Recharging A Flat Battery

[bednobs]

had a flat list night. Fortuneately i have one of those jump start battery things in the car (and amazingly it was charged!) so was able to start.
How longs should you drive for to re-charge after that? and does it matter if it's mtorway or pootling?

[bookbinder]

A fast run of about 20 minutes out and 20 minutes back should be enough to keep a battery charged up. But you should do that fairly regularly. Once a flood might not be enough.

[bhg481]

Do you know why the battery was flat? If you eg, left the lights on so ran it completely flat you might have wrecked the battery. If you've just been doing lots of short trips which haven't been long enough to charge the battery properly a few good trips should rescue it. The bottom line is to make sure your emergency starting gimminck is fully charged and keep it with you for a week or two.

[bednobs]

thanks - i was waiting outside the sports hall for my daughter and left the key in. I think it leave the running lights on if i do that, but it was lightish so i didnt notice.

[gingejbee]

^yes, I'd be wondering why it happened, too. Is the battery in good condition and is the charging system working efficiently?

[bhg481]

Running lights are usually quite low-power so, if that was the cause, your battery is getting tired anyway. Places like Halford's will do a free battery check.

[bednobs]

the battery (i was told, so laymans terms here) isnt the right battery for the car (too "small"?) i just had an MOT which informed me id done about 3k miles since the last one, and only doing mainly small journeyys

[bhg481]

It sounds a bit like battery-abuse then. Investing in a battery charger could be a good scheme, particularly if you can get the car in a position where you can charge the battery without taking it out of the car or having trip-wires across a public pavement.

[bednobs]

thanks all. perhaps i should report myself to rspcb?