05 Sprint St Charging Issues

Sadly, my first post is a pela for technical help.

I have a 2005 Sprint ST 1050 with 45k on the clock. It's been neglected a little but is mechanically in good condition.

The major issue is that it keeps eating voltage regulators. The history suggests it's had no end of electrical bugs & when it developed issues, I did some research & discovered the vulnerable alternators. Sure enough, mine was damaged.

So in February, the alternator, regulator AND battery were all replaced. The alternator & regulator are both brand new Electrosport items, a brand which had been recommended from several sources. I did consider an Electric Works, but the feedback is a bit mixed & I'm not confident with cable modifications.

The problem has returned however. The battery is receiving charge when the engine is cold, but once at temp it no longer is receiving charge & the regulator was so hot I couldn't touch it at all. I've carried out a resistance test on the alternator & is fine, & there is no scorching of the connector, so I'm looking at the reg again.

As I mentioned, the bike has been neglected a bit & sure enough the coolant level was very low (I was told it had been serviced when I bought it!), so topped that up along with the oil in the hope that it was the engine overheating the regulator that was causing the problem.

The only other thing I can think of was it was functioning fine & then I reconnected the Oxford heated grips. They function fine so unless the Sprint's electrics don't like accessories connected to the battery, I'm out of ideas.

Any ideas would be helpful. I'm ordering another regulator, making it 5 in 3 years & 3 since October!

EDIT: I should add before the alternator & regulator were changed, the main fuse blew. It's a 30A slot but had a 25A fuse in it. I replaced it with a 30A fuse but it's bugged me why a 25A was installed & if there's any relation to the main issue.

 

I did as soon as I noticed the battery was low, hasn't solved the problem. I was more wondering if this could be causing the issue.

 

It is still on the right hand side. That's good to know, will definitely look into relocating it.

My bike does have what looks like an extension bracket in the original position. I think it's from some non-standard thing that was fitted (It's not for crash bungs or anything else significant, just a metal bar with threaded bolt holes at either end). The bracket is adjustable obviously to allow it to line up. It would lift it away from the engine a bit so might try that.

I've been thinking about a volt meter. I'm getting very good at spotting the early signs the battery is a bit low to be honest, but that looks a nice, neat solution. Would need to hang onto the user manual .

I fashioned a dip-stick to check as I can never read water bottle levels (Same on every bike I've had). I didn't fill it enough for any to go into the overflow pipe & took nearly 1/2 a litre so it was probably below min level.

 

Heard mixed things about the Mofset regulators to be honest. Some say they're perfect & don't go wrong as often as normal regulators, others say they are just as prone to failing as any other reg & absolutely trash batteries when they do.

I'm also not too keen on having to do cable modifications, so I'm not keen on the Mofset regs

 

Right, I *think* I may have resolved the issue.

I’ve rotated the reg on the aftermarket bracket so it is away from the engine. Air can now get behind it & the fins are almost entirely exposed to air.

Ran it until the radiator fan kicked in & the battery never dropped below 14v (14.17v nominally, 14.08 with fan running).

Hopefully this is the last I hear of the issue.

I really appreciate the input, especially Trudd who mentioned that the original location left regs prone to overheating. Going to give it a few days & see if the bike is now happy or if this is just one of many heads to be cut of the electrical monster!

 

Right, I *think* I may have resolved the issue.

I’ve rotated the reg on the aftermarket bracket so it is away from the engine. Air can now get behind it & the fins are almost entirely exposed to air.

Ran it until the radiator fan kicked in & the battery never dropped below 14v (14.17v nominally, 14.08 with fan running).

Hopefully this is the last I hear of the issue.

I really appreciate the input, especially Trudd who mentioned that the original location left regs prone to overheating. Going to give it a few days & see if the bike is now happy or if this is just one of many heads to be cut of the electrical monster!