On my last 2 trips to the SVA test I have had to use side lights on the way up. This has been draining the battery and has resulted in push starts at the petrol station. With the lights off the battery charges fine.
In order to get the side lights to work with ignition off they draw their power directly from the battery.
On the bike wiring the side lights draw there power from a direct feed from the rectifier which also supplies ind, ecu relay,headlights, ignition etc.
The remaining wires from the rectifier are connected to the +ve and -ve on the battery to charge it up.
As my side lights only draw power from the battery is it possible that the charging circuit cannot cope with the extra demand on the battery as these lights are normally supplied directly from the regulator?

i dont know the direct answer to your question but very much doubt that driving with side lights on would drain the battery. As you know cars are designed to be driven long periods in the dark with main headlights on.

Is the battery new or old and unknown? Is it a bike battery from a bike donor - ive heard of these failing after long lay up periods.
Are you sure the car is wired up correctly?

Its a brand new gel red top battery(14ah) and the car had been running for about an hour before I had to stop for fuel.
The bike wiring system doesn't have any lights operating directly from the battery when the engine is running.
The only thing I know about the regulator output to the battery is that it reads 15volts which is only a couple of volts above fully charged battery voltage.

There is definatly something wrong.
With the engine running, it should supply masses of electric to run your lights with or without a battery.
So it would seem that either the battery is not being properly charged, or,
there is a massive power drain on the system ie more than just the lights.
I think you need to check the charging circuit / battery connections.
And check the drain on the battery with "just the sidelights" on. It should'nt be more than about 2 amps.
HTH
Col

I had a similar problem with my blade when first connected (i also had a red top battery). It was caused by the rectifier which was slightly overcharging because it had a been previously cooked (probably by me when building without enough heatsink). Unfortunately the battery was dead so I had to get a new battery (standard bike) and recifier with more heat sinks. As its the same battery type I wonder if the batteries are a bit delicate.
I didn't suspect this at first as it didn't seem to be massively overcharging but I took it to a bike shop and they rev'ed the N**S of it and it went upto 16.5/17 volts.

Hope this is not the case for you but something worth checking.

I've just been out to check the battery. The voltage at the moment without the engine running is 14volts which seems quite healthy to me. That is after the 1 1/2 hour drive back from the SVA yesterday.
Unfortunatley the exhaust is off at the moment for modifications(reduce the noise) so I will run it and do some more investigation in the next day or so.

Regarding the red top batteries they are used in the Harrier jump jet and by quite a few race teams and have a reputation for working in the toughest of environments.

I just wasnt sure how much power the side lights would draw from the battery before it would be impossible to turn the engine over.

I've got a screen on my fury and I can run the wiper motor and all lights + fog no probs so its either

1. Charging circuit not working correctly.
2. Battery had it.
3. A leakage in the system somewhere but if the batteries going flat as quick as you say it should be easy to see on a meter.

My battery also kept showing 14ish volts but quickly fell back when I applied any load (full beam for instance) so you could try that.

battery is for storing oompf to turn the engine over when starting. once running, the alternator should be capable fo powering all the lamps plus have some spare to keep the battery topped up with oompf.

either alternator is bad or wiring.

Hopefully I will get a chance to run the engine tomorrow(if the rain stops) and do a few more tests on the system with lights on etc.
Ill let you know what I find (if anything)

Dave

Well got the silencer on and ran the engine.
Engine running with all lights off - 15volts
engine running with all lights on including hazards and fog - 15 volts

Reving the engine and the voltage still remained at 15 volts

I also carried out a resistance check on the rectifier. All ok

It was then that I found that the insulation on the loom earth wire at the connection with the battery had melted

The earth terminal on the battery has a large diameter cable to chassis earth and a smaller cable which is the earth from the loom. This is the one which had melted.

Any ideas what could cause this, as I didnt find any obvious short problems??

quote:

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Originally posted by wheezy
Well got the silencer on and ran the engine.
Engine running with all lights off - 15volts
engine running with all lights on including hazards and fog - 15 volts

Reving the engine and the voltage still remained at 15 volts

I also carried out a resistance check on the rectifier. All ok

It was then that I found that the insulation on the loom earth wire at the connection with the battery had melted

The earth terminal on the battery has a large diameter cable to chassis earth and a smaller cable which is the earth from the loom. This is the one which had melted.

Any ideas what could cause this, as I didnt find any obvious short problems??

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It does sound like the big strap has failed in some way - is your big earth cable a proper braided strap? Anything else is likely to fracture eventually.

These braided straps are available from any of the on-line car electrical suppliers - I've even seen them in Halfords, next to the batteries! Theirs were a bit thin and feeble though.

David

The large earth cable is the one used on the bike to connect to the chassis. Unfortuntely I didnt check continuity before I removed it. Now it is reconnected I have good continuity to the chassis through this cable.
What you say sounds like the reason for the melted insulation. All I can do now is run it for a bit and keep my eye on it.
I would imagine that this is the reason for the battery loss as the loom earth cannot cope with the return to the battery.

If you're using cable instead of braid then try putting an open loop in it to allow for vibration.

David

It's a good job you had the smaller lead. I've seen car engines earth themselves with the throttle cable when the main cable fails! This doesn't melt and causes fires!

Marcus