Just bought a Zap Xebra PK!

[voxelman]

Saturday a week ago my wife and I took ownership (with the bank) of a brand new Zap Xebra PK (for pickup). It's designated a 3 wheel motorcycle by the government but its pure EV. The PK model seats two and has a total payload capacity of about 500lbs.

The drive train consists of 6 deep cycle 100 amp-hour lead acid batteries wired in series that drive a 5 kilowatt (this is about 6.5 hp) electric motor through a Curtis controller with 72 volts. The batteries charge from a standard 15 amp electrical outlet and a full charge requires 6-8 hours.

Top speed is around 40 mph on level ground with a range of about 25 miles at an average speed of 30 mph. This latter figure requires a battery break-in period of about 100-200 miles.

I'm taking it very easy on the batteries because they are very susceptible to harsh treatment during the break-in period and at $2200 and up for a replacement set early retirement makes all claims of economy go out the window.

I am in the process of instrumenting the batteries with a PakTrakr, a device that monitors and records the voltage level of each of the batteries and the current being drawn or supplied to the pack once a second. In addition I am adding two other devices, a BattEQ and a Battery Life Saver that can potentially extend battery life. The BattEQ interconnects all 6 batteries and automatically equalizes the voltages. The Battery Life Saver prevents and removes sulfation.

While there are probably better EVs out there this one had a reasonable price (it lists for $12,500) and it seems very hackable.

The Xebra is supported by an active Yahoo group, Xebra_EV that is a treasure trove of information for owners. Several of the group members are Zap dealers and they readily contribute to discussions.

I’m keeping a Kill-A-Watt attached to the charging outlet and so far after three days of light use it is telling me that I can expect a total electrical use of about $42/year assuming .10/kilowatt-hr electricity.

The adventure begins...

[SVOboy]

Nice! I've heard a lot about these! Looking forward to your impressions!

[voxelman]

Originally Posted by SVOboy

Nice! I've heard a lot about these! Looking forward to your impressions!

So far it is about what I expected. I made the purchase after reading a lot of the Xebra_EV discussion. Much of it is about problems that owners were and are encountering.

What I like most is that it provides basic transportation within my range requirement. It was quite inexpensive. 2 cents per mile for the electricity.

What I don't like is its very harsh ride. There is an aftermarket spring kit that is supposed to improve the ride. At $450 it will have to wait until the battery care equipment is installed and the bank account has recovered from that $700+ expense.

My biggest concerns are cold weather performance and battery survival.

On the battery front there is good news. See www.fireflyenergy.com

[cfg83]

voxelman -

Welcome to EM! It's great to have someone with a real Zap on board. I think the pickup is the most practical Zap to have.

CarloSW2

[MetroMPG]

Interesting. Thanks for the details.

You're smart to have invested in battery monitoring (Pak Trakr). Same idea as the LED pack monitor we stuck in the ForkenSwift recently, but fancier. And with memory!

I'd be very interested to know your efficiency - kWh consumption per mile. Are you keeping a log?

[ebacherville]

very cool.. now if you can mod that thing to get 50mph and 60 mile range id buy one.. without a decent range and speed it just wont work for me... but if i were in a city , heck ya id have a electric like that.

[voxelman]

Originally Posted by MetroMPG

Interesting. Thanks for the details.

You're smart to have invested in battery monitoring (Pak Trakr). Same idea as the LED pack monitor we stuck in the ForkenSwift recently, but fancier. And with memory!

I'd be very interested to know your efficiency - kWh consumption per mile. Are you keeping a log?

I am currently keeping a paper log and I have a Kill-A-Watt on the extension cord that feeds it while it rests in its crib at night. As things evolve I am going to integrate a GPS tracker into the data stream that comes from the PakTrakr. The odometer is notoriously inaccurate so it is that or pay nearly $300 to get the speedometer calibrated.

