Corbin's Treehouse - Corbin Dunn, Santa Cruz, CA
Plug Bug

Archive for the 'Electric Bug' Category

Electric Bug: Running Again!

So, I got my new rebuilt transmission from MOFOCO. I put it back in the car and buttoned up the rear end entirely. I then attached the shifter…but, it wasn’t shifting! So, I posted on and the guys there said something might be wrong w/the nosecone setup. I had to drop the transmission/motor combo again. This time I decided to make a better cradle for it:


These pictures are mainly for my future reference so i can remember how it goes. The strap holds it on pretty well.


I popped the nosecone off and it was definitely shifted into a gear. It didn’t seem like it was shifted into two gears at the same time…but it definitely wasn’t working before. I pulled the three things below so they were all aligned, and put the nosecone back on. I could then shift it by hand, as I should have been able to do in the first place. Excellent!


Then it went back in the bug…and it seemed to be doing okay. I put it all back together…and did a quick test drive. Success! Back to electric driving. I’ve been missing it.

Final drive ratio in an electric conversion car

So, I’m getting a new transmission for my VW bug (number 3), and probably buying it from What drive ratio should I get? They can do a few different options.

My bug is/was currently running the stock stuff for a 69 bug:

Screen Shot 2014-09-04 at 6.10.30 PM.png

I have 165R15 coker tires, and the diameter was calculated via: &

The ratios I got from the VW manual, and the screen shot is from my Numbers spreadsheet (email me and I’ll send it to you).

Here are my current speeds for a given RPM and a given gear. Max motor RPM is around 5000 (maybe 5500, but that is pushing it), so I have to shift before then. I don’t use first; it is pointless (I have enough torque to not need it), too jerky, and would have to quickly shift.

Screen Shot 2014-09-04 at 6.12.07 PM.png

I always start in 2nd, shift into 3rd at about 40mph, and 4th at 65mph; this keeps me under the 5,000 RPM limit. I have a top speed of a bit under 100mph, based on the RPM.

So, the diff ratio is 4.375 (also called 4.38); also known as the “ring and pinion” gear ratio. What if I get a freeway flyer 3.88 ring and pinion? Dropping that into my spread sheet gives

Screen Shot 2014-09-04 at 6.19.11 PM.png

So, if I did this, I would: start in 2nd, shift to 3rd at about 45 mph, and shift into 4th at about 75 mph. I rarely go 75 mph; the car starts to shake a bit at high speeds, and it just isn’t designed to do that. The lower ratio would probably make the car less torquey, so I’ll stick with the standard ratio.

Electric VW: Transmission Killer

In my last post on the bug, I had mentioned that I replaced my brushes, hoping it would fix some noise I was getting in the transmission/motor area. It didn’t help, and I then replaced two CV joints, as one was worn pretty bad. That also didn’t help.

So, I bit the bullet and removed the transmission/motor. This isn’t fun; I have to remove some of my cells in the rear seat area as they cover the hatch that lets me undo the transmission from the shifter. It isn’t too bad; I simply undo the red hold down strap, disconnect the BMS and cell wires, and then pull out the center set of cells.


The hardest part about getting the rest of the stuff out is to remember how to do it. I had made a motor mount thing that I used to slip under the motor and get it out, but I forgot that it doesn’t work anymore (for some reason), and I simply use a piece of plywood under a jack to lower the motor/tranny combo. I have to first remove the “ears” on the transmission to get it to do this; it is a pain. Once I remembered all the tricks, it slid right out (this took a while).


Now, here’s what failed. The bearing that holds this shaft in place is blown (not the throw out bearing, but the bearing on the case itself):


The shaft wiggles like mad, and the bearing has clear damage that I can see, and it is obviously leaking when it shouldn’t leak from there.

So, time for a new one. Last tranny was from Bugformance in San Jose, CA. I’m going to try this place next: which means waiting a few weeks…

Electric VW Bug: Brushes replaced

The rear end of my car has been making quite a bit of noise lately. It seems to only happen when I apply power, and I wasn’t too sure of what it was. If I put the car in neutral or pushed in the clutch it would also go away, so it seemed to be related to the motor. I was guessing it was the brushes; on the two brushes per section, one seemed worn about 1/8″ to 1/4″ more than the other. The brush springs aren’t worn out, but I figured they might need replacing:


So, I got some of the newer better brushes (with 4 wires in the top) from .


It shows how much wear has happened, assuming the original brushes started out this size. I put them in and ran the motor on a 12v battery for a while (not too long before it was dead…I’d charge it a bit and run it again). I then did some slow driving for about 80 miles…still lots of noise. So, it wasn’t the brushes, but the new ones should work better.

Brush change electric mileage: 37,550.

So, I did some searching on bugs, and it seems to be the CV joints (Constant Velocity joints) on the old VW bugs. I pulled the CV Joint dust cover off, and a ton of oil poured out! I wasn’t expecting this; they are supposed to be filled with grease, so now my ground has a big oil stain on it. It turns out the cap on the transmission popped out, and allowed transmission gear oil to seep into the CV Joint. This low viscosity oil is not good for the CV joint, and it caused it to wear away. I see visible grooves in the joint from the bearings, and lots of bits of metal. So, I got new ones from Bugformance in San Jose. I’m going to just replace the ones next to the transmission. HI bought the good german ones (more expensive).

