Solar charging of electric bike

ok now that the electric bike is functioning with feedback on speed and battery status what's next?
Walmart had these solar chargers on sale
https://www.walmart.com/ip/Rayovac-High-Performance-6V-Solar-Battery-Charger/37424618

for $10!!!

We got two of them because only two were available :(
Now two of these in series can charge the 12V batteries...

May have to put in some safeties so that we dont fry the batteries (the bike is 24V with two 12V in series and would have to charge them in parallel)

Electric Bike enhancements

The first thing Rithvik wanted was to know was how fast he was going!! what is it with boys and speed and fast cars and trucks? Adwait suggested we add a battery status as he was thinking how far can I go and return without the battery running out. Recall the battery was sized for 30 min but we dont keep track of long it was run before fully charged.

1. Speed: A simple hall effect sensor on the spokes and a magnetic pick up to time between pulses and with diameter of the cycle known we know the speed. Thankfully someone has already built this device with additional info such as time, distance.
https://www.amazon.com/gp/product/B0792YQ65C/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

2. Battery status: From almost 20 years ago battery modelled as a huge capacitor and internal resistance and SoC (State of Charge) can be determined from voltage and current.  A lot of info can be estimated purely from battery voltage and such a device exists for 24V.
https://www.amazon.com/gp/product/B01E0SDTBO/ref=od_aui_detailpages00?ie=UTF8&psc=1

Now we know how fast we are going and how much energy we have left Yay.

The electric Bike

All this started 15 years ago when I first saw the prius. I believed that electric vehicles were going to be the future (aka jetsons). I had bought a 4 wheel drive truck which I wanted to convert to a electric drive vehicle with the option of using gas. Unfortunately it needed a timing belt change which would have cost more than what I paid for the truck. After Changing the timing belt the truck ran for a month and had to be sent to the cemetery. (BTW toyota makes vehicles that run forever truck had almost 200k miles). Rithvik had been talking about how we have spoiled the earth and need to have clean mode of transport which triggered the old  idea and we bought a kit from amazon.

https://www.amazon.com/electric-Bicycle-Conversion-HOMEMADE-Modified/dp/B01DBK1UJ0/ref=sr_1_6?ie=UTF8&qid=1529903616&sr=8-6&keywords=250w+electric+bike+kit&dpID=51kAPLOcbUL&preST=_SX300_QL70_&dpSrc=srch

Now I did not realize that it did not come with a battery and it was meant for a bike with a rear axle which would accomodate a sprocket on the other side to allow for pedaling and electric drive.

Being the cheapskate (cost efficient) I figured it can be modified to accomplish the electric bike.

Rithvik had the awesome idea to hold the batteries in a basket on the handle. We found a office CD box in walmart that would do the trick. We went to several battery places to find a right battery (24V) and finally had to settle for two 12V deep cycle battery with 7AH so that we can have atleast 30 minutes run time.

The kit was mad for a 26" bike, and it wouldnt fit our mountain bike so we adapted Rithvik's bike.

The maiden run by be went ok, but when Rithvik's rode it, his enthusiasm the motor torque twisted the bracket and broke five spokes.

Another run to homedepot and with fender washers installed the bracket held and Rithvik had a blast riding it after I test rode it. 

The batteries are deep cycle gel lead acid batteries to stick to our budget (Li-ion batteries would be better but 4 x the cost but are lighter). Lead acid have more history of data and I have a state of charge circuit from 16 years ago that will allow us to estimate the health of battery unlike the iphone.

To do:
- add a speedometer, maybe even a gps receiver to show where this bike has been.
- add a cool oled display to show state of charge and speed and time left
- modify or add freewheel to be able to pedal if out of charge.