The BatteryMinder Solar Charger-Controller is a 12 volt, so-called ‘smart’ trickle charger for automotive, motorcycle, and other larger 12 volt batteries, powered by the sun using the included five-watt solar panel (by the way, the product illustration is actually of the 15-watt version - the 5-watt panel is only one-third the size). Importantly, the BatteryMinder is designed to safely charge and maintain all sizes, types, and brands of 12-volt automotive, lawn equipment, and motorcycle batteries including starter, deep cycle and sealed types. This includes the new absorbed glass-mat or AGM batteries, as well as sealed batteries with gelled electrolyte ("gel-cell battery") made by various manufacturers. The BatteryMinder is regulated to prevent overcharging, no matter how long it is left on charge – days, weeks, or even months.
Recommend this product?
The company's original BatteryMinder charger, using household current, has been well received by consumers. Living in southern Arizona, it appeared this solar-powered version of VDC's BatteryMinder would be an ideal solution for keeping my truck's twin matched set of new gel batteries fully charged. With solar panels, I could dispense with the need for an extension cord; in time, the use of free solar energy (as opposed to household current) would - eventually - pay for itself.
The BatteryMinder Solar Charger, like its plug-in cousin, incorporates an automatic battery charger together with a battery desulphator and temperature control module. Attached to a battery, the module provides a low (.333 amp) trickle charge to maintain the battery at full capacity (as a very low-power trickle charger, the Solar Charger isn't designed to restore a dead or low-charge battery, and while it may eventually charge a battery with a slight undercharge, it can take forever to do so).
At intervals during operation the BatteryMinder sends a 'pulse' of electricity into the battery to help fight sulphation and extend battery life (Sulphation is the process whereby sulphate deposits effectively reduce the exposed surface of the battery’s internal charged plates, preventing exposure to the electrolyte. This effect reduces the battery’s storage capacity and prevents full charge). The pulse tends to break loose sulphate crystals to expose more of the plate’s surface, restoring storage capacity. VDC claims this process is beneficial to gel-type batteries in order to extend their life as well. A temperature control unit monitors the module's temperature and shuts off the unit to prevent overheating. A diode prevents reverse current drain from the battery whenever the solar panel is not supplying current (night, etc.). Once fully charged to 14.2 volts, the charger control module shifts to a maintenance charge/pulse charge mode, maintaining the battery at approximately 13.4 volts.
The Solar Charger also includes a second module, a Battery Condition Indicator (BCI) equipped with indicator LED lights to indicate battery and alternator status. No light indicates a battery with less than 11.2 volts; a red light = 11.2-11.8 volts; a yellow light = 11.8-12.3 volts; a green LED = 12.3-12.8 volts (fully charged battery); and a second green LED to indicate 13.2-14.2 volts (alternator charging system is working properly). A standard push-on automotive fuse mounted inline with the Solar Charger's wiring protects the system from excessive current loads.
My Solar Charger came with short wire leads equipped with push-on connections on one end and a ring-end terminal on the other, and a 3-amp automotive-type fuse and holder mounted inline with the wire. These wire leads are semi-permanently attached to the battery’s terminal posts and vehicle frame, and provide a fast plug-in connection when the BatteryMinder is to be attached to batteries installed in a vehicle for charging. I fitted both of my vehicles with a total of three plug-in leads; two for each of the gel-cell-type batteries installed in my diesel truck, and a third for the single conventional wet-cell battery on my car.
Before attaching the BatteryMinder to the battery, one must erect the five-watt solar panel. Theoretically it can be attached to a vehicle, or propped behind the windshield when the vehicle is parked. However, the solar panel is rather heavy and bulky, and charging more than one vehicle presents a problem. Constantly moving the solar panel, charger module, and drooping wires back and forth or taking them indoors for storage is something of a pain.
I eventually mounted the panel on top of a platform next to my vehicles exposed to full sun, using the supplied prop legs. The latter consist simply of two round rods threaded on the ends and screwed to the back of the panel. They were equipped with plastic suction type feet - which promptly fall off if not glued to the legs. Without them, they will certainly scratch any delicate surface, such as the paint on a vehicle's hood. They work - sort of. The threaded rods tend to unscrew themselves over time.
