battery charge question pleease

[duetto owner]

camping here and its very cold. the habitation battery is getting low as blown air heater on a lot.

to re charge from van battery do need togo gor a drive or just stay still still engine running.

need some swift replies as weather here cold and heater cutting out not on a camp site so no hook up.

[Dr Dave]

No difference in charge rate if you are moving or not tick-over is not good as you need some revs to get usable output from the alternator, however whatever you do the charge rate will only be about 10 - 15 amps so you need to run it a while to get any useful charge into the battery but you have no option as it is cold so run the engine at about 1500 rpm for at least an hour. Good luck.

Dave

[Cliffy]

Just run the engine on a fast tick over.

Just a light touch on the throttle maybe try and find something that will keep at that speed otherwise your foot will soon get tired.

Higher the revs the more charge to a point but just being on tick over may just power what you are using and not leave any excess to charge the leisure battery.

 

 

[Brian Kirby]

I don't agree with the above. If you battery is down to the point at which the heater is cutting out, it suggests it is somewhere around 12V, or nearly flat. The ideal, under those circumstences, would be to get yourselves to the nearset source of hook-up and just plug in and relax. Even then it will take several hours to get the battery back up to full charge, as I suspect you will be consuming small amounts (fridge ingiter, for example) all the time. Running the engine will take even longer, depending on the alternator output. You don't say what the type or capacity of the battery is, or where "here" is, but unless there is some other fault at work (duff battery?), or the wiring to the heater is causing excessive voltage drop, your battery is heading for "flat" - in which condition it will be liable to be damaged unless fully charged again as quickly as possible. Simplest, if practical, would be to head for a site with hook-up for 24 hours. By all means run the engine until you leave, it will help.

[Dr Dave]

You may not agree Brian but the guy wanted a quick reply at 8:39 PM as he was cold. EHU was not a stated option either go for a drive or just run the engine. I could have suggested many other options including EHU, Generator, Fuel Cell, More battery capacity but that was not the question. What would you suggest given the two options given and the time of night? After all i did not want the OP to suffer from Hypothermia.

 

[Guest Joe90]

Precisely.

[StuartO]

But Brian was responding the following day, with an aditional suggestion which is also a useful one for the OP. Perhaps his opening phrase was a bit provocative but I doubt he intended that. No need to get the hump.

 

Using the MH's engine to recharge a flattened leisure battery is going to be hard work and if the OP needed heating all night I suspect he;d have had to keep the engine running all night too. If he'd had an option to drive to somewhere where he could plug into the mains that would have been a better way to deal with the problem than leaving the engine running all night.

 

You do get useful charge out of an alternator with the engine at tickover revs, probably enough to keep the heating and a bit of lighting going, if not to put much charge in the battery. He'd get some heat from the engine via the cab heater too, eventually. But we're talking survival strategy rather than a good way to get the battery recharged here aren't we?

 

Even a full day's driving will not usually recharge a flattened battery, or at least it won't fully recharge it, so the OP would also need to rethink his plans and getting on to an EHU asap to put an overnight charge into the battery would be a sensible first step. And once he's achieved that he will have time to replan for the longer term. It doesn't sound like he has the wherewithall on board to cope off EHU in cold winter conditions.

[Guest Joe90]

He said quote " I don't agree with the above " ;-)

 

we could all have come up with a different solution for the next day... not sure how that would have helped the bloke freezing his wotsits off that very night though ;-)

[Dr Dave]

StuartO - 2014-12-28 4:07 PM

 

But Brian was responding the following day, with an aditional suggestion which is also a useful one for the OP. Perhaps his opening phrase was a bit provocative but I doubt he intended that. No need to get the hump.

Stuart.

I have in no way got the 'hump' I just cant see why Brian did not agree with running the engine to facilitate enough charge to run the heating on a cold night when you are desperate. If i was cold i would run the engine for as long as needed. His choice of phrase 'i don't agree with the above' is strange as there is nothing to disagree with because (excluding problems with the split charge system) if you run your engine at a fast tickover the heating will continue to operate due to the alternator supplying enough voltage to maintain the heater above its low voltage cut off. The OP mentioned that he was not on site so no hook up so that suggests that he is familiar with the concept of charging the leisure battery from the mains.

Dave

[duetto owner]

given up and gone home. Thank you for replies. the hot air system is normally good for 3-4 days running off the battery. [my duetto has two vehicle batteries rather than one leisure]. I think it was the minus one cold snap that kept the fan hot air running all the time to keep the temp up, it kept cutting out completely after only two hours on the second night of each location .

 

when we have been out in -7 our coldest camping experience we were on hook up and were ok warmand snug, but been wild camping last 18 months now.

