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[essexceltic]

hi all one problem to another.

yesterday i had a new earth strap fitted to my omega 2.5 v6 got up this morning and battery was dead. i put jump leads to the car and started first time left the car ticking over for about half hour then took the car a run for about 15 mins. came back turned engine off and battery was dead again when i try to restart. the car does start first time from the jump leads. could this be cos of the earth strap draining my battery or altanator prob. when the car is driving all the lights are bright example brake lights

forgot to mention the earth strap is going from the battery to the bulk head.

any help please
thank you in advance

[Lazydocker]

Check the voltage at the battery with engine off and running... I reckon you'll find that the voltage regulator in the alternator is knackered and thus overcharging (any higher than about 14.5 V IIRCC)

The good news is that you can refurbish the alternator fairly easily, there's a How " in the Maint Guides I think, but the bad news is that the Battery is probably toast.

[essexceltic]

thanks for reply lazydocker

i have changed the battery and all looks ok now. will give it a few days to see if the battery runs down. voltage is good now.
many thanks

[Lazydocker]

thanks for reply lazydocker

i have changed the battery and all looks ok now. will give it a few days to see if the battery runs down. voltage is good now.
many thanks

Have you checked the running voltage too??? If it is overcharging your battery will be toast in a couple of days!!

Sorry to be a scaremonger, and I hope I'm wrong, but I know that the batteries for these aren't cheap!!

[Kevin Wood]

Any battery problems, it's worth checking the voltages (before replacing anything, TBH, but too late in this case).

I would do as follows:

Ensure the battery is reasonably fully charged. If in any doubt charge it at 2-3 amps for an hour or so.

Let the battery rest for a while after charging and connect a multimeter on volts across the terminals.

With no load the reading for a good battery should be around 12.5 - 12.8 volts.

Switch on the headlights and watch it for a few minutes. Voltage will drop to perhaps 12.2 but if it continues to fall to below 12 and the battery was charged at the start, battery FUBAR.

Now start the engine and look at the voltage at normal idle, fast idle, and fast idle with a good few electrical accessories on (headlights, blower fan, heated rear window, etc.)

I would expect to see 13.5-14.5 volts at idle, 14-14.5 at a fast idle and it should hold over 13.5 with plenty of accessories on, at a fast idle.

Any lower than this and the alternator is not charging the battery adequately, which may explain it not recovering form a flat battery after a drive. Higher than 14.5 and you have a regulator failure in the alternator and risk damaging the battery and other electrical items.

If the charge voltage is low, check all connections between the alternator and battery including chassis negative connections and straps between chassis and engine. Failure of the crimp connection at the positive battery terminal is a favourite (poor connections will get warm while the load is on them, which can help identification).

Kevin

[Entwood]

Excellent advice Kevin ..  

Almost worthy of a "How-to check your Battery & Alternator" in its own right !!