Battery Tender Junior 12V, 750mA Charger and Maintainer: Automatic 12V Powersports for Motorcycle, ATVs, and More - Smarter Than a Trickle Charger - 021-0123

We have a '98 Lexus ES300 with a 2.5year-old Toyota battery installed, and this winter the car has been parked outdoors and goes several days without starting (second car). However, on the day one of us needed it, the car failed to turn over as the battery had really run down due to loss of charge. AAA Service tech was called, he did a battery check, found it to be still useable, did a jump start, verified that alternator was putting out required charging voltage, and told us to run the car for at least a half-hour, when the battery should more or less be charged up...which we did, and it was. The service tech also suggested installing a trickle charger, which brings me to this review. After checking all the user reviews on Amazon for both the Battery Tender (BT) Junior and the BT Plus, we opted for the lesser-priced Jr., being aware that many users recommended the BT Plus for automobile battery use over the Jr.. The Jr. arrived about 3 days after our flat-battery incident, and following mfr. instructions, we connected ring adapter to battery, attached the 25ft extension cable, and plugged the unit into one of the interior garage 115V outlets. The indicator light went to solid RED, and stayed that way for between 36-42hrs, when it then went to blinking GREEN, and shortly thereafter to continuous GREEN. Car starter cranks immediately, all systems running, and it certainly looks - without an independent check of battery amperage - that the Jr. did its job, and placed the battery at full charge and switched to "floating' or maintenance mode. Interestingly enough, the user manual states that the "blinking GREEN" condition (at least 80% of full-charge) is seen only for the 1.25A version (BT Plus), but it also was noticed for the Jr.'s status light. After a week, we are totally satisfied with our purchase, as the device works as advertised, easy to install, and seems reliable to date. It should also be noted that all electrical connections are made either indoors or under a (closed and locked) hood, with the extension cable itself being the only part of the charging system exposed to the elements. Will monitor the BT Jr. throughout the winter to check on longer-term reliability issues.

I couldn’t be more thrilled with this charger. It’s an absolute lifesaver for anyone who owns motorcycles, ATVs, or other vehicles that require regular battery maintenance. Setting it up is a breeze, even if you’re not particularly tech-savvy. The design is compact and lightweight, making it easy to handle, store, or even take with you on the go. One feature I really appreciate is how it automatically switches to maintenance mode when the battery is fully charged. This gives me peace of mind, knowing my batteries are protected from overcharging, which can cause damage over time. I’ve used it multiple times already, and every single time, it’s performed flawlessly. My motorcycle battery used to struggle during colder months, but with this charger, it stays in top-notch condition and starts up like a dream. I also love how dependable it is—no sudden glitches or errors to worry about. It truly does what it’s supposed to do, and it does it exceptionally well. Honestly, it’s worth every penny and has saved me a lot of headaches. If you’re looking for a trustworthy, efficient, and easy-to-use charger, this is the one! It’s the kind of product that quickly becomes a must-have in your toolkit. I wouldn’t hesitate to recommend it to anyone in need of a reliable solution for battery care.

