RC-Monster Forums - View Single Post - Doing a Brushless Conversion. Advice Please.

spiftacu1ar · 02.15.2009, 04:18 AM

Ok, so I finally finished building my truck, I plugged in my lipos (not fully charged, the cells are at 3.7v each, so at storage charge, not dead either) The first thing I noticed was a large spark as I plugged in the batts. The car still ran, but I am not sure that it is normal. I am using deans ultra connectors, and have the batteries wired in series via a "Y" shaped adaptor I made using 3 deans and 3 wires. (mamba + to battery 1 +, batt 1 - to batt 2 +, batt 2 - to mamba -) All works well when plugged in, as I can drive the car (only went in a small circle in my room to make sure everything works). THe spark was pretty big though, and it kinda scared me, so I wanted to make sure that the spark is normal. Is there something I can do to prevent it?

Also, i noticed that running the vehicle produced a very high pitched noise under acceleration. Also wanted to verify that this is normal.

Lastly, I have a question about mounting lipo's. Is it better to keep them snug and surrounded by only aluminum, or is it better to leave some space around it with foam. I currently have the lipos surrounded with aluminum, with foam in front and behind. The sides are directly up against aluminum. I thought this would help with cooling. I don't know if its the "safe" thing to do with lipos, as I have never used them before, and for me, as a weekend basher, safety comes first

To define snug for those bateries, this is how I have it set up. I have one L bracket on the left side of the batteries. With this in place, there is a little bit of movement with the batts. I then put a 1/32" alum sheet metal on the right side of the batts, which is a slight squeeze to get in. Basically, there is no movement side to side. There is another wall I put in front of the batts, which leaves about an 1/8" of space. I filled this by squeezing a bunch of foam in fornt and behind the batteries. I also bent the 1/32" sheet (to the right of the batts) so that it would also cover the top of the batts. I put a thick piece of foam above the batts, and below this sheet. When I tighten down the velcro straps, the foam is reduced to 1/8" thick, and the batts pretty much don't move in any direction. I will posts pics later, I don't have my camera with me right now.

My basic question is: Should I increase the space to the left of the batts and stuff some foam in there? Or should I leave it as is, which will allow the slum to keep the batts cool.

	(#14)
spiftacu1ar RC-Monster Carbon Fiber Offline Posts: 62 Join Date: Nov 2008	02.15.2009, 04:18 AM Ok, so I finally finished building my truck, I plugged in my lipos (not fully charged, the cells are at 3.7v each, so at storage charge, not dead either) The first thing I noticed was a large spark as I plugged in the batts. The car still ran, but I am not sure that it is normal. I am using deans ultra connectors, and have the batteries wired in series via a "Y" shaped adaptor I made using 3 deans and 3 wires. (mamba + to battery 1 +, batt 1 - to batt 2 +, batt 2 - to mamba -) All works well when plugged in, as I can drive the car (only went in a small circle in my room to make sure everything works). THe spark was pretty big though, and it kinda scared me, so I wanted to make sure that the spark is normal. Is there something I can do to prevent it? Also, i noticed that running the vehicle produced a very high pitched noise under acceleration. Also wanted to verify that this is normal. Lastly, I have a question about mounting lipo's. Is it better to keep them snug and surrounded by only aluminum, or is it better to leave some space around it with foam. I currently have the lipos surrounded with aluminum, with foam in front and behind. The sides are directly up against aluminum. I thought this would help with cooling. I don't know if its the "safe" thing to do with lipos, as I have never used them before, and for me, as a weekend basher, safety comes first To define snug for those bateries, this is how I have it set up. I have one L bracket on the left side of the batteries. With this in place, there is a little bit of movement with the batts. I then put a 1/32" alum sheet metal on the right side of the batts, which is a slight squeeze to get in. Basically, there is no movement side to side. There is another wall I put in front of the batts, which leaves about an 1/8" of space. I filled this by squeezing a bunch of foam in fornt and behind the batteries. I also bent the 1/32" sheet (to the right of the batts) so that it would also cover the top of the batts. I put a thick piece of foam above the batts, and below this sheet. When I tighten down the velcro straps, the foam is reduced to 1/8" thick, and the batts pretty much don't move in any direction. I will posts pics later, I don't have my camera with me right now. My basic question is: Should I increase the space to the left of the batts and stuff some foam in there? Or should I leave it as is, which will allow the slum to keep the batts cool.