still trying to figure this out - 2016 r1200rs

[ritterjr1200rs]

Still haven't figured this one out -
fully charged, checked and load checked battery
charger working
checked ground for resistance
checked for parasitic leakage
checked the voltage regulator
all lights and electronics work
starts up right away after charging over night
go out for a ride, everything works, Amp reading on the dash is a steady 14.4
get back home after a 30 minute jaunt...fun as hell, like normal
stop the bike at home, shut it off - try to start again in 1 minute - nope! - sounds like a dying battery though the reading is 13.4 off the terminals...
about a half hour later - starts!
something that gets warm or hot - and then doesn't work - but works when it cools down?
i'm perplexed. I have a BMW dealer appt on May 27 but would love to figure this out with some help! Please!

 

[r0ckrat]

You could try re-checking the ground *when it's hot and not starting*.

That's all I can think of off the top of my head.

 

[pglaves]

You could try re-checking the ground *when it's hot and not starting*.

That's all I can think of off the top of my head.

Long shot: bad starter nose bushing. I had a VW Golf that would not start hot. When torque was applied the armature could shift slightly and cause it to rub if it was hot. It had to sit 20 minutes or so. Or crawling under the car and tapping the starter with a hammer while an associate, friend, or passerby was cranking the starter sometimes worked. This was particularly fun in an Interstate rest area after an urgent bathroom stop. A new starter fixed that problem.

I saw the same problem on a /7 and replaced the nose bushing and all was well.

 

[Omega Man]

CAREFULLY add another battery to the system……like you were getting a normal jumpstart. See what that does.
OM

 

[drost]

What’s your voltage at battery terminals while cranking after a ride? I would replace the battery if it is the original. Voltage check while cranking will tell a lot. Sounds like the battery is on its way out from your description.

 

[windsailor97]

+1 on needing a new battery.

How old is the one on the bike?

 

[lee]

This thread in the camhead section shows what has been checked so far.

https://forums.bmwmoa.org/showthread.php?102181-2016r-1200rs-charging

 

[r0ckrat]

Reading the other thread, OP mentions that the battery drops to 9v when cranking. Based on that, it sounds like a cracked plate. When the bike is cold, it starts fine, as the cool battery is able to maintain 12+v. When the bike is at operating temp, so is the battery, which could warp the defective plate opening a connection gap, and reduce output.

The only way to know is... load test the battery hot, or replace with new.

Sent from my SM-N970U1 using Tapatalk

 

[lee]

The only way to know is... load test the battery hot, or replace with new.

Sent from my SM-N970U1 using Tapatalk

In the other thread he took it back to the store to be tested and they said it was ok.
He didn't say if it was load tested.

 

[windsailor97]

I have had a situation where an older battery is fine until it gets hot. I am sure there is a technical reason but this does happen.

 

[Omega Man]

Local auto parts stores make me nervous testing things. Probably cuz I’m
OM

 

[pglaves]

Since, if it is the battery, the failure happens when the battery is hot so a test of the cold battery may not reveal the defect. I do not know how much the battery might warm up under test load - I am sure it does warm some but maybe not enough to fail. Gary (OM) suggested trying the hot start using a jumper battery. If the battery is at fault this test should reveal that.

It seems obvious to me that the defect is something that happens when hot but not when cold. That could be the battery, a connection, defective (corroded inside the insulation) wiring, starter drag, or something else.

 

[ccolwell]

+2 on the battery -- low hanging fruit here. How old is it? More than 3 years and I would just put a new one in.

 

[lee]

+2 on the battery -- low hanging fruit here. How old is it?

It's a new battery.

 

[Omega Man]

It's a new battery.

Doesn’t mean that much nowadays. Worth a real test.
OM

 

[lee]

Doesn’t mean that much nowadays. Worth a real test.
OM

I agree.