MH alternator not charging battery
On my Bailey Autograph 765 the alternator doesn't appear to be charging the leisure battery, or running the fridge on 12v while the engine's running. Has anyone got suggestions? (Sorry if this is covered elsewhere.)
Charging the battery is fine when we are booked to the mains and as far as I can tell the battery itself is in good condition. I've checked the voltages in various conditions as follows:
Battery, off-charge: 12.5v. Left for 48 hours, all lights on: still around 12.4v . Plugged into mains hook up, charging: 13.6
Engine on, fridge NOT on: 12.5v (implies not charging?) Engine on ,fridge on: 12.4v and dropping steadily down to below 12 before I decided it clearly wasn't right.
My understanding is that in order to charge ,the voltage across the battery from the charger must be more than 12.5, let's say 13.5v to 14.4v. My dealer is sort of saying the bare 12.5v we see is ok. I haven't yet convinced him there's a problem. But as it is, I need regular hook-ups and can't run the fridge while travelling.
All thoughts welcomed.
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I assume there is a split charge relay somewhere as there is for a caravan's fridge & leisure battery. What's fitted to trigger it? It's often a voltage sensitive relay in a car and they usually have the means to tweak them so the contacts close when the engine starts ie when the alternator is charging.
Some vehicles though have 'smart' alternators which appear to be not quite as smart as they think they are & I know sod all about.
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May I suggest that you join the Facebook group ' Bailey Motorhome Owners Group' we have just sold our Bailey MH but have found wonderful help from the above group during our ownership.
There are some very helpful and knowledgeable members who I believe have had the same problem you are describing. I'm sure they would be of some help to you. Hope you don't mind my suggestion.
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Is there any physical evidence that the fridge is not working on 12v when the engine is running? Are things melting in the freezer or appearing not to be cold? My 740 Approach has a light in the fridge which would indicate the power is getting through. Do you pre-cool the fridge on 230v before setting off on your initial journey. I never look at voltages if things are working OK so can't give you any readings.
David
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A leisure battery is usually around 12.7 volts but this varies a little as there are several different types. I would consider 12.5 volts partially discharged and 12 volts very low. Based on your voltage readings it would seem that the alternator is simply not charging the habitation battery but as I don’t own a Bailey cannot comment on whether this is switch settings or maybe a fuse failure. 13.8 volts is about normal for maintaining charge although if you had a smart charger you may see a higher voltage if the battery is flat.
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DK, the fridge light will come on when any of the settings are selected, so even if you have no EHU plugged in but have the dial to electric the light will come on inside the fridge. The only time the light stays out is when the fridge is actually switched off.
As I suggested up thread to the OP there have been a number of Bailey MH's that have had a problem with their fridges not working on 12v off the top of my head I can't remember what the cause was but I do know that some owners did suspect it was the alternator that wasn't charging the leisure batter sufficiently
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I never got to the bottom of it. We've now sold the MH (not because of this - I'd have gone on kicking until they solved it).
The service company on the same site as the dealer did manage to confirm that they couldn't find a charging voltage to the leisure battery from the engine, but as we sold back to the dealer, any rectification was after our ownership. I think there was still a degree of disbelief from sales that it was possible for there not to be a charge "because the way they're wired means it just can't happen". (Well, it did and it seems we're not alone.)
I did have meters on both the engine output and LB terminals to prove that although engine was producing 14V alternator output (as per spec) the LB terminals showed either 0V if discharged, or 12V if already charged off mains (you'd expect to see 14V at the terminals when the engine is running, same as the general feed from the alternator). That convinced me there was a real problem and no just a duff battery. Dealer's sales manager wasn't techie enough to believe this however.
I also had a thermometer in the fridge that never moved from ambient while on alleged low voltage supply.
Tip: to see the available voltage when engine is running, Amazon do neat little plugs for the cigarette lighter that have a voltage display and 2 USB sockets - so a worthwhile purchase in any circs.
Sorry not to be able to shed light on it.
(PS: as I'm no longer an owner I'm going to unfollow this thread now.)
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