120v Ford Think! Need help powering 12volt accessories

Hi All. I’m a new owner of a Ford Think. I’ve been reading through the posts here and finally decided to sign up. We’ll I purchase a Ford Think which had been modified to 120V. I noticed under the hood that two wires were plugged into the dc converter adapter coming directly from the battery. From reading I believe this is not a good idea. So how do I get my lights, horn,wipers etc., to work correctly? I know I can buy a normal 72 to 12v dc converter so that’s why I’m hoping someone can lead me to finding a solution. Thank you in advanced.

I would think that with a 120 volt dc system you would want a 120 to 12v dc to dc converter. The converter should be wired through the disconnect switch so it’s not powered all the time. You could also wire in a relay so it’s only powered when the ignition switch is on. I would love to see pictures of this setup. If it’s lead batteries where did they put them all? How fast does it go and what’s the range?

Thanks for the speedy reply. Here are a few photos. I’ve topped out at 42mph but the previous owners mechanic said he was able to do 50mph. Not to sure of the range but I drove 10+ miles and the battery was still at half. That’s considering that I was topping out and using the blower they installed to keep the motor cool. It’s all disassemble as of now because I want to get it right. Since I’m new to all of this I will need the extra guidance on fulfilling your answer to my initial question. I don’t want to get shocked by 120v or shocked at all if you know what I mean :grinning: Also what converter would you recommend?

Sevcon makes good converters but I’m not sure if they make one that can handle 120 volts. I would send them an email and ask. You would probably want 500 watts or higher since it has a radio. I would be cautious about buying a cheap converter.

What motor is in it? This setup is very interesting

Ok. I’ll look in that option. Not sure of the motor but the builder said it was high performance hence the reason for adding an external blower for the motor. Since it was one of his first builds he didn’t really know everything about the car but he only made one 4 seater with these modifications. I’ll see if I can get under to see what motor in in there. So it’s a no on the cheap converter right? One other thing I noticed and not sure if it’s normal. The vehicle does have a separate ignition switch to the right or the regular switch. The regular switch pretty much powers the headlights,wipers etc, however the car does still operate with that switch off as well as with the service switch off. If the service switch is off the radio won’t function either.So I’m assuming the 120 bypasses the service switch since it still drives without it.

Wow, Impressive that it all managed to get squeezed in there! I bet this is one heavy cart. Now go load it up with 4 adults and see how she runs. Keep track of those tire pressures!

I’m wondering if the mechanic just tapped off the original 6 cells for the DC-DC converter? Is that what you are referring to when you mentioned the two wires coming off the packs? It is a simple solution, but probably not the best, especially if left on all the time. OTOH- you probably don’t have much of a 12v load. I would follow the wires from your Sevcon to see where it gets power from, or probe the plug and see what it is being fed.

It looks like the Zivan charger was cranked up to handle the 120v pack. Interesting to see.

What I don’t really like is (up at the forward group) that there is one cell with a 7/18 sticker on it. Are all 6 dated the same? They all look dirty so I am guessing - yes. Looking at the 4 in the booty are marked 2/21. This appears to be a very recent mod. It may not be fully shook out yet and done to just sell the car?

If you really want to get into this- (you should probably watch out for this)
Check each of your 10 batteries at rest(unplugged/cooled off). Write the results on a pad to keep track of all these numbers, or put a patch of tape on the batteries themselves. Compare their numbers after a good run, then after charged back up again.

But the real truth shows up in a load test. Either get a cheap tester from Harbor Freight or look up instructions in the archives here on how to do a brake test (but it is harder on your car, more difficult to keep track of the numbers, and you may need an assistant)(brake test is more to check for a bad cell). Point being that a load test is a better indicator of condition of the batteries.

When you get this car back on the road it would be really interesting to see how the forward group is performing compared to the rear group. Maybe go buy yourself a couple cheap battery meters and wire them up so you can compare a battery from each (front/back group)at the same time while driving down the road. Do a run and move to 2 more cells.

It would be good if your batteries aren’t too far off from each other. An unbalanced pack works the newer cells harder and possibly leads to premature failure. If the front cells discharge too quick you may not notice because the new cells in the back are carrying the load. You may tend to run the car longer and bring the front down to really low levels trying to get home. Then all the packs are being charged equally at the same time. You might be cooking the new group.

Hopefully, you got the original mechanic in the divorce. He will probably be a good guy to keep on speed dial and pick his brain (at least until you get to know your new car). But I’m not sure I’d fully trust him yet.

Yes it’s heavy forsure. I would like the lithium modification in the future to reduce the weight if possible. As you can see in the picture the DC converter is not even connected. Two wires had run from the battery terminals directly to the black and orange/purple wire to power the headlights, wiper, horn etc. Looking at some of the documents of the vehicle the car was modified when then sold in 2013 to the previous which who I just purchased from. The original owner is one of the owners at OC Monster carts here in California. They are known for modifying carts. I know the mechanic who was servicing the cart has a lot of information and gave the ok for me to reach out to him about the cart. I know they replace the 3 batteries prior to my purchase because they were bad. This was covered by the original owner so no out of pocket expense for me there. I plan to reach out to the mechanic tomorrow to see how much he know about the cart before I start making too much changes. I spoke with Bob the cluster guy as I had to replace the cluster due to a blown voltage regulator. He said the guy who built the cart is very knowledgeable. So I guess I’ll take that as he probably knew what he was doing when building the cart. But I’m eager to get it back on the road. It still runs of course but I just want to make sure everything is done right. Thank you for all of your responses so far.

I tested the batteries with a load tester and all tested good. I will have to go purchase a meter to see how they are performing together.

