Caravan Battery we think is dead even though we have solar

[ProfJohnL]

Ok woke up this morning and the Noco is at solid green light.

Just out of curiosity, when I disconnect the charger from the battery, there won’t be any loss of power while it sits in the garage?

Whenever you leave a battery standing it will eventually lose all its charge, the question is how long will it take, and that depends on the design of the battery and its condition. and its state of charge and the temperature of the storage location.

Another question to consider is how do you test the state of charge? Most people would use a voltmeter and as a guide a fully charged 12V lead acid battery should show a terminal voltage of 12.6 to 12.8Vdc The charger should be disconnected for at least 2 hours before this measurement is made.

If the terminal voltage is down to 12.2Vdc the battery is at about 50% state of charge

If the terminal voltage is less than 11.8Vdc the battery is considered to be fully discharged and should be recharged as soon as possible.

If the terminal voltage is below 10.5V dc, and has been standing form more than a couple of weeks, a 12V battery may have suffered permanent damage and should only be recharged under supervision with a smart charger.

In practice a typical 100Ah 12V lead-acid battery, when fully charged and disconnected, experiences a self-discharge rate of approximately 3 to 6% per month

 

[Saxo Appeal]

Had a call from the Dealership this evening, someone who was more clued up on the solar panel issue.

Was told to use a multimeter negative (-) on the middle point on the below, and the positive (+) on the next one to the right. If I see 12V on the display then it’s trying to draw current to the battery, if there I see 0V then the fuse under the Sargant Fuse box needs to be located and investigated.

He did mention there was an issue with this a while back due to Swift fitting a less Amp fuse which then needs to be swapped over for a 20 or 25A fuse.

 

[borderbilly]

if he knew Swift had a issue, why do they not change the fuse themselves, before selling the caravan, lazy barstools.

 

[Saxo Appeal]

if he knew Swift had a issue, why do they not change the fuse themselves, before selling the caravan, lazy barstools.

Of course, let it happen then worry

 

[JTQ]

This LINK I believe is for your controller's user manual , if you haven't this to hand.
On page 10 it shows the status LEDs, where having the "Battery low" LED illuminated, as in your photo, could be because the mentioned fuse has blown, therefore well worth checking.
However, if the photo was taken in the dark, then the only power that could illuminate any LEDs has to be coming from the battery ,via a viable fuse, as in the dark it can't come from the panel.
So what that info is telling us depends when you took the photo, in the light of day or at night. Though possibly reflected light off the moon might just throw my logic here.

 

[Saxo Appeal]

Sorry forgot to add, the guy at the dealership said to check the (-) and the (+) when it’s dark outside, or cover the solar panel with a carpet if during the day

That photo of the Truma Solar unit was taken at 14:30pm

 

[Saxo Appeal]

Haven’t managed to get down to the caravan to check the fuses

Although after disconnecting the battery at home from smart charger on the 06/01 at 15:28pm, the multimeter testing it right now 08/01 at 16:58pm is reading 12.60/12.59.

Presume from this I don’t have a faulty battery which is good news, as I don’t need to buy a new one or try claiming from Dealership,

 

[Saxo Appeal]

Checked this morning again and it’s held on at 12.55

I’m currently also down at the Caravan and forgot the ladder so I can’t cover the Solar panel to the battery as it’s light outside

I have went into the back of the Sargent and spotted a RED 10A blade fuse, checked with the multimeter and it bleeped, so that’s all good and has not blown. Presume this is the blade from Panel to Battery

 

[JTQ]

Is one or other of the feed wires from the solar panel accessible enough to temporarily disconnect it? Then the solar panel is out of the "picture" re analysing things.

I would have liked to be seeing a little more on the battery resting voltage than 12.55, it having supposedly been fully recharged. But lead alloying and meter inaccuracies affect readings. Once coupled to the solar panel, and a bit of sunlight a battery with a rested 12.55 volts, should jump to 13.4 volts or more.

 

[Saxo Appeal]

Sorry I wouldn’t know where to start looking 😕

Is there anything I can do at the Solar Unit below?