Although the panel is relatively heavy, it is still made of glass. In high winds additional bracing or secure mounts will have to be fabricated to adequately secure the panel. Unless mounted high off the ground or secured behind a winshield in a locked vehicle, the solar panel and its wiring is an attractive target for vandals.
While the solar panel needs to be mounted in full sun, this is not true for the rest of the system. In fact, VDC warns that the charge control module must be mounted or rested under the hood or otherwise protected from the elements (rainfall, excessive sunlight/heat) to prevent malfunctions and ensure reliable operation.
When properly attached, a green LED on the main BatteryMinder module indicates trickle charge of the battery and - where required - begins the desulphation process. When the green light begins to flash, full charge has been achieved, and the solar-powered BatteryMinder goes into maintenance mode to maintain the battery's charge level.
Charging any battery involves a certain amount of caution to minimize risk from spark and battery explosion. You MUST read the owners manual and follow all of the instructions when connecting the Solar Charger in order to charge your battery in a safe manner. VDC also has a website and technical department that can answer additional questions regarding charging procedures.
In use, one problem immediately surfaced. Although all of my batteries were relatively new (less than three months old) and fully charged when I attached the Solar Charger, the unit rarely achieved maintenance charge mode. Instead, the controller's LED lights would indicate that the charger was still attempting to reach full charge on the battery. I reviewed and minimized or eliminated parasitic current losses on both vehicles, made sure each vehicle battery had a full resting-state charge, then reattached the charger. No effect. I sent the charger control module and BCI indicator back to VDC, who checked it thoroughly and found no problems.
It made no difference whether I attached the BatteryMinder Solar Charger to the twin gel batteries of my older, non-computer-controlled diesel truck (no parasitic current draw) or the single wet cell battery of the car (minor parasitic losses from the computer in ‘sleep’ mode). In either case, the charge control module rarely achieved the 14.2 volts required to activate the 'maintenance charge' mode. I finally concluded that the five-watt solar panel – even in full Arizona sun for many hours per day- was insufficient to supply the BatteryMinder. After all, the current plug-in version is rated at 1.0A - 1.33A output, the five-watt solar panel, a mere .333A. It was usually enough to offset the parasitic or resting losses (from storage), but inadequate to charge the battery to the level needed to activate maintenance charge mode, except on rare occasions.
If you’re determined to use solar power for your BatteryMinder, you might consider the model equipped with the full 15-watt solar panel, making certain you can expose it to full sun for several hours per day.
The other issue I found with VDC's solar-powered BatteryMinder was with the wiring. The nature of the solar model (when fully assembled) means more components to carry out and attach to the battery when the panel and its charge control module are not installed in the vehicle or to a solid surface. Despite the greatest of care, this movement invariably puts stress on the insulated copper wires, which on my unit were not equipped with a strain relief. Instead the twisted copper small-gauge wires were merely screwed down with small clamps inside the main charge module. After a time the wires would break off at the point of attachment, requiring the ends to be stripped and re-attached to the modules. Over a period of two years I was forced to repeat this repair process several times before finally deciding to mount the panel on a fixed platform, while modifying the charge module with a homemade wire strain relief.
I used the solar-powered BatteryMinder continuously for about three years. 90% of the time the charger was attached to the batteries on my truck, which was not used for daily driving; the rest of the time it was attached to the battery on the car. While I cannot say if the product extended battery life, I can state that the original batteries attached to it are still going strong, and recently passed a load test with flying colors.
Eventually, a high wind broke the improvised mount attachments securing my solar panel and it crashed to the ground, destroying it. Rather than replace the panel, I opted to obtain the company’s plug-in BatteryMinder model; it has worked well.
The BatteryMinder Solar Charger with five-watt panel worked reasonably well as a battery maintainer, but barely adequately as a trickle charger. In my experience the solar energy available from the five-watt panel proved insufficient to reliably achieve the voltage required to shift into maintenance mode. I would instead recommend consideration of VDC’s other, more powerful versions of this product for long-term battery maintenance.