TheBrickDad

'Lunas', on 14 Oct 2014 - 11:56 AM, said:

for lipo hobby king has excellent prices and sells through amazon...
charger

I second Lunas on this point. Hobbyking has a good selection and great prices.

Lipos man, you can get some great (in my experience) Turnigy Nano-tech Lipos from Hobbyking's USA warehouse for anything from $4-10.

What motors are you using, stock? Perhaps someone more informed than me can chime in, but the importance of high voltage vs high discharge current may be an important factor depending on which motors you're using.

'Draconis', on 06 Oct 2014 - 06:07 AM, said:

I call bullshit on those shots-per-charge calculations. 300mAh is a tiny battery. Stock motors have winding impedances of something like 12-15 ohms, right? Even if we give them a relatively conservative number like 20 ohms, they'll still be pulling about 300-350mA at 7.4V. That gives them less than an hour of operation under ideal conditions. So I don't buy it.

It looks like I get to call bullshit on you calling bullshit. Check out the OP, I have updated it with test results for shots per battery charge. We were both very wrong, this rig can put out at least 850 darts and possibly 1200 darts on one charge!

Anyone know how many shots per charge people are getting out of their 2S IMR rigs?

'Draconis', on 06 Oct 2014 - 06:07 AM, said:

I call bullshit on those shots-per-charge calculations. 300mAh is a tiny battery. Stock motors have winding impedances of something like 12-15 ohms, right? Even if we give them a relatively conservative number like 20 ohms, they'll still be pulling about 300-350mA at 7.4V. That gives them less than an hour of operation under ideal conditions. So I don't buy it.

I thoroughly agree your hypothesis may be correct since I oversimplified the estimated battery life by assuming it's drop would be linear, so there is significant room for error. As such, I have added "estimated" to the current battery life numbers I have listed. When I get around to wasting God knows how much of my time finding out the real world answer I will post it as my "observed" battery life under controlled non-game conditions.

That said, you have stirred my interest to find out the actual dart capacity it takes to reduce each cell to 3.3v on these 300mah Turnigy Lipos.

'Lunas', on 05 Oct 2014 - 03:58 AM, said:

If that is the one thing you remove from the internals i highly suggest it. It is just a mechanical lock that gets in the way more than it helps honestly i would pull all the mechanical locks and trim the top of the rev trigger so the dart trigger does not hit it rather than trimming the dart trigger like most guides suggest.


Also what are the run times like for that battery pack?

My next mod is going to be the addition of a volt meter inside my stryfe when i do ill get pictures of my rewire with solid core 18 gauge it was interesting to work with. I may or may not swap the stock rev switch to a 10A switch. and i may or may not use the jam door switch to turn off and on the volt meter i also thought about placing the volt meter where you have your battery so when i check the voltage i flip it up get the reading close it turns off the meter. I tested it and when placed against the plastic you can read the numbers through the plastic so it can be super stealth.

Good tips, thank you. I like these ideas.

I have not formally monitored the battery life. However, I have fired about 200 darts through my Stryfe with the Turnigy Lipo and it's dropped from 4.16v/cell to 3.96v/cell, which linearly extrapolates to 860 darts before the Turnigy Lipo needs to be swapped out (low voltage alarm is set to go off at 3.3v/cell.

Start/End Voltage: 4.16/3.96 = 0.2v used
Darts Fired: 200
4.16v-3.3v = .86v/.001 = 860 dart battery life (SD +/-80)

Dang, I like the idea of a digital voltage meter. I could probably trim out a window on starboard side and rig my digital voltage meter/alarm for viewing. I like your top side idea better though, more functional.