I live in a cold winter climate. The kind where you question why you live in it every winter, meaning my vehicles’ batteries are suspect when the temps drop significantly (single digit temps). I don’t drive very often and there’s an older SUV with a parasitic drain that always gives me reliability pains despite charging it several times with one of those 60-amp behemoth chargers. Those chargers can occasionally overcharge a battery, causing smoke and a rotten egg smell (don’t ask me how I know). So I thought I’d check out this NOCO Genius 10 Battery Charger and Maintainer that I’ve seen people ranting about to see if it could properly charge and restore the battery, allowing me to ditch the giant charger.
Build Quality, Initial Impressions, and Features
The NOCO Genius 10 is effectively a 3.3 pound charging brick that feels substantial in the hands. It comes with a 72″ AC power cord, a X-Connect 56″ cable for both your positive and negative cables, and a plastic mounting bracket with a strap. So that’s over 10 feet of room to work with. Extending mine out, I measured around 131 inches.
Assembly
The NOCO Genius 10 is fairly idiot proof to set up. Your battery clamps plug right into a harness already attached to the Battery Charger and Maintainer. There’s a pentagon and circle inside so if you can figure out a shape sorter from you’re childhood, you’re probably good to go. I will say one of my connector pins was slightly off and I did need to adjust it in order to insert the harness, though. Either that or I don’t know how to use a shape sorter…
Charging Modes
There’s only one button on the NOCO Genius 10 Battery Charger and Maintainer, which uses long or short presses to navigate to whatever charging or maintaining mode you need. There are modes for 12V Charge, 12V AGM Charge, 12V Lithium Charge, 6V Charge, 6V AGM Charge, 12V Supply, and 12V Repair. The data sheet states that it can charge marine and deep-cycle batteries too. For this review, I’m focused on the 12-volt lead-acid charging on my vehicle.
Battery Clamps
The battery clamps feel good enough. They are easy to use and you don’t have to use much force to get them to open and close. The positive and negative clamps have integrated eyelets (additional ones can be purchased separately for multiple vehicles and/or batteries) so one could permanently mount these onto inaccessible batteries and then just attach to the Genius 10 Battery Charger whenever it’s needed. I suppose this could be useful for the regular charging mode but there is an issue if you’re wanting to use the 12V Repair mode (12-Volt Lead-Acid Batteries Only) because the manual explicitly states in order to minimize risk to electronics one has to disconnect the battery before using said mode. So you’re not gaining much benefits there if you need that feature. Alternatively, you could use quick release battery terminal clamps in order to safely access that mode, but something to keep in mind.
Mounting Bracket & IP Rating
I initially thought the mounting bracket used Velcro straps to safely mount the Genius 10 somewhere near the battery while charging inside the hood of the vehicle, almost like an added assurance it wouldn’t fall, but that doesn’t seem to be the case. Instead, it’s used with self-tapping screws for mounting on the side of a tool box, a wall, et cetera, for quicker access. That’s not really something I’m personally looking for at the moment, but I could see some use cases for it, especially if you plan on keeping the NOCO Genius 10 plugged in an extended period of time for battery maintenance. NOTE: I have seen people mount the entire battery charger in the engine bay of a vehicle, but keep in mind it’s IP65 rated (protected from dust and water jets from any direction) so I’m not entirely sold on that setup yet. I would have liked to see a higher rating to deal with rain or snow (you’ll see why below).
Storage
Astonishingly, the one thing the NOCO Genius 10 doesn’t come with is a storage case. It’s sold separately and can be purchased for $24.95 on their website, but that’s kind of egregious not to include. However, the people who are mounting this somewhere probably won’t be moving it very often, so I guess there’s that.
NOCO Genius 10 in Cold Weather – Use
Since we had single digit temperatures approaching (and below zero with wind chill), I thought it to be a useful and extreme scenario to test out the NOCO Genius 10. I suspected the battery charger portion would work temporarily but I was very curious about the 12V Repair Mode’s ability to restore a battery manufactured in 2023. Note that this battery was drained to approximately 11.98 Volts and it was unable to turn on the vehicle. Current temp highs at this time were below 20 degrees Fahrenheit with snow on the way.
