VR6 keeps dying/draining battery

[Prabz 0]

I bought a VR on Friday. When i went to go and see this first and give depoist it ran all fine drove well. Came to pick it up and the guy had it on a battery booster. Said i may need a new battery. I thought this shouldn't be a problem.Went and checked into hotel in St Ives which was fine. Woke up next morning to a dead battery. Thought this was odd but the guy i bought it off did say give it a good run and the battery will need changing. I didn't have any tools with me at this point. Quick trip down to there local Halford's store to pick up a brand new battery and some tools. Went back and fitted the new battery in and boom she fired up. Drove from St Ives down to Cardiff to where i was going to stay on Saturday night. Woke up on Sunday first thing i done was went out and check if the car will start, guess what she didn't. Mileage not displaying or anything. Jumped her with another car and she came back to life but then cut out while driving down the road.

Prabs

[VR6Pete 1,455]

Got a multi meter mate? Attach it to the battery when running and check the output, should be around 13.8V from memory on a healthy alternator.

If it isn't that then its time to look at other electrical items... Any ICE equipment installed or anything?

[Lukey. 381]

Yea from the sounds of it alternator could be a likely culprit, it could be that the alternator isn't charging or it could be that it's not giving enough current.

To check if the alternator is even functioning what you want to do it check the voltage across the battery posts with a multi meter with the car running and turned off.

If the alternator can charge the voltage when running should be about 14v and when turned off you should get 12v. But if your battery is ruined through not charging you may get a lower reading on the battery itself when the car is off.

You could have a dodgy connection somewhere too so check all the thick cables, they go underneath the battery tray and connect to the starter motor and on to the alternator, and there's a big earth cable fastened to one of the front gearbox mounts, you can check the continuity of all the cables with a multi meter too.

Another thing you can do us find out what amp your alternator is and what Ah your battery is, if they are quite close you could have a scenario that you are never giving the battery enough juice

For instance if your alternator is a 70A and your battery is a 60Ah, a car can typically use 35-50 amps when running, so you'd only supply a smaller amount of amps to the battery and would need 2 to 3 hours for a full charge, so short time journeys would struggle to give the battery additional power, so the cycle continues till the battery is drained so much it won't hold charge.

This scenario above actually happened to me and I replace the alternator for a 120A version and haven't had a problem since

[Prabz 0]

So i done what you both mentioned to do. I first had to jump the vr with my other car. Once i had this running my mate checked with a multi meter, the readings were low between 5-8. I took the jumps of the vr and it would cut out little while later.

Luke as for the alternator its a 70A. My mate did say go for a 120A. The battery i have is a 60Ah. So will be looking for a alternator and get this replaced as soon as. Will let you guys know what the outcome is. Thanks!

[Lukey. 381]

Cool hopefully your new battery isn't wrecked from this and you don't have to get a new battery again too.

[Prabz 0]

Hey Lukey,

Could you let me know where you got your alternator from? I do have warranty on the battery .

[Lukey. 381]

Mine is genuine VW, expensive, but they do have an exchange subsidisation on them.

[Prabz 0]

So i called up VW to see how much they would charge. I gave them the number from the alternator and what make it is. They said they have a newer version of the 70A Alternators? I did ask do you have any 120A and he said no not under this number. If i did buy a aftermarket 120A i will need to change a couple of things? Would anyone know what i would need to change?

Prabs

[Lukey. 381]

Give them this number

[Prabz 0]

Thanks Lukey,

Will call around and see what i can get. I guess you didn't have to change anything. Bolt off and bolt on the new one?

Prabs

[Lukey. 381]

Yea it fits exactly the same.

[Prabz 0]

Thanks all for your help. So got my alternator replaced with a 120A one. Much better results. Also they added a wire from positive to the alternator too? What does this do? Since i have had this done car unlocks and fire's up all fine .

Prabs

[Lukey. 381]

There is a wire from the alternator to the positive anyway via the starter motor, but another one isn't going to hurt, its the path for the alternator to recharge the battery.

[VR6Pete 1,455]

Result, glad to hear your on the right path mate now your all fixed up, are you coming to our rolling road & show and shine on the 16th? @ stealth racing in Warwickshire?

[Prabz 0]

Thanks for your help guys!!!

Pete if i change my 185/35/17 with 195/40/17 then yes i will be coming The way i bought the car i think the police around my area will not like it so will need to change my profile on tyres (get rid of the massive stretch) If anyone has any hit me up

Prabs

[VR6Pete 1,455]

haha yeah those police folk don't like stretched tyres these days should be easy enough to sort out, don't forget stick your name down mate