Why Do We Really Need A Quick Change Battery System?
#16
Quick change would really only be truly useful in a long endurance race which most of us don't run in. If you have to come in for a battery change, obviously you'll finish the race better the less time you have in the pits. An endurance race is all about overall strategy and pit time plays an important role.
For just everyday rc cars at normal races or those that get bashed, I don't understand the need for a quick change system. Convenience is nice but there is no fundamental reason to be able to do it any quicker other than that. I don't even see why people need to charge a battery at faster that 1C.
For just everyday rc cars at normal races or those that get bashed, I don't understand the need for a quick change system. Convenience is nice but there is no fundamental reason to be able to do it any quicker other than that. I don't even see why people need to charge a battery at faster that 1C.
#17
Tech Elite
iTrader: (19)
There really is no point to running longer than 15 minutes imho. Occasionally, I've had to run 20-30 minute mains with nitros and have been able to do with no issues and proper setup of car. I ran a 25 minute main with no battery swap in my buggy on decent sized indoor track (6s/1400). I believe I used a 6s 4000 pack if I recall correctly.
Electric buggies can run longer but it would take manufacturers to invest in making them a little lighter. When I converted my 810 to electric I got SIGNIFICANTLY longer run times using higher voltage. The car is just barely over 6lbs. I am pretty confident I could run a 30 minute main with maybe a 6s 3300-3600 pack in that car.
I hate long mains as the field gets spread out too thin and car attrition. Maybe they are ok for the handful of top tier races that occur each year, but at the club level anything longer than 15 minutes is just a waste of time imho.
Electric buggies can run longer but it would take manufacturers to invest in making them a little lighter. When I converted my 810 to electric I got SIGNIFICANTLY longer run times using higher voltage. The car is just barely over 6lbs. I am pretty confident I could run a 30 minute main with maybe a 6s 3300-3600 pack in that car.
I hate long mains as the field gets spread out too thin and car attrition. Maybe they are ok for the handful of top tier races that occur each year, but at the club level anything longer than 15 minutes is just a waste of time imho.
#18
I think there have been such things in place for years. Maybe they just need to be adapted to off road racing. I remember when the pan cars were running that superdrome track and Chris Lett was setting speed records they had a quick change system that dropped the battery out of the bottom of the chassis. they could perform a pit stop quicker than you could fuel a nitro car. I'm sure something could be developed for a buggy/truck that would keep ouot the dirt and not weaken the chassis.
The design was simple, the chassis was a basic pan car chassis with a saddle pack configuration. The thing was though, the entire "saddle" part of the chassis was removable. The main chassis of the car was actually very narrow and the "saddle" sat right below it. There were two metal pickups on the main chassis that you would solder your speed control to. On the removable saddle were two other metal pickups that the batter was soldered to. The battery would be strapped into the saddle. This meant for every pack you were going to use, you had to have a "saddle" tray for it. Not cheap. For a 30 minute main, in the days when cars would go 4 minutes on a pack, you'd need 8 batteries and "saddle" trays just to run a main.
The saddle had a couple of screws in it that stuck up and mated up to a couple of slots in the main chassis. In the middle of the main chassis was a little bracket where the front of the "saddle" would slide into. Inside that bracket was a spring that would push back against the "saddle" tray. To lock the tray in place, a spring loaded rod ran up next to the antenna and had a big hoop at the top. This hoop would stick out of the body. The rod matched up to a hole in the "saddle" tray so that when it was pulled, the rod would come out of the hole and release the tray.
The way the pit stop would work is you would have two guys. The first one would grab the car by the front bumper and batter ring as it came into the pits. In one move he would pull up on the ring releasing the "saddle" tray. The spring in the front of the center bracket would shove the tray back slipping the screws in the tray out of the slots in the chassis. As he was doing this, he would swoop the car up off the ground and hold it vertically by the front bumper so the bottom of the car was now facing the second pit guy. This would allow the spent batter in the "saddle" tray to fall free of the car. When it did pit guy 1 would release the battery ring.
Pit guy two would then slap the fresh battery in it's "saddle" tray into the slots of the chassis, slide it forward, and would hear when the battery ring locked in place to secure the new tray. At that point he'd take the car from pit guy one and toss it back down on pit road. With practice guys could do this in 1-2 seconds. It was increadible to watch and fun ass hell to do.
If you guys have never ran an enduro race with a pit crew, battery swaps, and trying to do quick fixes to get the car to work then you don't know what you're missing. It's a ton of fun.
I'd love to see something like this in off road but I don't know how you'd accomplish it without sacrificing durability. The Bolink Enduro, performance wise, was well outclasses by the Associated RC10L and RC10LO but because battery changes were so fast with it, it was the chosen chassis for all endurance races. I would think for chassis where the batter runs down the center of the chassis you would use a similar system as the Bolink but where the center part of the chassis is like a "trap door" that drops down and out of the chassis when released. For off-center battery layouts though or saddle packs this would be more difficult.
#19
I'd love to see something like this in off road but I don't know how you'd accomplish it without sacrificing durability. The Bolink Enduro, performance wise, was well outclasses by the Associated RC10L and RC10LO but because battery changes were so fast with it, it was the chosen chassis for all endurance races. I would think for chassis where the batter runs down the center of the chassis you would use a similar system as the Bolink but where the center part of the chassis is like a "trap door" that drops down and out of the chassis when released. For off-center battery layouts though or saddle packs this would be more difficult.
