Tag Archives: D & D Motor Systems

Motor Replacement

Ramps jack up the front quickly

The majority of the day was spent replacing the stock General Electric 48 volt motor with the ES-40D-56 from D & D Motor Systems. A local CitiCar enthusiast handed me a set of ramps from his garage, and it helped make the process of jacking up the car a bit quicker.

The first thing I did was to dethatch and remove the lead acid batteries.

A little boo boo from the motors weight

The process of taking the motor off of the car went pretty quick. I was aware of the seal that I had the break, and that I would have to be ready to catch differential fluid. Just like last time, the final step of lowering the motor from the car proved to be a bit difficult. My pinky finger ended up being crushed for a brief moment with 60 pounds of copper.

I had a question that I shot over to the C-Car community in how I could add the intake vent onto the new motor. In the meantime, I moved to the next thing I could tackle.

Removing cables

I started removing every battery and motor cable from the car. I was surprised to find that the main fuse for the motor itself was almost blown. Rather than one, the car had two separate fuses. One of the 250 amps fuses had already blown, and the second was on its last leg.

Fuse labeled as 250V. EAGLE UND LAB LIST 250A

Driving with only one semi-in-tact fuse is a bit concerning. I’ve seen the amps around 250 when starting to go up a hill, and once spiked at 350 amps. If I had continued to drive around with these fuses, I would shortly find myself in quite a pickle.

Controller Nostalgia

Although the motor controller no longer had any of the thick cables connected to it, I was able to confirm that the contactors would activate as I pressed down on the accelerator. I was delighted at the results and decided to keep the contactor.

The main contactor, series contactor, and reversing contactor tower

I’ve got a little project after the conversion to set up a special “user mode” that will activate the contactors while mimicking the original speed jumps/jerking with the motor controller.

Air Intake

I got a few conflicting responses, but the general consensus was that cutting into the case itself would compromise the integrity of the motor. I settled for drilling a few holes into the side of the motor plate, and threading two on the face to attach the original intake.

A rotary tool is used to cut bolts flush with the motor plate

I didn’t attach the vent for air to exit the motor. The D&D Motor has holes along the entire circumference on the other end of the motor. Another approach is needed to evaluate if the air can be captured, or if a different heating source should be used to heat and defrost the CitiCar.

Mounting the Plate

Motor plate with gasket maker around the shaft and each bolt

A thin material was found between the differential and the original motor plate. There was a red sealant in some areas as well.

I cleaned it off with break pad cleaner and then used a gasket maker to draw an outline of silicon around the hole and the bolts.

Afterwards, I tightened everything by hand and let it sit for awhile before tightening with a ratchet.

Motor Bumper

The splined motor bumper

I learned previously that many golf carts often have a spline motor bumper rubber grommet that sits inside the shaft to reduce the vibration of the motor shaft hitting the metal. I didn’t find it in the CitiCar’s stock motor, so I picked one up. I covered it in some grease and stuck it down into the new motors shaft.

New Motor

The last part was actually installing the motor. It was simply lifting it up on the jacks and tightening some bolts. Once the motor was in, I lowered the car. Without any batteries, I pushed it into the garage.

The new D & D Motor Systems ES-40D-56 motor is nestled in its new home
CitiCar Motor Replacement

Popular Science Mechanics

Popular Mechanics July 1974 cover

Today I received a Popular Mechanics magazine from July 1974 with a five page article for the CitiCar. I did a bit more research and found another magazine in the archives. I found a used copy of Popular Science for June 1975 (page 61-63) and made a purchase.

An adjustable angle antenna arrived for the car. I’ve already been successful installing another, so it’s not needed now.

Lots of critical components to replacing the power train are about to arrive by the end of next week.

  • Chevy Volt Battery Module Charger – Monday
  • Two Chevy Volt Batteries 48 volts, 50 amp hours – Monday
  • Two Bluetooth BMS – Monday (same package as batteries)
  • Replacement Portable EVSE – Saturday

Things to be shipped soon

  • ZERO J1772 adapter from Tucsan EV – pinged for a status update
  • New motor from D & D Motor Systems – any day ready to be shipped
  • Forward & Reverse switch – tracking label created…

After two months of researching and gathering parts, I’m getting a bit excited that I’ll be able to start testing things soon.

