Advertiser Disclosure
​Getting a flat battery at any time can be a pain. Even if the vehicle is in storage, you’ll want to start it up and get the juices flowing from time to time.
Or maybe your battery has been removed from a vehicle. You could just be storing the battery while your summer toy has been put away for the winter. Or perhaps you are ensuring that your RV batteries are good to go. Whatever the reason, it’s important to understand that even when disconnected, your battery will lose charge.
​To stop that happening, you can run the vehicle for a while. If that’s not possible, you could let the battery go flat and then charge it when you need it, right? Well, you could, but that’s not ideal. Besides, if you let a battery get too flat, you may never be able to recover it.
​The simplest solution all-round is to attach a battery maintainer to it. Just keeping the battery topped-up to the minimum charge level, without overcharging it, because that can be just as damaging.
​That’s why we’ve reviewed five of the best battery maintainers and tried to cover the topics that we think most people will want to know. Hopefully, you’ll find some value in our reviews.
​The Best Car ​Battery Maintainer
Battery Tender Plus 021-0128
- Rating: 4.9 / 5
- Brand: Battery Tender
​A fully-automatic 12V only battery maintainer that’s been designed to offer fast-ish charging and maintenance, with a 1.5A rating. They say that it will charge at the same rate (at least) as a 3A charger. But, it won’t do any of the damage that a trickle charger will do.
​​This battery maintainer comes with two connectors – a regular alligator clip style and the proper ring terminals should you want to make the connection more permanent. It also has a ‘quick connect’ harness for harder to reach areas.
It has built-in protection for reverse polarity and automatically detects when to switch over from charging to floating charge – just maintaining the charge.
​It’s worth remembering that most of these chargers or maintainers won’t give you the instant 10-minute boost to get a car started. This one is no exception. A full charge (battery dependent) could take between 24 – 36 hours.
Schumacher SC1319 Battery Maintainer
- Rating: 4.8 / 5
- Brand: Schumacher
​The Schumacher SC1319 battery maintainer​ is the ideal accompaniment for a motorcycle, ATV or boat​. It automatically detects and switches between 6V and 12V. No worries in remembering to switch it over. It also has built-in reverse polarity detection and microprocessor-controlled multistage charging.
​Once charged, it will switch over to float mode monitoring, keeping the lead-acid battery at optimum charge levels. Rated at 1.5A, it will need a number of hours to fully charge a battery from a completely drained state.
​Included in the box are heavy-duty alligator clips and ring terminal leads. For the money, it’s ​the best cheap battery maintainer. Complete with a 2-year warranty.
BLACK+DECKER BM3B Automatic Battery Charger/Maintainer
- Rating: 4.6 / 5
- Brand: BLACK+DECKER
​Similar to the Schumacher, this will work with both 6V and 12V for most types of batteries – AGM, Gel & Wet cell. However, switching isn’t automatic. You have to remember to slide the switch​. With a 1.5A rating, it’s the same as the others for charge times.
​This cheap unit does come with three levels of protection built-in – overcharge, reverse polarity and short-circuit. ​Aside from its ​protection, the BLACK+DECKER BM3B includes alligator clips, battery terminal rings ​and ​12DC accessory lead for easier charging.
​Also, note that ​you do ​get just a one year warranty, but that’s a no-nonsense Black+Decker warranty. So, you shouldn’t have too many problems. It’s also supplied with ​a mounting bracket molded into the rear of the unit for easier and convenient mounting.
Optima Digital 400 Performance Maintainer and Battery Charger
- Rating: 4.5 / 5
- Brand: Optima
​Optima makes some of the best vehicle batteries in the business, so it’s no surprise that their charger and maintainer is also a quality product. Thanks to their built-in health mode, the​ device automatically maximizes battery performance and lifetime.
​The Optima Digital 400 uses a ‘hybrid LED’ battery charging gauge​, and charges a 12V only battery with 1.5A. A neat touch with the Optima is that it can recover a battery right down to 1.25V. Not many will pull back a battery from the brink of death like that.
​I like the fact that Optima has put some thought into the design as well. It has a dual purpose hook and tilt stand, along with a wall organizer bracket for easier storing – both of the units and the leads.
The​re are alligator clamps and ring terminals included and attached, it has a 3-year warranty.
NOCO Genius G4 Advanced Battery Trickle Charger Maintainer
- Rating: 4.5 / 5
- Brand: NOCO
​As the name suggests, yes it’s clever, and yes it can charge four batteries at once, regardless of different charge demands or battery type​.
​Everything is all automatic. No need to tell it what the voltage is or even what type the battery is. Plus, it can deliver up to 30Ah. This is battery charging of the future!
​These NOCO Genius G4 charger and maintainer comes with everything you need to get started – 2 x 2′ alligator leads, 2 x 2′ ring terminal leads and 4 x 10′ connecting leads. However, all the leads and other specialist leads are available to purchase separately. It’s super handy if you lose or break one.
​It has built-in overcharge protection, along with reverse polarity monitoring and spark-free connection.
​This is aimed at the higher end of the market. Perhaps even semi-professional use. It’s backed up with a 5-year no-nonsense warranty.
​Fixing the Maintainer
​When looking to use a car battery maintainer, you need to think about whether you want it hooked up permanently, with a ‘flying’ lead, or just occasionally with some alligator clips. I tend to fit a lead with proper terminals so I can hook it up without having to access the battery each time.
​Another option for connection is a 12DC accessory plug that plugs into the cigarette lighter socket​. You should be aware that this type of accessory won’t work in all cars. If the accessory socket is live without the ignition on, then it’ll work. However, if the ignition needs to be switched to make the connection, ​you’ll need to do that for the maintainer to charge the battery also. Not great if you’re leaving a car in storage.
​Using a Maintainer & Charger
​You should understand that these are aimed at keeping a battery well maintained. If you’re by the side of the road with a dead battery, these aren’t going to help you, unless you have 24 hours to spare. Think of it as preventative maintenance, rather than emergency help.
​Although these systems are designed to be left attached for long periods of time, you should always check that the battery or maintainer isn’t getting too hot. Also, make sure it has switched to a floating charge rather than still trying to pump a full charge into a charged battery. Batteries can (and do) explode. I’ve seen it happen.
​For my money, ​I’d definitely choose the NOCO Genius G4. The simplicity of it and the ability to charge 4 batteries at once makes it the ideal candidate for the best battery charger maintainer.
​Finally, if you choose to hardwire the ring terminal to your battery, make sure that everything is safe and working correctly. If in doubt, ask a professional.
