Electric motor and battery

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murphkart

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Hey everybody,

I've been reading this forum and it's awesome. A lot of smart people who are happy to share info and I'm into it. I'm working on a related project at the moment, which is dropping an electric 10hp motor into a gas outboard engine for a boat. It's probably going to be a Manta II motor (48v) and my hope is to power it with lightweight batteries. I'm considering building a large lithium ion battery and didn't know if anyone has done this before either for a kart or for an outboard conversion, but wanted to throw this out there and see if there were any tips/suggestions so I can avoid some of the inevitable stumbling blocks I'm sure I'll encounter. That's what I got!
 
itsid

itsid

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I hope it's NOT going to be a Manta motor (I HATE that crap!)
buy the Motenergy ME0709 instead!
basically the motors are almost identical (the manta uses the motenergy case and armature anyways, they just rip out temperature sensors and relabel the motor with absurd values and claims)

Also, no LiPo cells, certainly no homemade LiPo pack!
the reason is simple, the current you'll be drawing is heating up the cell significantly,
unbalanced cells during weldment, a forgotten or misplaced temp fuse, or even a weak connection at one point WILL result in a runaway cell (when Lithium cells burn, all you can do is run as far away as possible.. or swim in your case.... no way of putting the fire out, not enough time to do anything but running)

A bought pack maybe, but not from china, needs to be a quality brand and new not used..
so we talk about 700++ for something like 20Ah or so...
(wich is a third of the weight of lead acid and 20 times the price)

So no.. I'm afraid, I'm not exacly big of a fan of anything you said you'd like to do here ;)

water isn't a problem, the motors don't mind if you put a prop on instead of a wheel

'sid
 
anickode

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10 hp, even at 48V is some major power drain. I'm talking in the 200 amp range at full power. That would be like 6 minutes of runtime on a 20ah battery, IF you didn't destroy the battery by draining it too fast. This thing ain't gonna run on A battery pack in the sense you think it will.

If you could find a 200ah battery, that would start getting you into a useable capacity range. Batteries have 3 variables:

Big power
Light weight
Cheap

Pick two.

4 full size (group 31 or bigger) marine dual duty (starting and deep cycle) batteries would be sufficient to power that for just an hour at full power.

Let me guess... Stealth duck boat? Or something less legal...?
 
Functional Artist

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anickode

anickode

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Functional Artist said:
I have the same motor on my electric motorcycle El Moto.

https://www.youtube.com/watch?v=NdwRuXyiqms

Running @ 36V I get ~30 min run time off of (3) 12V 35AH SLA batteries

I am moving it up to 48V before long

How long do you think one of these 48V 47AH Chevy Volt Battery packs would last?

...in his or my situation?

http://www.ebay.com/itm/2012-Chevy-...d=222552892596&_trksid=p2047675.c100005.m1851
Click to expand...

Well, boats tend to be run at sustained full throttle more than motorcycles, so getting 30 minutes of use out of 35ah may not be realistic for him. You probably also wouldn't get that kind of life if you just ran It Wide Open from a dead stop, topped it out, and kept going that fast indefinitely.

I would be cautious using the Chevy volt battery. Battery modules like that are one of many installed inside an enclosure inside the structure of a vehicle designed to afford at a certain level of physical protection. Even building an enclosure for it on a motorcycle won't protect it the way it would be installed in a Chevy Volt.

The battery module itself probably does not have internal regulation on it either, as it is one module out of many in an assembly in the vehicle, so charging systems and over drain protection what all have to be factored in with the controller and charger.

For what that thing costs, I would probably steer clear of it, simply for the amount of additional work it's going to take to make it usable and safe, especially to have it between your legs.
 
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