I have an old 24V CityBug scooter that I have added another 12v 12A battery to. The controller can handle it and the scooter flies. Now the question. I have another battery. If I took the two extra batteries and wired them in parallel and then added them to the existing batteries, I would have 36v with more amperage. Would this just give more range. I just ride a mile or so to work so extra mileage is not really necessary.

First off if the scooter was a 12v system you are lucky it hasn't burned out running 24v. This is an ify thing. If the motor/controller handle if fine but I wouldn't recommend going to 36v.

If you are truely paralleling the batteries (+ to + and - to -) this is a parellel conection and it does not increase the voltage. It increases the available amp hours which will reduce the voltage sag making the scooter run faster especially on take off. So you can add 10 batteries if you want it has no effect on the controller or the motor other then as I explained. However, if you actually wired the batteries in series (+ to -) then you increased the voltage from 12v to 24v but the available AHs is = to the smallest battery.

[QUOTE=go4it;168134]First off if the scooter was a 12v system you are lucky it hasn't burned out running 24v. This is an ify thing. If the motor/controller handle if fine but I wouldn't recommend going to 36v.
QUOTE]

Thanks for the explanation. You may have misread what I wrote in that the scooter was 24 volts...not 12 volts. It came with 2 12v 12AH batteries. I was just adding another 12 volts with an additional battery. With the extra battery the motor does heat up more a bit, but I am only going a short distance. At wide open throttle though, it does let out a serious moaning whine!

[QUOTE=beachwalker556;168146]Yes I think I must have missed read your post...Da! I'm old so live with it..LOL just kidding (but I am old).

As you have likely read a lot of people over volt their motors/controllers. The problem is while the motor is producing more power it's also producing more speed (RPMs) to accomplish it. Keep in mind that motor/controller may not be cheap if you need to replace it.

To answer your original question yes if you have 2 additional batteries and you wire those batteries in parellel and connet them to the original 2 batteries again in parrellel you will still have 24v. However, if you series connet the new batteires to the original then you would have 36v. Remember we are saying the 2 new bateries are first connected in parrellel then you conect those in series to the original batteries to acheave 36v. Be careful you don't connect all 4 batteries in series or you will have 48v. OPPs!

So I added the extra 4th battery wired in paralled with the 3rd....and I definitely got a surge in acceleration and a little extra speed on the top end. I want to have my wife clock my top speed with her car.

So bottom line if I remember correctly your now running 36v on your 24v scooter. Correct? The addition should have reduced the battery sag on the "solo" battery giving you more torque and of course the added speed. The problem wit hlead is always the voltage sag and weight of course.

Exactly right!