Editor’s Note: In each issue of Snow Goer magazine, our team of experienced product testers reviews various aftermarket products in the Cold Tested department. This review was printed in the December 2013 issue of Snow Goer. Subscribe to Snow Goer now to receive such reviews, 7 times per year delivered to your home.
Lithium batteries power cell phones, cordless tools, pacemakers and more. If they can reliably run the heart of a human, is there any reason why they can’t start the heart of a snowmobile? We installed an EarthX lithium iron phosphate battery on our 2013 Ski-Doo MX Z TNT E-TEC 800R demo snowmobile to find out if the technology has a fighting chance in the cold, harsh environment of snowmobiles.
The EarthX ETX36D battery we tested is a lot smaller, dimensionally, than the original lead-acid battery that came with the snowmobile, so we installed stick-on foam blocks and pads that were included with the lithium battery. Since our test EarthX has come out with another version of the ETX36D that’s the exact size as stock so blocks aren’t necessary. The original version like we tested is still available.
According to a digital shipping scale, the EarthX lithium snowmobile battery weighed 10.5 pounds less than the stock lead-acid battery. Other advantages of the EarthX lithium battery are virtually zero maintenance requirements and long life. Its built-in Battery Management System is designed to extend service life by controlling current and voltage to each individual cell within the battery, which ensures that all cells are recharged to the same voltage as one another. This is important because if one cell goes bad, the whole battery will be shot.
The chemistry of lithium batteries helps them tolerate being in an at-rest state better than lead acid batteries — a real advantage due to the seasonality of snowmobiling. EarthX claims the discharge rate of its batteries is 2 percent per month, while lead acid batteries suffer a 30 percent loss.
The most frigid conditions to which we subjected our EarthX battery were when our MX Z sat outside overnight on a trip in north-central Minnesota. A gas station worker said the air was minus 10 degrees F when we filled up in the morning, and we assume the temperature bottomed out at least a few degrees colder. That morning the engine hesitated to turn over and the battery sounded weak during one revolution, but then it suddenly spun quickly and lit up. Air that registered warmer than zero degrees didn’t phase the EarthX battery.
There’s a reason why the EarthX at first sounded weak below zero. Lithium batteries have more resistance to electrical current in a cold environment than do lead acid batteries. This characteristic means lithium batteries are actually more resistant to lose charge or go dead in cold weather, but if weather is so cold that there isn’t enough electrical current flow, it won’t be able to power a device. Fortunately, lithium batteries quickly heat up with use.
Within a half second of when an EarthX lithium battery is called to task — such as spinning a starter motor — that small draw on the battery creates enough internal heat to make resistance drop to a normal level so it can sufficiently power the snowmobile starter motor.
Priced at $349, EarthX lithium-iron phosphate batteries are expensive, no doubt, but major weight loss, less maintenance and claimed longer service life are real advantages.