FAQs

In this section we have tried to answer some of the questions you may have about our charge controllers and also about solar energy in general. If you need further information please contact us using the email link below.

How do SunWorks solar charge controllers work?

For a single or dual battery system, the controller will decide when a battery needs charging, allowing the current to pass as necessary and then disconnecting once it is fully charged. The charge controller will always put the maximum charge possible into your batteries.

Why do I need a solar charge controller?

The amount of electricity produced by a Photovoltaic (electric) solar panel depends on the amount of sunlight falling on the panel. During low sunlight periods the panels will only produce small amounts of electricity, in high sunlight situations a great deal of electricity can be produced. A flat battery can absorb a high current from a solar panel but a charged battery will be damaged by too much current. A charge controller will gradually reduce the current from the solar panel as the battery charges up.

Which controller will suit my 120 watt panel?

Depending on the manufacturer, a 120 watt panel will produce about 6.5 amps of electrical current in direct sunlight.  So you should choose a controller that will handle at least 10% more than this. A 11 amp controller would be most suitable.

Which controller is best for my motorhome?

Our most popular controller for motorhomes is the SB1C. This handles solar panels up to 11 amps.  If your solar panels produce more than 11 amps then we suggest you consider our SB2C which handles up to 15 amps.

Can I also charge my engine battery from the same solar panel?

If you wish to charge your engine battery as well as your domestic battery, then choose the DB1C controller for solar panels up to 11 amps. For larger solar systems our DB2C can handle solar panels up to 15 amps total.

I have more than one solar panel. How do I choose a controller?

If you intend to connect your solar panels together to make one large panel, then you simply add together the amps rating of each panel. For example, two 120 watt panels wired in parallel will perform as a 13 amp panel. Choose a controller that can handle at least 10% more than this total, i.e a 15 amp controller.

Can I use a SunWorks charge controller on my boat?

Our controllers have been use on all types of boat and yachts including transatlantic rowing boats! As with all electronic equipment, the controller must be installed inside the boat, where it will give many years of reliable operation.

Is it easy to install a SunWorks controller?

SunWorks charge controllers are straightforward to install by the average DIY enthusiast. Essentially there are two wires for the battery and two for the solar panel. Details of wire type and fuses to be used are included in the comprehensive instructions.

Is it easy to use a SunWorks charge controller?

All our controllers are fully automatic and need no user operation.

Do I need to use diodes with my solar panel?

For the average motorhome it is not necessary to use isolating diodes. These are only required on much larger solar panel systems.

How does a charge controller work?

A SunWorks charge controller will control the electrical current from your solar panels to your batteries. Maximum current will be applied until the battery approaches full charge. The current is then reduced to safe levels. The battery charge is constantly monitored and the appropriate electrical current is applied to the battery. Battery life will be maximised and the performance of your solar panel system will be enhanced.

Can I wire several solar panels together?

Panels for motorhomes can be connected together, in parallel to effectively make a larger panel. We recommend that you do not exceed three panels in a normal motorhome system without taking special precautions.

What is a MPPT charge controller?

This type of controller was developed for use on large solar panel systems such as those found on building roof-tops. In these situations they are essential and work well.
We do not recommend these controllers for use on 12 volt motorhome and boat systems because:

  • The long cables found on motorhomes create a ‘voltage overhead’, making it difficult for the MPPT controller to work efficiently.
  • The additional complexity means they have an inherent loss of up to 15%.
  • It is less expensive to add a little more power to your system by using a slightly larger solar panel or adding an extra panel to an existing system. This solution is also more reliable than a complex MPPT controller.

MPPT charge controller can often be successfully used  on:

  • 24 volt battery systems.
  • 12 volt battery systems where the cables are short and are of large cross-section.

For answers to other questions, please get in touch with us: