Archive for the 'Electric Bug' Category

I’m working on getting pictures of my car with other’s of its kind (but more modern, in general).

Silver Leaf, at Apple.

RAV 4 EV (in Santa Cruz, today). Ken Adelman’s car.

Blue leaf, Cupertino.

Chevy Volt (does that one count?)

…with Girlventures!

The Elithion Lithiumate BMS uses a serial cable to talk to the computer. That’s kind of a pain to see additional information that the SOC display doesn’t tell me. It is also nice to see how the batteries are doing “on the fly”, or when I’m charging at work.

I bought a WiSnap and made a little case for it:

The red/black cord is for a 9v power supply, but it doesn’t need it as it can get its power from the RS-232 input. I can now connect to an adhoc Wifi network with my iPhone (dubbed “PlugBugBMS”) and see all the serial data from the BMS controller. Pretty cool!

I still want a better display, and eventually I want some easy software that displays cool battery status in a nice graphical package. I thought the serial port might be good to do it, but it won’t work. I need to tap the CAN bus line and somehow emit the data to my phone. Bluetooth would work, but the bluetooth connection kit (and SDK) for the iPhone is not free. I’m also not sure if the iPhone can connect to more than one bluetooth device, and I really want it to always connect to my hands free headset and car stereo. Now…only if that bluetooth device could tap into the CAN bus and report additional packets of information to a custom app on the iPhone…

I got my charger back from Manzanita last thursday and put it in the car Friday night. They weren’t sure why it busted, but the bridge rectifier had to be replaced, and they did some general tune ups. Unfortunately, it was out of warranty, so I had to pay out of pocket for it. But oh well…I’m still saving money on gas!

Here’s a picture of my charger’s bracket to allow me to mount it horizontally:

I also got my Belktronix DC-DC converter to replace my ailing IOTA DLS-55. Good news from IOTA is that they are taking the issues I brought up to heart, and apparently now have a prototype IOTA DLS-55 that is ruggedized and specialized for EV use! Cool! Evolve Electrics is helping them test it out.

Here’s the new DC-DC converter (the big hunk of aluminum):

No fans, so the car is now dead silent again. Yes!

Some other mods an recent issues. My brakes started leaking and went soft one day. The rear line I installed was rubbing against this member and got a small hole that let it leak out:

I replaced it and bent it better.

I had moved the radiator underneath and inline with the car, and covered it by some white screen to protect it:

It didn’t seem to cool the controller quite enough, so I moved it directly into the flow of the air. This involved some new pipes:

A new bracket:

And mounted:

The fans are still on it, but I may not need them anymore. They are still controlled by a temp switch:

I now have over 3000 miles on my car. Up till today, the only problems I have had have been with the IOTA DC-DC Converter. I’m supposed to have a replacement soon, as my IOTA may fail again at any moment.

Now that I have some driving experience, I have a better idea of the range. It’s not good to say that an electric car gets X mile range, since X various by many factors. Those factors are: how heavy you are with the pedal to accelerate, how hard and often you brake, how many hills you drive up and how fast you drive. I have one big hill on my commute (or, when I go *anywhere*), so I can never remove that factor, and I always want to drive at least the speed limit. But I can control how “soft” I drive.

If I drive the car “soft”, meaning reasonable acceleration and driving at the speed limits on the freeway (usually 65 mph), I could get a 100 mile range to 0% State of Charge (SOC). Last Sunday I drove 64 miles according to my odometer (or, about 62 miles according to google maps). The BMS said it took 122.3 Amp-hours and the SOC was at 39%. This drive was mostly at 65mph, aside from the 2 miles driving up my “driveway”, and then going 50-55 up and down highway 17. I had maybe one stop light each way on my trip. 122.3Ah * 48 (number of cells) * 3.2V (nominal voltage per cell) = 18785 Watt-hours (18.8kW). 18785.28Wh / 64 miles = 294 Watt-hours per mile. The batteries are rated at 200Ah. So: 200Ah*48*3.2 = 30720 Watt-hours of energy in the battery. 30720Wh / 294Wh/mile = 104.5 miles.

