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Old 15-09-2018
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devans devans is offline
dbw Pro Legend
Join Date: Apr 2013
Location: Brisbane
Posts: 1,256
Lithium-ion battery or regulator fault?

I have a 2015 300 SEF-R Factory model that has never missed a beat since new. On Friday before a two day ride I replaced the original Yuasa battery with a Lithium-ion battery. It started fine after fitting the battery, and started fine the morning of the ride. However over the course of the weekend it was hit and miss. Sometimes the bike would start fine and then other times was completely dead .i.e. no headlight or fuel pump prime. I checked fuses and connections and couldn't find my issues.

On Monday after arriving home I tested it with a multimeter and had the following results.
Connected but ignition off:
New Lithium-ion battery - 14.42v
Original Yuasa battery - 12.62v

Ignition on but engine not running:
New Lithium-ion battery - 0.174v
Original Yuasa battery - 12.12v

Engine running:
New Lithium-ion battery - Bike would not start i.e. no lights, no fuel pump prime. This was after two days & 100+ Km's of riding.
Original Yuasa battery - 15.52v

I connected the Lithium-ion battery again after starting the bike using the original Yuasa battery. It took 3 attempts to turn over & was sluggish. Once running it was outputting 15.4v. I tested it again with the ignition on but engine off and got 13v this time.

A couple of people have said my bike shouldn't be putting out more than 15v. Are maintenance free lead-calcium batteries more tolerable of higher voltage output, as I've never had an issue with the Yuasa YTX5L-BS battery? It would be highly unlikely the regulator became faulty at the same time I purchased an Li battery.

I've submitted a warranty claim on the battery, but am wondering if anyone else has experienced this with a Lithium-ion battery, in particular on a 2015 model SEF-R?
2015 Sherco 300SEF-R Factory
Past: '73 Kawasaki KV75, '86 Suzuki RH250, '96 Husqvarna WR250, '76 Honda CR125 (Vintage MX), '11 Suzuki DR-Z70, '00 Kawasaki KDX200, 2015 Kawasaki KLX110.
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