Solar Panel Updated Prices

[Alan de Enfield]

10 minutes ago, Dave Payne said:

They were just grab from the air numbers.

That's what solar panels do.

They just convert 'light' into some random numbers.

[Robbo]

20 minutes ago, Chewbacka said:

Think of your battery as a kitchen sink, the solar panel/ alternator is the tap running into the sink and the load - fridge, tv etc  -  is the plug hole outlet.  If water coming into the sink is faster than water going then out the sink (battery) will fill up (charge) if they are both the same, the sink (battery) will stay at the same level (no change to the state of charge) and if water (power) leaving the sink (battery) is faster than new stuff coming in the sink (battery) will empty (dis charge).  So even on a sunny day, if you don't have a lot of panels and you use a lot of power, then the battery may even continue to go flat.

That is still incorrect, as you with a battery you can't empty and fill it at the same time.

The battery can only either charge or discharge, it can't do both at the same time!

 

 

Think of a pipe with everything coming off it. Solar, loads and battery.  This pipe is the backbone.  Now your loads take water from the pipe your solar adds water to the pipe.  Batteries can do either but not at the same time.  So if solar is adding more water into the pipe than the loads can take the battery can take the excess.  And vice versa if solar is not adding enough water the loads want the batteries can add water to the pipe.

 

[Dave_P]

17 hours ago, Dave Payne said:

I think im sold on one, £26 is not bad for another gadget to keep me amused.

It is addictive.  I can't stop looking at mine when I'm not on the shore-line.  I daren't press any buttons though, the instruction manual was pure gobbledegook.

[Alan de Enfield]

4 minutes ago, Dave_P said:

It is addictive.  I can't stop looking at mine when I'm not on the shore-line.  I daren't press any buttons though, the instruction manual was pure gobbledegook.

Was this the manual you got - or - the 'scrap of paper' which I found confusing ?

 

 

Solar MT50 Controller Manual.pdf

[reg]

19 hours ago, Robbo said:

It means that you are getting 10.8a at 14.6v from solar.  It may not all go to the battery as other running stuff may get it like a fridge.   So if your fridge is using 2amp, your batteries will only be getting 8.8amp.

If you don't mind I would just like to clarify your statement a little I think it should read

 

It means that you are EFFECTIVELY getting 10.8a at 14.6v from solar panel..... 

 

In fact, according to the display shown, the solar panel is inputing 96.9v and 1.6a into the MPPT. The Mppt is converting that into a charging voltage of 14.6v and is giving out 10.8a

 

This I think is a very nice example of why an MPPT controler outshines a PWM Controler in that it can take 1.6a input and multiply it, in this case, by 6.75 times to give 10.8a at 14.6v.

Clever technology methinks

 

Robbo makes this clarification below

"It's not multiplying it, it's transforming it.  In this case from one voltage to another"

Edited May 25, 2017 by reg
Add Robbo's clarification made below

[Alan de Enfield]

9 minutes ago, reg said:

In fact, according to the display shown, the solar panel is inputing 96.9v and 1.6a into the MPPT. The Mppt is converting that into a charging voltage of 14.6v and is giving out 10.8a

Pretty much what a 'battery charger' does :

It takes 240v at (maybe) 4 amps and converts it to 14v at (maybe) 60 amps.

 

Damm clever stuff this electrickery.

[Robbo]

21 minutes ago, reg said:

This I think is a very nice example of why an MPPT controler outshines a PWM Controler in that it can take 1.6a input and multiply it, in this case, by 6.75 times to give 10.8a at 14.6v.

It's not multiplying it, it's transforming it.  In this case from one voltage to another.

A PWM doesn't transform that's why the panels need to be the same voltage as the batteries.

Edited May 25, 2017 by Robbo

[reg]

5 minutes ago, Robbo said:

It's not multiplying it, it's transforming it.  In this case from one voltage to another.

A PWM doesn't transform that's why the panels need to be the same voltage as the batteries.

Correct I was just trying to use plain English. The main point I was trying to clarify was

The readings on the LEFT of the screen are what is going into the MPPT from the solar panel. 

The readings in the MIDDLE are what the MPPT is outputting to the batteries. 

I don't think we are in any disagreement to here. The clarification was not for you but more for those that get confused by what an MPPT Controler does

 

 

 

[Richard10002]

2 hours ago, Robbo said:

You mean like a fridge like I originally said! 

However your not technical correct as batteries can either take or give they can't do both at the same time so any load is on and taking amps the battery never sees those amps.

For the ordinary Joe, it doesn't really matter how it happens, and I understand your pipe analogy. Perhaps my explanation can be considered an analogy, if it isnt technically correct.

However, if the solar wires are connected to the battery, and the load wires are connected to the battery, surely the batteries are involved somehow.

Edited May 25, 2017 by Richard10002

[Robbo]

2 minutes ago, Richard10002 said:

For the ordinary Joe, it doesn't really matter how it happens, and I understand your pipe analogy. Perhaps my explanation can be considered an analogy, if it isnt technically correct.

However, if the solar wires are connected to the battery, and the load wires are connected to the battery, surely the batteries are involved somehow.

It's good to be technically correct.  My explanation is easily understandable for the ordinary Joe.

One of the reasons to be correct is to come away from the batteries are the backbone of your electrical installation, they are not, they are just a part of it even if the terminal on top of the battery has all your connections for loads and charging equipment.

[Mac of Cygnet]

I have a question about flexible panels, which are presumably fixed direct to the roof.  My roof gets too hot to touch on a hot summer's day. Can this damage the panel? 

[Alan de Enfield]

6 minutes ago, Mac of Cygnet said:

I have a question about flexible panels, which are presumably fixed direct to the roof.  My roof gets too hot to touch on a hot summer's day. Can this damage the panel? 

Heat seriously affects the output performance of the panels - You need an airflow all around to keep your panels producing anywhere near their potential. I would never recommend 'stick-ons'. Use conventional panels raised off the roof a couple of inches.

 

You will find that you achieve MAXIMUM output from your panels on a bitterly cold, frosty, day with plenty of sunlight.

[Robbo]

14 minutes ago, Mac of Cygnet said:

I have a question about flexible panels, which are presumably fixed direct to the roof.  My roof gets too hot to touch on a hot summer's day. Can this damage the panel? 

Heat will make the panel less efficient.  I doubt it will damage the panel tho.  "Flexing" the panel damages them tho, they are designed to only flex in one direction for installing not got hold of to make thunder sounds.

 

4 minutes ago, Alan de Enfield said:

Heat seriously affects the output performance of the panels - You need an airflow all around to keep your panels producing anywhere near their potential. I would never recommend 'stick-ons'. Use conventional panels raised off the roof a couple of inches.

Even tho it affects the output performance, on the days that it is hot to degrade the performance there is more than enough daylight hours to make it not worth worrying about.

Edited May 25, 2017 by Robbo

[reg]

1 hour ago, Robbo said:

It's not multiplying it, it's transforming it.  In this case from one voltage to another.

A PWM doesn't transform that's why the panels need to be the same voltage as the batteries.

Had a ponder on this whilst out for a walk and I agree that the word "transforming" should of been used. The transformer and its associated heat sink are  essential parts of a MPPT controler.

To the layman this knowledge can be used when purchasing a true MPPT controler, or more accurately avoid purchasing a fake MPPT controller. If it is flimsy and light it is unlikely to contain a decent transformer and heat sink. 

 

To quote from bimble site

"An MPPT needs a large transformer coil and Capacitors inside, it is a bigger heavier unit....... "

Happy to stand corrected on the use of the term. Will edit previous post