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Solar Regulators Pulse Width or MPPT ?
 

Solar regulators how to choose between Pulse Width (PWM)  or  MPPT (Multi Power Point tracking). we can now look at sourcing Charger controllers or solar regulators for your systems batteries. Before I explain the differences between (PWM) and (MPPT) we need to find out what unit is going to suit out system.

A good place to start is by taking the AMPS from your (PV) or solar panels. Lets say that number comes to 15 AMPS. What we then do is get a solar regulator that will exceed that 15 amp limit say the say the Morningstar 20A from solar online -  Below I have explained the two main types of solar regulators.

 
Pulse width Regulators
 

There are many types of regulators on the market which are simply x on/x off or pulse with controllers (PWM) are sold state.

 These types of controllers will do the job, but they will only charge the batteries in a limited way, not using any type of battery sensing voltage. This can can if left unchecked cause issues in the long run for the batteries. They do sense what voltage you have an the batteries, and or limit the ammount of PV volatge from the solar array. Hence they may over charge a lead acid battery causing the electrolite to evaporate or turn into sulpur oxide hense exposing the lead plates, causing them to bend or buckle under the added temperature. This will most probibly cause a open circuit fault or in the worst case (may explode if it comes in contact with a naked flame).

Solar Regulators MPPT (Multi Power Point Tracking)

There MPPT regulators do all that the above (PWM) regulators do with two main advantages, the first being these will monitor and deliver the maximum voltage to your batteries from the array basicly giving you 30% power for your systems needs.
The other is a 3 stage charging option witch means stating of at (bulk) chatge until the batteries reach a voltage of 14.4, then switching to a absorb or aceptence charge at that voltage for a min of 3 hours or 180mins, but the regulator will sense the battery volatge and switch to float at 13.6 volts to maintain the batteries. This means you are less likely to damage your battery bank.

Also as an addition to these more up market MPPT regulators they will have an option for a Battery Temperature Sensor (BTS) will will also regulate the chatge via temp as well as voltage.

If you have the money go with the Multi Power Point Tracking option, if you want to know more about multi point tracking click on the Page below:

I have fitted both of these regulators bought from the friendly staff at Solaronline;

Bluesky SB3024DI (MPPT) Solar regulator

The Bluesky Sb3024di  30amp (rated)

Xantrex XW 60A (MPPT) From Solaronline

The Xantrex XW 60A MPPT Solar Booster Regulator  (60amp) rated

Watt and amps Formula Rv solar power

Watts and Amps what does it mean, when trying to choose your Rv or Motorhome Solar Power requirements.  This will include what equipment you will need such as; equipment draw in amps and the watts over voltage conversions.  This simple formula is designed to help you gauge what power needs you require for you rvs system. 

Terms used:

Voltage – Weather you are running at 12/24 volt or 240 volt
Amps    - Current draw of the unit you are running per hr
Watts    – Watts used by your appliance or accessories

First and foremost you need to determine what you are going to run on your solar system. To do this you need to make a list of the equipment you’re wanting to run and what power type they are/or require (i.e. 12 volt or 240 volt).

 How to determine your Rv solar power needs,  here is some of my list to help you on your way.

LCD TV 23 inch.                                  12 volt
500 watt Pure Sinewave Inverter     12 volt
LED lights x 8                                      12 volt

Wayco Fridge freezer   12/24 volt/240 volt

You may have more on your list but that does not matter at all. This will allow you to safely choose how many batteries, solar panels you will require to run on your rv solar system. What you want to have in your motorhome is why we are all different, you can have what ever you want in your RV as long as you match the solar system output to the equipment you wish to run.

It is also best to over estimate the power usage of your system as degrading of amps can occur if you have long runs in the conduit (wires to and from the solar panels and your batteries). Simply just follow the formula and advice below and you wont have any worries.

You then have to find out how many watts each of the units will use:
 

For instant the Wayco fridge of mine uses 65 watts to run so all we need to do is divide our 65 watts by the voltage we want to use, which in this case is 12 volts and you get 5.4 amps per hour.

See the figure below:

65 watts
———-   =   5.4 Amps per Hr
 12 volts

If you are unable to use this formula it will take you to a Watts into Amps converter page. It is very simple to use, just add the voltage and the watts into the correct boxes and it will calculate the AMPS for you.

Heres the link to the inverter, http://www.supercircuits.com/resources/tools/Volts-Watts-Amps-Converter

* Special Note: I cant find what watts my unit uses?

No problem, if you cant find the watts perhaps the AMPS are already listed on the unit instead. If this fails do a search on the model number of the unit in your internet browser, most websites will give you the specs of the unit online.

Goodluck and I wish you all the best for your solar system designs.

