Fitting solar from scratch

I’ve watched quite a few of his reviews and tests and I’m going to order a Epever Tracer AN next week hoping that might solve the problem I have.

 

This time of year you can have voltage at the panels but poor current.

Are you sure it isn't just the time of year or has it been like it in the heat of the summer in direct sunlight?

 

You could be right and I’m expecting too much.

Before I bought the solar system, I read all the TLB threads and reviews of the numerous panels and controllers, I considered what we have in the bus powered from the leisure battery and decided 200watts of panels through a MPPT controller would be more than ample – but I made some assumptions that have proved to be wrong. The compressor fridge uses more power than anticipated, a 100w panel doesn’t produce 100w and a MPPT controller isn’t as efficient as advertised.

I wanted a system that would just work, I didn’t want a remote display and I definitely didn’t want to monitor what was happening on a ‘phone so I installed the panels and controller at the beginning of June and left it to do what I thought it should do.

I don’t often stay a campsite for more than one night and the split charge relay keeps the leisure battery charged so I wasn’t particularly concerned when I noticed the battery voltage dropping. But after two nights on site it was obvious that the battery want being charged so I looked at what the solar was doing – next to nothing. I have never seen more than 1.2 amps from the controller.

 

With the common positive controllers you can only have isolated negative on the load.
Also the negative side of the solar cells is switched to the battery chassis by the controller. So the solar cell positive voltage is the same as the battery voltage, the solar cell negative will be negative by the difference between solar cells and battery voltage.


So dont connect the grounds on the controller "load" output to chassis only the controller "load" negative terminal. If you do ground anything other than battery negative on the controller you have just shorted out the load switch on the controller and stopped it working. This is what a simplified common positive controller schematic looks like.

 

Your 200w should more than cope with the fridge. I think you should check your battery, try the starter as suggested. For example over summer I spent 6 days at Silverstone. Granted It was very hot and sunny but the panel ran the fridge (a lot of the time freezing ice packs to -12), charging 2 phones and various power packs, charging lanterns, running the led lights and every day it was fully charged by early afternoon. It was a similar story during 10 days in France. Even on an overcast weekend a couple of weeks ago it was charging up to around 80%

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You got me thinking about what we have recorded in real life rather than just theorising about probabilities.

Chip has 2x90w (180) flexible CIGS panels and an ecoworthy 20amp mppt controller feeding a 115ah flooded lead acid battery battery with removable caps for servicing.
The panels were probably about the best I could buy at the time and are much bigger than modern equivalent output panels due to efficiency improvements on tech over the last few years. However the construction is top quality and they've collected and converted a lot of rays over the years!

In August 2016, 2 years after fitting the system, we had a weekend away to Langsett on the edge of the Pennines just north of Sheffield.
Chip's roof allows us to angle the panels and I tend to align so the sun moves E/W across the roof. It's a compromise.
Here's what we got,
South Facing roof

Spot input reading...


So, this system works and you may recall at the time we were running the OG Westy Campmobile absorption fridge which draws around 8 amps continuously from the battery. In southern Europe, travelling most days but often laying up for a couple at a time, this set up allowed total freedom from hook-up for 5 months travel. In Trieste we were stationary for 5 straight days with no hook up or engine running and the panels kept the battery healthy with us running the fridge, radio, charging phones, camera, using shower etc etc.

This summer I took a series of images for a write up on Goran.
Goran runs a basic 80 quid, 100w rigid glass panel bought cheap from e-bay. This was a considered decision because I wanted to evaluate how a low cost monocrystalline panel actually performs in real life because not everyone has the budget for high end kit. The fridge is high end though and is a Dometic CRX35.
It will pull up to 5 amps on a cool down but runs nominally at slight less than 1ah. In ambient of +40, this fridge ran at a consistent 2'c and for the 8 months we were away this year we didn't hook up. I actually have no 230v hook-up kit in Big G.

This image shows the panel is flat on the roof. Again considered because efficiency is reduced if you cannot angle the panel to the sun.


I do use the same model of controller though because I know, through personal experience, it is a generally reliable and robust unit.
The battery is a FLA type again but is a 145ah marine unit that weighs about 30kg. We have a 600w inverter and an on-board compressor for airing the tyres up so the battery needs to be 'substantial'.
Panel output is obviously much less, as you'd expect with just over half the input with no sun orientation. However the system is sufficient for summer travel, although struggles with constant UK use. A week without electricity was completed on @davidoft 's spacious and sunny drive in Hayling Island last month, but Mel used the inverter one day which was a draw too much and we had to plug in a remote charger.


Location....


and location...Taghazout just north of Agadir on the Moroccan Atlantic coast. We stayed here for 3 days on one occasion.


So, 2 different systems with very different inputs and different requirements. Both work exceptionally well in an overland scenario but have limitations which have to be accepted and managed accordingly.

It's going to be very interesting when you change out your controller to see what you get in France on a regular basis.
Matt, @pkrboo , & I often exchange condition related pics and info, sad gits that we are and it's a shame, but important to us that use these systems, to hear of your issues.
Looking forward to finding out what the problem is...

 

I know 200w should be enough but it isn’t and something is wrong; the panels, the controller or the battery? I was going to buy another controller next week but I think I’ll get a new battery instead. The leisure battery is old and it has been discharged too much and too often but I was still expecting the solar to attempt to charge it with as many amps as possible, maybe it doesn’t work that way. And I was going to try the starter battery to see if it would charge that but the weather has turned a bit British – the garden needs the rain - and if I can’t see the sun the solar panels won’t either.

Thanks for everyone’s comments, I appreciate it.

 

I am starting to think it's the panels.

@sandbay had two duff panels that would show voltage but virtually no current output

 

I hope not; they’d be a bar steward to remove. How can I test them?

 

Unfortunately you need another panel or controller or battery to test one or the other.

Which can be expensive!! Where are you as you could borrow a panel from me.

 

South of you where the sun shines and everyone breaks down.

 

Oh yeah, en France

 

Best bet is to mains charge your leisure battery, give it a full recondition (no extra cost)

Buy a cheap £10-20 PWM controller.

 

Current has to be measured in series not parallel.

Is that what you did?

 

Yep needs to be inline with the wiring, not accros it like when you measure voltage in a battery

Unless the sun is blazing and you are pointing directly at it you will struggle to get much power at all during the winter months

 

@sANDYbAY Are your panels Eco-Worthy by any chance?

 

As a solar panel test, on a sunny day, if you simply connect a couple of stop light bulbs in series across a single panel by itself, they should light. Thats about 3-4 amps at about 19 volts. A bit under run but they should still be quite bright yellow to white.


Even now in cloudy bright conditions a pair of 5 watt bulbs should light.

For instance although today the current from my panels read less than 1 amp into the battery with a fairly heavy overcast sky, I ran the fridge at 5 amps for about 20 seconds and then the battery recharged back to 13.8 volts/99% with solar power in about a minute.
My setup keeps the compressor fridge going 24/7 even on cloudy days keeping my cans of coke, cheese and ham cool for lunch.

I have tp admit though that although I was given my panels as water damaged scrap, they are Solbian SP100 listed at £700 each, as they were originally sourced as the best possible for a commercial project. At 23% peak efficiency.

One sneaking thought is that some lower cost panels are possible more leaky (producing electrical power which then is lost in directly heating the cell with the leakage current) than others .
These panels are unable to produce their rated power except in direct intense sunlight. The cheapest amorphous panels (maplins, look brownish) are worst for this, polycrystalline are better,(crazy paving appearance, bluish) monocrystalline (dark blue) are better still and multilayer (black) are the tops.