 

What i did in the end was leave our van ticking over 45 mins with vechile heater on, that seemed to help as the heater then ran all night ok. we were intending to head onto Lincoln, then visit york and harrogate but with the doubt about the heater and snow forcasts returned home this evening after just a week away.

 

I will plug the hook up lead into our garage tomorrow as advised above to be sure.

[Cliffy]

duetto owner - 2014-12-28 6:15 PM

 

given up and gone home. Thank you for replies. the hot air system is normally good for 3-4 days running off the battery. [my duetto has two vehicle batteries rather than one leisure]. I think it was the minus one cold snap that kept the fan hot air running all the time to keep the temp up, it kept cutting out completely after only two hours on the second night of each location .

 

when we have been out in -7 our coldest camping experience we were on hook up and were ok warmand snug, but been wild camping last 18 months now.

 

What i did in the end was leave our van ticking over 45 mins with vechile heater on, that seemed to help as the heater then ran all night ok. we were intending to head onto Lincoln, then visit york and harrogate but with the doubt about the heater and snow forcasts returned home this evening after just a week away.

 

I will plug the hook up lead into our garage tomorrow as advised above to be sure.

 

So doctor Dave and i did give the appropriate advice for the situation the OP was in. Brian.

 

[Brian Kirby]

Dr Dave - 2014-12-28 2:59 PM

 

You may not agree Brian but the guy wanted a quick reply at 8:39 PM as he was cold. EHU was not a stated option either go for a drive or just run the engine. I could have suggested many other options including EHU, Generator, Fuel Cell, More battery capacity but that was not the question. What would you suggest given the two options given and the time of night? After all i did not want the OP to suffer from Hypothermia.

TBH, I didn't notice the OP's original post was made the evening of the day before, I'd just assumed it was AM, not PM when replying (Specsavers?), but would probably have suggested either driving to EHU as quickly as poss, or returning home.

 

It would in any case have been better to act, than to post on here, under the circumstances. Why wait in the hope of replies? He was very lucky that you responded so quickly, and he seems to have made the best decision in the end.

 

Stuart has picked up on the time difference between the OP's request and my response (thank you Stuart :-)), something others seem to have missed, and no offence to anyone was intended. I still disagree, though I accept that your suggestion was, under the circumstances, the best immediate "first aid" remedy.

[Derek Uzzell]

duetto owner - 2014-12-28 6:15 PM

 

given up and gone home. Thank you for replies. the hot air system is normally good for 3-4 days running off the battery. [my duetto has two vehicle batteries rather than one leisure]. I think it was the minus one cold snap that kept the fan hot air running all the time to keep the temp up, it kept cutting out completely after only two hours on the second night of each location ...

 

May I ask you about the “...two vehicle batteries rather than one leisure”, please?

 

I think your Duetto is 2009-vintage and (naturally) will be Ford Transit-based. I’m aware that Transit Mk 7s can have two Ford factory-fitted batteries but, if your motorhome has that Ford option, I would have thought Auto-Sleepers would have fitted a leisure-battery as well.

 

Just curious...

[DJP]

I would have suggested a short drive to a B&Q and purchase a generator. Warm air heating obviously uses a lot of battery power (5amps on full blow) and at that temperature the batteries would have been down on usable power anyway. Running the engine for several hours would have minimal influence on the already possibly dangerously low leisure battery.

The generator, although possibly socially unwanted is an essential for warm air heating efficiency at this time of year.

Been there, done that, now have a van with a fire!

[Guest Joe90]

Only one slight flaw with that suggestion, the bloke posted his problem around two hours after B&Qs closing time. :-S

 

But I'm with you as far as these stupid heaters that require battery power to run, and power needed just at the time of year that a Solar panel is another waste of space, give me the convector type any day, sadly my Rapido also has a blow air system, and a hefty Solar panel, the only saving grace being we don't do Winter stuff much.

[DJP]

Joe90 - 2014-12-29 5:50 PM

 

Only one slight flaw with that suggestion, the bloke posted his problem around two hours after B&Qs closing time. :-S

 

But I'm with you as far as these stupid heaters that require battery power to run, and power needed just at the time of year that a Solar panel is another waste of space, give me the convector type any day, sadly my Rapido also has a blow air system, and a hefty Solar panel, the only saving grace being we don't do Winter stuff much.

 

Most B&Q close at 9pm, well my local does anyway :-D

[pepe63xnotuse]

Just curious:

But as a rough guesstimate, when it comes to 12v, which "blown air" heating is the most power hungry?

 

a) Gas fired

or

b) Diesel fired*

 

(*our '03 Duetto's heating was diesel but we didn't keep it long enough to see how much it belted the batteries).

