while most of the cells will still have more than one volt, the weakest cells will break down to zero and even reverse polarity.
If you have a volt meter, you could check it. Run the batteries down to the end of the capacity and measure the single cell voltages. You probably will get frightened and increase your low battery warning to not less than 1.15 volts (9.2 v total) per cell.
Reinhard
So the cells are absolutely empty.
The bigger problem will be, that the capacity of the single cells will not be absolutely identical.
That means, while most of the cells will still have more than one volt, the weakest cells will break down to zero and even reverse polarity.
If you have a volt meter, you could check it. Run the batteries down to the end of the capacity and measure the single cell voltages. You probably will get frightened and increase your low battery warning to not less than 1.15 volts (9.2 v total) per cell.
Reinhard
Re: Voltage Cutoff
Thanks for the insight. I was sooooo mad at myself. The plane was a H9 Piper Pawnee 40. I am new to the hobby still...stupid mistakes aren't cheap. I absolutely love the plane though...another is in the mail....
Re: Voltage Cutoff
One more thing. I'm still looking for a wall charger. I found a Futaba wall charger that is rated at 9.6v and 50mah. It was used for an old nicd setup. If it doesn't work, any idea where I can get an appropriate wall charger. Or even the right specs would put me in the right direction.
Thanks.
Thanks.
Re: Voltage Cutoff
My suggestion is to get a 1500 mah 3S LiFe or 2650 mah 3S Lipo. The cost is about the same as getting a charger for NiCd or Nimh, they last a lot longer than NiCd or NiMH (negligible self discharge).
http://www.hobbyking.com/hobbyking/stor ... duct=16529 (this is a tight fit)
http://www.hobbyking.com/hobbyking/stor ... _Pack.html (Better than 1st)
http://www.hobbyking.com/hobbyking/stor ... duct=17955 (easy drop in)
both are available at HK US ware house, search a little.
the 3S lipo runs a little hot, it is best to get 2 of them and convert to 3 2S pack then it is perfect. the 3S LiFe has good voltage for TH9X.
When I started, I used 2300 NiMH, sounds like the 1500 mah LiFe would last a lot less, but no, it lasts a lot longer than the NiMH, because the rechargeable NiCd and NiMH self discharge is just horrible. I still have 16 2300 mah NiMH for use for other things now.
I assume you have a LiPo, LiFe charger already, if not it is 20+ dollar to get one which can charge just about anything you have including NiCd, NiMH. you can also use it for recharging your Rx pack (also suggest change to Lipo)
http://www.hobbyking.com/hobbyking/stor ... duct=16529 (this is a tight fit)
http://www.hobbyking.com/hobbyking/stor ... _Pack.html (Better than 1st)
http://www.hobbyking.com/hobbyking/stor ... duct=17955 (easy drop in)
both are available at HK US ware house, search a little.
the 3S lipo runs a little hot, it is best to get 2 of them and convert to 3 2S pack then it is perfect. the 3S LiFe has good voltage for TH9X.
When I started, I used 2300 NiMH, sounds like the 1500 mah LiFe would last a lot less, but no, it lasts a lot longer than the NiMH, because the rechargeable NiCd and NiMH self discharge is just horrible. I still have 16 2300 mah NiMH for use for other things now.
I assume you have a LiPo, LiFe charger already, if not it is 20+ dollar to get one which can charge just about anything you have including NiCd, NiMH. you can also use it for recharging your Rx pack (also suggest change to Lipo)
Re: Voltage Cutoff
+1
1500mAh LiFe and 9x is a perfect match. Those 8pack battery cases are not reliable, let alone the battery chemistry tricks that NiCd and NiMH play...
1500mAh LiFe and 9x is a perfect match. Those 8pack battery cases are not reliable, let alone the battery chemistry tricks that NiCd and NiMH play...
Re: Voltage Cutoff
Totally forgot about that.
If you use the original battery holder, that may well be the problem.
Batteries fit very tight in the holder so that the spring in the holder sometimes is not able to shift the cells against the + contact.
The battery holder is known to make trouble.
Try the following:
In the holder, shift the cells against the spring.
Slowly release it.
If all the cells immediately slip back making good contact at the + contact you may have no problem
Check that the the + poles of the holder are clean.
Check the crimps where the battery wires are connected to tne contacts of the holder.
If the cells nearly dont move, cut out the separator between the cells. This give a little bit more room to move.
If you want to stay with AA cells, best will be to solder them.
Reinhard
If you use the original battery holder, that may well be the problem.
Batteries fit very tight in the holder so that the spring in the holder sometimes is not able to shift the cells against the + contact.
The battery holder is known to make trouble.
Try the following:
In the holder, shift the cells against the spring.
Slowly release it.
If all the cells immediately slip back making good contact at the + contact you may have no problem
Check that the the + poles of the holder are clean.
Check the crimps where the battery wires are connected to tne contacts of the holder.
If the cells nearly dont move, cut out the separator between the cells. This give a little bit more room to move.
If you want to stay with AA cells, best will be to solder them.
Reinhard
Re: Voltage Cutoff
Agreed Reinhard, if one wants to stick with AA cells, solder or otherwise fix a pack together. I would not use that plastic 8cell carrier that comes with the 9x - not worth the risk. Maybe you could find a different 8cell carrier that is more robust and mechanically sized correctly, but even that's not going to be as reliable as a properly designed pack.