So, a good “soft driving” estimate for my bug, including a large hill and mostly 65 MPH on the freeway, is 104 miles. Generally, I don’t want to do this, as taking the battery lower than 20% is not good for cycle life. I also don’t have my BMS setup to limit power when voltage drops to a certain level, so it is dangerous (meaning, I could cause damage to expensive cells).

If you are doing a bug conversion, use about 300 Wh/mile as an estimate for what you can get. I rarely get better Wh/mile, but that is because of my huge hill I drive up. Wh/mile would be better if I didn’t live in the Santa Cruz mountains.

Now, if I drive “harder” I can get about 375 Wh/mile. That’s about an 82 mile range. So, I can probably safely say my range is from 70 to 100 miles per charge, but I probably won’t want to go more than 80 miles to keep it “on the safe side”.

Today when I went to grab my car at lunch I discovered that the Manzanita Micro PFC-30 charger wasn’t charging. I looked at it, and the BMS (Battery Management System) also wasn’t on. The BMS is turned on along with the charger when I plug it into an outlet. So, I realized the 50 amp / 240VAC circuit breaker must have tripped. I plugged the car into another nearby 50 amp circuit, since I couldn’t reset the breaker and there was another charging station right next to where I was. The BMS came on, but the charger wasn’t charging. It also had flipped its little breaker on the charger (also known as the power switch), so I flipped it back on, and it went “pop” as it immediately flipped back off . It also tripped the 50 amp main breaker on that outlet too. Ah, bummer!

So I emailed Evolve Electrics and Justin is having me mail the charger back to Manzanita. I have followed the instructions to the T, so I’m hoping it is covered by warranty. I’m also quite curious as to what is wrong, since I’ve charged the same way nearly every day.

I also took a look at the BMS stats; 812 kWh have been put into the battery pack. I think the BMS got reset once when I had it upgraded.

Hopefully I remember how to pump gas!

I’m ditching my IOTA DLS-55 DC-DC converter. The inrush limiter I use (which replaced the AC bridge rectifier) eventually dries out and cracks, and then stops working. I got ~1000 miles on my last modification (I’m at ~1700 miles right now).

So, I’m doing research on what is out there to hopefully make the right choice. I’m only listing ones that I could actually use (ie: rated > 25amps, ideally higher, and have an input voltage appropriate for my pack at 154v nominal).

Belktronix – $300
675W ( up to 55 amps) 120V-350V (based on application)
Great support from the owner/creator – Bryan.
http://www.belktronix.com/isodcdc.html
http://www.belktronix.com/pricing.html

Cloud Electric generic brand. $280
Probably the same as the Kelly, but has a bit higher output, which I like.
132-168V nominal input 13.6V / 35A out (sealed type)
http://www.cloudelectric.com/category_s/8344.htm
Which are these ones imported from China: http://www.hztiecheng.com/english/ specifically: http://www.hztiecheng.com/english/Product/T16/38.html

Others that might meet my needs, but have concerns:

Vicor: 150V Input Maxi Family DC-DC Converter – $280′ish
But, these are just the bricks and not a complete system! Vicor produces high quality parts, from what I hear
http://cdn.vicorpower.com/documents/datasheets/ds_150vin-maxi-family.pdf
http://vdac.vicorpower.com/vdac/predefined/00predef-mods.asp

Kelly HWZ Series DC/DC Converter 156V to 13.5V 25A – $150
I’ve heard from two sources that Kellys are bad. Another source (Travis) has had good success with them.
http://kellycontroller.com/hwz-series-dcdc-converter-156v-to-135v-25a-p-536.html

Zivan – $498 – $525
14vdc / 60 amps output. I’m not so sure about the Zivan, since they seem to be more of an AC-DC charger, than a purely designed DC-DC converter. It looks like they come with an AC plug, which I don’t want. I want something designed for a car.
http://store.kta-ev.com/zivandc-dcconv100-200vinp.aspx
http://www.evolveelectrics.com/DC-DC%20Converters.html#elcondcdc

Elcon – $250, 25amps out
These seem to be the same one as the generic Cloud Electric ones, just rebranded. The pictures and part numbers are identical.
http://www.evolveelectrics.com/DC-DC%20Converters.html

So, I’m opting for the Belktronix — it gives the most output (35 amps) with no fans, and higher output if you cool it (up to 55amps). Plus, Bryan is quick to answer emails and seems to really support his products. Unfortunately, it has a 3-4 week lead time, and right now I’m using my car with the temporary fix again (another inrush limiter) which could fail at anytime.