In round numbers it takes about 4.7kWh to bring the batteries to a full charge when they are broken in. If the car is driven on the straight and level at about 30 mph in temperate weather it will go about 25 miles on a fully conditioned set of fresh batteries. Starting and stopping, hills, cold weather and higher speeds will reduce this figure.

An ideal calculation is 4.7kWh/25= .188kWh/mile. Since the Kill-a-Watt records every watt-hour going in it should give a fairly reliable accounting of my electrical usage. Right now after just three or four days of history it is estimating a yearly cost of about $85.

However, there is a rather nasty secret hiding behind this number called per mile battery cost (PMBC). The replacement cost of the Xebra’s current set of batteries is about $2200. If my average annual usage is 3,000 miles (probably high as I live in a small rural community in south east Iowa) then if the pack fails after 1 year my PMBC will be 73 cents/mile. Clearly electricity cost is negligible if the batteries fail early.

From my reading early failure or significant degradation is a real possibility if the pack isn’t managed carefully. This means not unduly stressing the pack with discharges greater than 50%, monitoring individual battery voltages and balancing the pack so that all of the batteries share the load equally, using available technical means to fight sulfation and keeping the pack fully charged.

Cold weather is also a challenge that must be met since the chemical processes that underlie battery performance are degraded at low temperatures. Iowa is cold and windy in the winter. If I am able to maintain these batteries for 5 years or 15,000 miles I might achieve a PMBC of 14.6 cents/mile. My 1991 Honda Accord gets 20 mpg city without much effort on my part. At $4/gallon for gas that works out to 20 cents/mile and it has a whole raft of creature comforts that the Xebra is lacking.

There is a saying in EV circles that your first set of batteries is sacrificed to the learning curve. Forewarned is forearmed. I’m trying to do this right and I’m willing to invest considerable time and energy in making this experiment a success. But as in all experiments the real results may not be what we wish for.

[MetroMPG]

188 Wh/mi would be a VERY respectable figure. At least based on what I've seen with the ForkenSwift (best drive/charge cycle to date is 244 Wh/mi).

Sounds like you're far more aware than the average person about the risks and precautions necessary to preserve battery life.

Please keep us updated.

[Ryland]

I have the paktraker as well and it is an amazing gauge, I would guess that it will pay for it's self in battery savings because of how accurate it is and the warningas that it gives you.

[voxelman]

Sorry for the long silence on this thread but here is a brief update.

Paktrakr, BattEQ and Battery Life Saver are all installed and working. Also installed Norm Woodward's spring upgrade and it has produced a real improvement in the ride. Norm's display and data capture add on for the Paktrakr has been purchased but isn't installed yet.

Casper (It's been named) is currently grounded because it's owners found out they are required to have a motorcycle license to drive it in Iowa. We have our learner's permits but have to organize getting Casper to the nearest driving test location which is beyond his range.

Prior to the grounding the following numbers were observed for energy consumption:

Date KWH Miles KWH/Mile Miles/KWH.
7/1/2008 2.22 5.5 0.404 2.477
7/2/2008 5.11 14.3 0.357 2.798
7/3/2008 2.20 4.8 0.458 2.182
7/4/2008 1.15 2.6 0.442 2.261
7/5/2008 5.67 18.0 0.315 3.175
7/6/2008 3.29 9.8 0.336 2.979
7/7/2008 3.52 11.1 0.317 3.153
7/8/2008 2.05 3.2 0.641 1.561
7/9/2008 2.17 4.3 0.505 1.982
7/10/2008 2.53 5.2 0.487 2.055
7/11/2008 3.15 6.1 0.516 1.937

This is a total of 84.9 miles within the first 200 miles of use. For
an average of .389 KWH/mile or 2.568 miles/KWH. This is about what is expected for early stage performance. Others are reporting closer to .3KWH/Mile or 3 miles/KWH.

That's all for now. Those interested in a broader view of the trials and tribulations of being a Xebra owner should check out the Yahoo group xebra_ev.