# 73 Super Beetle Build 1.0



## loopylupine (Jan 1, 2014)

Hi everyone,
I've been doing reading on this forum for a while and planning/scheming/dreaming and finally found a bug here in Alaska that was not a rust bucket, and went for it. Happens to be a convertible which will be really great for about 3 months of the year...
Anyway, it looks like the thing to do is start a build thread so I don't hijack any other thread with my noob questions.
Right now I'm doing a bit of repairs typical of these 40 year old beetles such as floor pans and brakes and figuring out why certain lights don't work. Actually there are a few rust issues to address, but the frame is straight and pretty solid. Hopefully I'll have these details worked out in the next month or so, and will be ready to begin installing conversion parts.
So, the plan is to do a 144v system. I'm looking into some 160ah batteries from this thread http://www.diyelectriccar.com/forums/showthread.php/voltronix-lithium-ion-3-2v-160ah-91276.html
I'm watching for used warp9 motors, but considering other motors also, and trying to read as much as possible about controllers and chargers. I'm hoping to retain the clutch. My target is $10,000 for the conversion. I'm hoping for 60-80 mile range and decent power to go up hills as I have about 1,200 feet to climb over 4 or 5 miles on the way home. I'm thinking at least 500 amp capacity for the controller to begin with, maybe up to 1000 amps if I come across one at a good price. I wouldn't mind a bit of acceleration now and then. I might need a bit of heat in this thing as well, haven't looked into that very much yet. 

SO, there it is, on the table for dissection and correction. Any help or guidance anyone can provide on any components will be highly appreciated. I have a couple sons, 8 and 10, that are excited to help, and we hope to be driving on electric power this summer.

Thanks,

Dale


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## wessss77 (Jan 4, 2013)

Hey Dale. Welcome to the site. I also did a 73 SB. I have a range of between 80-100 with 31kW traction pack when it is warm out. I bought a used ADC FB1-4001 9 inch motor for $1000 but everything else was new. From the sounds of what you are looking to do the traction pack is your biggest expense and will run between $6000-$9000. 

Good luck on your build and look forward to seeing how it goes.


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## Yabert (Feb 7, 2010)

Hi Dale
There is many beetle conversion around here and on evalbum. So, learn, take the best advice and let you inspired by the others good conversions and do your conversion nicely.

My first advice: Don't forget to add enough heater in your battery pack. It change everything on cold weather (performance, range, etc.).


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## loopylupine (Jan 1, 2014)

Thanks for the welcome guys. Wessss, I read through your thread a couple times, thanks, a lot of good info there. 

On the heater, I'm thinking of having it on a timer so that it comes on maybe 10 minutes before I leave in the morning, while plugged in, to relieve some of the heat requirement when I'm driving. Not sure if that will work out or not, but that's the tentative plan.


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## Yabert (Feb 7, 2010)

loopylupine said:


> On the heater, I'm thinking of having it on a timer so that it comes on maybe 10 minutes before I leave in the morning...


Most prismatic cells suppliers suggest to charge their cell between 0 and 45°C.
So, under 0°C you will always need to heat your cells. That will give her longer life and better performance.
In fact, from experiment, I've been incapable to charge my battery pack at -15°C without heating because the cells didn't take any current.


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## loopylupine (Jan 1, 2014)

Yabert said:


> Most prismatic cells suppliers suggest to charge their cell between 0 and 45°C.
> So, under 0°C you will always need to heat your cells. That will give her longer life and better performance.
> In fact, from experiment, I've been incapable to charge my battery pack at -15°C without heating because the cells didn't take any current.


OK. I thought at first you were talking about cabin heating. Now I realize you said battery pack heating...oops.... anyway, I will keep that in mind and figure out a way to keep the batteries above freezing. My shop/garage is not heated other than a barrel stove, but generally is warmer than outside temps, but not always above freezing if it gets really cold..


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## loopylupine (Jan 1, 2014)

Some progress in the last couple weeks- fixed a front strut, pulled the seats and ordered some floor pans that are scheduled to arrive next week. Also have a controller, batteries, and a WarP9 on the way, probably 2 weeks out. Was working on some wiring of running lights and headlights today, and was wondering if switching to LED headlights is the best for a DIY conversion. In the summer around here they would rarely be used, but in the colder months we get a fair bit of darkness, and I'm going to be wanting every spare watt for a little cabin heat, so maybe the LEDs would be the way to go?


