***__ The 1/8 Onroad Think-tank __***

[myndseye]

What parts of the car did you use to determine to boundaries of your available space for the battery? When I did my Serpent 835, I made a custom top plate using the original one as a pattern, and placed a cutout in the center area where the gas tank was to let the battery come through. I then stacked A123 cells in a 3s2p configuration (three on bottom and three glued on top like a brick). When you break down the Dewalt packs to get the cells, the paper cylinder outers on them are very good for gluing using basic wood glue. I would guess that with the extra length of the 8th, you could probably go 4s2p.

Originally Posted by myndseye

What parts of the car did you use to determine to boundaries of your available space for the battery? When I did my Serpent 835, I made a custom top plate using the original one as a pattern, and placed a cutout in the center area where the gas tank was to let the battery come through. I then stacked A123 cells in a 3s2p configuration (three on bottom and three glued on top like a brick). When you break down the Dewalt packs to get the cells, the paper cylinder outers on them are very good for gluing using basic wood glue. I would guess that with the extra length of the 8th, you could probably go 4s2p.

I was using the available space under the top plate, extending out toward the body. Do you have a photo of your 835 with the cells in it?

I just want to reiterate that I need to be able to RACE continuously for 15 mins (10 mins. minimum) I'm not interested in just doing speed runs.

I have also found out that a high performance nitro engine out of a 1/8 can produce nearly 3HP. Is 2237.0996 Watts out of the question? Of course this would not be continuous.

[myndseye]

I had considered that when making my suggestion of the A123s. The first thing you need to address would be the power output match of a typical 8th in the small space that you are afforded for your conversion. I was looking around at the various batteries currently out, with your dimensions in mind, and nothing to meet your needs exists. The only hope you have would seem to be something you can quick change, akin to a fuel stop for a typical 8th. I don't really have accurate figures to go from, but it would seem that battery sizes (physically), are about 1 to 1 in runtime with the size of a gas tank when power output is that high. A typical 8th doesn't run that long without needing to be refilled, but I'd bet that if the tank was as large as a 6s high capacity battery, it could run that long.

[myndseye]

I have since changed the car over to 5s1p, but you can imagine what I was talking about. Sorry about the cell phone pics.

Originally Posted by myndseye

I had considered that when making my suggestion of the A123s. The first thing you need to address would be the power output match of a typical 8th in the small space that you are afforded for your conversion. I was looking around at the various batteries currently out, with your dimensions in mind, and nothing to meet your needs exists. The only hope you have would seem to be something you can quick change, akin to a fuel stop for a typical 8th. I don't really have accurate figures to go from, but it would seem that battery sizes (physically), are about 1 to 1 in runtime with the size of a gas tank when power output is that high. A typical 8th doesn't run that long without needing to be refilled, but I'd bet that if the tank was as large as a 6s high capacity battery, it could run that long.

Sorry myndseye, I made an error in my measurement of available battery space. It should of read like this.

H 27 mm
W 100 mm
L 160 mm

This is the available space under the radio tray. I still haven't decided where to locate the batteries. I'm also thinking if I use 3 seperate 2s1p 5000 mAh packs to get my 6s I can also use these packs individually for racing my 1/10 on-road. Mounting 3 seperate packs on the car wont be fun but at-least I will still be able to use the packs after the nitro 1/8 drivers ban me from racing, because I'm overtaking them down the straights.

Originally Posted by Countryhick

Sorry myndseye, I made an error in my measurement of available battery space. It should of read like this.

H 27 mm
W 100 mm
L 160 mm

This is the available space under the radio tray. I still haven't decided where to locate the batteries. I'm also thinking if I use 3 seperate 2s1p 5000 mAh packs to get my 6s I can also use these packs individually for racing my 1/10 on-road. Mounting 3 seperate packs on the car wont be fun but at-least I will still be able to use the packs after the nitro 1/8 drivers ban me from racing, because I'm overtaking them down the straights.

Uhm, why don't you use 2 3s1p maxamps 5Ah lipos?
http://www.maxamps.com/Lipo-5000-111-Pack.htm
They are 45mm X 138mm X 26mm so no need for 3 separate packs, only two...

Bye

I race 1/10 electric on-road usually and the 2s packs are the only ones I can use under the current rules. So if I use 3 x 2s packs I can use them in my 1/10 and 1/8 (just better bang for my buck). Looks like I'm going to run these. http://www.trakpower.com/

I now have a good idea of the hardware I need. Now I need to look at chargers and balancers. I have one of these already (only good for 4s I believe) http://www.robitronic.eu/elements/ap...erloader_e.pdf
1. What is going to be my best option for charging 3 separate "Trakpower" 2s packs at the same time?

2. I would like to get a balancer at the same time.

Recommendations please

Cheers Andrew

[ziggy12345]

Originally Posted by Countryhick

I was using the available space under the top plate, extending out toward the body. Do you have a photo of your 835 with the cells in it?

I just want to reiterate that I need to be able to RACE continuously for 15 mins (10 mins. minimum) I'm not interested in just doing speed runs.

I have also found out that a high performance nitro engine out of a 1/8 can produce nearly 3HP. Is 2237.0996 Watts out of the question? Of course this would not be continuous.

A .21 circuit engine produces around 1.8 HP regardless of what it says on the box and thats at a very limited rev range. The torque f the motor is almost non existant. It would be comparable to a 1hp electric motor.

Cheers