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Battery Slow Drain Fix

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My 2003 KLX400SR has the problem of slowly draining the battery, which will go dead in weeks without a battery tender. An ammeter shows the bleed down is happening in the controls and instrument cluster power circuit. I didn't chase down excactly where. I chose instead to add a switch in the fused small-wire (+) circuit at the battery.

Let's say I fly out for weeks and leave the bike in the airport parking garage. After parking I'll reach around the left side plate and push in the switch shown below. That cuts off current drain and also adds another layer of theft protection.

100404KLX400SRCurrentBleed-DownFix_.jpg

I machined a bracket and mounted it to the plastic battery casing. The switch is a 15A pull-on item from an auto parts store. It's made in China, and the knob promptly cracked and fell off, so I machined one from brass. I suggest a better-made switch. And use 14-gage wire as this curcuit carries the current for the headlight.

One question I had regarded safety. What happens if the switch goes open (disconnects) when riding? Answer: The lights and instrument cluster flicker, but the bike continues to run. The reason is with switch off and bike running, the alternator's recified (I assume) power isn't smoothed out by the connection to the battery, so it's more AC-like. I don't plan to ever run the bike that way, and if the Chinese switch dies, I'll stop and wire around it. Any of you electrical engineers know if the instrument cluster will care if the voltage level fluctuates?

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Couldn't you just cut the red wire at the instrument brick, cap the end going to the battery, and splice the end going into the brick into the orange wire? That way the instruments would only have switched 12v power.

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Wouldn't dream of leaving my bike in a public garage for anybody to access. But the issue is running the clock. It has to have constant power to do that. If you don't care about the clock...then your mod should be just fine.

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To complicate things: could you wire a laptop battery with a diode into the non-switched power feed to the brick? The additional battery would keep the clock and such in memory for short periods. But if that battery drained it wouldn't keep the bike from starting, or running properly.

Someone's probably already thought of this, haven't they?

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That design would still draw power off the main battery first. You'd have to isolate it and out it in parallel with the main battery off the charging circuit.

Huge amount of trouble for a clock. Just stick a battery operated clock on the bike instead. Guaranted to weigh a lot less.

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My 2002 DRZ-400S was doing the same thing, killing the battery in about 2 weeks. The fix was to replace the stator as it was shorthing the battery via the regulator/rectifier to ground. The fact the diodes in the rectifier allows this still tortures me.

The charging system always showed charging at 14.5 volts during all of this.

I thought it was the dash computer/clock, but it draws 3 milliamps and would take 3 months to make a dent in the battery.

I now have a nice Ricky Stator in there, and all is happy. Note that if you go with a Ricky stator on a S model that you have to use your old plug to the CDI.

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My 2002 DRZ-400S was doing the same thing, killing the battery in about 2 weeks. The fix was to replace the stator as it was shorthing the battery via the regulator/rectifier to ground.

Is there some way to test for this? Some place to attach the ol' multimeter, as it were?

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Easiest thing to do is install a Vapor. You gain a tach and water temp sensor and improve speedo accuracy.

The instrument cluster is the issue. mine would bleed down in 2 to 3 weeks. That said I got 6 years out of my battery so it wasn't stator related. There has been lots of threads on this over the years.

Personally I like having a clock. I hate watches and I like to know when it's time to turn around. So this switching idea wouldn't work for me.

I wired pig tails to mine about 6 months into it and it was never an issue. This is definitely an alternative though.

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I like the fact that it is a theft deterrent also. If you could find a really nice heavy duty switch that would lock on that would be great!

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Is there some way to test for this? Some place to attach the ol' multimeter, as it were?

Yes, please check the FAQ at the top of the forum for a tech article in how to diagnose your charging system.

👍

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The article in the FAQ is very good as bronco78 points out.

Also, it is best to check the stator hot. Short test: Simply check the each of the three yellow wires coming into the regulator/rectifier (disconnected). On your highest resistence setting (megaohms) you should not see ANY measurement to ground (it should read open).

As for the computer thing, I have heard of these drawing more then they should. That is easy to test (I confirmed a draw of 3 milliamps) and was not my problem.

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Easiest thing to do is install a Vapor. You gain a tach and water temp sensor and improve speedo accuracy.

The instrument cluster is the issue. mine would bleed down in 2 to 3 weeks. That said I got 6 years out of my battery so it wasn't stator related. There has been lots of threads on this over the years.

Personally I like having a clock. I hate watches and I like to know when it's time to turn around. So this switching idea wouldn't work for me.

I wired pig tails to mine about 6 months into it and it was never an issue. This is definitely an alternative though.

Interesting. I went out and checked out the Vapor instrument cluster. I'll check it out further. I'd be quite happy to just have analog guages. My preference would real needles and two trip set odometers, one for fuel range and the other the overal trip mileage rear direct. Just haven't been impressed with LCDs over the years.

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My 2002 DRZ-400S was doing the same thing, killing the battery in about 2 weeks. The fix was to replace the stator as it was shorthing the battery via the regulator/rectifier to ground. The fact the diodes in the rectifier allows this still tortures me.

The charging system always showed charging at 14.5 volts during all of this.

I thought it was the dash computer/clock, but it draws 3 milliamps and would take 3 months to make a dent in the battery.

I now have a nice Ricky Stator in there, and all is happy. Note that if you go with a Ricky stator on a S model that you have to use your old plug to the CDI.

I hope I don't have problems with the stator. I've done the grease in the connectors so won't have corrosion problems. Now I have to go check out what "Ricky stator" means. An improved-over-stock stator, but there are details to check into. I've been able to run a heated vest on a gear-way-up-bike so far no problems, so I don't think capacity is a problem?

I was not happy to not have simple analog guages on this bike like on my KLX250S. Those don't have problems like current bleed-down, and they're easier to see. No tach is also a pain. Hard to describe gearing changes without pegging to rpm.

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