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2005 Brutale 750s
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Discussion Starter · #1 ·
Ok I’ll try to keep this as short as possible.
So this past November I put the bike away with no problems and now it’s February with better weather and I wanted to ride. The battery was naturally dead so I just decided to buy a new one but this time a bought Lithium Ion battery for the weight. I install the battery and fire it up, no problem. Now riding, the battery light comes on.
So back at home, I check and the connections are fine but the 30 amp fuse behind the battery under the seat was blown. Put a new one in it and the light it still on. The battery light flickers at idle and is solid at higher rpm while riding.

Now not to sound dumb, but I’m sure it’s not the battery even thought there was nothing wrong before. It sounds like an alternator not charging coincidentally.

Has anyone experienced this? how difficult is it to change the alternato?

Now to check I know I need a multi meter but I don’t have one right now so I get one.

If anyone could help me out that would be great.

Thank you!
 

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First, that fuse should be 40 amp...
Second, lithium can present charging issues if the battery wasn’t properly fully charged prior to installation.
Third, ensure you installed ALL of the wires in their correct locations.
 

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2005 Brutale 750s
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Discussion Starter · #3 ·
First, that fuse should be 40 amp...
Second, lithium can present charging issues if the battery wasn’t properly fully charged prior to installation.
Third, ensure you installed ALL of the wires in their correct locations.
Is this because the alternator has to work harder that I need the 40 amp fuse?
 

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No, the stock fuse is 40 amp. Starting current is very high. The start solenoid wiring should periodically be inspected for corrosion and loose connections. Just give the connections a squeeze with some needle nose pliers to keep a tight clean connection. This is a class problem.
 

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Same thing happened when I put a Shorai battery into my Brutale 750, blew that main large fuse, caused an alternator light until I fixed it (right away hahah), the rest on the SPU are mini type.

it was probably because of improper charging before swapping, you’re supposed to put it on a lithium tender beforehand... whoops.

I’m going to have to disagree with silentservice for the first time ever, I’m fairly certain it’s a 30amp full sized auto fuse for the main circuit. I got like 5 or 6 backups in case it happened again.

Paranoia note: not too long after I did the battery swap my SPU started to go to piss, tach wouldn’t start intermittentlyeventually SPU burst into flames after I shorted a blinker a year or so later. it was the old blue one, not sure if related. Keep an eye out!
 

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I’m going to have to disagree with silentservice for the first time ever, I’m fairly certain it’s a 30amp full sized auto fuse for the main circuit. I got like 5 or 6 backups in case it happened again.
Well, here we go...you be the judge.

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Headed to the garage to take a peek, will update with anecdotal evidence. I’m an ‘04 if that makes a difference, though I do know the fuse was red, not sure if they make red 30 amps i could just remember wrong. Will find out later today probably!
 

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Fuses, at least in the US, are universally color coded.
 

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They are in the UK and it is 40amp my Yamaha replacement came with 30amp fuse they are loaded to 70 amp so can carry 40 amp no problem.
 

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2005 Brutale 750s
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Discussion Starter · #11 ·
Well I finally got my new fuses delivered because everything is still closed here in Germany. I bought 40 amps and now I have 10 of them. Thank you everyone for the help. I was just ignorant on the Lithium Ion battery topic. Honestly I’ve always just run agm batteries and I figured I’d swap for the weight savings. I usually conduct research but I didn’t this time. Thanks again!
 

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Test your voltage at the battery with a multimeter after you replace the fuse.
1/ motor not running.
2/motor at idle.
3/motor at revs around 3000rpm.
This will tell you if the charging circuit is OK.
 

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Do a search on all the threads on Lithium batteries -- There are a few -- I've written a few comments to the "facts of life" of Lithium Batteries .. One of them is the fact that Li batteries need a higher charging Voltage than a normal 12V Lead-acid battery .. A lot of bikes do not supply the about 14,4 Volts that a Li Battery needs to fully charge, so the bike itself will not fully charge the battery ..
Most people "check" their Li battery by pressing the built in Indicator or trust the simple chargers or Battery tenders they use -- Any Battery charger or tender with only two leads ( + and - ) Will NOT be able to tell you if a Li battery is OK -- Li "batteries" is really a "Battery pack" and can fail in ways where 1 out of the 4 cells connected in series in the pack has developed too high internal resistance (usually by the cell beeing "fatally" discharged below its fault tolerance) The "pack" will read full voltage, but voltage will drop very significantly when it is loaded with a high current draw ..
The only real way to check a Li battery is to measure the voltage across each individual cell under a significant load, which is what the "balancer -charger" does. This is why you need a charger with both the two charging leads and a smaller multipoint connector that measures each cell individually --
 
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