Understanding solar

[Milly Molly]

Hi everyone

We fitted 2x 100w solar panels a couple of years ago to our T6 Cali Ocean. We got the panels from Roger at Solar Camper Solutions and as promised they were really simple to fit.

I’ve been out to the van today and it is in full sun on our drive (29C and not a cloud in the sky) and only the fridge is running at Level 3. The leisure battery has gone down in an hour from 80% to 70% and when I checked the Victron app, it looks like its only generating 65W.

I don’t know much about electrics and I don’t really understand the app if I’m honest. But I would have thought that I would be getting more than 65W when it is in full sun? I’ve attached a screen shot of the app. Does it all look right? Any help gratefully received

Thanks all.

 

[EddieEagle]

Hi, my initial thought is the possibility of a build up of dirt, Sahara sand or other debris on the roof panels.
The battery voltage does look good on the app. On my set up the % on the control panel will often sit at less than 100% as it doesn’t ‘see’ the solar input until the engine is run.
Interesting to see the load output is on and drawing 1 W .

 

[dspuk]

I guess a few things to check. First, as said, how clean are they. I scrub mine regularly - they get dirtier up there than you think.

Second will be the angle to the sun, in perfect conditions you will still get less than the 200W, heat loss etc, so you should get, if the angle to the sun is right and the panels clean, you would get 140 - 160W. Turn the cali to the sun and pop the roof up. Make sure they are perfectly angled in line with the sun for checks.

It does look a little like *maybe* only one panel may be working - have you checked all the cables and connections and treble checked it was all fitted right when you did it? Could be you have been running on one panel all these years and not realised.

 

[Wannabecamperman]

The fridge has a compressor that cycles on and off depending on a) the ambient temp (high! today in the UK) and b) the level set at. The draw when on should be around 40 - 50w or so, and negligible when fridge is up to temp. The 1w is probably this state. Even 56w is more than or equal to the fridge draw even when the compressor is on, so you shouldn't be seeing a reduction in batteries, quite the opposite.

The second issue is the 56w for 2 x 100 wired I guess, in parallel. Those should be giving 120 - 160w typically. You can help this by raising the roof so they are angled in the morning or late afternoon, when sun not directly overhead. This suggest that you have only one panel functioning possibly?

 

[WelshGas]

Hi everyone

We fitted 2x 100w solar panels a couple of years ago to our T6 Cali Ocean. We got the panels from Roger at Solar Camper Solutions and as promised they were really simple to fit.

I’ve been out to the van today and it is in full sun on our drive (29C and not a cloud in the sky) and only the fridge is running at Level 3. The leisure battery has gone down in an hour from 80% to 70% and when I checked the Victron app, it looks like its only generating 65W.

I don’t know much about electrics and I don’t really understand the app if I’m honest. But I would have thought that I would be getting more than 65W when it is in full sun? I’ve attached a screen shot of the app. Does it all look right? Any help gratefully received

Thanks all.

View attachment 138486

As has been said on many occasions the % readout is an iffy calculation based on the amps being consumed at that point in time. It does not take note of Solar input.
The voltage shown shows that your Leisure Batteries are fully charged and the Solar Panels are putting out sufficient power to compensate for the 4 amps being consumed by the fridge.
Solar Panels will only put out sufficient power that can be used. They will not put out more power than can be consumed but can put out less than is being consumed.
The voltage shown on the camping Control Panel is accurate.

 

[dspuk]

As has been said on many occasions the % readout is an iffy calculation based on the amps being consumed at that point in time. It does not take note of Solar input.
The voltage shown shows that your Leisure Batteries are fully charged and the Solar Panels are putting out sufficient power to compensate for the 4 amps being consumed by the fridge.
Solar Panels will only put out sufficient power that can be used. They will not put out more power than can be consumed but can put out less than is being consumed.
The voltage shown on the camping Control Panel is accurate.

View attachment 138506

Interesting. I’ll check my W going in later. I used to obsessively watch the numbers at the start but then realised the small box was cleverer than me and left it to its thing.

 

[Milly Molly]

Thanks for all your responses - love this forum! Think I need to go and do a bit more reading on electrics etc as it’s all just numbers to me! I don’t really understand what they mean! I’m sure somewhere on here is a handy guide.

I’ve emailed Roger too and as ever he has been fab and very quick to respond even on a weekend.

I was just hoping that with the sunny weather at the moment I wouldn’t need to keep the van plugged in when it’s on our drive to keep the leisure batteries topped up. We’ve been away before in much less sunny conditions with fridge, lights and sockets all in use and the leisure batteries always showed 100% on the control panel so I was just worried we had a loose connection or that our leisure batteries were dying.

I’ll go and turn the ignition on and pop the top and see what that does.

 

[Webbah_in_Switzerland]

Thanks for all your responses - love this forum! Think I need to go and do a bit more reading on electrics etc as it’s all just numbers to me! I don’t really understand what they mean! I’m sure somewhere on here is a handy guide.

I’ve emailed Roger too and as ever he has been fab and very quick to respond even on a weekend.