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## dougingraham (Jul 26, 2011)

loopylupine said:


> Some progress in the last couple weeks- fixed a front strut, pulled the seats and ordered some floor pans that are scheduled to arrive next week. Also have a controller, batteries, and a WarP9 on the way, probably 2 weeks out. Was working on some wiring of running lights and headlights today, and was wondering if switching to LED headlights is the best for a DIY conversion. In the summer around here they would rarely be used, but in the colder months we get a fair bit of darkness, and I'm going to be wanting every spare watt for a little cabin heat, so maybe the LEDs would be the way to go?


Switching to LED headlights will help but it really is not significant from a range extension standpoint. In my car the running lights used as much as the headlights. Count your 1157 bulbs and those draw about an amp each when they are used as running lights. I have six of those. I also have four side markers that each draw about half an amp. And the license plate lamps draw about an amp. Dashboard lights were not easy to measure so I don't include them here. So my non headlight load was 9 amps. Low beams with the original halogens were about 8 amps. Switching to LED headlights only dropped this to about 6 amps but there is a lot more light. switching the running lights reduced the load from those from 9 amps to about 2. Saving a total of 9 amps at 12 volts is 108 watts. At 300 wh per mile that would extend my 60 mph range by 0.6%. So range extension is not a good reason to do it when it will cost around $400. The better light at night is however a good reason and the tiny range extension is a free plus. It also is a somewhat dramatic lightening of the load on your DC-DC converter.


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## loopylupine (Jan 1, 2014)

Thanks Doug. Those are good points about the cumulative draw of the running lights, and also about DC/DC load. I'll look into cost on all of it and go from there. I do like the idea of a brighter headlight... wouldn't want to have a meet and greet with a moose after doing so much work on this project...


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## loopylupine (Jan 1, 2014)

OK, quick update:
First bits of ev parts arrived a couple days ago: Controller, display, and throttle. Got a classic netgain controller 1000 amps- bigger and heavier than I thought it would be, a nice looking piece of equipment. Pretty exciting to start getting the pieces together! 
Also I have the floor pans cut out and am doing a full one on the passenger side and a 1/4 pan on the driver side. Wire brushed and put some Ospho on tonight and will primer and weld the pans in this weekend. Not doing a full resto but getting her fairly tidy.
Batteries and Warp9 coming next week. Now I need a charger and a motor adapter to finish out the major components. Been looking at Elcon chargers and also looked at NEK at electriccarpartscompany ... anyone have experience with either of these chargers or would anyone like to chime in with a recommendation? It will be 144v of 160ah LifePO4 Voltronix.


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## loopylupine (Jan 1, 2014)

A little more progress. As the snow gradually melts around here, we finally got the ICE OUT.









It's nice to have helpers!

I have compiled all major components except the charger and motor adapter. Floor pand have been replaced, rear brakes re-done, and some other mechanical stuff fixed. Gas tank is out as well, and after pulling it I noticed the steering shaft was shot, which explains the play in the steering, so I'm ordering up one of those also... Anyway, I'll be working on some battery boxes next as I wait for the adapter for another couple weeks.
Since I'm here in the north, I'm looking for ideas on how to insulate and heat the battery boxes. I think I'll have 3 separate boxes. One behind the back seat, one where the gas tank was, and one in the spare tire well. 

So, here is where I could use some help:
I have read a little about this on some other threads, but would love to hear some feedback from any cold climate folks that have successfully kept batteries above freezing without a heated garage. What methods have you used that have worked? What should I avoid? I'm looking at heat tape, or pad heaters in the boxes, with temp sensors and thermostatic control, but the details are unclear with respect to how exactly to construct the enclosure and how to distribute heat evenly.
Thanks for any advice.


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## Ziggythewiz (May 16, 2010)

Good progress!



loopylupine said:


> I'm looking at heat tape, or pad heaters in the boxes, with temp sensors and thermostatic control, but the details are unclear with respect to how exactly to construct the enclosure and how to distribute heat evenly.


