I just experienced the power loss that happens when the batteries are too cool at a contest this weekend. I alleviated the loss somewhat by warming the batteries on the dash in the sun before each flight. Has anyone come up with a slick portable way to do this for contests where the vehicles are parked a long way from the pit area.

Thanks,
Verne

I flew in a contest last weekend in cool temperatures, so I blenderm taped off all of the air intake except the air that is ducted to the motor. I've left the tape on, and I'll only take it off if I fly in warm weather again this year (not a guarantee in Saskatchewan).

So, altering air ducting is one way. The other is to insulate the packs with something like a cloth or rag. Consider doing a glow-style full throttle run on the ground before take-off, too ;>

Thanks Adam. Bob Mairs and I were talking about taping the ducts, ala NASCAR, but didn't try it. I run my throttle up before each flight to set the controller. When I warmed the batteries on the dash, the power at run-up
right through take-off and the procedure turn was good. By the time I'd do the half reverse cuban and enter the box, it would be down a little, but not as bad as when I didn't heat the batteries on the dash. Taping the inlets that cool the batteries would have probably done the trick. I'd still like to figure out a way to pre-warm the batteries in the pits when my van is parked far away.

Thanks,
Verne

Back when I had the "older" 12 C PolyQuests 2600, I used to heat them (on colder days) on the dash with my car heating on full power. Once I forgot and they were almost too hot to hold in hand [X(]. Not sure if I have harmed them in any way, but the power was great. So how about to pre-heat them in the car and put them into some thermally insulated container, like a small portable cooler?

Verne when I worked we done alot of welding, to keep the welding rods dry we would make a metal box, insulate, and put a light bulb in it. I would think using sheet foam you could do the same thing sense you use the generator for charging, you could try different wattage bulbs to get the temp you wanted, even have a vent so you could make adjustments if needed later. Just have enough size that the bulb doesn't touch the batteries or even have a simple to 1/2 chamber divider.
Steve Maxwell

Hey Verne, I think I'm gonna try one of these heater fridges. Can run off the power supply/generator. Heats up to 120, but depends on the air temp, so may be just right for cold mornings.

http://www.autopn.com/store/pc/viewC...idCategory=220

Cheap enough to try. Then tape up air duct till air temps warm up.

Bob,
I was looking around today and zeroed in on those too. There's lots of different one's out there to consider. Dunham Sporting Goods shows some good possibilities and they have a store across the the street from where I work. I'll probably check them out tomorrow on my lunch break. I think we'd have been just fine if we'd taped off the inlets as Adam suggested in addition to pre-warming the batteries.

Verne

The glow guys are going to laugh at you if you prepare for a competiton flight by pulling your packs out of an odd looking box, hehe

Maybe we need a small thermostatically controlled damper? ;-))

Don Atwood

They're pretty much laughing at me all the time anyway......

Verne

Bob,
Buy anything yet? My work has kept me away from the office so I haven't had a chance to look at the one in the Dunham's across the street yet. I'm on the road again tomorrow but may get over there on Tuesday.

Verne

No, been flying in the afternoon so haven't needed it yet. Prob week after next. Got my batts. One had a dead cell.

Verne,
Picked up an old used Igloo cooler/warmer for $5. Motors kinda noisy, must have a gearbox.

Spliced in a deans connector to the power cord. Can run it off the cigarette lighter or power supply. Abot 13" long inside, 8" wide, 12" high. Tested it for about a half hour, and it was warming up pretty good. To heat or cool you just reverse the plug. Will be trying it out pretty soon, weathers been kinda crappy around here again. Will have to see if the generator/power supply can handle the cooler and 2 chargers at the same time.

Tried it out this morning. Air temp was 60-64F. Highest inside temp measured was 113F, that was close to 1.5hrs. Packs were coming out at about 85 -103, depending on how long they were in there, last one, 103, was prob close to 1.5 hours. Had good power from the outset. Handy to carry them in also, worth the $5. I would guess it was in the mid to upper 50's the morning we had problems?

I picked up a similar unit for $30.00. I tried it on the cigarette outlet and it was getting pretty warm after about 15 minutes. I'm pretty sure my power supplies won't handle any more than the 2 chargers each they're already running so I'll have to add another smaller power supply for the heater. Hope to try it at the field this weekend at the field if it doesn't rain. It's definitely cooler out than it was at Quincy so I'll need to do something. I thought Quincy was more like low to mid 60's. Have you taped off your air inlets or are you relying on just pre-warming the batts?

Verne

I taped off half the inlet this morning, but I'm thinking that just warming the batts is the biggest thing. Logged my last flight this morning. Voltage never went under 36 volts until after 3 minutes into the flight. Also went up 8 amps. Pack temp was around 100F when I put it into the plane. Been running a 15xl with a 22x12. 2700 watts with the heated batt today. Definitely improves the performance.

Well I just picked up a nice cooler&warmer at Linens and Things $29.99.
http://www.lnt.com/sm-vector-12v-min...i-1986206.html

Steve Maxwell

We're gonna need them after seeing next weeks forecast.

Tried the warmer tonight and it worked great, it's rated at 120degrees and I thought that may be to much but it takes a good while for the batteries get up to tempI took them out at 108 degrees and seemed fine. Temp was only 66 today.
Steve Maxwell

Steve, did it make a difference in performance in the air?

Didn't get to fly but should tomorrow, started raining just as I finished testing props.
Steve Maxwell

Takes longer than I expected to warm the batteries in the warmer the highest mine got 108 degrees the warmer gets to 120, already got the cowl and half the cheek openings closed off. Got the same feeling as you guys did testing the warmed packs compaired to the cold packs, using more throttle to get the same performance. It's time for more tape LOL.
Steve Maxwell