Topic

And I mean dead. Very dead. I last drove the TF about 10 days ago when everything was fine. Came to start this morning and there was nothing, not a glimmer. Luckily I have a Halfords power pack so jump started and let it tickover for a bit before a ten mile run to our local MG specialist garage. Turned the engine off for a few mins then tried to restart and all I got was a few clicks. After another jump start and a check of the voltage whilst ticking over the technician said that it was charging fine and will be the battery. Not sure of the age of the Exide battery that had been fitted, couldn't find any date codes. But I have fitted a new Bosch from Halfords. I connected a DVM over the batter and took it for a bit of a run. The voltage from the alternator seems to be sitting between 13.5 and 13.8 over the battery whilst running. This seems a bit low to me, my Mondeo sits around 14.2 for the same conditions. I am wondering what other people have found. I could do with checking if anything is draining the battery whilst parked. I expect a small amount of current flow to the ECU etc. but not sure how much. has anyone got any figures and is there an easy way to check via one of these connectors that go in place of the fuse. Which are the best fuses to go for. I don't fancy disconnecting the battery terminals and upsetting things.

Had the same thing happen without warning on cars in the past, just change the battery and wait to see if it happens again. The cells in the battery can just breakdown without warning. Went on a boating holiday once, got back to the car 6 days later, dead as a dodo. Got a jump start, it died again 30 miles further on. RAC came out got a new battery, the car was fine till we sold it 3 years later, still going strong. Don't look for a fault till you have one, it saves so much aggro.

I must admit I have had a battery just up and die before with a similar experience to yours. I think I was just a bit worried about the lower voltage that it seems to be sitting at. It's probably ok.

I think the voltage will be a bit low until the new battery is fully charged. Take it for a mega drive then check it all again.

I think the charging voltage will vary with the amount of charge already in the battery. I think that charging voltage is fine, tbh. You'd probably get a higher charge voltage into a flat battery than a fully charged one.

The issue of testing for battery drains is problematic. To test for a battery drain you need to disconnect the live feed from the battery to place a meter in series. this will show any current flowing when the car is all switched off. Unfortunately the act of disconnection is enough to reset relays etc that may have been causing the drain in the first place. so when you connect in your meter, it shows no drain. So catch 22.

I know Clive has addressed this issue with a special terminal gizmo. Hopefully he'll be along later.

The terminal gizmo sounds interesting. I did pick up one of these yesterday http://www.maplin.co.uk/car-fuse-adaptor-lead-set-217881 in the hope of just pulling a fuse and measuring current draw on that circuit. But like you say, if it is an intermittent relay it will probably reset.

I think Clive fitted something like this:- BATTERY DISCONNECT CUT OFF ISOLATOR SWITCH - BETTER THAN DISCARNECT Completed