Ford Think - Lack of battery endurance

Seeking help with a power issue on my Ford Think.
Acquired a two seater Ford Think. The overall conditions of the batteries were unknown.

I fully charged the batteries and measured the voltage for each battery. Here are the results.
Battery 1 13.90 volts
Battery 2 13.12 volts
Battery 3 13.20 volts
Battery 4 13.16 volts
Battery 5 13.24 volts
Battery 6 13.19 volts
All Batteries in series 79.10 volts

I drove the Ford Think and got unacceptable results. After only 7 miles (22 minutes) the battery indicator on the cluster reflected zero bars and the flashing square box.

When I returned home, I immediately measured the individual batteries again. The second results are reflected below.
Battery 1 12.22 volts
Battery 2 12.14 volts
Battery 3 12.29 volts
Battery 4 12.21 volts
Battery 5 12.24 volts
Battery 6 12.90 volts
All Batteries in series 73.80 volts

I made the decision to replace the batteries with Deka Gel batteries from East Penn.
After installation of the new batteries, they were fully charged. Prior to driving the Think, I measured the voltage on the new batteries. Here are the results.

Battery 1 13.45 volts
Battery 2 13.50 volts
Battery 3 13.37 volts
Battery 4 13.32 volts
Battery 5 13.57 volts
Battery 6 13.49 volts
All Batteries in series 80.40 volts.

I again drove the the Think. Unfortunately, I got the same results. Within 7 miles, the battery indicator on the cluster showed zero bars and a blinking square box.

I recorded the voltage on each battery and got these results.

Battery 1 11.85 volts
Battery 2 11.96 volts
Battery 3 11.90 volts
Battery 4 11.86 volts
Battery 5 12.08 volts
Battery 6 12.03 volts
All Batteries in series 72.10 volts.

Not sure what I should do next. Any trouble shooting advise or other suggestion would be greatly appreciated.

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I am having same issue, but haven’t had my meter at home to test voltages I assume they will be similar. I have the old charger but upgraded motor, i am not sure about the controller so I am going to dig into it again this weekend and see. I also have new updated cluster and og factory delta q charger i need to install but need a harness. I will try to update this if I find anything note worthy. I figured I would replace those first since the cluster and charger are both known to cause issues from what I have been reading. I am a newbie so I’ve been trying to read a s much as i can to familiarize myself. this forum has a wealth of knowledge, poke around.

Please email me directly. If we figure it out we can post our solution later.

@apowell and @mikemars,

Were you able to solve this issue?

I have not, went through all the battery leakage diag tests with no luck really. Swapped batteries with known good and still have same issue, I have original 4hp motor with programmed rev 2 I believe(it does 35 so i assume) so i have kind of narrowed it down to motor or controller. I have tested resistance in motor and it passes compared to ohms spec it should have but I don’t see how a controller would draw so many amps it would kill my batteries that fast. So I think I and going to have to bite the bullet and take it to a cart place, its now above my knowledge. Unless I can get input on how to test a controller

Thanks for the reply and good luck getting it figured out!
Electrical gremlins are the worst.
You might have better luck taking it to a car electrical mechanic than a cart place though who knows.

Now that you have been running this way for a month, are the numbers about the same on your battery test? Sometimes it takes a few cycles for them to take a “set”. Make sure they are all working evenly by balancing them closer to each other. See if you can get them closer than .23v between your highest and lowest.

Logic would say that the electrical energy doesn’t just go away. It usually gets converted into work or heat.

If the motor or controller is at fault one or the other will be overly hot. They could be fine and just working harder than normal.

After your several mile run(or even less) give a light touchy/feel of your brakes. Is one wheel hotter than the others? You could even jack up each wheel and make sure there is not a brake dragging or a wheel bearing going bad.

On level ground give a push on your cart. Does it roll easily? What tires are you running and are they properly inflated?

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Solutions start with measurements.

How many amps? Test equipment is cheap. Monitor volts, amps, ahs, and whs.
Sounds difficult, but it’s not.
Should be less than 250 wh per mile.
Let me know if you have trouble finding a monitor, I should have extras in my parts drawer.

Yeah I am an automotive mechanic so I would trust a cart guy that has dealt with these more!! I have a local guy that is very familiar. @AssyRequired cart rolls fine haven’t felt for brake heat but I know it doesn’t pull or drift like it is dragging. Honestly haven’t checked the tire pressure I know that can play a role for sure so I will check. @Inwo My field we deal with one battery and when it dies alternator is bad or something is drawing amps when it shouldn’t be so I said amps thinking that the motor is going out and drawing more amperage than it should. But I don’t know if a controller can either. I suppose it could. So an amp clamp would have to be before the motor but after the controller to test that theory or before controller correct? I know you are very knowledgeable when it comes to electrical so I am all ears! Also the electrical leakage light still comes on while driving so according to the testing procedure in the manual it states to remove the connectors and turn the key on if the leakage light doesn’t illuminate to replace that part for both controller and motor, well the light doesn’t come on while disconnecting either of those so there is that also.

The motor is most likely to leak. Test that first. Should be a few meg ohm to ground. (guess)
That much leakage something will get hot.

BUT, you don’t no anything yet. Put a battery monitor on, and you can see if battery is supplying rated ah. If not, then it needs better charging or replacement.

If battery has enough energy but car is taking over 250 wh per mile, then something is wasting the energy. Rolling resistance or bad motor/brushes.
The controller is self policing and should tell you if somethings wrong. I would never say never, but low on my list.

After all is said and done, problems are 80% batteries. (guess)

Need to ask voltage. 500a is good.
I expect that it’s 120 volt.

This one is 120v and easier to connect. Using current transformer or hall effect.

Thank you @INWO, for delivery time I looked on amazon and am having trouble finding one that will be here before July, I found a 300a 120v monitor is that enough?

Yes, rarely need over 300a. Won’t hurt overloading it. Shunt will get warm and lose some accuracy is all.

Awesome thank you for your help @Inwo i appreciate it. I will repost with results this weekend sometime hopefully.

I know I started this thread and I have been MIA for awhile. I am still experiencing the same problem that caused me to start this thread. The electrical system troubleshooting that is being suggested is beyond my skill set. I will be following the experts contributing to this thread.

Check for dragging brakes

Any updates ? Could someone please post how to setup the battery monitor? My batteries are acting like they are on their way out and I am considering a Lithium upgrade if it is relatively straight forward…

alright, so got the battery monitor installed and ran it around the block, took pictures of monitor at every mile, but messed up and took some while driving and some while still. so some voltages are lower while driving than following mile. started at 81.2v and following data at approx mi marker
mi V wh
1 77.4 46
2 76.1 84
3 73.5 105
4 76.3 169
5 76.1 203
6 71.8 299
7 64.7 332
.so that being said i was just cruising the whole time and that was the longest range my cart got before battery started dropping bars and performance. I have a local guy going to come out at check the controller to see how it is programmed , its a D1 found that out. I thought only D2 could be programmed but the local guy said its possible and he has seen these cranked to try and get speed and it will kill any battery endurance. @cij follow the link on amazon i posted or one from INWO they are easy and come with instructions.

I just went through a similar situation with my Think. 6 new batteries, all reading very close voltage except 1.
The Think would go 3 to 4 miles then go down to flashing battery low warning. II would charge it back up and after the car sat for a bit, the batteries would read around 12.79, except 1 that read 12.1. Was suggested to test amperage on the one batteries. I did and found out 1 battery was defective. I replaced the one battery and now the Think goes 16 miles with only a 2 bar loss. Not sure what motor is in it, but it tops out at 27mph on a level road.