What Happens When You Short Out The Pack

Here is why I always wear gloves and eye protection!

Today, I was doing the spring battery maintenance, which consisted of topping off the water and tightening the battery terminal connections. For the tightning, I use a 1/2" box end wrench that is wrapped with electrical tape. The only exposed part is the box end.

Today, however, I needed an extra wrench and I just grabbed another, unwrapped wrench. Unfortunately, it slipped and shorted across the entire pack of batteries in the rear of the car. This was "only" eight of the sixteen in the car. When it crossed the terminals, it was like a Fourth of July display, with hot molten steel flying in all directions. I can't imagine what would happen if full pack had been shorted.

In the second picture, you can see chunks of molten steel and tracks across the battery tops where the hot metal rolled across.

Word to EV builders and owners: BE CAREFUL.

Possible Design Defect

In my opinion there is a design defect in the Electro Automotive VW wiring scheme:

I have lost two 12 vdc vehicle aux. batteries. Last week, the second aux. battery ended up fully discharged … and frozen. (The temp in my barn has been in the 0-25 deg. F range.)

Remember from my last blog entry, I discussed long maintenance charges?

Here's the problem:

Whenever external power is plugged into the car outlet for charging, the 12vdc fan is activated to ventilate the rear battery box. The fan is powered from the aux. battery During this time, there is no recharging of the aux. battery. It's the same as leaving the car lights ON, when leaving the car ... albeit, with a much lower current draw.

I frequently plug in my charger in the afternoon, upon return home, and leave it ON all night, as my PFC-20, turns OFF at the appropriate time. It seemed like there was no downside to this technique. Several times, when the power was plugged in for extended times, even with the charger OFF, the aux. battery became fully discharged, eventually resulting in my buying a new battery.

During the worst of this winter, my car stays in the barn. In order to preserve the batteries, I use my PFC 20 to frequently charge the batteries. Last week, I left the charger on for 24 hours, in 10 deg. weather, with the charger set at the appropriate float voltage. When I checked later, I discovered the fan stopped, the aux, battery dead ... and frozen! I now have to buy another new battery.

I think it's a poor design to run the battery box ventilator with a 12vdc fan, powered from a source that isn't kept charged. I plan on replacing the fan, ASAP, with a 120vac fan that runs from external house power whenever the vehicle is plugged in.

If this situation applies to you, I suggest you replace the 12vdc fan with a 125vac fan, wired in appropriately.

Just my opinion.

Winter Upkeep: Part 2

In battery lore, there are two critical numbers: The first is the "Charge to" voltage, sometimes referred to as the "Acceptance" voltage. This the the voltage the pack should be charged to after usage. The second number is the "float" voltage. This is the voltage the pack should be held to when not being used i.e., the pack should float along at this voltage when idle. Both voltages are computed, based upon battery type and battery temperatures, among other things.

In the case of my pack, the float voltage at the 30-35 deg.F, is 105.95 - 106.25 volts. Using a thermometer, my PFC20 charger and a lab quality digital voltmeter, I am going to float the pack for a day, or so, to do a rather lengthy "equalizing balance."

(CLICK photo for a larger image)

Winter Upkeep

It's not the best electric vehicle weather ... especially considering that we're having a hard time even getting our Volvo XC90 (4-wheel drive!) out to the county road.

So, for the time being the VW is staying in the unheated garage/barn. While there, I'm being very careful to keep the batteries fully charged. I have a chart from the battery manufacturer (U S Battery) that states the "charge to" and "float" voltages. Using my HP precision digital voltmeter to monitor my Manzanita Micro PFC20 charger, I periodically do a charge to the "charge to" voltage, followed by a 30-min equalizing charge. This is the same technique I used last year. Even though the vehicle sat for about three months in temperatures as low as -10 degF, when I reactivated the VW, last spring, I saw virtually no loss from the batteries! I hope I can say the same thing this spring!

As far as the video, I mentioned in an earlier blog, that will have to wait until spring. I will get it done ... promise!

No Heat - No Problem

For some time now, I have been "getting ready" to take on the task of adding a heater to the Cabbie. There are, by my count, about three reasonable possibilities:



Option One: Replace the old hot water heater with an electric ceramic element. The ceramic element would be installed in the original VW heater box, along with the appropriate electric controls to run it. This would make a nice professional installation and the heater would function much like the original VW unit. I actually have all the parts gathered together ... I just haven't gotten around to it.



Option Two: I have read about several heater installations involving conventional hair driers. Since the hair drier really doesn't care if it's plugged into the household 115 vac outlet or my 98-volt DC battery pack, the hair drier will run just fine (maybe even better!) and put out copious amounts of hot air. Some builders have stuck the end of the drier into one of the car's air vent lines and simply switched it ON/OFF manually. An advantage of the hair drier is it can be pointed directly at the windshield for fast defrost or defog. I'm thinking: If I constructed a small metal box as a "docking station" to hold the hair drier, the box could direct the warm air from the drier into the cabin area. Then if I needed defrosting or defogging, I just lift the hair drier from it's "docking station", then return it when the windshield has been cleared. I actually am beginning to favor this approach ... to the point that I will probably give it a try ... after I get tired of Option Three!



Option Three: Do nothing! I've been driving quite a bit in 25-28 deg. F, weather with no heater and it really isn't all that bad! With a warm coat, light gloves and a warm hat, I don't mind it that much during my nine-mile work commute. After all, it would usually take three or four miles for a conventional car to warm up, so you would dress warmly, anyway.



BOTTOM LINE: Don't get too worked up over how to get heat into your conversion. Just make sure all the holes in the vehicle firewall are plugged. I had one pretty good sized hole where the old heater assembly came out and that let in a lot of cold air, while driving. Once the air leaks were plugged, as I mentioned, "It really isn't all that bad."



HINT: If I have the chance, I "pre-heat" the cabin, using a small 115 vac ceramic type heater. (Yes, the one that I planned on taking apart to permanently install in the car.) If I know I'll be driving in 15-30 minutes, I put the heater on the floor of the passenger side, being EXTREMELY careful that it isn't in any position to overheat any part of the car (Like in: Catch on fire!) The warmed up car feels pretty good and the heat will persist for several miles.

What it like to drive an EV

Stay Tuned:

Before too long I'll grab the video camera and take you on an informative tour and ride in my "Electric VW."

Road Report

It's been about two weeks since I have the car back on the road after the front end rebuild.

It drives almost like a new car. I am particularily impressed with the Bilstein shocks. The ride is "Euro-Firm." I like it: It reminds me of my last Audi i.e., great road feel and very positive steering. It also helped to get the lower anti-roll bar reinstalled, along with the upper strut tower support fixture. (I have to ask myself: "Why didn't I do this sooner?")

Next project will be headlights and heater.