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locking battery in...

2K views 9 replies 5 participants last post by  propfella 
#1 ·
G'day all first post on this site and just from a short look around here is alot of great stuff on here..

im in abit of a bother. after having nitro cars i brought a brushless boat twin hull off ebay just a cheapie just to get familiar with it. it just had double side velcro stuck to the hull (middle) and other bit you stick to the battery running port and starboard. after 5 min i flip the boat and the velcro on the hull let go. so what is my other options on a more permant fix. and also would i be better off running the batter fore and aft. it is abit of a tight access for the battery....

battery is a 5000mah 35c-45c turnigy

cheers rob
 
#3 ·
3mm x 30mm X (the length of your batteries) marine ply strips with 3mm marine ply stand off's glassed onto the bottom of the hull. Leave a 20mm long gap between the stand off's, 20mm in at both ends for the velcro straps to slide under.
 
#5 ·
Depends what achieves the right COG for the boat to run well, bow/stern will keep the weight down lower in the hull which is better but it doesn't always work out that way.
If it flipped from a standing start you probably have too much weight aft. Either that or some awsome power in there.
 
#6 ·
lol it flys!!! 2048 kv 5000rpm motor. it sit rear end heavy just cruising around but when it launches it levels out... i might try some velcro tape again and try port/star and fore/aft see how it goes before i start boxing something up.i havent really turned to fast yeah didnt want to roll it lol. to get the battery in i have to slip i down one side of the hull and slide it around... battery prob abit to big...

i think my nitro truggy is easy to deal with.. :)
 
#7 ·
Good call! Get the trim right, then do something permanent. I'm working on getting my 30" .21 nitro hydro going but it has been put on the back burner, as I'm building a truck for someone at the moment.
 
#8 ·
You need to get yourself a piece of rod or dowel and set your hull up on a flat surface, find where it balances measure that and find the % of the hull length, try around 32% and work from there maybe? Any other takers of a start COG??
My old 41' gas mono was perfectly balanced and would always land flat off of any waves but I still flipped it when launched at too high rpm!LOL
 
#9 ·
You said it's a twin hull, is it a cat, tunnel or hydro? Either way it should turn really easy without rolling. If it's a tunnel or cat, you should be able to give it flat stick and turn full tilt and not roll it over.

Damn Ozpulse, I should have thought of you earlier. I recieved $200 for the truck build i'm working on and should have bought that engine off you. Bugger! Already spent.
 
#10 ·
Hi,

The reason you're rolling could be the fact that you're running with the battery port and starboard, (LEFT TO RIGHT) Due to that battery being so heavy and long it's actually raising your center of gravity vertically, not horizontally. For a boat the best CG is as low as you can go. That's the reason a Yacht will have a ton of lead in it's keel. It puts it's CG below the waterline and makes it very hard to turn turtle.

Keep your battery as low as you possibly can to get that CG lower. If that's a bit awkward consider splitting your power source by using two batteries as far apart and as low as you can go. If you are running a 4s then use the same , or more Mah, 2s batteries and use a Y harness. This gives exactly the same power to the motor but it comes in smaller packages. You sound smart enough to figure out how to run two batteries into one ESC.

As for the Velcro. You don't know how long it's been in there, I'd recommend you pull it out and use a higher quality type. Some cheap velcro isn't much better than sticky tape. A quick tip for Velcro users..... Always stick the spiky velcro inside the boat or plane and the furry velcro on the item being removed. Do the opposite and before long you'll find the spiky velcro picks up all sorts of fluff, cotton and junk plus gets flattened spikes if it's placed spikes down. This greatly diminishes it's ability to stick. Finally I've seen boat batteries suspended upside down by velcro. It worked well but the owner couldn't figure out why his boat did the same as yours. :)
 
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