Jump to content

Battery Charging From Alternator


potus4388

Recommended Posts

Good morning all!

How can I test to see if the leisure battery is in fact charging when the engine is running?

I have reason to query this as I drove six hours from Dover to home, when I arrived back home, just to check, I switched the Avtex TV on to 12 volt, it immediately came up with a message on the screen saying "no power turning off" So not enough power to even put the TV on!!

I have had the battery on charge and it is now fully charged, checked the voltage with a meter and that seems to be fine, just over 14 showing.

It is a new van so should be OK I guess but just wondered if there is an easy way for me to check?

The battery is an Yuasa AGM ..

Link to comment
Share on other sites

With my system if I check the voltage on the display and then switch the engine on the reading jumps up to over 13.4V, so I assume there is a charge going in. Alternatively if you have a multimeter (worth having even if only to check which flat AA batteries have got mixed up with new ones) and you can access your leisure battery take a reading across the terminals with the engine off and then running. If there doesn't seem to be an increase in volts it could be the inline fuse has blown or the terminals are corroded.
Link to comment
Share on other sites

The fact that you switched the TV on to test the battery, after a 6 hour journey suggests that you must have had some cause to doubt the battery charging function.

 

Given the age of your vehicle is there any possibility that it is fitted with a smart alternator?

 

Smart alternator control systems drop the output voltage when the starter battery is seen as fully charged. By all accounts, smart alternator systems are not compatible with the traditional split charge relay system.

 

Alan

 

Link to comment
Share on other sites

potus4388 - 2019-10-22 11:09 AM

 

I guess but just wondered if there is an easy way for me to check?

 

...as you seem to have a meter, the simple answer to your question is yes!

 

Allow the battery to stand off-charge for a while (an hour or so). The resting voltage should then be measurable around the 12.7-13V range.

 

Start the engine and measure again (with the engine running). If the charging system is functioning, then the voltage should now be noticeably higher. (say 13.8-14.5V depending on how things are set up).

 

If you see no immediate rise in measured voltage, it is probable that you have a charging issue.

Link to comment
Share on other sites

Thank you all for your advice.

I did check with a meter whilst battery not on charge, then put lights on to discharge the battery somewhat, I then started the engine tested again and the voltage did increase so it is charging from the engine. Having said that, I am at a loss to explain why there was no power in the battery after a six hour drive?

With regard to a smart alternator, I am not certain if my Boxer is fitted with one or not, but as it seems to be charging, is that an issue? I will contact my dealer to see if they can do a load test on the battery, if it is faulty then I need to resolve this sooner and not later whilst it is under warranty.

I am not clued up on the electrics so thanks for your comments/advice

Link to comment
Share on other sites

Did you have your fridge turned on to the 12 V setting whilst driving back?

 

If so this may be the cause of your problems.

 

Some manufacturers wire the fridge feed off the habitation rather than the vehicle battery battery to save wire length. If the charge feed from the vehicle battery where to fail, or be inadequate, the fridge would flatten the habitation battery thinking it was being charged from the alternator.

 

Keith.

Link to comment
Share on other sites

I should mention that I also have a 100 watt solar panel, 80% charge to the leisure battery, 20% to the vehicle battery, although recently I guess not much going in from there.

When I tested when not on charge the control panel was off, as soon as I switched the control panel on, the reading dropped by 1.2 volts, is that normal?

 

Link to comment
Share on other sites

potus4388 - 2019-10-22 4:44 PM

 

Keith,

Yes the fridge was on 12 volt from the vehicle battery on the drive back from Dover. The handbook says it works from the vehicle battery whilst driving though.

 

OK, What happens to the habitation battery voltage if you turn the fridge on whilst the engine is running?

 

You may have a wiring fault or faulty fuse/relay meaning the fridge is actually flattening the hab battery whilst driving.

 

Keith.

Link to comment
Share on other sites

Hi Keith,

I will check on that tomorrow and let you know(I borrowed a meter from a neighbour and will ask again tomorrow)

You make a good point and I will be interested in the result, that could explain a lot, although as I said according to the Elddis handbook, it operates from the engine battery.j

Link to comment
Share on other sites

potus4388 - 2019-10-22 6:35 PM

 

Hi Keith,

I will check on that tomorrow and let you know(I borrowed a meter from a neighbour and will ask again tomorrow)

You make a good point and I will be interested in the result, that could explain a lot, although as I said according to the Elddis handbook, it operates from the engine battery.j

 

John,

 

A multi meter is an invaluable aid when owning a MH!

 

They are typically less than a tenner for a basic but decent one, eg https://www.screwfix.com/p/lap-mas830b-digital-multimeter-600v/75337 so I would suggest you add one to your Christmas list :-)

 

Keith.

Link to comment
Share on other sites

I know, you are absolutely right Keith! I have meant to get one but never got round to it, but I will now, thanks for the link, I have a Screwfix not too far away and will call in when next in the area??

In the meantime, I'm sure my neighbour will oblige and I will report back tomorrow.

 

Link to comment
Share on other sites

Hi Keith,

This is going to make you smile, bearing in mind what you said yesterday about having my own multi meter but......... my neighbour with the multi meter is out!!

I guess it just proves your point and I fully intend to get my own now.

Thanks for the advice.

 

Link to comment
Share on other sites

Keith,

He is now home!(my neighbour)

I can report the following results:

Battery tested at rest with fridge off - 14.17 volts

Battery tested again with fridge on 12 volt - 14.17 volts.

I guess therefore the fridge is not running on the leisure battery so that is not an issue.

As I mentioned before it is an AGM battery. I just wondered if perhaps the battery is not holding its charge properly, although I took it off hook up yesterday and the battery panel on the control panel has all the bars lit up this afternoon. I am taking it into the dealer tomorrow for a number of things and have asked them to look at the battery and do a load test.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...