I think the main parts left for research are battery cables (make my own or purchase?), wiring harness, and a good set of tools for crimping.

Custard package drop off

Teddy and I had a destination with custard on our minds. It was going to be a long trip – perhaps the longest. We took the quickest route without stop-and-go traffic. Along the way someone started asking about the car while we were at a stop light.

Teddy patiently waits to eat his custard on an outing with the CitiCar

I had previously purchased a portable EVSE that turned out to be faulty. A return was accepted for a replacement. I dropped it off at the UPS store.

We arrived at B & L’s Custard, just a few feet from the UPS store. Teddy and I grabbed a quick lunch snack. I went with a small cup, and Teddy got his usual “pup cup”.

Teddy is always happy to get a cool treat when we go out. He was fairly distracted with a dog behind a fence barking at us. While we were there, a gentleman asked about the CitiCar while he was waiting for his order.

The ride home was pretty good. I had a little range anxiety, as I kept thinking the car might be starting to lose some power. It felt like the longest trip we’ve ever been on, pushing the car to its limit.

As I arrived home, I saw a USB charger for a cars 12 volt socket setting in front of my driveway. I had forgotten to clear off the roof before I left. Taking a quick look at the odometer, it registered our trip at 9.5 miles. It certainly was the furthest on one charge.


Curtis Albright SW180-93 contact switch

The contact switch arrived from D & D Motor Systems today. I wired it up to my regulated power supply and a multi-meter for a continuity test. When 12 volts was applied, I could hear something, but nothing was moving and contact wasn’t being made. Bumping up to 22 volts, the contact started to move half way. At 32 volts it was almost instant. Unfortunately, it appears that the coil is meant for 48 volts rather than 12. I’ll have to rethink how I’m going to set things up – potentially using relays, or purchasing a new switch.

Other news

I ordered a PlastiFix kit and Super Clean to prepare for repairing cracks in the CitiCar’s body.

The UPS Store1,129.34.7
B & L’s Custard1,129.30.0
RatekWh9.85¢0.97 mph
Total2.46 kWh25.0¢09:50
Per Mile259 Wh2.6¢01:02

One Hundred

As of this morning, I’ve lost 100 pounds this year. I started losing weight so that I could increase range and fit in the CitiCar easier. I couldn’t even get the seat belt to buckle when I first got it.

Too big for a CitiCar seatbelt
Before and after photographs losing 100 pounds.

Ice Cream Run

I really wanted to get some local ice cream yesterday. I enjoy training Teddy with ice cream at the park. It was time for another adventure. Teddy and I arrived downtown to find that main street was blocked off again. I took a detour and parked behind the buildings on Main street.

Band with a harmonica

Teddy and I walked over to the town square and meandered through the park. While we were there, a small band was playing some music on the side of the road. One of the guys had a harmonica. We sat down on the curb and listened for awhile. I kept giving Teddy back scratches and massages.

It was time that we headed over to C & C Frozen Treats for ice cream. In front of the shop, there was a dunking booth with a giant teddy bear setting on the seat, and some pie throwing cut-outs for people to stand behind. The little shop was packed with kids. We waited for people to leave before going inside. The dairy-free choices are often limited, but good. I got a quart of brownie ice cream to take home. Teddy got a scoop of strawberry mango.

It was getting late and I wanted to get home before dark. I decided to stop at the post office on the way back. I hadn’t been there to pick up my mail for roughly eight months. When I opened my PO box, I found that it was packed tight.

Storage Idea

Arriving home, I started working on an idea to utilize the empty space in the CitiCar a bit better. I wanted a place to install some car speakers, a camera, lights, and a few other things. Nothing really seemed to be ideal to do anything.

I can’t get anything around the roll bars to mount things onto. There isn’t anything to clip onto. Nothing is magnetic, and I’ve had trouble getting adhesives to stick. It’s difficult to mount anything.

