Melted Battery Terminals

[dropstharockalot]

Also note that if the battery gets low and you keep cranking the bike over things get hotter (less volts means more amps means more heat) so make sure to keep the battery charged up and in good shape.

I called the local Duc dealer this AM to order a replacement battery and had a quick discussion about battery set-up with the parts guy.  He and his service techs won't let the battery leave the shop until they've charged it overnight... too many experiences with poorly set-up batteries going bad too soon.  In contrast, the Honda dealer that I got the battery from just topped it off and let me walk out with it, with instructions to charge for a couple hours.

Looking at the acid levels, they are waaaay low... so probably the combination of poor set-up leading to low power and cruddy connections did me in.

As an aside, the Duc shop is beating the Honda shop's battery price... and the internet retailers, too.  Who says exotic bikes cost more to maintain? 

[Speeddog]

Pretty sure your Duc has what I consider a questionable power wire configuration.

Ground wire from the battery to the frame at the bottom of battery tray bolt on the left side.
Then a short jumper from the inside of the upper front footpeg bracket bolt to the crankcase.
Positive wire goes from battery to a 'Y' connector.

Better to go directly between the battery ground terminal and the engine, like later Monsters.

Not sure what your options are for the positive cable, perhaps that Powerlet kit has the answer.

[dropstharockalot]

Good news - the dealer that sold me the battery that melted down honored the warranty.  Hooray, refund!

His opinion - he compared the damage to something he used to see on Honda MXers in the '70s - he said the regulator/rectifier would go bad and allow all the current from the charging system to stream into the battery uncontrolled.  It would melt terminals and boil off the battery acid.  His theory was that the damage was done prior to the day I had the trouble starting...

Looking back, I took it out for about an hour and a half the day I put the carbs back together... when I got back to the garage, I heard a bubbling sound from around the tank.  It was quiet and intermittent, so I didn't pay much attention.  It could have been my battery acid steaming off as he described. 

I've found a couple threads about regulator testing on here that I intend to try out.  Does anyone have any tips or suggestions?  Also, any weight to his theory about the bad regulator?

Thanks again!

[ducpainter]

I can buy the bad RR boiling the battery, but not melting the terminals.

You can check the RR by running the bike and checking voltage at the battery with a meter. 13.5-14.5 at 2500-3K rpm is all you want. If the voltage is higher the RR is suspect.

[Howie]

I can buy the bad RR boiling the battery, but not melting the terminals.

You can check the RR by running the bike and checking voltage at the battery with a meter. 13.5-14.5 at 2500-3K rpm is all you want. If the voltage is higher the RR is suspect.

Absolutely.  Uncontrolled (high) voltage will boil the battery dry and can take out bulbs as well as other electric/electronic components.  Melt terminals?  No.

[dropstharockalot]

Ok... so I blow the regulator and boil off the battery.  No acid = no or low starting power.  When I try to crank it over with no/low power and the corroded terminals I discovered the other day, then maybe it creates enough resistance to melt the terminals?

Just spit-balling here, trying to connect the dots...

[suzyj]

At a guess, loose battery terminals blew your rectifier/regulator, which then boiled your battery.

Rectifier/regulators don't like running without a load.

[ducatiz]

That can only happen from high resistance which typically happens from a bad connection, or a bad starter.

Check all the connections in the starter circuit by taking them apart and cleaning and tightening or do a voltage drop test. Be careful of the connection at the starter. It is easy to damage the starter.

You'll need to replace the battery unfortunately.

make sure the grounds are good as well. 

[Howie]

Ok... so I blow the regulator and boil off the battery.  No acid = no or low starting power.  When I try to crank it over with no/low power and the corroded terminals I discovered the other day, then maybe it creates enough resistance to melt the terminals?

Just spit-balling here, trying to connect the dots...

Low voltage or amperage at a connection does not create resistance, a bad connection does.  And yes as suzyj stated, the connections could have killed the regulator

[H-2 CHARLIE]

  How about your stater grounding out inside and catching fire or melting stuff ?

[ducpainter]

  How about your stater grounding out inside and catching fire or melting stuff ?

Duc starters are pretty reliable.

[dropstharockalot]

I can buy the bad RR boiling the battery, but not melting the terminals.

You can check the RR by running the bike and checking voltage at the battery with a meter. 13.5-14.5 at 2500-3K rpm is all you want. If the voltage is higher the RR is suspect.

Everything is back together.  Battery reads 12.5 uninstalled.  I'm getting about 12.5 to 13 at idle, up to 14.5 at moderate revs.  The highest I saw was 14.7, but it only flashed that up once or twice.  I'm going to take it out for 15-20 mins to see if the battery gets bubbling after some sustained rpms.

With the new battery bolted in to shiny terminals, the starter had no trouble whatsoever turing the bike over... two cranks and ignition happened.

Argh!

[dropstharockalot]

...aaaaaand no bubbling, boiling, anything.  I ran it for about half an hour with a little bit of everything - sat at a couple lights, pinned the throttle on a couple country roads, up and down through the gearbox once or twice - the bike took it all in stride.  After I parked it I put the tank up and got in close, and the engine is throwing off plenty of heat but the battery feels just fine.  The acid level is right where it was when I left.

I'll still do the volt drop test to be sure, but it's looking like I just f'd things up with my cruddy terminals. 

Thanks for all the input and advice in this thread!

[bikepilot]

Very good!

FYI your shop guy was BSing you wrt the honda MX'ers.  MX'ers, even in the 70s, didn't/don't have batteries