I was just hoping that with the sunny weather at the moment I wouldn’t need to keep the van plugged in when it’s on our drive to keep the leisure batteries topped up. We’ve been away before in much less sunny conditions with fridge, lights and sockets all in use and the leisure batteries always showed 100% on the control panel so I was just worried we had a loose connection or that our leisure batteries were dying.

I’ll go and turn the ignition on and pop the top and see what that does.

It looks like the time was late in the day at almost 6PM based on your screenshot. Can you post the history tab? Look at PMax values. Solar irradiance peaks midday.


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[Ch1pbutty]

You should be able to get figures for 24hr periods (& longer) on the victron app, looking at one point in time is not a good measure.

The app will look like below (basis 3 panels). The light blue at top of graph shows float - batteries fully charged, no longer charging - so you if you have some light blue at the top, you are producing far more than you are using. Also looks at min/max figure at bottom - min should be above say 12.3v max (battery charged, on float, resting) / + 13.8v (charging).

 

[KGCali]

Your solar is providing 2.9A and the batteries are using 4A whilst the fridge is running so the solar controller is bulk charging the batteries and the control panel will show the batteries discharging which is normal. Check the figures again once the fridge goes idle.
As said you could have dirty panels or one may be dead, easy to check if you disconnect the the solar panel plugs on the roof and check each is producing about 19v with a multimeter.
Also check the cube fuse on the 2nd leisure battery in the boot is not blown.

 

[Milly Molly]

Here are some screen shots of the control panel now and the history tab. Based on the table above from WelshGas it looks like my battery is actually fully charged at 12.6v even though it only says 60%. Am I interpreting that right?

 

[Milly Molly]

Control panel photo was take when the fridge was idle.

We’re going to go up and clean the panels today as well.

Just wish I was a bit more technically savvy when it comes to the van! I’m good with tech but cars and van systems just perplex me!

 

[Webbah_in_Switzerland]

Here are some screen shots of the control panel now and the history tab. Based on the table above from WelshGas it looks like my battery is actually fully charged at 12.6v even though it only says 60%. Am I interpreting that right?

View attachment 138522

View attachment 138523

View attachment 138524

Looks like you are getting use of both panels. My guess is this is mostly with the roof down and the panels flat. Roof up and angled to the sun will increase power.


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[Webbah_in_Switzerland]

Looks like you are getting use of both panels. My guess is this is mostly with the roof down and the panels flat. Roof up and angled to the sun will increase power.


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Here’s an example from mine showing solar irradiance right now. It’s a bit cloudy here today. Solar panels are rated typically with a solar irradiance of 1,000. You can see how it peaks midday and drops off later in the afternoon.

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[colintfcolintf]

But as WelshGas pointed out your batteries are ok

 

[WelshGas]

Control panel photo was take when the fridge was idle.

We’re going to go up and clean the panels today as well.

Just wish I was a bit more technically savvy when it comes to the van! I’m good with tech but cars and van systems just perplex me!

If you leave your fridge on then overnight with No Solar input the battery voltage will drop and in the morning with sun up then the solar panels will start producing maximum power to recharge batteries and run fridge. As the batteries get recharged to maximum then the solar output drops down until it is just providing enough power to compensate for the fridge running.

 

[WelshGas]

Your solar is providing 2.9A and the batteries are using 4A whilst the fridge is running so the solar controller is bulk charging the batteries and the control panel will show the batteries discharging which is normal. Check the figures again once the fridge goes idle.
As said you could have dirty panels or one may be dead, easy to check if you disconnect the the solar panel plugs on the roof and check each is producing about 19v with a multimeter.
Also check the cube fuse on the 2nd leisure battery in the boot is not blown.

The panels are in fact producing 4.18 amps at 13.22 v

19.08÷13.22×2.9 = 4.18 amps.

Allowing for inefficiency loss this is the 4 amps the fridge is consuming at that point in time.

 

[Razor Crest]

I don’t think any of the Cali control panels I have owned have been accurate when looking at the percentage. I have since added a Victron Smart Battery Sense to each battery, gives me peace of mind.

 

[Milly Molly]

I don’t think any of the Cali control panels I have owned have been accurate when looking at the percentage. I have since added a Victron Smart Battery Sense to each battery, gives me peace of mind.

View attachment 138530

Ooh that's a good idea! Will ease my battery anxiety when off grid! Did you just connect it to the battery under the cupboard in the boot? And then one to the engine battery? I take it you don't need one connected to the second auxiliary battery under the passenger seat?

 

[Razor Crest]

Ooh that's a good idea! Will ease my battery anxiety when off grid! Did you just connect it to the battery under the cupboard in the boot? And then one to the engine battery? I take it you don't need one connected to the second auxiliary battery under the passenger seat?

I only have two batteries, so attached it to both, but they are so cheap it is probably worth connecting to all of yours. I initially just installed with crocodile clips and watched as I tried various things like leaving it for a week without touching the van, how it reacted when solar power was good etc.

 

[Wannabecamperman]

Looks like you are getting use of both panels. My guess is this is mostly with the roof down and the panels flat. Roof up and angled to the sun will increase power.


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Agreed - the peak of 112w 6 days ago means that the second panel IS indeed working, albeit poorly in terms of yield. A clean and roof tilt to face the sun should bear fruit I feel.