Mocking up cabinets between the CitiCar frame

I got some inspiration when thinking about how my camping trailers had been built in the past. Almost every spot available is made into cabinets or made available in some clever way for storage.

I made a template of the area between the roll bars in the back. I decided to work on making an area that can have doors, drawers, hooks, and some magnetic metal bits to clamp, affix, or hook things onto. I’m mocking everything out using cardboard for now. I’ll upgrade to the final materials once I’ve got it all worked out.

Other News

I purchased an Alltrax SR-72500 Series Motor Controller (SR72500) and a Albright SW180 48 volt Solenoid Kit with a resistor and diode. I missed a call from D & D Motor Systems regarding the solenoid kit. I called back and left a voice mail and later followed up in an email with details for what I was using it for.

A few magazines arrived.

  • Hope on Wheels: New Cars for the Gasless Era, Douglas Bartholomew, New York Magazine, May 21, 1979, pages 38 – 42
  • The Electric Tropica, Frank Markus, Car and Driver, March 1994, pages 95-97
  • A Shocking Discovery, Pat Foster, Hemmings Classic Car, September 2018, page 38
C & C Frozen Treats1,119.64.3
Post Office1,120.40.8
RatekWh9.85¢0.59 mph
Total2.35 kWh23.9¢15:52
Per Mile253 Wh2.6¢01:42

Motor Performance Test

I heard back from D&D Motor Systems this morning. It seems the motor is a stock motor – no temperature or speed sensing. I’ll need to figure out what to do in regards to the speedometer.

One of the other CitiCar owners I’ve been speaking with mentioned he was considering using a speedometer based on GPS. My concerns with GPS is in situations that you are unable to receive a signal. I want to know my speed immediately, in real time, with accuracy, regardless of where I am. I’m lacking in the accuracy department at the moment where my speedometer seems to think I’m going 4 miles faster than I really am. Perhaps I need to inflate my tires.

Along with a few answers to my questions, D&D Motor Systems also sent along a performance report of the motor.

Engineering Performance Test for ES-40D-56

The stock motor that came with the car has the following information on its plate:

Ratings Plate on a stock 6HP CitiCar Motor
Time RatingINT
MOD5BC 49 JB 327 C
Serial NoAMN
CitiCar specifications on a 6HP motor

I’m not clear on how to compare motors. At first, I thought it was simply comparing which motor had the most horsepower. However, HP is variant based on the load. Voltage is similar. RPM’s… Let’s just say there is so much involved when comparing motors. I had to start reaching out for something to compare.

ComparisonStockD&D Motor
RPM40001444 – 5020
Amps12552.5 – 583.5
Horsepower6in: 3.34 – 30.70
out: 1.90 – 19.24

I feel a bit confused. The motor is both better and worse… I’m certain I’m comparing apples to oranges here since I don’t have a similar table for the stock motor. I’ve heard from another CitiCar owner that the amps can shoot up pretty high on the stock motor while going up a hill. This brings me to wonder, how did General Electric know what to stamp into the motor plate?

As stated in the owners manual, the CitiCar has a 250 amp fuse on the motor.

The same is true driving up long, steep hills. By driving in first speed, and sometimes second speed, under these conditions, you are likely to blow the Citicar’s 250-amp fuse located in the controller box behind the seat.

CitiCar 1976 ½ Owners Manual, Sebring-Vanguard, 1976, page 19

The Mother Earth News article about the CitiCar in Israel had also mentioned the range of amps with the stock motor.

Although initial current draws can reach 500 amps, the average pull at cruising is around 100 amperes.

Israel’s Solar Powered Car, The Mother Earth News, September/October 1980, page 120

Even at that rate, it appears that the new motor will have cruising speeds at 50 amps; half of what the CitiCar can do.

I plugged the performance numbers for the ES-40D-56 motor into an excel spreadsheet and started making some graphs. I like visuals, and I thought it may reveal a pattern and help to compare against with the stock motor that came with the CitiCar.

I saw lots of compounding curves. I wasn’t sure if I was onto something, but I started out comparing RPMs. At 4000 RPM, I assumed the CitiCar motor would use 125 amps and deliver 6 Horsepower – the ratings on its motor plate.