I've heard both methods used with no issues. I don't use active heat but I'd recommend trying to just do 2 batt boxes if you can to simplify things. it would be difficult to insulate and heat a box in the spare tire slot.


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## loopylupine (Jan 1, 2014)

Thanks Ziggy. I'm thinking of going with pads secured to 1/4" aluminum plate under the batteries to disperse the heat evenly, and insulate around that. Then use a PID control and thermocouple to control the heat.

On another topic, I am pondering cutting out the front bracket support for the gas tank, so that the forward battery box can be big enough to hold 25 cells. I'll have 20 cells in a box behind the seat, so then I would just need two boxes. Any buggers cut this bracket out? I don't think it's structural, but... maybe it gives some rigidity to the front? Probably I could leave about 1" of the bracket, as it would be below the batter box.
I'm not concerned about ever restoring this to a gasser again... Thoughts?


Thanks!


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## onegreenev (May 18, 2012)

Do you have a picture of the bracket your talking about? My 62 Bug has the steering running through part of that fuel tank hole. Bummer, cuts out lots of usable space. The SuperBeetle is laid out different than the normal Bug. I don't remember what the SuperBeetle looks like under the fuel tank area. I have 34 100ah cells where the rear seat once lived.


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## loopylupine (Jan 1, 2014)

Here is a pic. Yes the steering axle goes through there. Actually I just removed the shaft today since the U-joints were shot... But I was thinking of making the box in sort of an L shape so, it could get to full width where the shaft goes down to the steering box.
I'm keeping the back seat but 20 cells will fit behind it. probably will make the convertible top stick up a little, but not much...
Anyway, here it is. If I cut down the bracket, I would extend the battery box maybe 6 or 8" into the area of the spare tire well. Could actually fit 30 160ah cells there and get 160 volts....
Crazy?


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## loopylupine (Jan 1, 2014)

Put some coil over shocks on the rear last night. Got the new steering U-joint linkage, but waiting for my son to help with that..
Still haven't cut into the gas tank support bracket to make room for a bigger battery box- any sage advice from buggers on that?


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## Zak650 (Sep 20, 2008)

loopylupine said:


> Put some coil over shocks on the rear last night. Got the new steering U-joint linkage, but waiting for my son to help with that..
> Still haven't cut into the gas tank support bracket to make room for a bigger battery box- any sage advice from buggers on that?


I fit an 11 kw pack (34 Calb CA100 cells) and charger all in the front of the car. I would not cut that bar if I were you, it's the necessary cross member between the McPherson struts. I put 24 calb CA100 cells in the spare tire well, no cutting. 3 against the cross strut, 4 rows of 4, then another row of 3, 2 in the very front. Second box on the right side of the car gas tank area level with 10 cells. 4 kw charger on the left side. Sorry no photos, taken apart for painting. Both boxes have pet warmer floor heaters, 1/2 plywood insulating walls and floors with 1/8" heat dispersion plate beneath the batteries. Upper right side has an outer aluminum box, main front box has just wood sidewalls with aluminum angle around perimeter bolted to tire well deck. Additional cells could go in back behind the rear seat.

If you have to remove the gas tank support you could weld or bolt in another replacement cross strut between the top of the McPherson strut towers. I would advise having it in place before cutting the other one out.


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## loopylupine (Jan 1, 2014)

Zak650 said:


> If you have to remove the gas tank support you could weld or bolt in another replacement cross strut between the top of the McPherson strut towers. I would advise having it in place before cutting the other one out.



Thanks for that, Zak. Yes, I suppose it does have a structural value. I'll work around it. Thanks for the description of your boxes, and the pet warmer idea. I'll look into that. Are you using your own thermostat and controls for those, or just using them with the built-in temp regulation?


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## Zak650 (Sep 20, 2008)

I'm using three of these:
K&H Heated Resting Mat for Small Animals, 9 By 12 Inches about $30 @ Amazon
You can get them from a number of sources 110V ac 25 watts they have an internal thermostat. Since I'm using 3 I'll probably run them on DC and see how they do since it's close to my pack voltage. The bottom of the battery box has 1/2 plywood with a through hole and recess the pad screws to. The aluminum sub plate under the batteries rest directly on the top of the pad and the perimeter is 1/4" away from the internal sidewalls to avoid heat transfer outward. A slot has to be cut for cord clearance. I plan on spraying foam between the wood sides of the main pack and the tire well after it's in place. cover everything in carpet. The plywood components are painted with good quality oil based paint to seal them.


