Has anyone built a bob-style push trailer to boost range and add some top end speed for a scooter? I'm planning on building one using a scooter hub-motor at 72V ($250 hub+tire, $250 controller, $260 Batteries + $ metal / $800 total). I'll put some pneumatic dampers at the hinge point to reduce sway and jacknifing.
I'll probably only use both motors for hills and maybe for a "turbo" feature.
Im going to fabricate the frame from 3/4" thin-walled steel with an aluminum battery box
Questions:
1. Anything to be aware of, common problems?
2. Will having the trailer batteries run in parallel with the scooters cause any problems (the scooter is also at 72V). I'm bank charging the batteries at the moment but I'm planning to switch to the string charge + 2A soleil finish charge method. This would allow me to mount the 72V charger in the bike frame and just plug into any socket to charge (both the bike and trailer).
3. Any other advice?
Thanks
Andrew
One comment; using bank charging is a great idea but using a string charger to end the charge process is backwards. You should end the charge with the bank charging method. Using the string charger is what causes the battery pack to unbalance. To finish the charge in this fashion is counterproductive.
First you bank charge to balance the pack then you us a string charge and unbalance the pack.
No No No
First you string charge with a high current charger to get the batteries near 80 to 90% of charge, use a timer. Then use bank charging to balance the pack and finish the charge process. This is the better way to do it. You can still use the on board string charger to get those opportune charges when you are away from your bank charger, just don't try to get a full charge so you don't unbalance the batteries.
Grandpa Chas S.
Hmmm...obviously wasn't very clear in my posting!
I'm planning on doing the charging method you mentioned - string charging with a ~11.5V cutoff 72V charger, then finish charging with banked 2A Soneil chargers.
Not to get off topic (and I know this forum is obsessed with charging and battery balancing), but has anyone done the push-trailer idea with a scooter?
Thanks
Andrew
OK One more comment;
Yes the pusher trailer has been done by several people and it works very well. The biggest problem is a good solid connection between the bike and the trailer. I remember reading about an experience from one person who told of an accident caused by the pusher on wet streets when trying to accelerate around a corner, not a pretty site...
I was thinking about building one also, I can see advantages to having a setup like this. It would be easy to just add a throttle to any bike and connect the powered trailer. A great way to allow you to change bikes and still have the power boost. It would also allow you to remove the trailer and ride the bike without power and all the extra weight.
Grandpa Chas S.
I was thinking of doing the same thing, or maybe a sidecar with batteries, controller and a hub motor.
Philip
Philip
2011 Nissan Leaf SL
I think the pneumatic dampers should help a lot with any cornering issues.
There is plenty of metal around the rear wheel mount to weld / bolt the trailer support. I don't think the trailer would be a good idea without a solid support to the bike. Mounting to the swingarm as close to the rear wheel as possible will minimize any vertical movement of the trailer.
Philips sidecar idea is interesting, but it would effect handling and leaning into corners.
On a completely different topic, anyone tried the Motorino 2-speed motors? Is this a double winded motor or a controller PWM setting change?
Thanks
Andrew