# How long to re charge a flat battery



## 105430 (Jun 25, 2007)

Our auto Trail miami doesn't have a fire so a fire fitted so we had to keep the blown air on most of the weekend.Unfortunately we were not on hook up and by saturday tea time the battery was in a sorry state(of charge!)Could anyone who has a similar set up please advise if there is anything we can do to help if we find ourselves in this position again.also how many miles would I need to drive in order to recharge the battery via the alternator.It is a 120 AH battery.Any suggestions would be really appreciated,We need to have the van heating on as our 2 little girls are only 2 and 5.


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## devonidiot (Mar 10, 2006)

With the price of diesel these days it is better to charge the battery in situ.

If it is the leisure battery the simply hooking up will re-charge.

If it is the vehicle engine battery then a cheap charger will do the trick.


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## Scotjimland (May 23, 2005)

As advised above, driving isn't a very efficient way of charging.. nor will it fully charge the battery.. at best it will only pump in about 80%. 

During winter months when not on ehu there are large demands on the leisure battery, heating fan, lights, TV , pump etc they all eat into the reserves, I would..

a) Instal a second 120 ah battery, this will effectively double the power available. If unsure about this contact a motorhome dealer. 

and as an emergency back up

b) Buy a small genny, preferably a suitcase inverter type, a 1kva will be adequate to charge the batteries, I recommend a Honda but if your budget is tight look at the yellow Kipors on ebay, about half the price of a Honda.
I wouldn't get a cheapo one as sold by the likes of B&Q, they are noisy, smelly and have poor voltage control which can damage motorhome electronics..


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## blondy (Aug 23, 2007)

*Battery*

I agree with scotjimland, but would add Have a stirling battery to battery charger fitted, this charges the leasure batts quicker and puts more power in them, we have this setup and are very pleased with the system.
Don


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## teensvan (May 9, 2005)

Hi colyoung.

Your 120ah battery would take 12 hours to charge at a rate of 10 amps per hour in theory, but a charger would reduce the rate of charge as the battery becomes charged. You should never charge a battery at more than 10% of its amp hour rate. ie 12 amp would be its max, but this would start excessive gassing and overheating. I would think 15 hours would fully recharge your battery. It does not do the battery any good to discharge it below 50% as it also takes longer to recover to full charge, and starts to damage the plates over time.

steve & ann. ---------- teensvan


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## andyman (Aug 31, 2006)

[/quote]we had to keep the blown air on most of the weekend.
It was because of blown air heating only and camping without hookup that i choose a M/H with the option of just gas heating. If i'm correct the fan uses arround 4 amps.


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