Fair comment Walt, it will be easy enough to slip a square of thin plastic in there too for what is just a trial. Once we don’t have mixed rules like at the NCR I will be switching to 3 cell holders which I will shortly have a stock of ready to go in AA and AAA.
No reason a cut-to-length piece of balsa wood or dowel couldn’t be used instead of an old battery, and it would save most of the extra weight of that battery, which is the main purpose of the whole battery issue in the first place. Not any space savings with this solution though…
Regards,
Bill Nielsen
Oakland Park, FL USA
This is purely to comply with the ‘old’ rules being run at the NCR in Orlando next week Bill. After that a 3 cell holder is going in assuming that three cells do prove to be sufficient in reality.
Graham
Hi Graham,
OK, I think I see, but is there some other reason you don’t want to use the E2 (non-rechargeable) cells instead? I believe 4 of them is about the same weight as three of the rechargeable cells, and I haven’t heard of anyone having over-voltage issues with the E2-nr cells. Of course, when they go down, you do have to spring for another $10 to replace them instead of just recharging…
Regards,
Bill
It’s too bad you can’t just use solar cells. Even on a 1M, you can’t, using the older generation cells (not enough current) but with the new cells it might work. I read the sailplanes are doing that.
These are the non-rechargeable cells Bill. If you look back at entry #16 in this thread the figures I posted and Walt’s comments on the apparent lack of voltsge drop under load explain why I am testing 3 cells. The only over voltage issues I have heard are the ones earlier in this thread, but considering the voltage available with these primary (non-rechargeable) cells it seems to me to be worth trying the 3 cell packs.
Others have mentioned rechargeable cells in this thread but I have been talking about the primary cells all along.
Graham
If you are using 3 cells, how low can you get the voltage to before you lose radio control? That’s my biggest concern and the main reason why I only use 3 cells for testing and 4 cells for sailing.
That depends on the receiver’s requirements. Spektrum states that their 5ch/2.4ghz receiver has an operating voltage range from 3.5v to 9.6v. Futaba doesn’t state their range, but it’s probably similar (at least for the low end). I have found that with alkalines, when the voltage gets down to less than 1.25v per cell, the cells need to be replaced. I suspect this is because at that voltage, once the extra load of an energized servo is added, the voltage drops even more. My Futaba transmitter doesn’t like it’s alkalines when their voltage drops below 1.31 volts per cell. I haven’t tested any rechargeable batteries yet…
Regards,
Bill
I’ve done a bit of testing with a Futaba 2.4Ghz, seems to work down to 3.1v but I’ve no idea whether range is affected. Does open the possibility of using 3 1.2v cells. Of course servo torque will be limited which may be a problem.
David
To move this thread from theory into practice I can report that I sailed the Footy NCR on 3 active and one bypassed (as illustrated) Energiser Lithium (non-rechargeable) AA cells. This included Friday afternoon testing and all of the Saturday and Sunday races on the same cells without any detectable loss of winch power. Wind was at times pretty strong so I think this was a good ‘real world’ (as they say) test. Range was good in fact the course at times took the boat further away than I typically sail. Radio was a DX6i with small low range receiver, the type with the two 1" antennas. In fact radio performance was nothing short of perfect.
I also sailed a ‘new rules’ boat (Dragon) on 3xAAA Energiser Lithium for an hour or so on Friday with no range or winch power issues.
Looks good to me 
Graham