Battery Draining

[florence]

Hi, hope someone can help.  When left for more than a day or two the battery drains to flat.  Has anyone else had this problem or am I going to have to put in a battery isolation switch?

[Johnwebley]

how old is the battery?

 maybe the rectifier is faulty?

[florence]

the battery is new and charges fine but then when it stands for a day or so and I come to ride it it's almost completely flat, which is rather irritating. Is the rectifier in the circuit still when the ignition switch is off?  Maybe the ignition switch is faulty?  Just wondered if anyone else had experienced this to save me going through all the electrics with a meter.  I have to say I'm not sure I would know what to look for anyway ...??

[deltarider]

Have there been any changes in the wiring? If you have a DMM you could measure the amps by removing the battery + and connect the meter in between the battery + and the thick + wire. Caution: during this test NO starting or you'll melt the testwires.

[florence]

Deltarider, thanks, no changes to the wiring.  I will try your test. 

[deltarider]

 

I will try your test.

So this simple test is done without the motor running, enginekey off and will tell you how many amps are drawn. Do not attempt to start! When testing you could open and close the killswitch but I doubt you'll see any difference as the killswitch receives power via the ignitionkey. On the other hand you never know. Please report back.

[florence]

thanks DR, I will have to charge the battery a little first, then will get back later,

[Lobo]

Hi Florence,

Further to DRs comments, and assuming the wiring is unmodded - same as CB750 which I'd reckon likely...

The battery in the OFF position is hard wired to..
(1) the stater motor relay
(2) the rectifier
(3) the ignition switch.

As DR says, put a meter (Amps setting) between the battery main +ve post, and the detached main RED. NO current should flow, ie the meter reads 0.

IF you have a drain...
(1) try disconnecting the stater relay in case there's an earth leak there
(2) try disconnecting the rectifier (large plug, 3 yellows, red(striped?), green)
(3) take out the main fuse... ie feed to the ignition.

If #3 above is the culprit you'll have to start looking at earth leaks in the switch itself or its feed...often the fuse holders themselves are dirty / corroded / the culprit so perhaps have it out and give it a good clean.

If none of the above put the battery in the bench overnight & check before / after voltages just in case you've been sold a duffer.

Good luck,
Simon.

[wolfheze]

Would have thought the most likely reason is that the battery is knackered. Could have sat on a shelf for years.

[Spitfire]

I recently fitted a nice new battery, worked great, then it went flat, connected up to the Optimate and it said forget it, the battery was U/S. The strangest thing was that I then topped up the old battery, charged it and hey presto it worked, not perfect but it got me through this summer.


Cheers

Dennis

[florence]

Well, thanks for all the advice.

Following your recommendations I charged the battery and left it on the bench for 24hrs, tested it and was surprised to see it had gone flat all by itself, nothing to do with the bike.  I will chase up the agricultural merchant on Monday.  The battery is an Oregon 12v 12AH for a mowing machine and the last one I had lasted for 10 years. (no bike shops around here)

Thanks again for all your help.  As always it's the obvious things one should check first.

Steve