I tried to make a few formulas in the spreadsheet. At 4000 RPM, the new motor would be using around 75 Amps and 4.7 HP. If that’s the case, it’s got a much higher efficiency at only half the amps with less HP to maintain that load/speed. Unfortunately, I’m thinking in a linear scale, so at 4000 RPM’s, it would be just a bit higher for HP and amps – but not by much.

I’m learning about electric motors, and slowly grasping at how to compare them. I believe it will be an improvement. If my calculations are correct, this means that the motor can go further on the same amount of energy.

Coupling the improvement in the motors efficiency with an actual motor controller will further extend the range. I also purchased two more batteries last week to double the range and lessen the load on each of the Chevy Volt batteries.

Other News

In other news, the garage has been cleaned to a point that it is actually organized. Shelving units for indoor gardening have been broken down and moved back into the garage. I have a whole shelving unit dedicated to CitiCar parts. I even have my screw drivers all in one place. Usually I’m having trouble just finding one screwdriver – but now I’m having trouble fitting them all into one container.

Holding CitiCar motor in place

After a great deal of effort, the stock motor is back on the car. The thing is very heavy and difficult to move around while you are laying on the floor.

Battery terminal with nut

A battery nut arrived in the mail, but again – it’s too small. I decided to order nuts that are 7/16 in size, as well as in metric for M8 and M10. I feel like one of those has got to work.

I started on replacing the differential fluid over the weekend, but I got stuck trying to remove the breather cap – which you shouldn’t do. After watching a few videos, I found the filter and drain plugs. I had three #8 Allen wrenches to remove the drain plug, but I had to order a #10 for the filter plug.

I purchased an old General Electric Motor Bumper for a club car to put inside the armature after I saw a video of someone mentioning not to forget to transfer the bumper into your new motor. It’s supposed to help make the motor a little quieter. Maybe… we shall see. I like the wine the motor makes. I just didn’t see it inside my motor and would like to try it out.

I also started playing with an Aukey DRA5 dash cam.


D&D Motor Systems ES-40D-56
25 Qty 7/16-14 Zinc Plated Serrated Flange Hex Lock Nuts (BCP272)7/16″ > 3/8″
Flange Nuts Hex Lock Self-Locking Metric Thread Serrated Nut 304 Stainless Steel Assortment Kit 125Pcs,M3 M4 M5 M6 M8 M10 M12Metric #8, #10 > 3/8″
Pico 0852PT 3/8″ Stainless Steel Battery Hold Down Stud Nut 2 per PackageToo small
EKLIND 14620 10 MM Long Series Hex-L Key allen wrenchFilter Plug
Chevy Volt BMS w/Bluetooth for 48v 12 cell battery w/cell balance & charger contgoes with batteries
NEW Lithium Ion Chevy Volt 48vdc 2kwh 50ah battery Golf Cart Off Grid Solar EVmore range, shares the load
Club Car Electric GE Motor Bumper (Fits 1982-Up)Curious on quiet noise
AUKEY Mini Dash Cam 1080p Full HD Dash Camera with 1.5” LCD Screen Car Camera with 170° Wide-Angle Lens, G-Sensor, WDR, Motion Detection, and Clear Night RecordingFor fun…
Stuff I’ve purchased / ordered

Motor Quote

I’ve been working with D&D Motor Systems to upgrade the motor on my CitiCar. I’ve gotten to learn a bit more about my car while I was gathering information to pass along to them.

I heard back from them today. They offered a motor with part number ES-40D-56, and provided an outline of the motor to review. It looked like the motor was 11.45 inches long, and 6.7 inches in diameter. It was much longer than my 9 inch motor. It will just barely fit within the space that I have available.

ES-40D-56 Motor Outline by D&D Motor Systems, Inc.
Vanguard Multi-Voltage
Speed Control

One thing I noticed is the placement of terminals was different. All of the terminals are the furthest away from the motor control. Given the wires were at the exact length needed, I would need to replace them with longer wires. I’ll need to upgrade my motor controller to use the new motor, so I may just put it in the battery box next to the terminals and use really short wires. After all, I’ve seen 1D10CRACY do the same thing with his controller placement in one of his videos, and it looked like a really efficient way to set things up.