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## loopylupine (Jan 1, 2014)

*Battery placement*

I'm debating these two scenarios, given that 20 cells will fit behind the back seat, and 16 cells will fit in the gas tank well. I'm going for 144 volts, 45 cells, so this leaves 9 cells to put somewhere. These are 160ah cells, about 3"Wx7"Lx11"H, about 12 pounds each, so we're talking about 108 pounds plus bus bars, battery box, so maybe 120 pounds or so.

A) Put the 9 cells in the spare tire well. Total 3 battery boxes. Advantages: Easy, close proximity to box in the gas tank well. Disadvantages: more weight in the front end, uses up trunk space.

B) Put the 9 cells under the back seat, 5 on passenger side, 4 on drivers side. Total 4 boxes. Advantages: Weight distribution is lower, and more weight in the rear where I have adjustment ability with the coil over shocks. Disadvantages: One extra box, would need to replace the stock back seat with a custom solution since the cells are too tall to fit under seat; more cable connections.

Any thoughts? The crux of it is really whether the bug will handle ok with 300+ pounds (25 cells) in the front...


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## Zak650 (Sep 20, 2008)

Have you gotten or settled on brand & size of cells?


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## loopylupine (Jan 1, 2014)

Zak650 said:


> Have you gotten or settled on brand & size of cells?


Yes, I have them already. Voltronix 160ah. I have 48 but planning on just using 45, and I'll have a few backups in case I find any problem cells.


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## loopylupine (Jan 1, 2014)

Well, not much feedback on my battery placement question... but I think I'll keep it simple and not mess with cells under the back seat, just put 20 behind back seat, and 25 in the front trunk/gas tank well. 

Anyway, here's a pic of my mock up for the control board. It's plywood, I'll make an aluminum plate soon. I'm going to use the stock VW gas pedal to work the Netgain throttle pedal mounted on the board because I don't see how to fit that thing where the gas pedal lives. I'll probably cut off the pedal part, although it looks kind of funny, like I'll have an elf riding back there pressing the pedal...
L-R from top: Row 1 - Main contactor, coolant reservoir, solenoid for fan and coolant pump, room for a redundant contactor at top right; Row 2 - Controller, coolant pump, fan/radiator; and near bottom left is the throttle pedal temporarily mocked up with vice grips.
DC/DC will go under back seat, and charger in the front trunk, or maybe under back seat.
Anything seem way out of line here??


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## onegreenev (May 18, 2012)

Keep the weight just forward of the transmission and low. Sort of like a mid engined vehicle. No need for too much weight up front but you should have some.


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## loopylupine (Jan 1, 2014)

*Motor bolted on*

Finally got the warp9 bolted up today. Tried last night, but had an issue with the hub not seating all the way down onto the motor shaft. When we tried to push the motor assembly onto the tranny, the flywheel was hitting the tranny casing. So... tried without the key just to test, and the hub seated against the motor as far as it would go. But still the flywheel teeth were hitting the tranny... so, had a friend lathe off the teeth of the flywheel today, and I cut the key down to about 1" so the hub seated, and viola, it spins freely. Honestly, I was a bit peeved, thinking that an $825 adapter would have these considerations taken into account and it should just work, but, oh well, at least I have progress now. I'm sure it's just the first of many little setbacks, so, I just have a homebrew and don't worry...
Did a 12v spin test with the rear end jacked up, and it spun the tires... nice feeling.
Tomorrow I hope to finish cutting the aluminum plate for the control board, and mount some of the components.

Cheers,


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## onegreenev (May 18, 2012)

*Re: Motor bolted on*

Just to let you know, not all the VW transmissions were the same. Even among the castings from the factory the inside dimensions were different. Ive had some fit perfect and some required extensive grinding of the inside of the transmission to allow proper fitting. Some times it was just the flywheel and others it was the pressure plate that hit. This was a problem even among the engine cases from VW. All the transmissions from a singe mold were exactly alike but they had many molds. Also different years were changed slightly and they also had multiple molds for each year or change. Odd but thats how it is and remains today. No company can account for all the changes. This is also a problem among flywheels. Some flywheels are larger than others and narrower and some have different lengths front to back. I had that issue with my current setup. The flywheel length was causing my flywheel to wobble when fully mounted on the adaptor. Rebirth Auto has fixed that issue. But the issue of flywheel teeth hitting or pressure plates hitting is a hit or miss affair. Easy to grind down some metal to allow proper fitting. A pain, yes, but doable. 

