Ultracapacitors, Are they worth it?,...

[JimT]

I know this is a bit of an old thread at this point, but figured I'd add some updated information.

RIP Maxwell.

Maxwell as a company got bought out by Tesla some years back, mainly for their patents. Not terribly long after they were sold to a foreign company (i forget the name) which has since discontinued some of the product offerings. The ESM was one of those products. I found this out when my own Maxwell ESM up and died on me. One day it worked fine then it stopped charging. On board diagnostic LED's indicated an internal fault. Went to look for help and discovered the ESM was no more. The Maxwell ESM was installed 9/26/2022 along side new batteries, a new alternator and a new starter. It failed on 7/3/2023 after only 28,000 miles. And no, it wasn't due to dozens of starts per day. I operate regionally (New England) and seasonally 300-600 miles a day. My guess is shock/vibration probably contributed to some internal failure.

The replacement:

In the failed process of looking for a replacement Maxwell I found a new ESM, the SkelStart, made by german company Skeleton Technologies. They advertise it as a super capacitor, but other then 14v output instead of 16v it's spec'd the same as the Maxwell.

Review:

Now I had another thread where I originally mentioned this, but I didn't want to review or endorse it until it proved itself. Well, it's been about 18+ months / 50,000+ miles and I can say It's been solid and has far outlasted the Maxwell. It's worked flawlessly. Even after the tractor sat for 8 months this past year all while the batteries were maintained on a float charge. Starts exactly the same every time. Install is identical to the Maxwell though the terminal layout is in slightly different spots. There's not much else to say. It's a legit product with double the reliability (in my experience) of the Maxwell. You get multiple starts on a single charge. 9-16v input, 14v output, 2130 CCA. A PDF brochure can be found here or here.

Availability:

This was the tricky part. The SkelStart had been readily available in Europe but finding a North American retailer, specifically one in the USA, wasn't as simple. C8 Energy (a canadian company) is the exclusive North American distributor. They do supply a few dealers in the US, but not many physical location stores. I found a few online but they seemed fishy (ebay, find it parts). C8 doesn't list the retailers on their website so I contacted them directly via the contact form on their site. Not only did they confirm the legitimacy of the retailers but they offered to sell me the ESM directly. Priced similar to the Maxwell, it shipped quickly from a PA import warehouse. Honestly if I needed to buy it again I would contact them directly.