We are looking for advice on what batteries to purchase for a Ford Think. We are a high school engineering shop and this year inherited 3 Ford Thinks in various states of disrepair from our Autotech shop. Our team’s goal is build one into an autonomous vehicle. At this point the team is building steering ad braking control. In order to test the drive control though, we need batteries. We have $1794.00 to spend on batteries and charger. We would like to go with lithium and do not need a lot of current capacity, since at this point we are only testing and even when it is fully working it will never leave the schools grounds.
I modified your post. The choice you made would not be good for your project. 50AH . is significantly lame. Since your on a budget I would suggest you stick to Flooded or AGM golf cart batteries. If you are set an Lithium 3 of our members are supplying this kits country wide. They fit your application at considerably less than retail.
This sounds like a fun project. Feel free to show progress pics,
What parts are left over from the previous owner/project?(How stripped down are the cars?) If you aren’t going to use some of the original parts I bet some people here will trade or offer cash for the parts you don’t want.
Do you have a charger?
What motor and controller do you plan to use?
Yeah, our students work on a lot of fun projects. They are with us for over a third of their time during their four years at high school.
We have the original chargers from each of the cars, but our plan is to use a different battery system so we will need a new charger. Any thoughts about this option? It fits our budget and the vehicle will never need to go farther than the confines of our campus. We plan to use the existing 72V motor. Our students are just now extracting one of the controllers. We found a site online that sells an interface and software, so we will see how far that takes us. Thoughts?
Sam
PS: The vehicles are mostly intact. We will inventory parts at some point and let the list know.
Where are you located? If one of our network is close to you this may be an advantage.
Talk to Inwo. It looks like he sent you a PM. Look at the upper right of your screen for your avatar (in your case it is a circle with an S in it. Click on that for access.
Don’t toss those chargers just yet. There may be a chance that can be programmed or tuned for your needs. We can help Identify what you have.
There are several battery options available that will suit your needs. Again- Talk to Inwo.
If you haven’t figured it out yet, your Think control systems rely heavily on the round display in the center of the dash. This is called the “Cluster”. It monitors several safety circuits as well as controller status. It is probably the weakest link in the car and not built very well. Thinking ahead → For your needs it should probably be bypassed but you will also lose the ability to monitor the controller error codes. We will have to get another way to monitor controller errors.
Not trying to design your project but perhaps the DC drive isn’t the best for your project purpose? An AC drive might be easier to control at slow speeds? I’m guessing 5 MPH will be Max on this car?
(Others of the group are free to offer their input on this)
The group here are some of the smartest and creative Gem people on the planet. Much of this translates over to the Ford Think. There are even a few that specialize in the Ford Think and it’s systems. Do you need a Service Manual? (include your email address).
I want to believe everyone who says my suggested battery will not work, but I haven’t read an explanation of why. Could someone provide an explanation of exactly why a 50amp discharge rate will not work with the 72V motor on the Ford Think? Or even better exactly what discharge rate is required and why.
Because peak amps are 350 (or 500). Look at controller specs. Plus we have real world experience building batteries for Gems and Thinks.
You can certainly reprogram the controller for say 25% torque but it would barely move. I program some (other) cars for economy at 80% and it is sluggish as hell.
ps.
I know that math tells you 50 amps for 5hp, but evs need lots of peak hp to get moving and dc motor system is 50% efficient at best. Leaving 2.5 peak hp.
Driving at 25mph steady level ground will most likely be more than 50 amps. The ac car I’m tuning now is 80a. It seems something is wrong with it, but I have no expectations of getting it under 50a.
ps ps
Don’t get ideas of just buying two or three batteries to parallel or series parallel.
Just don’t!
We spend way too much time fixing this mistake and some of us may get grouchy.
You have to think of EV batteries as both your fuel tank and kind of the engine too. A 50 amphr battery would be like running a car with a 1 gallon gas tank (probably ok for what you are saying you want to do), a 200 amp hour battery would be like having that 12-15 gallon tank that cars have. On the “engine” side that 50amp battery would be like having a weed wacker motor in a car vs having a V8 engine, yes you still need a suitable electric motor to power the think car but it will only be able to put out as much power as it can take in. The batteries you suggested have a very low maximum discharge rate and will severely handicap the 5hp motor you have in your cart.
