I have a Schwinn S750 with 2 12 volt 15 amp batteries. The batteries won't take a charge anymore, so I'm looking to get 2 new 12 V 15 amp batteries, but adding 2 12 Volt 18-26 amp batteries in parallel, of course. Will I have to replace my controler because of the added amps? The 2 12 volt 15 amp batteries alone make the scooter practically useless for any practical purpose. I help the grand kids on their paper routes, and the 2 15 amp batteries did not last long.
I figure I'd be spending about $200 for batteries. Plus the charger than came with the scooter lasted about 6-8 months. Junk! So I would have to buy a new charger. Maybe I should just buy a Dirt Dog gas scooter for $350.
Sounds like you are planning on buying four new batteries? Is there any reason you would not want all four to be the same size (AmpHour capacity)? It's generally not a good idea to mix Ah's within a pack. The smaller ones get drained to a deeper depth of discharge sooner than the larger ones. This will shorten the life of the smaller batteries. It will also cause problems if you continue to recharge all four together with a 24V "series" charger.
You could buy four all the same size and wire them into a series/parallel pack, OR two separate 24V packs and run on one till it gets too weak, then switch to the other to get back home. Separate packs would NOT need to be the same Ah, but WOULD need to be recharged individually.
Your controller will not be affected. Larger Ah batteries will NOT force more amps thru your controller.
Have you ever considered charging in parallel from one 12V automotive charger? You'll be doing some rewiring anyway if you add batteries, so now might be a good time to convert to parallel charging and get rid of the string chargers.
Hope this helps.
BTW, I don't think you are allowed to mention "gas scooter" on an electric vehicle forum. (just kidding)
You've given me two pieces of valuable information. If I buy the batteries, I will get all four the same size. I won't mix the amps. I hadn't considered what the larger batteries might do to the smaller ones. I have already started charging the two batteries separetly with an automotive float charger. I made a charger out of a telepone transformer - 13.5 volts 350 milliwatts - and used that to keep the batteries peaked in my 40 degree garage this winter.
I mounted a milk crate over the rear wheel that has an interior of 12" x 12". I don't know. Maybe I could get by with 4 - 15 amp batteries, but it seems that I need at least 4 times what a manufacturer promises. Helping the kids deliver papers is a lot of stoping and going and in and out of driveways. One mile of paper route is probablly 6-10 miles of straight travel.
Sorry about the gas scooter transgression, but I need something that WORKS. I am very sensitive to the environment, but I am on a fixed income, and expense is crucial in every decision that I make. That is why I bought an Echo in 2002 rather than a Prius. It seems that one must be wealthy to save money.
I bought a Honda Helix and had training wheels put on it to do deliveries with this summer. I'll be using about 2/3's less gas there. I'm trying! We started back in the early 70's. I rode a Honda 90 to classes, and we had a 66 VW Beetle. I've kept a smaller bike of some kind since(nothing bigger than 400 cc) and economical vehicles. It just seems to me that the electric just isn't very practical and economical yet. I DO love the relative silence and peace of the electric scoot. LOL! I had a yellow jacket chasing me last summer. Wife said I sound like a bee coming down the street. People smile when they see an old fart buzzing around on electric.
Who sells the best batteries for the least money?