Pete


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## loopylupine (Jan 1, 2014)

*Re: Motor bolted on*



onegreenev said:


> Just to let you know, not all the VW transmissions were the same. Even among the castings from the factory the inside dimensions were different. Ive had some fit perfect and some required extensive grinding of the inside of the transmission to allow proper fitting.
> 
> Pete


Thanks Pete, that makes sense. I'm pretty accustomed to modifying parts to suit my needs  . In the big picture, not a big deal, it's in there now. I think there's maybe 1/8" at most in there between tines of pressure plate and throwout bearing. Clutch showed no sign of slipping with 12v applied in 4th gear and tires jacked up but with a little ground friction, so hopefully it will be fine.

Dale


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## loopylupine (Jan 1, 2014)

Made some progress this weekend. Finished fabricating and insulated my battery boxes. Installed pad heaters siliconed to the bottom of two boxes. I used two pad heaters on my 24 cell box and one on my 5 cell box. Ordered two more to use on my 16 cell box.
I put the sensor in the 5 cell box, siliconed and aluminum taped down about an inch or less from the edge of the pad heater, under the insulation, and tested my temperature controller and it worked fine. that was with 120v AC, I don't have the traction pack powered up yet, but am planning on running the pad heaters off of the 144v.
Bolted up the control panel, and got the throttle pedal hooked up via the gas pedal cable. Made an adjustment mechanism by drilling a hole in a bolt that the cable goes through. A nut and washer adjust the throttle cable tension. Got a bit sidetracked helping my son with his electric go kart, and with mother's day, but I got some visible progress anyway


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## loopylupine (Jan 1, 2014)

More progress this weekend. Got the packs in place and loaded up with cells. The one in the gas tank area presented some problems with squeezing it in there with the 3/4" insulation around the box. The lid will be a tight fit under the hood. Had to snip back the compartment that houses the wiper motor and the defroster squirrel cage. Cut it back, flanged it out, and screwed a cover on it- caulked it up so it is sealed. I'll be building a duct that comes off to the right of the pack (in pic, looking from the front) that will house a ceramic heater, so I made sure to seal up the chamber so it will draw the intake air through the heater only. Had to seal up the little grill on the top. 
Looks like I'll be using part of the heater duct to get my high voltage lines back to the back, but I need to pick up some 1 1/2" ABS to push in there to sleeve the cable since there are some sharp edges and rust in there, so that will wait until next weekend.

Cheers,


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## loopylupine (Jan 1, 2014)

Spent a good deal of the weekend working on connecting the dots to make the wiring complete. Today it culminated in actual motion of the bug. Elvis has left the building! 









Still a lot of work to do, but got a big EV Grin on today for sure. Actually drove down to my friend's house in the neighborhood and picked up a carboy of beer that I had lagering there... a successful round trip.
I may have an issue with the clutch... I knew it was close with the adapter plate, maybe slightly disengaging the clutch when I bolted it on, but hard to tell. The clearance is very close. Will take more driving to confirm, but definitely the clutch slipped as I accelerated up a hill. But I may have been in 4th, not positive, it's hard to tell. Again,,, more research needed... in any case, I count today as a success!
(I'll leave out the story of the couple hours wasted when I inadvertently scratched up the back of the interface module circuit board when I was mounting it, and had to solder a single strand of copper wire to repair the destroyed connection...)
I have some questions forthcoming, but for now... HOORAY!


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## davidmillin (Dec 14, 2013)

Congratulations on getting your build mobile


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## loopylupine (Jan 1, 2014)

Spent the last few weeks working on the convertible top, buttoning up wiring, installing tachometer, removing studs from tires, and yesterday finally got the batteries bottom balanced and charged up. Went for the first official drive to town today, about 35 miles total. Pretty sweet! The Netgain classic controller was overheating on the long hill home, and cut back power, dropped down to about 35mph, so I will be addressing that next by adding a supplemental capacitor and by plumbing the controller coolant lines into the cabin and through a heater core for cabin heat... but other than that it was a successful and fun first long drive.
EV Grinning!