Rv Solar Panels are not all made Equal

Solar Panels and the choices, Brand and wattage, How do we choose which is right for us. Well there are many solar panel types and sizes, all will use the suns Uv rays and covert them into usable 12 volt power but not all panels are made equal. Please let me explain.

There a lot of ways you can get solar panels and from many different sources and brands Such as Sharp or BP solar. You can buy the solar cells themselves (wire them together) purchase a suitable frame, and assemble, connect them in a frame of your choice then cover with glass or you can purchase either the “black panel” or the “blue panel”.

Option 1 – Monocrystalline Black panels are cheaper to purchase but can be affected by low light and incorrect positioning of the panels. These panels will still do the job but they do have there draw backs. These panels are normally more in the watts department but don’t be fooled by the output of the panel.

Option 2 – Polycrystalline Blue or Green panels on the other hand are quite a bit more expensive but the benefits of these panels is that they are shade tolerant (which simply means will work better in the early and late evenings compared to the Black type).

In my humble option, I would suggest you go with the Polycrystalline (shade tollerant) panel you will thank yourself in the long run. I have installed 3 x 125watt at 7.16 amps max sharp panels in  (which have been superseded to 130watts now) in parallel (which means mulipling the amps 7.16amps x 3 panels) in my parents setup which will produce at max 21.4 amps to the batteries.

RV – How to install and Repair an extra 12 volt battery in parallel to your RV or Motorhomes solar system:

Materials and tools needed for this section:

- Solder
- Conduit
- Socket set
- Cable Ties
- Multimeter
- Heat Shrink
- Wire strippers
- Soldering Iron
- Ring eye terminals
- Red and black wire, 40 amps (battery cable)
- 35 amp inline auto reset-able fuse 12volt.

- *Note: Battery of suitable size and type – should be the same AMP hrs as the original

Choosing the battery type

Hi again, and welcome to the next level of installs for your RV or Motorhome. Here we need to understand three things before we start.

1. The battery must be the same type i.e. lead acid (wet type) or the more common AGM (Absorbed Glass Matt Battery type) these are true deep cycle batteries. Some examples of these are Concord and Full River. There is also a GEL battery type on the market.
2. The batteries must be the same AMP hours i.e. 80 amp/hrs or 120 amp/hrs and the same type.
3. Always measure the area that you have so that the batteries will fit without rubbing or pulling on the wiring and the battery cases.

Locating the Battery

Please make sure that if you are using the (wet type) battery as in sulfuric acid type, you have these mounted outside the cabin or living space as these batteries give off hazardous fumes that can cause harm to humans and can explode if exposed to naked flames.

The other types AGM, GEL batteries can be mounted in the cabin or living space, and these are the type of batteries that I would recommend to use in this application as they are true deepcycle. The main reason for this is that deep cycle batteries can last longer then normal (lead acid or wet type) batteries and are designed to be maintained (charged) by solar systems.

Also you are able to mount them anywhere and you won’t have worry to about fumes. Once you have found an appropriate spot for the batteries, it is time to add them to your system.

How to add the 2 x batteries in parallel to your solar system

Please see the diagram below on how to install/add your new battery to your solar system.

Wiring diagram for 2 x 12 Volt Batteries in Parallel

It is very simple to do this, and all we need is two cables. The cables will be made up from your RED and BLACK battery cable and ring eye terminals as listed above. All we do is trim off enough cable of each colour so that it reaches from the positive on the first battery to the positive on the second battery.

Then we strip the wires, grab our heat shrink and slip that onto the cable at both ends then fix our terminals with our terminal pliers. Then just slide the heat shrink up the terminal and use our heat gun to melt it to the wire and the terminal. Then fit conduit to the cable to cover the wire and the base of the terminal (this will be yellow in colour). Please repeat this process for the negative cable.

Connecting the batteries to your charger controller

*Note: Leave the Positive from the charger controller detached from the positive battery terminal at this stage.

From your charger controller there will be two wires, one being positive and one negative. Attach the Negative to the Negative terminal on the second battery (as stated in the diagram above). Please note that all your accessories will have to be hooked up in this manner also i.e. (TV, radio, fridge, and inverter). Now before you connect the positive to the first battery please make sure that you have at least a 30amp auto reset-able fuse at 12volt, inline on the positive side between the charger controller and the batteries.

Once you have done this, you can now fit the positive cables.

Testing the Solar System

Once all your leads are connected we take our Multimeter select DC voltage from the settings and put the red lead on the positive of the first battery and the Black lead on the negative of the second battery. What you should be seeing is 12.5volts on your meter.

If the charger controller is operating i.e. showing 4 to 25 amps you should then see what is showing on the charger controller LED display (if you have one, and most do) lets say 14.4volts for example. This shows that both batteries are being charged and you have hooked things up correctly.

Then all you do is check your accessories and your done, very simple.