The Elec-Trak E15 Electric Tractor and PV System

This is our project to recondition and E15 Elec-Trak electric tractor. The aim is to get the Elec Trak into good enough shape for lawn mowing and snow throwing tasks as well as (hopefully) to integrate the tractor with my existing grid-tied PV system so that

I'd especially like to thank Mark Frerking who not only wrote the article below for Build-It-Solar on the Elec-Track, but also found the Elec-Track that I bought, and has also been a great source of information on rebuild -- Thank you Mark!!

I bought the E15 used from Joe in Colorado Springs and hauled it all the way up to Bozeman in a small trailer behind our Honda Pilot. I'd like to thank Joe and son for being patient and very helpful through working out the pick up logistics, the loading, and passing on a lot of useful information about this E15.

What's an Elec-Track?

In a nutshell, the Elec Trak tractor was a GE product in the 70's. It is a series of electric tractors and mowers that use an onboard bank of lead acid batteries to power the tractor and also to power a large array of accessories that GE offered. There were something of the order of 30,000 of these tractors made by GE and the companies that GE sold the operation to. The machines are very functional and very durable. The Elec Traks have developed a devoted set of followers and there are probably thousands of them running and being restored -- this is pretty impressive given that the last new one left the factory in early 80's. There is also an active Elec Track online owners club and a couple of good places to get parts from.

If you are interested in learning more about the Elec-Track, here are a few good sources of info:

- An Elec-Trak description and history from Mark...

- The Elec-Trak Owners Club Online Forum...

- Georges most excellent My Elec-Traks site...

I particularly like George's site -- he has an incredible collection of beautifully restored Elec-Traks. There is also a lot of very good Elec Trak reference material on the site, including many of the original manuals. Note also the solar electric array on the Elec-Trak barn roof!

Mark's beautifully restored E20

One of George's many restored Elec Traks

Goals for our Elec-Trak Project

1 - Mow the Lawn and Blow the Snow

The immediate aim is to get the tractor back into condition to mow our much too large lawn (about an acre), and also to do some of the snow plowing chores in the winter. The tractor came with a mower deck, a front mount blade, and a 42 inch snow blower as attachments. Until recently, the tractor was being used, so I'm starting from a pretty good base.

When I got the Elec Trak, the battery pack had about had it, and there is quite a bit of rust to clean up, and a few things to fix. But, I had the advantage of starting with an Elec Trak that had until recently been used.

Here are the details on putting a bit more life in my E15:

- Cleaning up the rust, painting, ...

- A new set of batteries and cables...

- Fixing a few things...

- The new charger/inverter...

- The snow blower and mower deck...

2 - Solar Charging the Elec Trak

My initial goal was to have a dedicated solar array and charge controller to charge the Elec Trak batteries. This seemed like a nice clean solution, but the more I thought about it, the more it appeared to make more sense to just charge the Elec Trak from grid power and to expand my existing grid tied PV array to cover the extra Elec Trak energy usage. This way the PV panels can be active all the time, instead of dedicating PV panels to the Elec Trak that would only be used a small part of the time. We have been planning to expand the PV array anyway, so this just makes the expansion a bit larger. This approach also fits in well with the scheme to integrate the Elec Trak with out current PV array to provide power during power outages.

3 - Integrate With Current Grid-Tied PV System for Emergency Power

We currently have a grid-tied PV system that works very well and that helps us offset some of our electricity consumption. But, as with all grid-tied systems that do not have battery backup, when the grid power goes down, our grid-tied PV system also goes down -- so, no power from PV in power outages.

My aim for an extended power outage is to use the Elec-Trak battery pack with an inverter to supply power to the house, and to do reconnect of the PV modules in our grid tied system to feed a regular PV system charge controller to charge the Elec-Trak battery pack during the day.

The battery pack will supply about 5 KWH of usable stored energy, and this is enough to supply a few key loads via extension cords for an extended power outage. The loads would include fridge, a few lights, the furnace, and a few other odds and ends like a laptop and small TV. To charge the Elec Track battery pack, six of the PV panels in our existing grid tied PV array are reconnected to feed an Xantrex MPPT charge controller. This provides enough power to fully recharge the Elec Trak pack on a sunny day, and to provide a good charge even on a not so sunny day.

Back when we put in the original PV system, I thought about putting in a grid-tied with battery backup, but the added cost of the fancier inverter and a battery pack plus the long term cost of maintaining and replacing a battery pack just seemed not to be worth it. This is especially true given that our power is reliable, and the battery pack would just be sitting there doing nothing 99.9% of the time. Putting the Elec-Trak battery pack into service for backup power is really appealing to me in that its a battery pack that is already earning its keep with lawn chores, and this is a chance to let it take on another job without adding more battery pack expense and maintenance.

All the details on how this emergency power scheme works and the first test results here...

Elec Trak ready to be charged by PV

The Xantrex Charge Controller
and fused disconnect below.

Its cloudy, but still getting
286 watts of charge.
Sunny conditions charge
should be over 1200 watts.

The charge controller, cables, etc.
ready to go back to the barn
where they live between
power outages.