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## loopylupine (Jan 1, 2014)

Well, it's been almost a month since I updated this. Been driving the plug bug (apologies to Corbin, but I think since I'm in Alaska it's far enough away to use the name) almost every day as a daily driver. Pretty fun, especially since the weather has been great, and have only had the top up a few times. Installed the DC/DC converter which is working fine so far...
My main struggle has been with the classic netgain controller. It wants to heat up pretty much instantly upon any significant amp draw to the motor (over 250 amps). I added another circulation pump and another radiator to the cooling loop, which did help some, but the controller will still get to 135 and start cutting power on my 4 mile uphill ride home. Maybe I need some air cooling in addition to the water cooling, or maybe I just need a better controller...
But in general, the bug is working well. The speedo cable broke last week and I just fixed it today so not sure of total ev miles, but I would guess around 400-500 miles.
I just bought a jld404 and will be wiring that in soon, so I can track amp hour usage better. Installed a stereo, so now people can hear me coming...
In general, just enjoying driving on battery power, and happy that the conversion was a success, at least so far...


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## loopylupine (Jan 1, 2014)

*1000 miles!*

Past the 1000 mile marker today whoop whoop!

I now have the JLD 404 hooked up and it is telling me that I use 2.4 AH per mile on average. This is higher than most people cite for their bug builds, but I have to cruise up a pretty big hill, and gain 1500 feet on the way home, so that takes its toll on my efficiency. Plus, there is a lot of construction here and a lot of stop and go. No matter, I still have plenty of range for getting to work and buzzing around doing errands and whatnot. Now I need to get the electric heater installed because it's starting to cool off around here.... I also have a front disc brake kit on the way, it should be here this week, along with a new clutch disc. I noticed when installing the motor that the throughout bearing seemed to maybe be already applying slight pressure to the pressure plate. It is of course difficult to tell since you can't see in there, but in any case I have had a case of the slipping clutch lately. It doesn't help to accidentally put it in 4th when I think I'm going into second, but never mind that... I will carefully check when I install the new clutch and make sure there is enough clearance.
The old netgain controller still heats up more than I would like, but with an extra circulation pump it is more or less tolerable. I will continue to explore options on that.
Oh, and I got the "dome" light on the rear view mirror to work yesterday, just in time for winter.

Cheers!


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## loopylupine (Jan 1, 2014)

Installed a front disc brake kit today and adjusted the rear brakes. the EMPI kit was pretty easy to install. Took a little test drive for a couple miles and it definitely stops better! 
I got a little square electric heater and will be making a duct for it hopefully this weekend so I have some cabin heat and defrost... It will use the defrost fan to draw air through the heating element that will run off of pack voltage- winter just around the corner.

That's all for now...


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## piotrsko (Dec 9, 2007)

GOOD thing it's a round window super. Flat windows take a months work of work to get warm after sealing the trunk.


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## loopylupine (Jan 1, 2014)

piotrsko said:


> GOOD thing it's a round window super. Flat windows take a months work of work to get warm after sealing the trunk.


 Hopefully it won't take months... but I do have some window rubber to replace to reduce some drafts...


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## akseminole (Jan 5, 2014)

Hi, I am wondering what you used to insulate your battery boxes and how much R value that you went with?

What are the coldest temperatures that you are likely to see in Homer?


I had a hair brained idea earlier, (I'm still in the planning and research stage)
I wonder if anyone has ever considered using a large Coleman cooler as a battery box? I'm thinking about the 70-150 quart sizes. Idk what the R value of one is, or if it would be adequate to protect the batteries in a battery box kind of way.

My project vehicle to be is a vw Sandrail/dune buggy which currently has one of those Keg style gas tanks on it. It seems the appropriate replacement for that kind of stylistic affectation would be a Coleman cooler(or maybe a yeti or pelican for greater strength and R value)...

It was mostly a passing idea, I'm not attached to it, but if it'll work I think it would look the part.