I'm a greenhorn at car-care, but this product was pretty much foolproof! I'm using it to keep the battery topped off for my family member's car, as she has just had surgery and won't be driving for 2 months. I do not need it for months and months of storage and maintenance, so the 2018-era reviews complaining about "now it only lasts for one year" after the manufacturer's move to China, really don't matter to me! I really appreciate the built-in safety feature of no sparking if you touch the clips together. Current won't flow through this product, even when connected to the outlet, until it senses 3 volts. This could make it hard to charge a TOTALLY dead battery with this product, but it worked perfectly for us. To put this thing together, you'll have to pick either small-ring connectors - which are for the non-car uses that will sit for over 6 months, like an ATV or motorcycle or boat - or the alligator clips, which are for cars and bigger engines that will be connected for just a few months. You'll also have to have color vision to discern between red and black, since the alligator clips confusingly have a (+) symbol on one side of their jaws. On the second jaw, they differ (+) and (-), so if you can't tell them apart at first glance The most difficult part for me was step 6e/f in the instruction manual - determine if your car engine has negative-ground or positive-ground status. Like I said, I'm a greenhorn here. Sure, the manual says "most cars" are negative-grounded, but I didn't want to mess it up, cuz car batteries are big hefty things you don't play around with. After real careful inspection, I found that the battery of our car had a wire going directly onto and behind the hefty metal of the vehicle body or "chassis" I learned it is called, which came from the (-) side of the battery. The (+) side had a complicated plastic cover over it, which made connecting the alligator clip a bit difficult, and that side's wire led to other engine parts. That's what made me 90% sure that the negative side was the "grounded" side. So I connected the (-) black clip to the (-) side of the battery, and the red clip to a nut-and-bolt part of the engine. I was able to close the hood on the car most of the way by turning the clips sideways and flat as I could. It's not latched at the moment, but sitting in our garage, it should be plenty protected from spiderwebs and dust and whatnot. No option in our case to thread the cable thru the front grille since it's pretty jam-packed with engine parts right behind it. My one complaint about this product is that the cable ending in the two alligator clips splits pretty close to the jaws end, and it would help to have it split further up, to help users reach a part of their engine block or chassis more easily. Also, I highly recommend addition of diagrams. There are words saying "connect wire to engine block or vehicle chassis, not sheet metal or fluid lines" but some of us need an illustration of what is a sheet-metal body part vs the vehicle chassis! Once connected to the engine, I turned my back on it just in case, to plug in the "wall wart" (credit to Mythbuster Adam Savage for that term) and the light turned steady red! This was encouraging, since when I had tested it earlier by plugging it into the wall with no connections made, it blinked red. So I was confident I did not have a defective wall wart box. 6 hours later, the light had turned blinking green, and 6 hours after that, it had turned steady green, which the manual says is the perfect state to leave it in for 'drip feed' of electricity to keep the battery operable while not in use. So I am perfectly satisfied! Our car's battery was diagnosed by a mechanic as "being on its last legs" anyway, so this comparatively cheap product, for 2 months of use only, is perfect for our needs. I'd recommend anyone with a really expensive car or battery that needs storage for 6 months or more do a bit more research and spend a bit more on it.

I have used Battery Tender chargers for many years, mostly on motorcycle batteries, with good results: quick starts, longer battery life, less maintenance. I have two lawn tractors now (a Sears 48" conventional type mower, and a commercial grade Exmark Lazer ZTR) that live in the garage, and normally aren't run much for the three-ish months of late fall-winter in Texas. If you live in colder climates, this charger is even more critical. Hooking it up is a breeze. If you can take a nut off a bolt, you know all you need to know to install the harness. Remove the positive (red) battery cable (this is a good time to clean up the cable end and battery terminal with a small wire brush). The Battery Tender cable has a loop type butt connector on it, so just slip the red harness cable end over the battery bolt, put the positive cable and nut back on and you're halfway home. Repeat on the negative (black) cable. That's it for the harness hookup. Simple, right? Tie wrap the harness in a convenient place where you can get to the connector end, as the harness stays with the battery full time. Kudos to the manufacturer for putting a cover on the connector end to keep it clean. The original Battery Tenders didn't have that! The connector to the charger is a flat two-conductor end that can only be connected one way, so no screw ups there. Even if you manage to do it wrong (wiring the harness backwards on the battery, for instance), it won't hurt the charger, it just won't charge. Connect the harness and charger together, and plug the charger in. There is a light that reflects charging state, and also lets you know if the battery is too dead to charge this way or if the harness is wired wrong. Once it gets back to steady green, you are charged. Now it will turn on and off as needed to keep your battery at optimal levels until next use. This maintenance charge also limits buildup of sulfates in the battery, the main reason unused batteries short out. Yes, it does cost about the price of a lawn tractor battery. In my experience, it doubles the life of the battery and lasts for years so it will pay for itself. But the real value is never coming out of the house ready to go and have a dead battery stop you in your tracks... waiting hours for the charger to get it back into shape, then seeing it not hold a charge because it is sulfated. I do not miss that frustration, and this is a pittance cost-wise to avoid it. A good product from a company that has been making them for long enough to know how. They also make bigger ones for larger batteries. I have owned both types, and they work similarly. It isn't fancy, and won't wow your friends, but it does exactly what it's supposed to do. I like that in a product.

