Off-grid solar setups consist of several parts. The most important are undoubtedly the power source – the solar panels, and what stores that power for later use – the battery. Simple and small setups just require everything to be connected with the right cables and you’re good to go. But what do you need to power more than a phone or a couple of lights? Along with several panels, and a battery bank consisting of one or more batteries, a solar charge controller (or solar regulator) to regulate and monitor how batteries are charged.
What are Solar Charge Controllers?
A solar charge controller is a device that manages the charging and discharging of the battery in the solar battery bank. It is basically a voltage and current regulator that prevents the battery from overcharging. A solar charge controller regulates how much current and voltage from the solar panels reach the battery. This is important because most panels designated as 12V in fact put out more power, roughly between 16 and 20 Volts. This is too much voltage for 12V batteries (which are fully charged at around 14.5 V) so there’s the likelihood of batteries getting damaged.
Why You need a Solar Charge Controller
Solar controllers have several functions in a solar setup. The most important is to prevent the battery from overcharging and overheating. This is especially true in clear, hot weather as the added charge for longer periods can literally cook a battery.
In addition, the controller prevents reverse polarity, or the battery draining the stored electricity back into the panels when dusk sets. Lastly, a controller can automatically disconnect appliances or devices that it sees as draining too much power in conditions when the charge is at extremely low levels. This prevents over-discharging, which too can shorten the lifespan of an expensive battery.
The benefits of controllers are that they are relatively cheap for the function they serve, as you can find something of quality like the affordable victron energy solar charge controller made for the job without the worry it would drain your wallet. They keep your entire investment in panels, batteries, cabling and other solar gear from unnecessary damage. And this is especially true if you have more things feeding off the panels, and a bigger solar setup.
How About Brands?
Though there are dozens of controllers on the market, each promising the best efficiency, fastest charging times and the ultimate protection, you’ll want something that’s tried and tested. Established brands like Victron Energy have been producing a range of solar gear, including chargers, inverters, converters, transformers, cabling and solar charge controllers for almost half a century.
A victron energy solar charge controller is therefore part of a well-defined ecosystem from one of the most revered brands in the field. That they are wholly invested in what they sell, Victron also offer some of the longest warranties available. Their extensive range meets the requirements of anyone thinking of going solar, either in an off-grid system, particularly in motorhomes, caravans or smaller 4WD-based setups, as well as residential and commercial systems connected to the grid. If you’re still doubting the benefits of renewable energy sources and solar panels in general, maybe this will change your mind.
Types of Solar Charge Controllers
There are two types of solar charge controllers – PWM (Pulse Width Modulation) and MPPT (Maximum Power Point Tracking). Each has their pros and cons, and each will be better suited to a particular solar system. They do however work in entirely different ways.
PWM Controllers
A PWM controller charges batteries in a series of short charging pulses. The strength and frequency of these pulses depends on the current state of charge in the battery. Batteries nearing full charge receive pulses of current less frequently and in less power. A battery that is discharged to over 50 per cent capacity will be charged constantly and in shorter and more frequent pulses.
One of the drawbacks of PWM controllers is that panels and batteries need to be matched in the same voltage. !2V panels will work best with 12V batteries, and 24V panels with 24V batteries. If you mix and match panels and batteries while having a PWM responsible for regulating charging and discharging, the system loses out in efficiency. Systems with 24V panels and 12V batteries lose half the available power. Even for 12V setups, a PWM controller steps down the voltage to just under 12V, so batteries are never quite fully charged. A disadvantage is that charging times are also longer.
This is why PWM controllers are better suited to smaller solar systems using less power. For camping and off-road purposes, with a couple of 12V panels and a single battery, this is more than adequate. To make up for lower efficiency, a PWM victron energy solar charge controller comes in at a fraction of the cost of more capable MPPT controllers.
MPPT Controllers
The benefit of MPPT controllers is that they charge the battery or battery bank with the maximum voltage they can take. This allows for more versatility in combining panels and batteries without losing in efficiency. For example, you can have 24V panels feeding charge into a 12V battery. Here, the MPPT controller steps down voltage, but increases the current so the battery is charging at the max rate.
This is what is referred to in the name – maximum power point – basically all the generated power from the panels is stored in the battery and at a faster rate. All this means is that batteries will constantly be near full charge, and a depleted battery (in the morning) will be charged much faster.
The convenience though means that buyers will be paying a bit more than for a PWM controller, but to keep all your gear working as it should, as well as protected, it’s a small price to pay. Victron Energy supply both PWM and MPPT solar charge controllers in different current and voltage ratings to efficiently power all your connected gear.
