Battery orientation (help)

Post by **morris1970** » Thu Oct 23, 2008 4:47 pm

hi this sound s possibly a stupid question, but does the plus sign on the battery go to the drivers side, and this one --to passengers side when connection battery ? cheers

Title changed by Onne for clarification.

Post by **Alec** » Thu Oct 23, 2008 5:27 pm

Hello Morris1970,

there is more to this than you may think, firstly the terminals should be away from the battery retaining strap, i.e on a Minor the terminals are nearer to the bulkhead. Normally the earth terminal is connected to the passenger side, so on a positive earth vehicle, that would be the + terminal. If the car has been changed to or is negative earth then that terminal would be the - terminal.

Batteries are available in either configuration, i.e. front left terminal + and front right - or vice versa.

So it depends if your car is negative or positive earth and has the correct orientation of battery terminals to suit?

Alec

Post by **bmcecosse** » Thu Oct 23, 2008 8:23 pm

As I explained earlier - early dynamo cars were supplied +ve earth, but many will have been converted to -ve earth by now. If you have a radio or stereo in the car it will almost certainly require -ve earth. The dynamo can work either system - but it must be 'primed' to tell it what is required!
Can I just say - it would help us to keep track if you could put a clue as to the question in the title - rather than just 'Help' !!

Post by **leyther8008** » Fri Oct 24, 2008 8:19 am

Mines been converted and the battery just turned round! its dead easy to short out the terminals (Big big spark) when fitting the clamp bar, its one of those jobs I,ve been meaning to get round to to fit longer leads and turn the battery the right way round again.

Post by **alex_holden** » Fri Oct 24, 2008 8:23 am

This question's in the wrong section...

Post by **Onne** » Sat Oct 25, 2008 10:41 am

Also moved it to the correct place.

Post by **Cam** » Sat Nov 15, 2008 8:00 am

To get an idea which way round the battery is supposed to be connected on your car, have a look at the terminal clamps. They are different sizes as one terminal post on the battery is a bit bigger than the other and the clamps should only fit easily one way round!

Also, on some terminals, the + or - is marked.

Post by **rayofleamington** » Sat Nov 15, 2008 12:22 pm

Can I just say - it would help us to keep track if you could put a clue as to the question in the title - rather than just 'Help' !!

Indeed!
I've been renaming every 'Help' post so far so that forum users might have some clue, and moving loads of posts (not just from one user - also from a lot of the regulars who post technical queries in General section

)

So a request to help all the website users - Please can you put a sensible topic title so people can know which question is which, and also use the correct topic areas for technical questions, NOT the general section. Ta.

Post by **mick64** » Tue Feb 03, 2009 7:06 pm

If the car turns over with the positive on the chassis and the lights work have a got it on the right way round?

Positive earth...

Will have a look at the sizes....cool tip...

Post by **bmcecosse** » Tue Feb 03, 2009 7:57 pm

Not necessarily! It will turn over and lights will work either way round! If you have an alternator - it will be -ve earth. Original cars were +ve earth, but over the years many have had wireless sets fitted - and modern ones are all -ve earth, and so cars have been converted to -ve earth, even though they still may have a dynamo! This is no problem - you just take a wire (jump lead will do fine) and connect it to the +ve terminal on the battery - and then 'spark' it against the smaller of the two terminals on the dynamo, a couple of times. Now the dynamo has been re-polarised to suit the new -ve earth arrangement - and should charge the battery. The coil terminal wires should be swapped over - and the ignition points and the fuel pump points should be cleaned!

Post by **mike.perry** » Tue Feb 03, 2009 9:04 pm

Why doesn't the heater fan/electric screen washer pump run backwards?

Post by **alex_holden** » Tue Feb 03, 2009 9:19 pm

mike.perry wrote:Why doesn't the heater fan/electric screen washer pump run backwards?

Late heater fans do run backwards when you reverse the polarity. Mine was practically useless until I swapped the wires around. Electric washer pumps do too IME.

Early heater fans had a field-wound motor which turns in the same direction regardless of the polarity. I think this is because the polarity of both the rotor and the stator gets reversed (whereas with a permanent magnet motor the orientation of the stator field stays the same).

The starter motor and I think the wiper motor are field-wound too.

Post by **bmcecosse** » Tue Feb 03, 2009 9:25 pm

I'm surprised the heater ran backwards! Mine certainly didn't. And of course the washer pump is finger operated on a Minor!
I wonder on early cars with the 'fast' fuel gauge - does it need reversing too? The later 'slow' fuel gauge is ok - because it's just a hot-wire system.

Post by **alex_holden** » Tue Feb 03, 2009 9:35 pm

No, the early fuel gauge doesn't need reversing.

Post by **millmoo** » Tue Feb 03, 2009 10:51 pm

If you want to make sure your car is correctly polarised to positive earth, do you attach the wire to to the negative terminal on the battery, and then to the dynamo?

Post by **bmcecosse** » Tue Feb 03, 2009 11:04 pm

Yes! Smaller of the two terminals on the dynamo - just flash it a couple of times.

Post by **mick64** » Wed Feb 04, 2009 6:20 am

bmcecosse wrote: This is no problem - you just take a wire (jump lead will do fine) and connect it to the +ve terminal on the battery - and then 'spark' it against the smaller of the two terminals on the dynamo, a couple of times. Now the dynamo has been re-polarised to suit the new -ve earth arrangement - and should charge the battery. The coil terminal wires should be swapped over - and the ignition points and the fuel pump points should be cleaned!

Thanks, I will change it over...