1D10CRACY: Installing the Chevy Volt batteries into the CitiCar

They asked me to make sure that the pilot on the motors mounting a plate along with the four holes used to mount the plate to the trans-axle were the same as my existing motor.

Frame where motor bolts onto axle

I must admit, I’m a bit confused about this. I’m not sure what an “A Plate” is, and I didn’t see any measurements for the pilot screws Maybe there are measurements, but I am unable to identify them. I was going to print out the outline, but I found that it wasn’t at 1:1 scale to line up with my motor or axle to compare.

The motor can run off of either 48 or 72 volts. This is great since I’ve already purchased some 48 volt lithium batteries. But now I’m wondering if I should look into a 72 volt system. The problem would be that the 48 volt batteries would sit, doing nothing. I found a few things online that have my concerned about the voltage, as well as in the motor outline itself. It seems this may actually be a 36/48 volt motor.

The price for the motor is $635 + freight with a lead time of two weeks. The price motor seems to be around the ballpark figure I was considering. I’ve got so much stuff with a long lead time, that waiting two weeks before they can build the motor isn’t going to be a problem.

Jacks holding up motor on CitiCar

If this is the same as the motor on golf cart catalog only rated for 2825 RPM, it would appear this would lower my cars maximum speed from 36 down to 26 mph. At almost half the horsepower, I imagine it wouldn’t have any pep trying to accelerate.

I’m wondering if my math is off, or if I’m just not thinking about electric motors in the proper way. I keep thinking that motors have got to be more efficient today compared to 45 years ago, but in the end, they are still composed of about the same amount of copper. I simply don’t want to buy a new motor if it’s worse than what I have. Maybe it’s the motors controller that makes all of the difference.

I asked for more information

  • What are the specifications? RPM/HP/Amps
  • What is the type? Series, shunt? Does it support regenerative braking?
  • Does it have a heat sensor? How hot is too hot?
  • Is it compatible with a speedometer cable? Is there a way to detect how fast it is spinning?
  • How far apart are the pilot holes in the outline?
  • Are there recommended controllers for this motor?
  • How heavy is it?

Now that they have no more need of additional details about my car, I can put the original motor back on until I have everything to replace the drive train. That thing was heavy. Maybe I should wait a few weeks…


After a few days, I called over to the front desk. I hadn’t heard back from the engineer and I thought maybe he had sent me a standard part number that sales would have all of the specs for. Perhaps I could just go through sales to get the info I needed and order over the phone. I called in and… they paged him. He seemed friendly and all, but I felt horrible for bothering him. Just my luck, a part used in the motor has been used up, and the lead time is three to four weeks now. He explained that he hadn’t gotten to his email over the past few days to see my questions on the specs and that he’d look over it and get back, if not tomorrow, then after the weekend.

I must admit, the company seems a bit more on a personal level. I feel that most companies are a faceless corporation. With D&D Motor Systems – I’m talking with people. I’m talking with an engineer – directly – one on one. Like – me of all people… no chain of command of twenty or so managers, team leads, salesman, and what not – where details are lost and conversations are difficult to have in real-time.

Hilly Option

I’ve been in contact with D&D Motor Systems, trying to upgrade the motor I have with something that is a bit stronger, speedier, and possibly with some regen capability.

With all of the information I had available, it just wasn’t enough without taking the engine off and going in for a look inside. I reluctantly went ahead and pulled the engine off today.

CitiCar motor on scissor jacks

It was a bit of a long drawn out process, disconnecting cables and wires, photographing and making videos of what went where. The hardest part was at the tail end where it was time to take the motor off.

At one time, I had three separate jacks that I was using. Two were scissor jacks, and I also had a trolley jack. With all of this, I still felt as if I didn’t have the correct equipment for the job. Wiggling the motor out was a fairly difficult process. After some time, the motor gave way and oil spilled out of the axle.