 

[JTQ]

Hang on, I will look up the solar controller's manual, and then respond

 

[Saxo Appeal]

Looks like the first 2 wires going into the unit are from the Solar Panel, then the next 2 are the feed to the battery

 

[JTQ]

The two left hand connections on the Truma SDC12 unit are from the solar panel, furthest left is +ve the next to it's right the -ve.

To take out the input of the solar panel you can remove, either, I would take out the wire feeding into the +ve, the furthest LEFT

Okay, see you got there before me.

 

[Saxo Appeal]

This is what I get, which the guy at Dealership said (-) in the 3rd and (+) in 4th

 

[JTQ]

With the solar panel's +ve wire out, as a further test measure the voltage of that +ve disconnected wire* to the 2nd from left [solar -ve] screw on the solar controller. This will give us the present open circuit solar panel's voltage. Looking for above 19 volts, but let us see what if anything it is.

* measuring the loose wire's end, to the fixed -ve connection.

 

[JTQ]

This is what I get, which the guy at Dealership said (-) in the 3rd and (+) in 4th

View attachment 10076

EDIT; Post removed

Sorry to have initially got it wrong, then I looked deeper

 

[Saxo Appeal]

With the solar panel's +ve wire out, as a further test measure the voltage of that +ve disconnected wire* to the 2nd from left [solar -ve] screw on the solar controller. This will give us the present open circuit solar panel's voltage. Looking for above 19 volts, but let us see what if anything it is.

* measuring the loose wire's end, to the fixed -ve connection.

This ok?

 

[Saxo Appeal]

There is an issue somewhere as it should be the battery's voltage, in your case 12.55, not only 0.7 volts.

You need to hunt for a blown feed fuse or missed set switch. I can't help on what switches you might have to look at, don't know your kit.

Remember the battery is not installed, it’s still sitting at home

 

[JTQ]

Better looking now; I see you are on the "right" ports, those with the battery's feeds.
You should be seeing the battery's voltage. so something is wrong

 

[Saxo Appeal]

So with the supply from the Solar Panel feed out, measuring the Voltage from the (-) second wire to the (+) I pulled out, we should be seeing a Voltage from the panel current. Because there is no Voltage something must be wrong…

I could not find any other fuses under the Sargent like what everyone said, only the Red 10A

This is a bit confusing

 

[JTQ]

Remember the battery is not installed, it’s still sitting at home

Okay, I had not hoisted that all important aspect in.
So you seeing 0.7 volts means something is giving power albeit very little.
Possibly its from the solar panel, but your view of my panel test is showing that is way down.

 

[JTQ]

Agreed, it is confusing, but is clearly showing the solar panel's output is way down of what I would expect in any modest amount of light.

Without the battery in your first test is not providing me with any constructive info.

Edit: all I can suggest is you repeat both these tests when the battery is back in place, and there is a bit more sunlight, or reflected sunlight as there is here today. That said I still think your solar panel or its connections has an issue, it should be showing much more voltage even if capable of generating near zero current.

 

[JTQ]

Just gone and checked a 30Watt panel's open circuit voltage in very poor indoor lighting and that's at 12.45Volts.
So I am confident in what I said, your 2nd test looking at voltage from the panel does mean there is a panel or its connect issue.

With a defective solar charging system your flattened battery is understandable, that might easily and hopefully be the extent of your problem.

Edit: need now to be away for a few hours.

 

[Saxo Appeal]

Thanks JTQ,

Just out of curiosity, would this be the box which is from the Solar Panel to the Battery fuse, which was connected to side of the Sargent main Fuse box?

Looks like a plethora of screws to get into this cage though…

 

[Danddandy]

Ok woke up this morning and the Noco is at solid green light.

Just out of curiosity, when I disconnect the charger from the battery, there won’t be any loss of power while it sits in the garage?

Was thinking to leave it in there till I’m able to find the fault at the caravan, which we can’t get to due to snow at the moment.

Need to check if it’s the fuse from the panels to the battery, as mentioned earlier

View attachment 10054

I think the green light should be solid green AND the red/amber lights should be off. If the red lights are still showing, then the battery isn't fully charged.