It was a bad day. We headed out to the garage to start our 2008 Shelby GT500 but it wasn’t meant to be. The battery had flat-lined. We weren’t going for that drive, and worse yet, we might be shopping for a new battery. That is until a new smart battery charger from CTEK arrived on our doorstep.

As owners of several vehicles, we know all to well that it’s important to keep the batteries of the rarely used machines charged. In fact, we already kept a CTEK smart charger in steady use, but the problem was that we only had one, which we shuttled back and forth between two Mustangs. Apparently, we forgot to swap the charger soon enough.

When your battery is dead and there’s goodies from CTEK, it turns that frown upside down. We added a CTEK MUS 4.3 charger, Smart Sense Bluetooth sensor, and a comfort indicator panel to our 2008 Shelby GT500 to ensure the battery stays in top condition.

Most battery problems are not due to a faulty battery. They are due to improper charging. — Bobbie DuMelle, CTEK

“Whatever vehicle you are driving and whatever battery you have installed, remember that most battery problems are not due to a faulty battery. They are due to improper charging!” Bobbie DuMelle, Executive Vice President of CTEK Power Inc., said. “We estimate that as many as one in four vehicles are driving around with a battery that needs attention. With the development in both vehicle and battery technology on modern vehicles, the battery is working harder than ever before, so battery care has never been more important.”


This install is simple. Both the Comfort Connect Panel and Smart Sense feature pre-terminated wires that can easily be attached to the terminals on your battery. Likewise, the Smart Sense includes double-sided tape, which we used to attach it to the shock tower with its sensor code facing upward. This code is needed to link the sensor to the Battery Sense app on your smartphone or tablet.


Modern Problems

Because of the increased electrical demands on modern vehicles, they need to charge the battery when the vehicle is not in use is even greater. The load put on the charging system by extra cooling fans, upgraded fuel pumps and aftermarket audio systems can deplete the system and the alternator won’t fully recharge the battery.

The Comfort indicator panel includes wires long enough for you to find a subtle mounting location. If you want to get fancy, you could cut a small hole or find an existing one in the sheetmetal, but we opted to nestle it into the factory fusebox wiring harness under the hood.

Optimum Power

For years we have run Optima batteries in our Mustangs because they offer spill-proof, maintenance free life and plenty of starting power. Also, due to their spiral-wound, absorbent glass mat technology, they are quite vibration resistant as well. While the standard Red Top battery is a great starting battery, our Shelby is loaded up with a big Kicker audio system, auxiliary cooling fans on its heat exchanger, and more, so we wanted a battery with the capacity to keep up, which is why we chose the Yellow Top. It lives up to three times longer than a traditional battery and is built to live through over 300 discharge/recharge cycles. Now that we have it on a dedicated charger, we shouldn’t see as many of those discharge cycles.

While a battery will naturally discharge about 0.1 volts per month, that doesn’t account for any current draw from the factory or aftermarket systems. When the battery is discharged, that can lead to sulphation, where the electrolyte solution in the battery breaks down and leaves deposits on the battery plates, which make it resist charging. Likewise, the acid and water in the battery can separate, or stratify, which hinders its charge-holding capabilities. Charging a battery above 12.4 volts will avoid these battery-killing scenarios.

We learned that the hard way. Fortunately, that package on the doorstep included one of CTEK’s latest smart chargers — the MUS 4.3 Test and Charge (PN 56-864) — which we quickly attached to our Optima Yellow Top battery and hoped for the best.

“I wouldn’t say that having a smart charger is more important with an AGM battery over other chemistries (you need a smart charger whatever your battery chemistry!), but I would say that most AGM batteries need charging in a different way to other chemistries such as wet or gel batteries,” Bobbie said. “AGM batteries benefit from being charged at a slightly higher rate of charge, which is why with our MXS 5.0 charger we have a dedicated AGM mode to ensure that these powerful and expensive batteries are maintained in peak condition.”