Installation – Battery not Charging
Initial installation was fairly simple. Hooking up the clamps for 12V charging wasn’t a problem but I immediately noticed issues with the Charge LEDs cycling through repeatedly and then the Genius 10 would go back into Standby mode. After trying and failing a couple times, I decided to try a different vehicle just to see what would happen. That vehicle’s connected battery seemed to charge just fine. Feeling a bit stumped, I opted to go back to the original vehicle and disconnect the battery terminals completely. Once I did that and reattached the Genius 10’s battery clamps to the disconnected vehicle battery, it began to charge immediately.
So what caused this? Well, I had aftermarket battery cable terminals that resembled these on there. They are quite thick and I wondered if that thickness and/or the paint was negatively impacting the Genius 10’s ability to go into charging mode (the other vehicle I tested had what I believe to be stock battery terminals that were pretty thin by comparison). I reached out to NOCO for some clarification on that but have not received a response.
Additionally, after recharging, I was reinstalling the vehicle’s positive aftermarket battery cable terminal and I noticed a very slight looseness in the attached wires, so it’s possible that could create some resistance and maybe even lead to charging issues too. I’m not sure what caused the looseness, though. It could have gotten loose as I was detaching or reattaching the battery cable terminal but hard to say. In subsequent tests, after tightening down the wires to the aftermarket battery cable terminal, I was unable to repeat the standby mode charging error. Therefore, for the time being, I’m hoping the charging mode error was related to that slight wire looseness and not a problem with the unit itself. However, that’s with the caveat that my old behemoth charger was still able to charge the battery in the past and the vehicle still ran too. So time will tell on this one.
Battery Charging, Maintenance, and Repair Mode
Anyways, the manual states that you’re supposed to do a full charge of the battery on the normal 12V Lead-Acid charging mode before using the Repair charging mode. As soon as you turn on the correct charging mode, the four Charge LEDs will begin to slowly pulse to let you know how far along you are in charging the battery back to 100 percent. Once you reach the 100 percent mark, the Green LED will be solid green and then the charger will continually monitor the battery and provide “ongoing maintenance and optimization” and this same LED will begin to pulse whenever these cycles are happening. One can also leave the charger connected indefinitely at this point, which is a nice option to have if you are not planning on touching the vehicle or said battery for an extended period of time.
I was able to fully charge the battery within a few hours and then started a 12V Repair charge as well. The highest voltage reading I had while repairing was 14.96 Volts. I’m unsure if I went through an entire repair cycle that night, though. I can’t find anything in my data specifying that so it’s simply lost to the annals of time. The next day I was at around 12.42 Volts and I decided to take the vehicle out to run some errands. To my surprise, I didn’t have any issues starting the vehicle up multiple times after that initial ignition. This was after multiple days below 20 degrees Fahrenheit, so I would consider that a win at that point.
A few days later we had dreadful single digit temperatures on our way. In preparation the day before, I opted to top off the battery once again in the morning while it was snowing. The vehicle had sat around three days and it was down to 12.06 Volts. It could be the cold temps or perhaps I even have a parasitic drain on this vehicle (I believe the vehicle was still connected to the battery from my previous trip three days prior). Regardless, I’m not attempting to diagnose it in the frigid cold, where the winter winds are hurting my face.
After charging without the battery terminals connected, I had a reading around 12.73 Volts that quickly dropped to 12.71, which is normal. I expected it to drop even further throughout the day. That was around 11:30 AM that day, with temp highs approaching a blistering 20 degrees Fahrenheit once again. About ten hours later with the battery terminals still disconnected, I was looking at 12.56 Volts. Note the terrible amount of snow that made it inside my vehicles’ engine bay. I had to use a leaf blower to blow it all out. Oopsies. Not ideal.
The next morning, with the battery terminals still disconnected, I was looking at a reading of 12.5 Volts. Again, not too bad given what I was experiencing outside in the treacherous cold from Beyond the Wall. The day’s high temperature was literally 12 degrees Fahrenheit (not a typo). Fast forward about a week later and I was sitting at 12.34, which for a vehicle exposed to the elements that long, is much better than what I was contending with previously.
Conclusion
For my particular instance of cold weather and a possible parasitic drain, the NOCO Genius 10 Battery Charger and Maintainer is an improvement. It’s a bit suspect to not include the protective storage case, though. Regardless, a 10 amp charger and maintainer is worth it if it keeps me from spending a fortnight just to get a battery up and running again, especially one that could be on its way out. Not having to start my car and let it run or drive it around to “safely” recharge the battery with the alternator greatly simplifies my life. I feel safe leaving it attached multiple hours, even days, and it’s a useful solution.
