Can someone explain my solar app readings in toddler level language please!

[Tonks]

I have a 180w solar panel on the roof, with a Victron MPPT 75/15 controller and a Yuasa 100ah lead acid leisure battery.

It all powers a Waeco 12v compressor fridge, plus runs lights and charges my phone. I'm not a heavy power user. The fridge is the biggest draw. On my last trip I noticed voltage drops on the lights, and the fridge seemed to run out of energy pretty quickly.

Yesterday I drove for 4+ hours arriving at my destination around 11.30am, and had a day with reasonable levels of sunshine. But by yesterday evening the fridge was already struggling. I drove again in the evening for about 45 minutes to an event. It didn't seem to make much difference to my on board power.

Today I noticed that the solar controller on the app is showing 'off', and the blue light on the controller is flashing as it does at night. I've been in pretty decent sunshine for most of the afternoon, but the charger has never shown 'on'.

In the past the solar has sown something in terms of watts even when it's been daylight, not sunny. Today the solar 'arc' at the top of the info screen in the app has shown 0w every time I've looked. In the 'solar' section underneath it currently shows 10.68v, with 0.0A current. I don't understand what any of these mean, except that 0 doesn't look good.

The battery voltage has now dropped to 12.02v. Under that the current shows 0.00A. and the 'state' is off.

The battery is only just over a year old, and was supposed to be an improvement over the last one!

I'd be grateful if someone could explain the different elements shown on the app so that I've got some idea of what's going on. At the moment it just feels like I spent a lot of money to update my van's power and now I'm getting no better performance than I was before. Of course I realise that the summer we've had means I would expect to have less gain than last year, but nothing at all on a sunny day in August seems nuts.

 

[Minxy]

Lenny HB

 

[Vansflyer]

Have you checked that the controller is "charger enabled" in the settings part of the app, can you do a couple of screen grabs in daytime and the "history" now?
Also worth checking if a fuse has been fitted between the panels and the controller / controller to battery and if so are they OK?
Sample screen grabs below.

 

[Tonks]

Have you checked that the controller is "charger enabled" in the settings part of the app, can you do a couple of screen grabs in daytime and the "history" now?
Also worth checking if a fuse has been fitted between the panels and the controller / controller to battery and if so are they OK?
Sample screen grabs below.

View attachment 800320 View attachment 800321

Thanks. Yes, the controller is 'charger enabled'. I suspect the battery has died, but I'm baffled as to why it's not holding charge, and dropping to the 8.__ levels as with a four hour feed through the alternator (not to mention being on EHU overnight before leaving) the battery should have been fully charged and able to supply the fridge and lights for a good couple of days. I used to get that before I had solar! It's only just over a year old.

 

[daveandsan]

How many amps does the fridge draw?

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[Vansflyer]

Ta for the screen grab.
Two days ago the battery floated so it I should have been charged and yesterday you got 115w max yield so solar is working, duff batteries don't often float.
I would do the basics first and put a clamp meter on the leisure battery to work out the load drawn and see if something is on pulling a high current. If an appliance/ product is sucking the juice out of it the meter will show you. Always turn off the solar charging when doing the test as in good sun the solar can hide the drain with the feed from the panel.
It could be that the battery has failed prematurely but I would double check the basics first.
Good luck.

 

[Guigsy]

8v means the battery was critically low and probably damaged. You may still find that it appears to charge (sometimes very quickly) and look like it has a reasonable voltage, but it'll have almost no capacity. As soon as you put any load on it, the voltage will sag.

 

[Bolti]

Do you have a flexible Panel?
Never had one last more than a year.

 

[funflair]

Do you have a flexible Panel?
Never had one last more than a year.

The screenshot suggest the solar is working fine though, it seems to be the battery that is failing.

 

[cyberyacht]

Do you have a flexible Panel?
Never had one last more than a year.

Mine are still going strong after three years

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[headlight]

Earlier this year I had a Yuasa 100AH battery fail at 13 months old.

 

[Jimbohorlicks]

From your screen shot thecbatteryvhas been losing power over a few days and not becoming charged up. Suspect the battery needs checking. A 100ah lead battery doesn't seem to be enough to run your fridge imo, probably OK when new but now its struggling to hold charge and hence power the fridge.

 

[Realist]

Re: Can someone explain my solar app readings in toddler level language please!

Hope this helps

 

[RedFrame]

Battery is goosed, it's been down to 8v the past two days.

I would hazard a guess that you're asking too much of it with the compressor fridge and this is why it's failed after 12 months.

Invest in a Lithium perhaps.

Cheers
Red.

 

[autorouter]

Are you sure that the battery is being charged while the engine is running? Does the leisure battery voltage go up to over 14V when the engine is running? If not, maybe a fuse has blown or there's a bad connection somewhere. I can see that the battery voltage is very low at times, but that might be caused by lack of charge while driving.

Also if you are checking voltages, you could check that the starter battery voltage goes up to over 14V when the engine is running. If it doesn't then the alternator might have a problem.

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[Otter Spotter]

Mine are still going strong after three years

Mine is 4.5 years old, I am only going to replace it with a 300w fixed panel when needed.