With everything wired up, we plugged in the CTEK MUS 4.3 to the Comfort Connect Panel, toggled through the options until arriving at those for an automotive battery, plugged it into an outlet and let it get to work.


Even Smarter

We love gadgets and the CTEK Smart Sense dongle and its companion Battery Sense smartphone app made it easy to keep tabs on the battery voltage of multiple vehicles.

CTEK Charging Stages

What makes the CTEK charger smart is that it pulses and regulates charging voltage to enhance the battery’s operation without damaging it. According to the company, these are the stages of charging offered by its smart charger…

Desulphation: Pulsing voltage removes sulphates from the lead plates of the battery restoring the battery capacity and preparing the battery to receive a charge.

Soft Start: Tests if the battery can accept charge – charging begins if the battery is OK. If the charger identifies that the battery is not capable of receiving a charge, a red warning light will appear.

Bulk: Charging with maximum, constant current until approximately 80% battery capacity. It is important that the battery isn’t charged to 100% in this stage as there is a high risk that the battery will over-charge.

Absorption (Ready To Use): Charging with declining current to bring the battery up to 100 percent of battery capacity. The CTEK charger will constantly monitor battery charge during this stage to protect against over-charging.

Analyze: Tests if the battery can hold a charge. If the charger identifies that the battery is not capable of holding a charge, a red warning light will appear.

Recond (Optional): Reconditioning function for deeply discharged batteries that delivers a higher rate of charge to treat heavily sulphated batteries and address acid stratification. This stage does not form part of the standard charge cycle but can be selected using the mode button.

Float (Fully Charged): Maintaining the battery voltage at maximum level by providing a constant voltage charge. The charger will remain in this stage for a maximum of 10 days to ensure a fast vehicle start. After 10 days however, the charger will move to Pulse Maintenance Charging (8) to ensure that the battery doesn’t dry out.

Pulse (Maintenance Charging): Maintaining the battery at 95 to 100 percent of capacity. The charger monitors the battery voltage and gives a pulse of charge when necessary, to keep the battery fully charged. If the charger detects that the battery has dropped lower than 95-percent charge it will go back to stage 1 and start the complete charge process again.

We also installed the company’s innovative Battery Sense interface, which wirelessly connects to a CTEK smartphone app via Bluetooth to give you an instant update on your battery condition without even going out to the garage.

“We strive to help people understand the importance and benefits of proper, proactive battery management and we offer them innovative, safe and easy-to-use tools for the task,” Bobbie said. “Battery Sense is a perfect example of an accessory that provides vehicle owners with an overview of battery charge status, and more importantly tells them when it’s time to charge — protecting against costly vehicle breakdowns!”

Within a day our Optima was back up to 100 percent and we can rest assured it will stay charged when the Shelby is off duty, now that it has a dedicated smart charger and an easy way to keep tabs on the voltage.

“A CTEK charger isn’t called a smart charger just because!” Bobbie said. “It’s smart because it constantly talks to the battery making sure it gets the safest, most effective charge for its needs, to safely bring it up to 100-percent charge without risk to the battery or the vehicle. Many traditional chargers (your Grandfather’s old linear charger for example) doesn’t have the capability to listen to the needs of the battery; so either undercharge as a precaution or overcharge.”

Besides reviving our discharged battery, CTEK says the regular use of a smart charger can prolong battery life by up to three times, so we are stoked to have one keeping our Shelby’s battery nourished.

For more on the CTEK smart battery chargers, check out the company’s official site here.

Whew. When we first attached the CTEK Smart Sense to our Optima Yellow Top in our 2008 Shelby GT500, a.k.a. Project Vapor Trail, things didn’t look good. After a day with the CTEK MUS 4.3 plugged in, things were looking bright again. Now that PVT has a dedicated charger and an easy way to monitor voltage, it’s unlikely we’ll see that first screen again, and that’s just the way we like it.