# Overcharging/Undercharging.



## Don (Jan 25, 2008)

Traffic light battery indicator shows 75% charged yet strong acid smell and battery warm, I assume that means overcharging, so why only 75% on indicator.

Don


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## terry1956 (Jan 25, 2008)

*battery*

hi don.
check across the battery with a elec meter, with the engine running it should read around 13.5 volts.
check the earth cable.
how old is the battery.
I had this fault on my old motorhome and the battery became red hot, and the system went down, ie lights etc.
found that the wiring had shorted to the battery.
The fault went down to the battery being breaking up inside and the regulator thinking that it needed more volts just give it more while showing the battery at 3/4 power.
you will need to start at the battery, as stated check the voltage, the earth and the age.
michael


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## GeorgeTelford (Jan 31, 2008)

The most likely scenario is battery cell breakdown.

If the charger is working then voltage at traffic light meter would read full unless a battery cell is duff. (essentially the traffic lights are voltage dependent)

A short should cause a fuse to blow unless the vehicle is wired incorrectly.

New battery needed I fear......

George


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## Tony Lee (Jan 31, 2008)

Agreed.

You may be able to verify it by - 
Checking if one cell is low on water.
Check if one cell is not bubbling when all the others are.
Feeling along the side of the battery if the heat seems to be localised.

Turn off charger and disconnect the battery. Measure the voltage after a couple of hours. Anything less than around 12.4 indicates not fully charged. Put a 5 amp load on the battery while measuring the voltage. A fast drop to less than 12V - may even go down closer to 10V - indicates a crook cell.


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## Don (Jan 31, 2008)

Hi George, Havent seen you around for a while. Any way back to problem.
Manual says, No charge will be put from charger if no battery connected. thias will enable to leave connected to main's. Meter across terminals show 2.3volts. Put a battery on and its 16.5 volts. Would you say charger unit is GOOSED.

Don


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## terry1956 (Jan 31, 2008)

*In answer*

Hi, the replacement battery you are trying as that a full charge, in good condition and the correct amount of acid, if so it looks like the charger is U/S.
michael


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## Nosha (Feb 3, 2008)

16.5v seems rather high to me, could be boiling the battery dry? I thought 14.2v was the maximum charge rate of a 'normal' lead acid battery.


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## Don (Feb 4, 2008)

Exactly, thats why I said, Do you think its goosed. At 16.5, I think so


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## Tony Lee (Feb 4, 2008)

Hard to diagnose something without some basic info on the system components.


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## Don (Feb 4, 2008)

OK Tony Lee. What basic info on the system components do you require ?

Don


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## GeorgeTelford (Feb 4, 2008)

Hi Don

Most of these OEM chargers work based on the batteries internal resistance, if this is altered due to cell breakdown a higher or lower voltage could ensue, however in this case in the original post the traffic light meter was I believe reported as showing 75% this equates to less than 12.8 Volts, now if a battery is causing a smell getting warm etc at this voltage, the battery is in my opinion FUBAR.

George


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## Tony Lee (Feb 4, 2008)

Don, there are two ways to fix something. Most common is to have a preconceived notion often based on ignorance and usually tackled by progressively buying new components to replace the supposed crook component. This often works, but sometimes the faulty part still in the system ends up damaging the new component. 

The other way is to use a bit of science. Important info might be the brand and model of the charging unit and the type of battery. At the very least an accurate description of what is going on would help.  Failing even that basic info, I suggested some basic tests that might help work out whether it is the charger or the battery. 
As they say, information is power. Without information, half your advisers say the battery is stuffed and the other half say it is the charger.

Your money. You choose.


