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MG MGF Technical - Charging a flat battery

I've not used my MY2000 F for about three weeks.
Went to start the car yesterday morning (car was in garage but it was very cold)... the battery was flat.
The engine turned over slowly a couple of times then gave up.

My question ... Does the battery have to be electrically disconnected from the car during charging.

Could I use my 4amp trickle charger straight onto the battery terminals without causing any damage.

I would appreciate any advice or comment.

Regards Richard
RL Lane

generally no*, but I would worry if the battery were _really_ flat**

* there are some chargers which connect into the cigerette lighter socket

** a 'fast' charger could put out more than 15 volts, which might upset the other electrics- but I think they are well protected (probebly up to - to pick a not entirely arbetry figure - 30volts ). But chargers tend not to push in smooth voltages, and if the battery were really dead I would worry about weired voltages passing theu the regulator (only really applies if the voltage is less than about 7 volts)
Will Munns

If you are going to go down the battery charge route, then may I recommend an 'Optimate' (series III)?

You get leads that sit permanently on you battery and a connector to hide (for example under your wheel arch).
Then, all you need do is fast-connect the MG when you need.

The Optimate checks the battery and chargs if needed.., then leaves the battery alone for a fixed period of time before re-checking the battery.
This way the battery is not being charged for days if you leave it over the weekend.., but you're always guaranteed a perky battery when you need it.

Neil H

I always use my trickle charger with the battery connected on any car - I even start the car with the charger still attached. Never done any damage (it must be 20+ years old) - it's probably similar to your 4 amp charger.
Having said that, I think it's only been on the MGF once in 6+ years - it's currently :-) doing sterling work on a sulking Seat.
The optimate (and similar) is certainly the charger to buy nowadays.

Thanks for the advise ...
Could not find the Optimate 111 charger on the net ... are they readily available in the high street.
Richard Lane

A similar product to Optimate is the Airflow battery conditioner...
David S

That'll teach me ...
My charger - 20+ years old - went up in smoke this morning! (I think the rectifier failed, allowing the battery to push lots of amps through it)
So I'll be buying myself an Optimate or similar for Xmas.

Question for Will

Can you charge through the ciggie lighter socket even though it is dead when ignition off?

Nope, not on the F,* but there are cars with permenent live sockets for running fridges etc.

* in fact if you did you might see some - errm - interesting effects like the ignition comming 'live' as what you are actually doing is feeding the circuit that is switched off with the key - in fact the AA use a technique like this to energise the ignition circuit on some cars.
Will Munns

This thread was discussed between 17/12/2003 and 18/12/2003

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