I have a couple of these as the Battery Plus Tenders are twice as expensive . This works well on my cars with good batteries ( No kidding 8 years old but always hooked up when not driving so they last ) . The downside is reading the trouble light if your not used to it and know only how the others work . The only other deficiency is it does not charge as fast if the battery is low to bring it up to the maintenance circuit . I think its around .75 amps instead of around 1.25 you can read at their site what the factual numbers are but thats about it . Still brought up my total loss deep cell battery eventually maybe 2 days instead of 1 for the others that I use in my campers when it was low from running the tv and lights with the engine off . I am older , severely disabled and drive only about 2k miles a year with 3 vehicles , a motrocycle , boat , camper etc . Since I have used these I have paid for them in battery savings and they last fairly well . The warranty isnt that good as you pay shipping bit I used it once it was better on the expensive ones that just letting it go . I always use the quick disonect and have the extensions for vehicles i park in the drive at times . I have had 2 of these 2 single tender pluses and a 4 bank . The oldest about 6 years old . Only problem I had was end plugs rusting when outside . I figured it would throw the circuitry off if I repaired it ...but it didnt . They all still work . Very pleased . It is a investment but living up North with freezing temps that will freeze a battery that gets a low charge seperating the plates and destroying it these are great . Plus if you plug in nightly the draw from the new digital equipment doesnt lower the charge which will cause more sulfation as you charge up from a deeper discharge . Like I said where I used to get 3 years or even less if I didnt drive a car for a few months for the life of a battery I have two in cars now 8 years old . I think they pay for themselves . With the quick disconect it is so easy . I just put a something on my hood in front of the drivers windsheild or on it to remind myself to disconect each time I drive . These are way ahead of the Harbor Freight ones that do not have the abillity to charge a battery up just trickle charge it and cut off at 13.8 volts . You will not be sorry . I had one car stored for 6 years , never started though we put stabil in it fresh yearly and it started right up and ran fine and improved after fresh gas was put in with sea foam another good product but a tad expensive . Star Brite or Star Tron is almost as good , stablizes gas and is very cheap if you use the Diesel one when it is on sale . God Bless . :-)

HIgh end quality product. Works really well, and saved me from getting stranded because of a dead battery. My OEM battery was about 4 1/2 years old and after using this tender I saw that my battery wasn't holding a charge and was weak. I don't know about others, but trying to start my car and finding out the battery has permanently expired is not a happy experience. I also plan to use it the next time I go on vacation and leave my car in garage. Batteries are always losing their charge, even when there is no drain on them.

I bought this one as a gift so I can't open it. I have the exact same one hooked to my car battery that's in storage. The battery is going on eight years. Considering I would have bought another battery by now, it's already paid for itself. I've never had a problem with it and it works flawlessly, just hook it up and plug it in. This is one battery tender I highly recommend.

This appears to be a quality item, it works great.

Perfeito

Great product. It's small, well thought-out and does what it says on the box. I travel a lot for work, so my car is parked at home for 2-3 weeks every month. I drive a BMW, and the electronics draw the battery down while it's parked. It will start after 2 weeks but not after 3 if no one runs the engine. So I picked up a battery tender junior and I've been very happy with it. It's small enough to tuck in the trunk, and the detachable leads are a great feature - I leave them attached to my car's jumping posts under the hood, so it takes all of a few seconds to connect or disconnect. It's kept my battery in great shape. In fact I've gained a few tenths of a volt both with and without the engine running, which is pretty fantastic considering my battery is 4 years old. I run a couple aftermarket amps, an obd2 wifi dongle, and a radar detector, which I know is taxing on my car's electrical device, so this guy gives me some peace of mind. And it's a steal for the price... it's a half to a third the price of a decent trickle charger, and it's better for my battery which is going to save me money over time. Very happy with this purchase.

Muy bien

What great product i bought depending on its reviews but it just last for 3 seconds and then it blow up … cheap quality

This item is really for the U.S. market and was of no use to me as can not be safety used with uk power system.