Earth cable from negative battery terminal

[Tamas Petrunin]

If it's internal it won't read anything.

Yeah I know, but I was meaning that a very small load (in the micro amps range) wouldn't drain the battery anymore than an the natural losses from a battery just sat there with nothing connected to it.

Last night I went and checked the reading inline again, this time on 200m. There was nothing on the meter, not even a flicker. <snip> All signs are pointing to the battery on its way out.

If your meter doesn't show any draw on the milliamp scale two things spring to mind...

1) is the meter working on that scale or have you blown the meters internal fuse ?

2) if your meters working then it's unlikely to be a vampire drain that is flattening your battery, the best thing to do next would be a "drop test", fully charge the battery and then take it to your local friendly garage and ask them to test it. Try to avoid places like Halfrauds & Kwikfit as they will almost certainly say you battery is knackered and then try to sell you a new one (even if your battery is okay)

If you want to simulate a drop test at home, disconnect the power to the coil (so the car won't start) then switch everything on you can and then get your glamous assistant to crank the engine while you measure the battery voltage with your meter, anything below 10.5 volts is suspect especially if it reads lower and lower the longer you crank the engine for. I wouldn't do it for more than 30-40 seconds because your starter really won't like it and will get very hot in the process.

[UKPhilTR7]

I am pretty sure that the multimeter internal fuse has not blown as when I put a little load on it (side lights) the reading went up. Think I will have to see about simulate a drop test at home, hopefully the weekend.

Last night though I did check the battery/alternator readings and I am pretty happy with the, well most of them. When the car was running the meter was showing:
Car running 14.36 – 14.37
Car running with side lights on – 14.29
Car running with main lights on – 14.18
Car running with main and fog lights on 13.64
Car running with electric fan on – 14.06

Not too happy about the main and fog lights on figure though.

[saabfast]

That readout does not look too bad with the drain of all the lights on.

As a side note, my wifes 207 was serviced about 8 months ago at Halfrauds. It has never had a problem starting and spins over rapidly. They said the battery had failed a drop test and may need replacing. I said to leave it and I would sort it when it failed. It is still fine despite her normal daily journey to work being only about 1 mile (too lazy to walk!) so it hardly gets any charging time to make up for the starting load.

[FI Spyder]

Never trust a garage. I had the wife take the Tercel in to a garage (national chain) to get tires and told her to get the brakes checked. They gave an estimate of $600 (replacing all brakes). I told her to get them to button it up and bring it home. I bought new pads and shoes and while the rears needed replacing (I had the e brake adjusted too close, lesson learned) the front pads were like new. I kept the pads and replaced them about 8 years later.

[Tamas Petrunin]

Last night though I did check the battery/alternator readings and I am pretty happy with the, well most of them. When the car was running the meter was showing:

Your meter's fuse is ok since you got a reading when you switched the sidelights on, and your figures look fine but that is only really testing that the alternator is providing power. Since it's your battery that you're worried about you need to apply a load on the battery when the engine isn't running.

Never trust a garage. I had the wife take the Tercel in to a garage (national chain)

That's why I said take it to your local friendly garage, I don't trust the national chains (they are only interested in selling you stuff wether you actually need it or not), find yourself a nice local garage that you can trust, they will usually drop test your battery for free, afterall it'll only take them a minute.

All a drop test is, you measure the voltage of the battery while you put a very heavy load of usually 100 to 200 amps on it, if it can't keep the voltage above 10 volts for a minute under that strain then it's not in the best of health.

Having said that a battery that is begining to struggle can last a long time on a car that's used regularly because it's alway getting it's charge topped up, especially if the car is a good starter and you don't need to crank the starter motor for a long time.

My old Toyota hilux always needs a plenty of heater plug if the engine is cold and it has a pair of batteries to make sure there is plenty of power left to start it, while the wife's Pug 306 starts as soon as the starter motor spins whatever the weather and only needs a few seconds of heater plug even when it's below zero outside.