Battery Recomendation

[captainkirk]

I just bought a Blast as was wondering what battery would be best to run with. From what I can tell it requires a 6 cell battery.

I was also thinking of making a custom battery pack for the boat out of AA NiMh. I think I can get 2 packs in almost the same size that a normal pack would take. I would then hook them up in parralel resulting in a 3100 mah battery pack. To keep them from burning each other up I will also have to connect them using lo loss shoky diodes.

Any one out there ever made there own batteries or have any good ideas??

I also thought about adding a solar cell to the top of the boat as the backup to bring it back in. I will let everyone know how that turns out. It will take some testing and finding some cells surplus because new ones are way too expensive.

Kirk

[pooycow]

sounds like a good idea! aspecially the solar cell!

[alcodesign]

sounds great! and solar cells have great potential. (except when it's not sunny )

[CChase86]

I like the AA idea, and yes, I have built my own cells. How would you ve doing this though? To wire a battery pack the cells are wired in series...

And about the solar cell - it wouldn't work because a solar panel that small couldn't produca anywhere near enough voltage to move the boat.

[captainkirk]

CChase86

What I plan to do is make 2 battery packs of 6 cells each. Each individual battery pack would be in series and then the two packs would be wired in parallel. By using 1550 mah AA batteries the two packs together would make a 3100 mah battery (give or take a little). The best part is that both packs would cost less than $25.00 which is considerably cheaper than what I have found out there for a 3000 mha NiMh battery.

On the solar cell issue. They do make some very high efficient solar cells that can probably do it but they can be expensive. I was just thinking of seeing if I could find a cell that would turn the motor enough to slowly move it through the water and back to shore. Anyway it is just an idea and a friend of mine has some of these solar cells that I am going to test with just to see if it works.

Kirk

[pooycow]

it might be better if you make an 8 cell pack of 3000mah cells, so you can fast charge them etc, with normal AA size batteries fast charging them deteriates them quite quickly!

[CChase86]

I get it now pooycow -- sounds like a good plan to me; I might even try it out in the near future on my Villain, then I can get 6200 mah

[RC Rick]

Get a peak charger, and a couple 3000mahs!

- Rick -

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¡Compito radio coches controlados!

[captainkirk]

Pooycow,

Just how much voltage can a motor with a 5.4 v wetted magnet take. The motor I have is a SpeedGem Saphire. AN 8 cell battery would result in a 12 v supply to the motor. I would think it would run really hot but I have never tried it. I am also not sure what the speed controller of the blast will take. They recomend using a 6 cell battery. Obviously you know more about this than I do so your help is appreciated. I just happen to have alot of these AA NiMh because I use them in other things and from what I have found they are considerably ceaper than the high capacity sub-c's. Yes I know they do not like to be fast charged but I have other (lower mah batteries that are NiCad's that can be. Besides in most cases I will just be going to the pond in my neighbor hood and running the boat untill I run out of batteries and then head home untill I go again with charged batteries. In the future if I ever find a few people who would like to start a boat club and race than having a 3000 mah fast chargable battery might be worth it.

Kirk

[This message has been edited by captainkirk (edited 03-28-2001).]

[pooycow]

i really have no idea, you will have to try it!

[CChase86]

Kirk,
I realize this wasn't directed to me, but I think I can answer a few of your questions. First of all, I would not recommend using the Speed Gems with 12 volts. The brushes and commutator would wear wuickly and there would be too much heat. This could result in an endbell meltdown, which can happen even in modets 7 cell applications.
As for the ESC that comes with the Blast; using more than 7 cells is not recommended as the speed control really can't handle that much voltage, especially combined with the power draw of the Speed Gems.

Hope this helps,
Curtis

[captainkirk]

Curtis,

That is exactly what I figured would happen if I ran that kind of voltage.

What would you recomend for my set up. A 6 cell battery or a 7 cell battery. I do have water cooling on the motor. I havent got the boat yet but will get it soon and be ready to take it out for a spin. Currently I have a 6 cell 1300 mah battery but plan on buying or building a better one. I am not shure what the space available is in the boat for batteries but if there is enough room I found some d cell NiMh batteries that are 7200 mah.

Thanks for the help

Kirk

[Hartleywindmill]

Are you guys just buying normal rechargeable cells and making pack out of them? I had considered it once, but figured there would be charging problems. Could you charge six generic "C" Ni-cd's in a home-made pack with a standard timer charger?

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Go Baby Go!

[CChase86]

You could do whatever you wanted to, but it will be cheaper and you will reap more performance from the performance oriented sub-C battery cells.