1150 eating batteries

Disconnect one of the leads and connect a voltmeter between the two set in AMP's mode. Don't start the bike or turn lights on as it'll probably blow the multimeters fuse. Using the value you can calculate how much wattage you are loosing and calculate when the battery would go dead.
 
There is some logic to my belief that 14.18V is a tad low. Especially when it stays at that voltage if you rev the engine.

Flooded cell batteries, which is what the standard battery is, tend to sulphate if left discharged, or partly discharged. This is overcome by an equalising charge, which causes the battery to gas, and dislodges the sulphation (at least, so goes the theory). This does not work with sealed/low maintenance batteries, which do not care for the 14.4V or more equalising voltage.

Batteries that do a lot of deep charge/discharge cycles use a lot more water, and that is one way of knowing that they are getting a decent charge. If you do not keep the electrolyte topped up, the effective capacity is decreased.

The acid test, if you will pardon the pun, is to measure the charging current going into the battery, but with a 70A alternator, you need to have a meter capable of carrying such currents. I am not so blessed. It is also a useful check to see what charge current goes into the battery with all the lights on, grips in etc.

It were girt cold yesterday too, and them wet batteries need extra voltage in the cold.

As to the relevance of the rectifier, I suspect that the 1150GS alternator is 3-phase, and so has a six-diode rectifier. If one of those diodes has overheated and failed open-circuit, then the voltage output of the alternator will slightly down, but the current will be reduced by 1/3, as one winding is no longer doing any work. Apart from stripping the alternator down to test the rectifier, which may well be encapsulated with the regulator, the only way to check this is to measure the charging current.
 
shugie said:
There is some logic to my belief that 14.18V is a tad low. Especially when it stays at that voltage if you rev the engine.

That`s because the regulator is doing its job and holding it at that level.
 
Thanks Tarka, I thought that this was the case, as I recently bought a battery for the Honda. Tip the acid in, push / thump the cover in place. This is ribbed to ensure that it's only a one way trip for the cover.

Just read the manual & got it in my head that it may be low.
 
the AA test for batterys is pretty faultless(tho based on cars it still works for most bikes..), firstly check static voltage , 12.2volts and above goto step two if less run vehicle for approx five mins to charge up.
step two , disable vehicle so it cant start-pull fuel pump fuse is best or isolate the pump..

then crank vehicle for approx 15 seconds.
during the cranking phase monitor the voltage on your meter .
the volts should stabilise at whats known as cranking volts .at this point check the meter..for the rest of the fifteen seconds..
you now have voltages on the brain..

1 as long as the cranking volts does not drop below 9.0v your ok
2 during the cranking stage if the voltage drops by more than .3 of a volt at the cranking voltage then the batt is tits up
if the drop is less -tis fine sir they all do that.

if it passes and you are sure you understood my destructions go make a cuppa sit down and drink it and think whats draining the battery cos it a good battery.


static volts 12.2 and above shows 50% charged battery.
below is no good need to charge up if you cannot achieve 12.2 v consider battery may be deep discharged and could need specialist charging..

cranking volts no less than 9volts..

and finally drink more tea for inspiration..
 
Dodgy rectifier diode

Had this problem on my R75/6. Eventually found that one of the diodes in the rectifier has shorted and was discharging the battery back through the starter soleniod, which was fried by the time I'd found the problem. New rectifier and solenoid solved the problem.
 
To determine if the bike is draing the battery.

Measure the current drain from the battery to the bike when the bike is off.

That simple maesurement will then tell you if the bike is draining the battery, by how much. You can even pull fuses and see if they make any difference at all.

Get some numbers and you can be objective rather than subjective (guess).

To get an idea of how much drain there is on the batery over 4 days (4*24 = 96 hours) take the battery capacity (say 18Ampre Hours) and divide it by the number of hours (18/96 = 0.188 amps). That figure showes the current required to TOTALLY faltten a fully charged battery over that time. I'd want the current drain to be a good deal less than half the calcualted current.
 


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