# Charging Leisure Battery Via The Engine Altenator?



## ched999uk (Jan 31, 2011)

After the Peterborough show and just surviving on our battery I was wondering what sort of charge rate the alternator would put in the leisure battery. i.e is it worth starting the engine to top up the leisure battery?
I was only thinking of doing this in an emergency situation.

Any ideas?

Thanks


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## DTPCHEMICALS (Jul 24, 2006)

It has been posted on here that you will damage your engine if it is left on tickover fo any length of time.


In winter I warm Scudo up prior to setting off for work.

Have done every day in winter with several vans and never had a problem

dave p


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## GEMMY (Jun 19, 2006)

It's supposed to 'glaze' the bore.

Wonder why coach engines seem to be permenantly on tickover :wink: 

tony


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## rosalan (Aug 24, 2009)

Unlike most of us, they often have a team of mechanics, ever ready to deal with wear and tear at the company's expense.
A long time ago I drove coaches and would sit basking in their warmth on a winters day. After the big diesel had been 'ticking over' for an hour or so, a young driver came to join us. The elderly man who sat in the drivers seat asked the young man to have a look up the exhaust for he thought he could hear something rattling. As the young man put his face by the exhaust, the chap in the drivers seat pushed the peddle down hard!! The young chap honestly turned black (his face anyhow). Now that was cruel; but we did laugh a lot.
Alan


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## rayc (Jun 3, 2008)

ched999uk said:


> After the Peterborough show and just surviving on our battery I was wondering what sort of charge rate the alternator would put in the leisure battery. i.e is it worth starting the engine to top up the leisure battery?
> I was only thinking of doing this in an emergency situation.
> 
> Any ideas?
> ...


I can only speak from my vast experience of radio vehicles in the Army. We were never on EHU and used to charge the radio batteries, which were very similar to habitation batteries from the landrover alternator. We normally had 2x200AH in parallel. There was a hand throttle fitted especially for the job. We never blew any engines up and it helped to keep the feet warm. 
How long you need to run the engine of your MH to put any useful life back in to your battery is anybody's guess


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## Scattycat (Mar 29, 2011)

All I can say is that when we had narrowboats it was customary when moored up for any length of time to charge the habitation batteries by running the diesel engine for an hour or so every day.


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## aultymer (Jun 20, 2006)

As a previous supporter of the ' you will glaze the bores theory ' I now feel that there is enough evidence from boat owners and coach companies to show that the 'glazing' problem is one of the past. 
Modern engines would appear to cope well with prolonged periods of slow running. 
Coach companies only employ enough engineers to carry out essential maintenance and would be quick to jump on idling if it caused increased maintenance bills. 
Many narrowboats and yachts have high output alternators fitted and these need little more than tickover to give a reasonable charge. 
I have no qualms about running our engine for an hour or 3 if I need to get some charge into the batteries. 
Then again I wouldn't be so keen if I had a Fiat.


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## DABurleigh (May 9, 2005)

ched999uk said:


> After the Peterborough show and just surviving on our battery I was wondering what sort of charge rate the alternator would put in the leisure battery. i.e is it worth starting the engine to top up the leisure battery?
> I was only thinking of doing this in an emergency situation.
> 
> Any ideas?
> ...


The charge rate is mostly a function of the thickness of the wiring between alternator and leisure battery, together with whether you can raise the tickover speed a tad.

When my batteries are drained to 50%, I get some 25A on tickover, more on fast idle.

Yes, I'd happily do that in an emergency. But I certainly wouldn't do it as a matter of routine.

Dave


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## GEMMY (Jun 19, 2006)

I looked at the charge rate on the thingy (technical term) and discerned very little difference between tickover and VERY fast tickover. :wink: 

tony


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## gingercat (May 25, 2010)

*Excessive Idling*

With an older generation engine with mechanical fuel injection equipment left idling for many hours, there could possibly be a build up of glaze on cylinder bores from unburned fuel residue.

This would have to be carried out on a very regular basis and would result in piston oil control rings no longer having a good seal in cylinder bores. Engine would burn more oil (blue exhaust smoke), gum up piston compession rings, valve stems/valve seats leading to a sluggish engine.

However modern engines are made of very good quality materials, run with tighter tolerances and use good quality oils with various additives to prevent residue build up. They burn fuel more efficently due to higher pressure electronic controlled fuel injection systems.

The odd bit of idling to charge/top up battery should therefore not hurt. If you were to carry it out on a regular basis the exhaust system would have a shorter life span from combustion residue and condensate rotting it from the inside out.


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## spatz1 (May 19, 2011)

GEMMY said:


> I looked at the charge rate on the thingy (technical term) and discerned very little difference between tickover and VERY fast tickover. :wink:
> 
> tony


i agree and can utube my meters on start up and tickover to demonstrate exactly that and show just how quickly the initial burst of charge drops to suprising low levels that dont increase with engine speed :wink:


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## HeatherChloe (Oct 18, 2009)

Okay, so I'm a bit rubbish at the technical details, but this is my understanding, which others can perhaps correct. 

My understanding was that leisure batteries and engine batteries are completely separate unless you have had a 'bridge' fitted. 

The engine charges the engine battery (ie the one which starts the engine and probably runs the car radio, cab lights, etc). 

The leisure battery is charged by hook up, or by any solar panels or generator you might have had fitted. 

If you have had a 'bridge' fitted and turn it on, then hook up or solar panels or generator can charge both. On the face of it, a 'bridge' should allow the engine to charge the leisure battery too (ie a two way bridge) but I don't know if this is the case. 

Do electricity experts agree with me in my layman's version?


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## spatz1 (May 19, 2011)

you missed the split charge relay that feeds the hab batteries when the engine is running... 

and the "bridge" i think they use to carry solar to the cab and the fuse is blown if they forget to remove it ...


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## HeatherChloe (Oct 18, 2009)

spatz1 said:


> you missed the split charge relay that feeds the hab batteries when the engine is running...
> 
> and the "bridge" i think they use to carry solar to the cab and the fuse is blown if they forget to remove it ...


I think that, maybe, mine didn't do that until I had the bridge fitted.

Now, I can turn on the bridge, and my generator charges the leisure and engine batteries equally.

I think, in my van, that the batteries were completely separate before.


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## FoweyBoy (Dec 7, 2006)

The advice when running a boat engine to charge a habitation battery is (was) to have the engine in gear (forward or reverse depending on how you are moored up). The idea is (was) to give the diesel engine some work to do, besides turning over the alternator, to avoid glazed bores etc. Clearly leaving a motorhome in gear while stationary would be somewhat difficult to achieve!


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