I now had a motor standing free on some jacks. I wasn’t able to move it back any further since the speedometer connection was still on the back. I started lifting it, but it felt as if it was catching on something. The motor is very heavy, I started to set it down, but the scissor jacks fell over. I did my best to lower it to the floor.

CitiCar motor shaft

I took a few measurements, counted 10 teeth, and then I was off to work out the gear ratio. I found a clip that I could put onto the shaft and setup my camera to look directly at it. I then went to the back of the car, marked each tire with a line of chalk, and spun both tires 10 times, calling out each revolution. It turned out to be 68.3 revolutions, which works out to be a gear ratio of 6.83:1.

Finding the gear ratio for a CitiCar

With a gear ratio of 6.83:1, my assumption is that there are 41 teeth meeting up with 6 – witch would actually be a ratio of 6.83:1, where it has an infinite number of trailing 3’s. I thought at least one of the numbers on the axle would have indicated the ratio, the number of teeth on the shaft, and what type of shaft it was.

Numbers on axle

This ratio was not recognized on the CitiCar wikipedia page. It listed earlier models with a ratio of 7.125:1, and later models with a ratio 5.17:1. The page also indicated there was a “hilly” option on the transitional cars with a higher ratio than 5.17:1 at a cost of speed, but didn’t specify what it was. A NASA article (NASA TM X-73638, October 1976, page 32) had mentioned a different ratio of 6.83:1 on their car, and a maximum speed of 32 mph.

Once I realized my gear ratio matched the one that NASA had, I was certain what the hilly ratio was, and that I had it. I’ve been in a similar situation trying to get up to 33 on level ground, but just recently found that my speedometer is four miles too fast as well.

CitiCar axle shaft

I went ahead and added the new ratio for the hilly option on the Wikipedia CitiCar page and referenced the NASA article. I may start making additional changes over time. I’ve got a treasure trove of documents, books, and links pertaining to the history of the CitiCar.

It’s been a long day. I’m tired. My goal has been completed. I’ll put the motor back on tomorrow. I had purchased a few items prior to replace the axle gear oil. I just wish I had played it a bit safer and be prepared for oil to come out. I suspect someone may have put too much inside. I’ll end up flushing it all out. I have no idea if the weight matches what I have, or how old it is.

Maximum Speed

CitiCar Speedometer

Let’s have a fun exercise to determine the maximum speed at which everything is rated.

The motor is rated for 4000 rounds per minute (RPM)

The gear ratio is 6.83:1

At 4000 RPM, tires would spin at 585.65 RPM.

I’m using 125R12 tires (the original stock size) with an overall diameter of 20.39 inches. The radius is 10.195 inches. Solving the the circumference (2 π r), I get roughly 64.06 inches.

One tire revolution would consist of traveling 64.06 inches. In a perfect scenario, this is only possible without any load, car, or gravity to make the tire… smaller.

585.65 revolutions per minute would travel at 37,516.739 inches per minute.

UnitPer MinutePer Hour

The combination of the motor, axle, and tires only permits the vehicle to drive at a maximum speed of 35½ mph.

Keep in mind, this doesn’t take a loaded radius, air pressure, or rolling circumference into account.

Re-Fuse to Fix

I’ve been talking with a few people in CitiCar and Comuta-Car groups and to someone at D&D Motor Systems to replace the motor that I’ve got. The model numbers of the motor and axle that I have do not provide enough information alone.

Dana spider axle and motor on a CitiCarv

For anyone going down the same route, here are the numbers that I see, that you can use for reference. The motor has some details on its plate, but some of the details are worn. I am unable to see the serial number at the moment:

GE 6HP Series Wound 48v DC motor plate
ManufacturerGeneral Electric
Horse Power6
Time RatingINT
Model5BC 49 JB 327 C
Motor plate information
Numbers 815107X and 5 on a Dana Axle
Numbers 20 and 820178-4 on Dana Axle

Numbers 820178-4, 5, and 20 appear on the axle. Another number appears as 815107X, but it may also be 8/5/07X or 8/5107X or 8/5107X.

The number five appears in the center of a circle, tilted on its side, with eight dots around it in odd positions filling eight of ten spaces.

There is also a letter “D” with a letter “W” inside of it.