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## Don (Feb 4, 2008)

Tony, You seem to have me sussed. “Most common is to have a preconceived notion often based on ignorance and usually tackled by progressively buying new components”. So let’s go back to the beginning.
The habitation battery is/was 85Ah linked to a vehicle 55 Ah Battery. In my ignorant opinion both these batteries are too small for days on end of wild camping.
My first choice was to up the habitation battery to 110 Ah. Battery was checked by meter and tested on a 50-Watt output to establish duration. Battery appeared to be in good shape.
Exchanged 85 Ah for the 110 Ah. And this appears to be the start of the problem. The battery was fully charged when put in, linked up to the van, checked again with meter and holding charge. Checked on van meter (traffic light system) only showing 75% connected to mains and charger kicks in pumping in 16.5 v. now normal charge would be 14.5 v. Charger is a Scheiber 30.63351.40. According to the instructions, No charge is given out while battery has charge above 12.02 v Today I have put an automatic charger on the battery and it shows full and puts itself onto standby, yet traffic lights show 75%. Go back onto van charger, will put out full charge and show 75%.
In my ignorant way I assume that the traffic light controls the charger and as the t/l is showing 75% it will keep charging.

That’s as clear as I can be 
.

Don


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## GeorgeTelford (Feb 5, 2008)

Hi Don

The traffic lights are a simple meter.

Where do you get the reading of 16.5 Volts from? are you using a multimeter?

Is there a change over switch between mains and habitation batteries?


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## Don (Feb 5, 2008)

Hi George. 
Where do you get the reading of 16.5 Volts from? are you using a multimeter?
The reading of 16.5v is from both a multi meter and the voltage meter on the charger.
Is there a change over switch between mains and habitation batteries? 
omly the on/off switch, as has been said before, the system allows for long term connection as no voltage is (should be) passed from charger once battery is fully charged, which it is, as shown on multy meter and volt meter on charger. but if i switch on the mains it charges at 16.5v.

Don


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## guerdeval (Feb 5, 2008)

Do remember that batteries can explode with tragic consequences, rog


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## Tony Lee (Feb 5, 2008)

Hi Don, 

I had a look on the manufacturers web site but your charger doesn't seem to be listed. They make three distinct types - a normal three stage charger, a non-charger that is more like a fixed power supply providing 13.7 volts, and another type that switches between two voltages.

You said in your last post -
"My first choice was to up the habitation battery to 110 Ah. Battery was checked by meter and tested on a 50-Watt output to establish duration. Battery appeared to be in good shape.
Exchanged 85 Ah for the 110 Ah. And this appears to be the start of the problem. The battery was fully charged when put in, linked up to the van, checked again with meter and holding charge."

so putting a different "good" battery in the system was the start of the problem.

No reason to think the charger would pack it in at that instant (although the difference between the traffic light indicators and the measured voltage needs explaining, but this could be just the way the unit derives the indication), so I would still be inclined to initially suspect the "new" battery or something to do with the installation of the battery even if it was brand new. The fact that the voltage rises to 16.5V is interesting - depending on how long it takes for the voltage to reach that point -- in that if the battery was good and the charger was current limited, I would expect a reasonable delay (many minutes) for the volts to get that high. A high resistance cell could cause that to happen quickly if the three-stage charger was trying to pump the rated bulk charge current into the battery.

Diagnosis using some of the visual and electrical tests I suggested above might narrow it down. Other than that, taking it to a battery place for a proper load check may be the best solution.

Voltages need to be measured right at the battery lug itself to avoid possibility of a bad connection. I assume that is where the multimeter reading was taken.


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## Don (Feb 6, 2008)

Hi tony, thanks for getting back.
110 Ah Battery was new. All test's ie multi meter and load testwas done off van and directly on battery lugs. The increase to 16.5 takes as many seconds as it takes to count incrementally from Example 13.5v to 16.5v. bearing in mind that the Multi Meter counts in 0.00, so it will start say at 13.5 onto 13,51-13.52 untill it reaches 16.5, then fluctuates or pulses as my indepandant charger does if I conect that to the Battery.
Hope that makes sense, as I tend to write as I talk and folk tell meI talk a load of crap.

Don


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