Unfortunately..even after changing out two CV joints, it still is making quite a bit of noise. It is either the motor or transmission; I’m going to just drive it…

Plug Bug: New front brake pads

I wear out brake pads faster than normal since I don’t have regenerative breaking or a normal “ICE” engine to slow me down. I replaced my first set of pads really quickly, but the second set seemed to be lasting a lot longer. I would keep an eye on them and see how they were doing every now and again, and a month or so ago they looked good. But today, the bug’s brakes were screaming (a crunchy metal on metal sound), and I knew something was up. The bug has also been pulling slightly to the right when braking, so I wasn’t too surprised.

The front right disc brakes looked like this:


The cheap EMPI disc brake calipers aren’t as smooth on one side, and the wear was twice as much on one pad as the other half! Of course, when I checked them, the pad with good wear was on the outside, so it was the one I could see and verified looked okay.

Doh! I replaced them tonight (I had a set on hand just in case!). The ‘ol Electric Bug has 32,170 pure EV miles.


I got about 20k miles out of those pads; I could have gotten at least 2-3k more if the wear was even.

“No Dino” stickers

Got em! On my J1772 inlet “gas tank” cover.



No Fossil Fuels Sticker

I finally cleaned up my “no fossil fuels” sticker for EVs! I just ordered a few stickers (8) from StickerYou — — the place has a decent website, but they have a terrible security flaw of emailing you your signup password back in plain text! That is just a huge security “no no” and I can’t believe companies do this. The order page also failed for me like 5 times; I had to finally use paypal to get it to work (which also took three tries!). We’ll see what the quality of the stickers looks like; unfortunately, they only accepted PNG, and not PSD files.

It was difficult to find a sticker printing service; I wanted stickers that were vinyl and could last outside. This eliminated a few sources. Check out: for a list of places. PsPrint could have done it, but to do a custom circle shape cut would have been at least a few hundred minimum. VistaPrint looked good and had nice PSD Layout files…but couldn’t do vinyl in the pure circle shape (they could do an oval shape). I still might try them (non-vinyl) if the ones I ordered from sticker you come out terrible. All others seemed to have terrible quality based on the reviews.

PNG below. Feel free to download it. I can email you the high quality 3″x3″ PSD file (with trim marks, etc). The outer red edge is meant to be used for cropping the cut circle, which is why it isn’t a perfect circle.

Jurrasic Park No gas logo 3x3 cropped2.png

Bug Down again.. and don’t use Fortes Brothers Towing in Cupertino!

First off, don’t use Fortes Brothers Towing in Cupertino! They are terrible, and don’t know what they are doing. AAA called them to tow my bug home from work (in Cupertino), and the guy had it almost setup and just said my car was too low and they don’t do lowered cars! I’ve had the car towed 3 or 4 times before; never have I had any trouble at all. Worst off, the idiot driver drove away with my laptop and at first they refused to acknowledge they had it! AAA said all I could do was file a police report. But, after I called the company, they admitted they did have it and would give it back. geez. I ordered a flat bed truck from AAA, but unfortunately the same tow company (Fortes Brothers) canceled the tow without telling me! I sat around waiting for a tow that never came.

But anyways, my car was having a “frame leak”, which means the high voltage had potential when compared to the chassis of the car. This should only be used for the 12v ground, as the high voltage battery pack needs to be completely isolated for safety. I realized something was wrong last week because my car was giving “GFCI faults” at the Chargepoint stations. However, it seemed to still charge okay on a 240V dryer plug at home, so I drove it to work and charged it there on one of those plugs. But then it wouldn’t start; my Elithion BMS was going crazy giving faults, and the controller didn’t want to click on. I realized it was a frame leak, and traced it to my Belktronix DC-DC converter. While waiting for the tow truck driver I popped it out (thanks to Shane for helping me at work and giving me a ride home!), and stuck it in the mail the next day.

Good Times!

A local weekly newspaper in Santa Cruz, The Good Times, did an awesome article on my VW bug and myself.

Check it out here: The Plug Bug and Corbin Dunn.


Broken EVSE (charging station)

I was charging my car last week at home and started to smell some burning plastic. It was coming from my EVSE (the “charging station” which is a gloried relay with a few electronic smarts).

Popping it open revealed that my plug attachment was shorting out a bit:


I now realize what happened; I had did the stupidest thing last summer and drove away with my car plugged in at home. I had shut the front trunk, and failed to unplug the car in some bit of absent mindedness. The cord got really taught as I was backing up and made a noise that alerted me to stop. It broke the J1772 inlet on my car, which I glued back together.I took a look at the EVSE and it seemed okay, but now I realized I had pulled the power cords out just enough to allow them to still work, but have high resistance.

I just hardwired them directly to the input wires with some electrical twisties.

(c) 2008-2015 Corbin Dunn

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