I need to pull the motor off of the Dana spider axle to see inside and identify the motor coupler, spline, or shaft it will need. I’m not at all a car guy, but that’s the lingo I keep hearing. I’ll just pull it off, snap a few pictures, count things, and make some measurements with my calipers. How hard can it be? After all, I’ve watched David Brunson install a motor on his Comuta Car, so I’m certain that I am an expert mechanic now.

I wasn’t sure if removing the motor involved axle oil spilling out. I was told no, but then a few people chimed in and started offering tips on how to replace the axle geese. I figured while I’m working in that area on a 40 year old car, what bad could come from fixing something that ain’t broke? It felt like general maintenance that should be done every X-thousand miles or X-years, whichever came first. Sure enough, the owners manual had something to say about it:

The 1976½ CitiCar Owners Manual


Check differential fluid level. Use 90 weight Hypoid gear oil. Fill to top. In cold weather lighter weight fluid may be used. It is not advisable to mix different weights. When changing types of oil, flush system. Use no lighter than 30 weight oil.

CitiCar 1976 ½ Owner’s Manual, Sebring-Vanguard, inc. page 22

I’m under the impression that the “every six months” is just topping off what’s already there, but this thing is so old, I’m wondering what I’ll find inside. I think I can just drain the fluid and fill it back in. If I need to crack it open, I’ll have everything on hand, just in case.

I previously had no clue what a differential was, but apparently it is something inside the rear axle. I watched a video by CitiCar Tom rebuilding his Terrell differential for a different axle than mine. I watched another about replacing differential fluid and ordered everything I didn’t already have, and got a nice 20% discount.

SuppliesPart #PriceDiscount
Mobil 1 Synthetic Gear Lubricant
LS 75W-90, 1 Quart
Permatex Ultra Black
Maximum Oil Resistance
RTV Silicone Gasket Maker (3.35 oz)
Performance Tool Multi Use PumpW1145$16.99$3.40
CRC Brakleen®
Break Parts Cleaner
Non-Chlorinated (14 wt. oz.)
FloTool Standard Duty
7 Quart Drain Pan
TEQ Correct
2 Ton Hydraulic Trolley Jack
Order from Advance Auto Parts

DC to DC

Buck converter and 12v socket

The other night, I had a few supplies come in. One was a DC-DC Buck converter from 24/36/48v to 12v. I was hoping I could hook it up so that it would work in both the 48 and 24v mode that the car runs in.

I had two sets of wired 12v sockets. I cut one of them in half and spliced the buck converter into the middle. I ran down to the car, hooked everything up and saw/heard an unexpected spark as the wire made contact. Nothing blew up.

I also got one of the cheapest 12v car devices I could find that was still a little useful, but I wouldn’t mind having it blow up if something I did would destroy it. I found a volt meter with 2 usb ports. I plugged it in and it showed 12.7 volts. Everything worked in both the 24 and 48 volt configuration.

Given that I saw the spark, I knew this would always be on, even when nothing was plugged into it. I went ahead and placed an order for a fancy latching switch button that lights up when the power is on. It comes with a pre-wired socket, and I believe I can setup the LED to run off of the 12v supply while the 48v power only flows through the switch itself.

In the mean time, I installed the other socket onto my accessory battery.

5A 60W 12V
24V/36V/48V to 12V Converter
Buck Transformer DC-DC Converter
13.1ft Adapter Plug Socket
with Eyelet Terminal
Lever-Nut Wire Connector
Assortment Pack
Conductor Compact Wire Connectors
Dual USB Car Charger
4.8A Output
Cigarette Lighter Voltage Meter
19mm 3/4″ Metal Latching
Pushbutton Switch 12V
Power Symbol LED

GPS Speedometer

The T600 has connected to Skynet

I purchased a little T600 Universal GPS Smart HUD. This thing is more of a curiosity to play around with, but I got it because I needed a battery monitor, and I like some of the features it came with.

This thing feels and looks cheap. It simply gives you the bare bones of features it advertises. The most fancy display has a round swoosh below your current speed.

I had to configure it first to bring the speed adjustments down to 100% and offset to 0 mph. I also played around with the three colors that it shows text in.