My other ideas involve using aerogel insulating blankets, which are capable of R10 per inch and just using a standard sheet metal style box. Which would probably weigh less, be stronger and have a higher R value, but just wouldn't have that same "*******" engineering aesthetic to it.

My other question is how much heat does using the coolant from the controller put into your vehicle through the heater core?

I had been thinking about this for some time and I've wondered why all these people opt to simply dump their waste heat and use a supplemental heater to heat their cab. (Even if the waste heat by itself is inadequate to fully heat the cab, it seems that using it with a heat exchanger on the cold side of an inline coolant heater would reduce the watts that you have to feed into the heater)

If your controller is putting off waste heat, why Not route it through the cabin heater core on its way to the primary radiator? It seems like it brings up the efficiency of the system by at least not wasting those BTU. 
So I am gratified to see that you've implemented it into your design.

I'm considering using coolant waste heat to warm my battery boxes, possibly using a radiant floor heater kit under the batteries or something. With the sand rails open design, using the heat for my "cabin" just seems silly, but I don't want to waste those watts into the open air if I don't have to.

Thank you for your build thread, it helps to see what solutions people in my state come up with. No offense to the many knowledgeable people on this forum, but, lower 48 folk don't have as helpful a grasp on the situation here as they might if they lived here themselves.


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## loopylupine (Jan 1, 2014)

Hi AKseminole,
I used 3/4" rigid foil faced insulation on the battery boxes. I'm not sure the R value, it's probably printed on there, but I can't see it. We really don't get too cold down here, it's common to be just in the 20's (F) a lot. Sometimes it will be below zero for a little while, but nothing like Fairbanks..

Not sure about the cooler idea, probably won't get a lot of r value out of those, but it would look Alaskan for sure.

Regarding the controller waste heat, yes I have it pumping first through a fan coil under the back seat, driver side, and it makes a little heat, but not much. Of course, I go down hill to town in the morning, so it is pretty useless at that time. Then it's warmer in the afternoon on my way home so I really don't need it, maybe in a month...
I added a ceramic heater that is switched by the defroster fan. Finally got it hooked up last weekend. It makes a reasonable amount of heat, but I fried a couple relays setting it up, and it stayed on a little after the fan went off one time, and melted a bit of the ceramic heater surround. It's about 4"x4", 1500 watts, draws about 9 amps from the traction pack. 
Hopefully that smell will go away soon, it still is lingering, but is not melting during operation now as I have a high voltage contactor running it, and I have been checking on it a lot.
Anyway, for heating your battery boxes, I think electric would be better and easier to control the temperature than trying to use the coolant from the controller.

Cheers,


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## loopylupine (Jan 1, 2014)

This past week I replaced the smelly ceramic heater core with melted plastic on it with a new one and installed with high temp silicone. It is working nicely for cabin heat and no smell. The defroster fan is a bit loud, but once I'm rolling it's not too bad.
Also I wired up my battery box heaters. They are heating pads installed under the metal boxes, inside the insulation. There is a temp sensor on one box and a STC1000 controller set at 8 degrees C. Last night it was down to just about freezing and the total usage for the night heating the batteries was about 0.45 AH. I can live with that. The bug was in the unheated shop with the door open. There are some insulation details around the top of the battery boxes that I should attend to before winter really sets in.

Any recommendations for temp setting on the battery boxes? Would 5 C be enough? 2 C? What do you guys use?
The way I understand it they just need to be above freezing for charging, but also there is some performance loss near freezing, so that is why I chose 8 (about 45 F).


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## Yabert (Feb 7, 2010)

loopylupine said:


> The way I understand it they just need to be above freezing for charging, but also there is some performance loss near freezing, so that is why I chose 8 (about 45 F).


 8°C sound right to me. That seem to be a good compromise between energy consumption(heat), possible performance obtainable from the cells and keep battery over freezing temperature for safe charge.
Then, if voltage sag is too high, increase the temperature...


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## loopylupine (Jan 1, 2014)

Thanks Yabert. What would you say constitutes too much voltage sag??
Nominally I have 144v.


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## akseminole (Jan 5, 2014)

Hello, I am interested in a status update? How has your car been doing this winter(if you have been using it in winter)?

A side question: Does it get cold enough in the Homer area for them to provide car plug ins for winterized cars? If so, do you charge from them?

Thank you.


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