Duff battery?

[spinna]

Hi guys. ive had a look through some of the threads but I'm none the wiser. My 2009 t330 2.4 TDCi 100ps is struggling to start. symptoms indicate dead battery. It will occasionally throw a dead key (all dash lights except glow plug light up). then it will start but slow wind over as if battery is dying. I thought the front battery under seat was starter battery so checked this with a charger and sure enough it was dead so put on charge all day yesterday and all night but looks like it needs changing. Anyway after looking on here it appears that the rear battery is the starter which mine is fully charged so now I'm confused as to what is going on. Sorry for long winded post. Any help greatly appreciated

[ned]

Yes the rear battery is the starter battery but if the front one is dead it will drag power from the back one causing the issues you have.

Rear starter
Front auxiliary

It is recommended that you change both together but if you have the rear battery tested for load and its good I would push the rear battery forward and put the new one at the back. N

[blue estate]

+1 typical front battery dying symptoms


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[spinna]

Thanks I will swap them round until I can get a new one.

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[Jim Archer]

Not going to make any difference, it's still shagged and dragging the other one down with it.

Jim

[Altransit]

Not going to make any difference, it's still shagged and dragging the other one down with it.

Jim

You beat me to it Jim

Whichever way around they are, they're linked together for starting anyway.
The factory dual battery setups use smaller capacity batteries than the single battery setup, and one of these smaller ones isn't really man enough to do the starting on its own

[spinna]

Bit of an update. I removed both batteries yesterday and a friend tested them for me. As it happens both red as good but needing slight charge. It turns out one of the negative terminals wasn't connected properly. I've charged both and refitted and everything seems OK at moment. I will do regular checks to see how things go

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[dumper]

Over the years I have tested batteries with old style one that got so hot it nearly melted it and the new update box of tricks that health & safety says we have to use indicate battery is ok and passes the test but the battery on the vehicle is no good as soon as new battery is fitted no more problems