SpeedSpeed AlarmDistance
VoltageVoltage AlarmDuration
Cardinal DirectionAltitudeClock
The features I like of the T600 Universal GPS Smart HUD

Leaving Home

CitiCar at Advance Auto Parts

Teddy and I started our trip to pickup some supplies to change the cars axle oil, and to pull the motor off to take a closer look at the spline for the shaft of a new motor. As we pulled into the parking lot, there was a police car strait in front of us. Sometimes I think they are going to make up an excuse to pull me over just so they can have a closer look.

Teddy waits to take off on another ride

We wern’t at the store for too long, as it was an online order for pickup. It started to rain a little when we took off. I took Teddy over to Gertrude Miller community park on the way home. It got really dark, windy, and rainy very quick. I started wondering if the wind was strong enough to blow the car over.

Our first trip in the rain

The trip home was… interesting. The roads were wet. The rain was pretty hard. I had the wiper running along with the lights. I saw my voltage on the accessory battery was down to 12.0v. I even tried the defroster to see if I could defog the window. When I turned on the fan, I didn’t feel any air coming through the window vents. The simple fix was to use my hand to wipe down the window. I’ll have to look into what I can do to defog the windows later.

Dead after arrival

As we pulled into the garage, I turned off the lights. Since I was playing with the GPS HUD, I flipped the switch for the lights back on and see how much they impact the accessory battery.


I suspected that a fuse had blown. I grabbed my multi-meter and tested all seven for continuity. I found the bad apple. When I matched the position up to the cover plate, it was labeled as a fuse for the break, turn signal, and horn. I turned on my turn signal and it worked. I pulled out the fuse… still works. I’ll need to re-label these fuses later. Even if I was reading the panel upside down, the other label indicated it would have been the controller.

Luckily for me, one of my first investments in the car was to purchase a variety of fuses and throw them in the back of my car. The cover plate indicated a 20 amp fuse would be adequate for the lights. I replaced the fuse, and all was well with the world.

I took a look at the burnt out fuse and noticed it was rated for 30 amps! My speculation is that the previous owner put that in there because they got tired of replacing 20 amp fuses. Since this happened at the tail end of the trip, I’m guessing that the wiper motor had too much trouble as I entered the garage. Since it wiped away all of the rain, there was a great deal of friction to continue.

In the meantime, I have a DC fuse block on order with sticky labels and LED’s that light up when a fuse is blown. I’ll add the lights and windshield motor to my list of things to upgrade later.


Regarding the GPS HUD, there were a few things enlightening about it. The speedometer on the car was reporting 4 miles faster than what I was actually traveling at. I was able to set my phone next to the GPS monitor and confirm its accuracy. I thought I was going amazingly fast the other day pushing the car to 33.5 mph, only to realize now that I was going under 30.

On a related note is that the distance I have driven on the odometer is much higher than this new gadget is reporting. There seems to be a large discrepancy in just a few short miles. When I punch my routes into Google Maps, It’s sitting in the middle of the other two.

Advanced Auto Parts1,
Gertrude Miller Park1,

With the battery voltage meter, I felt better to see how the lights and a wiper affected the voltage with a general idea of the batteries health. I would still prefer to see a capacity meter of some kind with a percent, colors of red/yellow/green, and a bar showing how much is left.

I used the altitude feature to get an idea about how high the hill is to get out of my little neighborhood. The top of the hill is at 648 feet above sea level, and the lowest point is at 508 feet. Every time I go on a little trip, I’m starting out with a 140 foot tall hill.

I know it’s super cheap, but here are some other things I wish it had

  • A separate set of leads to connect to your battery – monitor 48v battery voltage while connected to a dc-to-dc 12v converter
  • A switch to turn it on
  • Buttons on the front
  • Better sticky pad. It keeps pulling up from the dash
  • GPS coordinates
  • Ability to save trips coordinates to an SD card
RatekWh9.85¢0.55 mph
Total2.32 kWh23.6¢14:44
Per Mile273 Wh2.8¢01:44
Cost to recharge CitiCar batteries