Figuring out what batteries I will need for a new purchase

[aXis]

I did the math and you can easily use $25 car motors from hobbyking

Pretty typical ratings is 3 cells LiPo (11.1V), max 20 - 25Amps. If you do the math that's around 220 to 270W max power. Strap on four of those bad boys and you could have up to a 1kW skateboard - even taking into account transmission efficiency you're over 1 horsepower.

[Phido]

Im actually working on making my own electric scooter, board thing.

I got some 200w scooter motors for ~$20. I figured 2 x 200w = 400w would be fine for a scooter or skateboard given you usually give them a bit of a flick with the foot to get them started. That 400w is to just keeping you going.

http://www.oatleyelectronics.com/

was going to use SLA batteries. Jaycar has a wide assortment of odd shaped 6v and 12 v SLA batteries (some 30mm thin!). Given how heavy a person is the difference between Li and SLA is not going to be much.

Im over 120kg and over 6'6 so using a kids scooter scares me. I can build something to take my weight and also have some cooler features, integrated lighting (indicators, brakes, headlights, maybe a pic controller estimating range, speed etc).

Unfortunately I haven't had much time to work on it. I've got the parts sitting in a box.

[Renza]

Originally Posted by Phido

I got some 200w scooter motors for ~$20. I figured 2 x 200w = 400w would be fine for a scooter or skateboard given you usually give them a bit of a flick with the foot to get them started. That 400w is to just keeping you going.

You might want to note that an electric assisted bicycle must have a motor under 200w to be road legal in Australia. I assume that the same would apply for scooters

[Phido]

This is not for on road use. Just getting around big private sites etc.
One of the main reasons for double rear wheel is to increase load carrying capacity. I could in theory never hook up the other motor so it would remain under 200w.

The problem is most cops don't know how to rate an electric motor, basically what ever the motor claims it to be.

Generally people don't really care about electric bikes. They are quiet, people don't hoon around on them all day and they are generally used by much older people.

2 stroke conversions in the suburbs will get you pulled up. Esp if you take the same route every day and floor it everywhere early in the morning.

[OPM881]

Massive bump time!
Ok, used 2x 12V 9AH batteries, and it seemed to work fine, however I have come to an issue where for some reason the batteries were not charging. Went and got a stand alone 12V SLA battery charger and it says they are charged as well. I have taken the motor off its frame, the whole thing is still hooked up however, and I am currently in the process of running the batteries down some.

Ok, so, after I ran the motor for roughly 1-2 mins, the batteries did state that they were not charged fully and so I hooked them up to the stand alone charger, and it charged them in a matter of mins. I have hooked the whole skateboard system back up and am now running the motor. It really isnt running as fast as it should be(I am basing this off the sound it is making, not the same as it used to), even though both batteries are supposedly full. This begs the question, could the controller board be stuffed? The brains of the whole unit?

[Chamelion]

What charger are you using? You'll kill them fairly quickly if you're charging them too fast.. ie: 9ah battery, you'll want not much more than a 1amp charger. If you're using a 15amp charger to fast charge a 9a battery... Well, recipe for problems.

I figured that out after I killed a 3.4ah SLA battery after charging it at 10amps a few times. Switched it out with a 18ah SLA (running my fish finder on my boat) that I charge using the 2amp setting on my 5 stage charger.

EDIT: Type of charger can have a bearing too... Cheap linear chargers vs multi stage smart chargers. The latter are worth the extra outlay.

[OPM881]

Originally Posted by Chamelion

What charger are you using? You'll kill them fairly quickly if you're charging them too fast.. ie: 9ah battery, you'll want not much more than a 1amp charger. If you're using a 15amp charger to fast charge a 9a battery... Well, recipe for problems.

I figured that out after I killed a 3.4ah SLA battery after charging it at 10amps a few times. Switched it out with a 18ah SLA (running my fish finder on my boat) that I charge using the 2amp setting on my 5 stage charger.

EDIT: Type of charger can have a bearing too... Cheap linear chargers vs multi stage smart chargers. The latter are worth the extra outlay.

The charger is just the charger that came with the board and plugs into the side to charge both batteries at once. This is a photo of the bottom of it:
http://www.imgur.com/c3A78

The charger that I picked up from jaycar for charging the batteries individually is this:
http://www.jaycar.com.au/productView.asp?ID=MB3526

Neither charge at more than 1amp, but both go to trickle charge pretty quickly. Is there any other way I can check to see if the batteries are just stuffed besides going and grabbing some new batteries and chucking them in the board? In saying that, I dont know how the batteries could be stuffed. The only thing that I could think of, and I dont know how it would stuff them, is that the board was sitting in the boot of my car on its deck and was rocking when I was driving around with it, but I didn't think that would stuff them.

Also, I have pictures of the control board and the batteries as well if anyone needs them.