[Guest Joe90]

DJP - 2014-12-29 6:13 PM

 

Joe90 - 2014-12-29 5:50 PM

 

Only one slight flaw with that suggestion, the bloke posted his problem around two hours after B&Qs closing time. :-S

 

But I'm with you as far as these stupid heaters that require battery power to run, and power needed just at the time of year that a Solar panel is another waste of space, give me the convector type any day, sadly my Rapido also has a blow air system, and a hefty Solar panel, the only saving grace being we don't do Winter stuff much.

 

Most B&Q close at 9pm, well my local does anyway :-D

 

Even assuming it was 9 pm ( not according to their website ) the bloke would have found packing up, and finding one that was open and had stock of a generator a bit of a push in 21 minutes. ;)

 

B&Q Opening times

Mon-Fri 07:00 - 20:00

Sat 08:00 - 19:00

Sun 10:00 - 16:00

Seasonal opening

Wed 24 Dec 2014 07:00 - 16:00

Thu 25 Dec 2014 Closed

Fri 26 Dec 2014 10:00 - 17:00

Wed 31 Dec 2014 07:00 - 17:00

Thu 01 Jan 2015 10:00 - 17:00

[Dr Dave]

At the end of the day (pun intended) If you are cold and out of options run the engine. (I know Brian disagrees but in the real world, needs must)

I would not get a generator from B&Q when Screwfix have invertor generators starting at £189

http://www.screwfix.com/p/impax-im800i-700w-inverter-generator-230v/15760

Dave

[pepe63xnotuse]

...and don't most MHs have diesel gennies pre-installed anyway?.... :-D

 

AND they come with their very own "blown air heating"... ;-)

[Brian Kirby]

Dr Dave - 2014-12-29 7:55 PM

 

At the end of the day (pun intended) If you are cold and out of options run the engine. (I know Brian disagrees but in the real world, needs must)

I would not get a generator from B&Q when Screwfix have invertor generators starting at £189

http://www.screwfix.com/p/impax-im800i-700w-inverter-generator-230v/15760

Dave

No David, I don't disagree under those circumstances. If facing a cold night with no heating, run the engine to heat the van by whatever means.

My mistake was to assume he had posted that morning, and not the night before. But as above, I had not noted the time of the OP, nor of your (or Cliffy's) reply. So, for such an emergency, I do agree.

 

My disagreement was based on that misunderstanding of the timescale, leading me to assume that the OP had much greater time in which to fix his problem. Hence my original advice: "Simplest, if practical, would be to head for a site with hook-up for 24 hours. By all means run the engine until you leave, it will help" - which was clearly not relevant under the actual circumstances. Apologies to all for the ensuing confusion.

[duetto owner]

pepe ............our blow air heating runs off the diesel, does not appear heavy on fuel, also runs of electric when on hookup. left the van on hookup to our mains yesterday just to be sure.

 

will venture away again in another week or so once this cold snap is over then arrange a habitation check do had one done for ages. to check battery and heater etc.

[Brian Kirby]

But David, those diesel fired systems are much heavier on 12V than the gas fired versions, because of the current consumed in igniting the diesel.

 

BTW, you didn't answer Derek's question above regarding your batteries. That answer may give a useful clue, if you can provide it.

[StuartO]

As Derek asked, what is the "two vehicle batteries but no leisure battery" setup you have duetto owner?

 

It would be intersting to know how that arrangement is configured because I can't work out how a short (45 min) engine run would have taken you from flat battery and heater failing to the heater running all night.

[Derek Uzzell]

I believe the blown-air heater fitted to Transit Mk 7-based Duettos would have been an Eberspacher “Airtronic” D2 model, plus the “Airlectric” mains-powered add-on.

 

In this 2011 thread

 

http://www.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Three-years-with-a-solar-panel/22097/

 

there’s a posting by “dipsticks” (4 January 2011 5:27 PM) that mentions a second battery.

 

I think I recall that the battery configuration for Ford-based Auto-Sleepers motorhomes with diesel-fuelled heating involved two Ford (60Ah ?) factory-fitted ’starter-type’ batteries (with both used to start the vehicle, but only one used to power the vehicle’s electrical accessories), plus a 90Ah leisure-battery installed during the Auto-Sleepers conversion process. Not sure how the charging arrangement would work, but it’s quite likely that, with the Ford two-battery arrangement, there would also be a beefed-up alternator.

 

David’s plan to have the batteries checked is wise. If the batteries are original they’ll now be 5 years old and should perhaps be expected (given the type of usage he has described) to start to stagger performance-wise.