HID battery usage

[Jamo]

I've noticed that if I drive my car during the day my voltage around the battery is close to 14 yet the moment I switch on my HID lights the voltage is dropping really low.

Could this be an alternator fault?

[s2driveruk]

what's 'really low' Jamo?

[Rusty]

Is that at idle or when driving / higher engine speed. It is possible that the load will drop the alternator voltage at idle but it will recover with a few revs.

[Jamo]

It's both idle and driving between 12-13 volts, it's affecting the battery charge. I've been doing mainly night driving and the battery isn't getting enough charge.

[s2driveruk]

hmm, i seem to remember mine dipping the voltage a bit but not sure that far. Would go check but not in a position to start the car

[irishs2]

From my understanding the HIDs only have their max draw at startup, during operation they should be less current draw than standard bulbs. Have you tried the old bulbs to see if it gives same results which could point to maybe slipping or faulty alternator?

[Evilgoat76]

HIDs take a whack on startup but as stated above, the draw once started is very little. Time to warm up is very short. Does putting on any other big consumers do the same, EG rear demister.

[Sonic]

It'll be the amplifiers Jamo

[Fat Audi 80]

It will be the extra 0.3 litres of displacement....

[Jamo]

HIDs take a whack on startup but as stated above, the draw once started is very little. Time to warm up is very short. Does putting on any other big consumers do the same, EG rear demister.

It does yep, I know it's not the battery it's brand new and I had it tested yesterday

[s2driveruk]

check the condition of the key wires off the alternator....i happened to notice on mine that they were in poor condition with quite a few strands on the heaviest guage lead broken and guess that is doing nothing to help matters.

[dest]

I checked mine, the gauge does'nt even move a tiny bit when turning the HIDs on

[johne]

I assume you're reading the voltage off the voltmeter in the auxilary panel - in which case it's not the true voltage at the battery. Mine did the same, turn on the lights and it drops a bit. It's because that voltmeter is reading the voltage at that bit of the wiring loom it's connected to and it's affected by the voltage drop in the loom when you turn the lights on.

I'll wager that if you measure the voltage actually at the battery terminals you'll find it barely changes when you turn your HIDs on.

If I'm wrong, you've got a poor earth somewhere between alternator, block, chassis and battery -ve and you can find it by putting a voltmeter across each of those earths and see if you have any voltage across them.

John