How much would it cost me to drive a gas car for 4 weeks, assuming I can charge at work for free? I drive 40 miles/day on normal, and 50 miles when I got to the gym (twice a week). 40*3 + 50*2 = 120 +100 = 220 miles / week for 4 weeks gives: 880 miles. Say I drive the old Ford Focus we have, ~30mpg: 880/30 = ~29.3 gallons of gas. Times $4/gallon (which it basically is here in CA): $117. It would be worth it that much for me to get the converter earlier to avoid using the gas car. (NOTE: Edited my math).

I never knew much about how I paid for electricity. I didn’t know if we had certain hours that were peak or not. So, I called PG&E last week and they explained to me I was on the E1 rate. I told them I had an EV, and they suggested I go to E9 A or E9 B. They are listed here: http://pge.com/tariffs/ERS.SHTML#ERS

Like any good programmer, I decided to do my homework before blindly switching. It turns out that after I did the math, a PG&E representative told me they have a comparison spread sheet on their Plug-In Electric Vehicles page (here’s a direct link to the excel spreadsheet). That page seems to lump a bunch of assumptions together about energy use, but I found that page to be quite accurate in its rough estimates.

First, I wanted to understand the E1 rate. I made a spreadsheet in numbers that included the rates for E1 and E9. They charge a certain amount for a baseline kWh used, and then different amounts based on how much you go over:

Currently on days that I charge, I’m using ~1000kWh/day. Yikes…that’s a lot. Our new hot tub also dramatically increased the energy we use.

Based on the E9 rates, I did a quick hack comparison if I was charged that rate for the energy used:

Obviously, E9 Peek would be more. But, the key thing is E9 partial peak is lower, and when averaged with E9 off peak my total cost will definitely be lower. Here’s my spreadsheet (using Numbers on the Mac), which includes kWh used over a month. Change the values in the green cells to see updated costs change.

I also downloaded some of my day-to-day energy uses for a weekday and weekend. They include an hour-by-hour of when you used how much energy. I simply dropped the base E9 cost (based on the hour) in to compare it to the base E1 cost they already had listed. I did this on some days when I know I charged at a certain hour; although, I also assume I would move charging to off peak hours to get the best rates. My test showed that I could easily save 15%, and potentially up to 30%. So, all this data tells me to switch.

For the E9 rate, you pay based on the time of use. I made a little chart in numbers to get an idea of what rates occur when (click to download that file):

That will be handy for knowing when I should do laundry and charge the car. I now need to get an 240v AC relay to turn the car on and off automatically during off peak hours.

Here were a few recommendations from the nice people on the EVDL email list:

http://www.smarthome.com/48781/Intermatic-T101P3-SPST-Pool-Spa-Time-Switch-in-Plastic-Enclosure/p.aspx

http://www.smarthome.com/48760/Intermatic-P1121-Portable-15-Amp-Outdoor-Timer-Heavy-Duty-Outdoor-Timer/p.aspx

http://discountsales.com/shop/module.php?module=show_product&id=1161208837

The loudest part of my car when I turned it on was two fans for the water cooling setup on the controller. Ideally, the controller should turn the fans on and off and that will be a nice feature once Netgain Controls adds it in. For now, I needed a solution. Wayne, a fellow bug EV’er in Gilroy, suggested the a little CanaKit thermostat. I bought it and assembled it, which was pretty fun since I haven’t ever built any electronic kits before.

I then made a little box to surround it out of Lexan. Sorry…no pictures, but basically I heated up the lexan with a torch and bent it with a little jig I made. It worked out okay. I then mounted it in the car and set it to control the fans. The temp sensor is mounted on wires, and I simply zip-tied and taped the sensor around one of the water tubes to sense the water temperature. The water pump still runs all the time, but that’s okay as it is rather quiet. I tweaked the temp pot so that it doesn’t turn on when the car is cold, but does turn on once it has warmed up.

Now, the car has a nice silent drive when I start out. Perfect! Just what I wanted….

I got something I had been dying to get. The bug now has DMV approval to use the carpool lane.