I was thinking the same thing about the offroad cars and the pack running the center line of the chassis and dropping out the bottom. I would be concerned about weakening the chassis and having a ton of flex there but I am sure it could be compensated for.
-Joe
#20
It's stuff like that though that you'd never try during a "one pack race" that you try during an enduro.
I wonder if the flex issue could be solved in off road if you ran carbon fiber reinforcements along side the "trap door" longitudinally? (Or however you spell it...) Would help front to rear flex for sure. It's tornsional flex that would concern me and which I don't have an answer for...maybe a CF "box" the runs around the sides of the "trap door"?
#22
Tech Addict
iTrader: (3)
I can understand the quest for quick battery changes if you are running against nitro in a long race, but I also don't really think electric and nitro should be running together in the first place. If you run separate classes, this is a non issue as everyone would be "on pace" in a battery swap assuming someone doesn't mod their vehicle for a quick change system. Rules could be in place to prevent this.
1/8 scale e buggy seems to be holding it's own at a lot of tracks and most larger races anyway and they don't need to run with nitro just to have a class to run in. I'm sure that is not the case at all clubs though, but why do the nitro's need to run longer than 15-20 minutes at a smaller club race? The fast guy will still be the fast guy at 15 minutes. I know that pitting is part of the nitro racing strategy and part of the fun I suppose, but if your club can't support two separate classes, then make concessions. Or the electric guys can just deal with the fact that their pit will take longer. If you are using velcro to put your body on with and straps for the battery/s a swap can be done fairly quickly although not as fast as a refuel.
I do think quick change is possible from underneath. The DF-03 chassis idea would make this possible. You would just need a battery with exposed tabs that mate into tabs installed in the battery compartment. Pull a pin, drop a bat, throw a new one in, and install the pin and go.
I personally like the duration of 1/10 races. Same fun, but more heats can be run in much less time! I don't need to live at the track for 24 hours just to run qualifiers. But some folks love to spend all day at the track. To each his own!
1/8 scale e buggy seems to be holding it's own at a lot of tracks and most larger races anyway and they don't need to run with nitro just to have a class to run in. I'm sure that is not the case at all clubs though, but why do the nitro's need to run longer than 15-20 minutes at a smaller club race? The fast guy will still be the fast guy at 15 minutes. I know that pitting is part of the nitro racing strategy and part of the fun I suppose, but if your club can't support two separate classes, then make concessions. Or the electric guys can just deal with the fact that their pit will take longer. If you are using velcro to put your body on with and straps for the battery/s a swap can be done fairly quickly although not as fast as a refuel.
I do think quick change is possible from underneath. The DF-03 chassis idea would make this possible. You would just need a battery with exposed tabs that mate into tabs installed in the battery compartment. Pull a pin, drop a bat, throw a new one in, and install the pin and go.
I personally like the duration of 1/10 races. Same fun, but more heats can be run in much less time! I don't need to live at the track for 24 hours just to run qualifiers. But some folks love to spend all day at the track. To each his own!
#23
Tech Elite
iTrader: (19)
If there were a standard battery tray size, you could have some type of cartridge that clicks in the tray with exposed tabs. In fact, if battery trays were standardized, a mfg could sell a "shell" that would allow you to use most lipo packs and instead soldering a deans plug, you maybe solder to the "tab" in the cartridge.
The other advantage would be that it would eliminate the need for "Roar Approved" hardcase batteries. ROAR could approve the shell and then you wouldn't need individual lipo packs to be approved or at a minimum would allow for people to buy cheaper soft case packs.
This could work pretty well especially if you assume you don't need to run longer than 10 minutes per charge. This way you can use smaller batteries. In a way, you would almost have pit stops like nitro except it would maybe take 10 seconds instead of 3 or 4 like a nitro.
The durability issue is the only thing that concerns me. It is one thing to have trap doors in on road versus off road 1/8 where cars are casing 40 foot doubles at 40mph...
One race I went to had a 30 minute main for electric 1/8. The race director stopped the race at 15 minutes (you stopped whereever you were on the track) and then the pit men ran out on the track swapped packs and then teh race was restarted. It actually worked pretty well but a little different fromt eh pit stop strategy that nitros have.
The other advantage would be that it would eliminate the need for "Roar Approved" hardcase batteries. ROAR could approve the shell and then you wouldn't need individual lipo packs to be approved or at a minimum would allow for people to buy cheaper soft case packs.
This could work pretty well especially if you assume you don't need to run longer than 10 minutes per charge. This way you can use smaller batteries. In a way, you would almost have pit stops like nitro except it would maybe take 10 seconds instead of 3 or 4 like a nitro.
The durability issue is the only thing that concerns me. It is one thing to have trap doors in on road versus off road 1/8 where cars are casing 40 foot doubles at 40mph...
One race I went to had a 30 minute main for electric 1/8. The race director stopped the race at 15 minutes (you stopped whereever you were on the track) and then the pit men ran out on the track swapped packs and then teh race was restarted. It actually worked pretty well but a little different fromt eh pit stop strategy that nitros have.