 

[berni109]

First time out in van without solar at the time the domestic compressor fridge killed our battery in just over 24hrs.
With your solar would have thought the battery should keep up with demand.
Take the battery out and bench test it. Fully charge then apply known load. Check voltages - there is a table on here somewhere or online for lead acid batteries discharged voltage.

 

[Guigsy]

Shunts that keep track of power used are a fast better way of monitoring battery charge than looking at the voltage. It'll give you an idea how much energy you use, and how much benefit you're getting from solar.

 

[berni109]

Guigsy agreed but the consensus above is that the battery is probably goosed. The only way to be sure is to eliminate one thing at a time and the battery is easy to test.

 

[Guigsy]

Guigsy agreed but the consensus above is that the battery is probably goosed. The only way to be sure is to eliminate one thing at a time and the battery is easy to test.

I agree that the battery is probably knackered.

How do you test a battery? It might only have 5Ah of capacity left, but it'll still sit there holding a good voltage. The only way to test it is to charge it (when we're currently unsure whether the chargers are working) then run it down without anything like solar interfering.

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[Outdoors Dad]

Had a similar set up on our camp van, it could run the fridge all day if some sun out, but we had to turn it off at night time. The solar panel and battery arrangement simply aren't enough. Another 100watt and a lithium....plus check split charger as suggested.

 

[Tonks]

The solar panel and battery arrangement simply aren't enough. Another 100watt and a lithium....plus check split charger as suggested.

They have been enough up to now. I’ve been away off grid for days without any issue with the fridge or power in general. It’s only recently that I’ve had a problem.

I don’t have space in my VW for a second battery. I’ve been looking at lithium but up to now the cost has been prohibitive. The Yuasa battery is still under warranty so depending on what the tests show it may be a straight swap out for the moment.

I will also get the split charger checked.

 

[autorouter]

I will also get the split charger checked.

If you had a multimeter it's easy to check for yourself. A battery not being charged, with no loads on it, will settle at its resting voltage. For a fairly flat battery it's about 12.0V, and for a full battery it's about 12.7V.

If the battery is being charged (solar, mains, split charge) then the voltage will rise to over 13V. It should gradually rise to about 14.5V, and stay there for some time. When it's full it will drop to about 13.5V. When the charger stops, the battery voltage will drop back to its resting voltage - about 12.7V if it's fully charged.

Using that information you can see for yourself if the various charging sources are working by trying them one at a time. You can get a cheap multimeter from any DIY store for about a tenner, which will give you the information you need.

 

[Otter Spotter]

They have been enough up to now. I’ve been away off grid for days without any issue with the fridge or power in general. It’s only recently that I’ve had a problem.

I don’t have space in my VW for a second battery. I’ve been looking at lithium but up to now the cost has been prohibitive. The Yuasa battery is still under warranty so depending on what the tests show it may be a straight swap out for the moment.

I will also get the split charger checked.

There is a 210AH lithium in classifieds that worth looking at

 

[Nanniemate]

It is on when the sun shines and off when the moons out

Hope that helps

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[RedFrame]

Just had a quick look at your setup and assuming that you have the smallest Waeco Compressor unit, just your fridge will be drawing 26.4Ah a day out of the battery.

Assuming you have a new good 100Ah lead acid battery, after you have charged it on hook up at home, then driven for 4 hrs you will have around 50Ah available to use (before you start damaging the battery).

If, due to clouds etc, your solar only kicks out 80Wh in a 24hr period (as can be seen in the screenshot on two days), you are down to 31Ah available.

After 48hrs you have 12Ah available, and on day 3 your damaging your battery.

This is ignoring any other drain like lights or phone chargers, include these and you are most likely not making it to 48 hrs. (Edit: changed 24hrs to 48hrs)

If you do put in a replacement 100Ah Lead Acid, I predict you will have the same issue in the, not too distant, future.

As a ball park guide, for you, with your setup (if it is indeed a 50ltr fridge), when static for 2-3 days I would suggest you would want to see a daily yield of around 180Wh, more for longer periods.

Hope this helps.
Cheers
Red.

 

[autorouter]

It's easy to convert between watt-hours (Wh) and amp-hours (Ah). Ah is related to the battery voltage, usually 12V in a motorhome. So 26.6Ah at 12V is 26.4 x 12 = 317Wh. Similarly, if your solar panel yields 260Wh, that's 260 / 12 = 21Ah.

If the fridge is using 317Wh every 24 hours, then if you don't put 317Wh back into your battery every 24 hours it will gradually lose charge. With solar this depends on the weather, obviously, but at least with the victron app you can see how much it's captured, and decide whether you need to go for a drive to top it up.

 

[Bodoge]

They have been enough up to now. I’ve been away off grid for days without any issue with the fridge or power in general. It’s only recently that I’ve had a problem.

I don’t have space in my VW for a second battery. I’ve been looking at lithium but up to now the cost has been prohibitive. The Yuasa battery is still under warranty so depending on what the tests show it may be a straight swap out for the moment.

I will also get the split charger checked.

If it does prove that battery capability is inadequate, therefore needing an upgrade, it would be worth considering a Deep Cycle battery. These have the capability on being recharged from flat many times, if I mohomed without ehc it would be a definite requirement. I hope this helps.