What I am hinting at is there can be a great difference between building a car for a client, and building a car to get rid of it. It may work great for now, but be on the lookout for covered up problems.

I read a comment on FB a bit ago on on how someone was just going to toss in some batteries just to get it rolling and get rid of a car. This probably happens more often than we think. To do what is ACTUALLY needed there is no way to get what we spend on these things.

Forgot to answer your question regarding the tap into the original 6 batteries. Yes that’s the case. Two wired are connected to a single battery in the under the passenger seat. I believe it’s only functional when the car is placed in any of the 3 on positions. This of course is not the same with the actual moving of the vehicle as the vehicle drives without the the need to turn on the original ignition switch. There is a separate ignition to the right which runs the movement of the vehicle. So with that being said is having the 12volt run off the battery as bad as it would normally be?

You mentioned you want to do the Lithium battery conversion. I just did 30 Nissan Leaf modules under the front seat of my Ford Think. It stays at 72volts this way and we are expecting 50 mile range with a max speed of 48-52 mph with the different gearing. I modified the diff to use a chain drive. Swapped the motor to a AC motonergy ME1114 (34 peak hp).

Total weight of 30 Leaf modules = 244 lbs not including the copper bus bars you see in the photos.

That’s very interesting. Considering that I have modifications for the motor already could I just replace the batteries with the lithium? Any idea of the cost? I’m sure the car will speed up being that I have 10 batteries and it goes around 42mph. I wish I could tell you more about the car but I’m just starting to look into the modifications. When I called OC Monster carts the builder said that when he owned the vehicle it would go around 60mph. Not sure what has been done since to reduce the speed but I don’t think I would want to go that fast anyway…I think :thinking:

60 mph in a cart sounds real scary. It probably didn’t happen very often (if at all). What does this cart have for brakes? Depending on what you have for a motor, gears in your trans and tire diameter it may not even be physically possible and might be just a bench racing story. Using the (assumed) numbers of a 24in tire and 10.3 trans, it takes 7250 rpm to get to 50 mph. 8700 gets you to 60. Be aware: If you get some of these DC motors spinning too fast the centrifugal forces will fly them apart.

Running a tap off ONE 12v battery is the lazy way but I understand why it was done. Either the Sevcon unit fried with an Input of 120v or somebody was guessing it was going to and just bypassed it. It sounds like enough of the original electrical system has been bypassed to run the car without 12v and right now is just fluff and cosmetic.

Depending on how you intend to use the car will direct what needs to be done. The accessory load on ONE battery is a bigger problem than what I was originally projecting when I was thinking the Sevcon was still tapped on the original 6 cells. I’d feed the old unit some power and check to see if it has an output. Simply running all of your 12v accessories off one cell in your pack is not the best idea.

You have several different solutions. Each have their pros/cons.

  • see if you can find a converter that will handle 120~130 vdc input.
  • tap converter input off 72v
  • install a dedicated 12v battery just for accessories. It will need it’s own charger.
  • If you keep running into too many volt related issues, consider stepping the car down to a lower voltage (96v?) when you convert to lithium? Some of these components can only handle so much before they let out the smoke. Follow the threads of other successful builds.

How loud is the chain drive? As much as I would like to drown out my wife sometimes I don’t think this is the way to do it lol.

Lithium is the way to go and you could fit 120 volts no problem. I’m running 96 volts and they only take up the space where the four middle batteries use to go so you could probably get them all to fit under the seat and get your trunk space back. I’m running 3 16s chevy volt packs that I modified to 8s packs making for a total of 24s. If you added one more you would have a 32s at 128 volts charging the cells to 4 volts each. So pretty much what you have now with a lot less weight.

I just tested the harness where the converter was plugged in. I got 78 volts but zero volt on the output. So I’m guessing this cart is wired so that the 12volt accessories only see the 6 batteries therefore the sevcon 72v converter should work. I ordered a new converter from edrive.com. I think I mentioned this but the motor has an external fan to keep it cool. If I can recall my conversation with the builder he said the motor was wound up specifically and was a boat motor. Now don’t quote me on that but that’s what I thought he said. As far as the brakes it has disc brakes on the front and drums on the back. The tires a 195rs15. When taking off it sounds like a prius or other electric vehicle. After that it’s not loud at all. I’ll have to look more into the lithium conversion once I really understand the cart.

Any idea how much and where I could get the lithium batteries ? Also could you tell me what I need here. Seems like this relay was bypassed but I want to make sure I get the right one to fix it.

Yeah, so there is this guy on ebay you should check out…


Contact Michael @LithiumGods or David @Inwo about a pack, charging options and a BMS. That’s who I would start the conversation up with. They have the experience and knowledge to tackle something like your one-off vehicle properly. I can see how your vehicle could easily pull some crazy high amperage…

Everything is expensive and difficult at 120v.
IMO start over.
A $450 DQ-dci charger will take care of charging 96v and supply 12v power. All in one nice package.
Then put in a 24s lithium battery. Makes it all easy, as that’s what we do here.
Us Chevy Bolt, 6 x 12s Chevy Volt, new leaf modules, or Tesla if it fits.

They did 120v to pull the lead around, and put more lead batteries to get 120v.

The relay is a Omron G8JN-1C6T-F-R-DC12
G8JN.fm (siliconexpert.com)

I would keep the 120 volt setup if you don’t mind spending the time to figure it all out. It obviously already has a charger capable of charging over 130 volts. Hooking up a BMS should be easy enough. The cheapest thing to do is buy a complete battery pack out of a wreck car and take the packs you need and sell the rest.