Product Description

Battery Tender Junior 12V Battery Charger is much more than a trickle charger. It has a brain, is lightweight, compact, fully automatic and very easy to use especially in small spaces. This battery charger will keep the battery fully charged so that it is ready to go always. It has a microprocessor controlled fully automatic charger and maintainer and is designed to extend the life of any lead acid battery commonly used in automobiles, motorcycles, ATVs, personal watercraft, RVs, boats, airplanes, golf carts, back-up generator systems, etc. Any vehicle or battery-operated piece of equipment not used on a daily or regular basis is a candidate for a Battery Tender charger. The advanced technology will bring the battery back to a full charge without overcharging and then float or maintain the battery for an indefinite period of time. The Battery Tender Junior comes equipped with alligator clips and ring terminals for easy hook up. An optional 25 feet extension cord (part number 081-0148-25) is sold separately.

Product Details

• Amazon Sales Rank: #2 in Automotive
• Color: Black
• Brand: Battery Tender
• Model: 021-0123
• Released on: 2006-12-01
• Dimensions: 9.00" h x 4.00" w x 8.00" l, 1.80 pounds

Features

• Spark proof during lead connection, reverse polarity protected and includes a 12-foot output cord and 5-year warranty
• Perfect for charging all 12-volt lead-acid, flooded or sealed maintenance free batteries (AGM and gel cell)
• Complete 4-step charging program (Initialization, Bulk Charge, Float Mode) allows for optimization of battery power, without overcharging
• Automatic charge cycle functionality switches to float mode after fully charging the battery
• Solid state two color LED indicates stage of charger

Amazon.com Product Description

The Battery Tender Junior 12-volt/75-amp battery charger is the small and simple solution to the challenge of keeping vehicle batteries optimally powered when not in use. It is able to charge any lead-acid battery, including standard and sealed AGM and GEL Cell battery types and is also designed to be easy to use in small spaces, to utilize a 4-step charging program and safely function in a fully automatic mode. Taken together this makes the Battery Tender Junior 12-volt charger an excellent means of ensuring that your battery is fully charged and ready to go when you are. 4-step charging with automatic float mode. View larger. Charge any lead acid battery, including AGM and gel cell. View larger. Safe, 4-step Battery Charging The Battery Tender Junior 12-volt charger is much more than a trickle charger. It has a "brain". Utilizing a 4-step charging program (initialization, bulk charge, absorption mode and float mode), it allows you to simply connect the charger to a battery, either in or out of a vehicle, and forget about it until you are ready to put the battery to work. Like all Battery Tender chargers, at the end of the regular charger cycle it automatically switches its output voltage to a safe, storage or float level that eliminates the need to worry about the damaging effects of overcharging, and the resulting need to check on the condition of the battery. If/when the battery voltage drops too far under load, output power resumes and the charging cycle begins again. The unit also features sparkproof connectors, short circuit and reverse polarity protection, an easy to understand charging status indicator consisting of a single LED, and almost no current draw from batteries connected to it. Key Features: Perfect for all lead-acid, flooded or sealed maintenance free batteries (AGM and gel cell). Complete 4-step charging program (initialization, bulk charge, absorption mode and float mode). Automatically switches to float / maintenance voltage after fully charging the battery. If the battery voltage drops too far under load, full charger output power resumes. Solid state two color LED indicates stage of charger. Spark proof and reverse polarity protected. 12' output cord. 5 year warranty. Charger Models Output Voltage Output Current Charging Software*/ Battery Type AC Voltage/ Frequency Input (Volts) (Amps) Battery Tender Junior 6V Battery Charger 6V 0.750A 3 Step STD & AGM 120 VAC, 60 Hz Battery Tender Junior 12V Battery Charger 12V 0.750A 4 Step STD & AGM 120 VAC, 60 Hz Waterproof 800 12V Battery Charger 12V 0.800A 3 Step STD & AGM 100 to 240 VAC, 50/60 Hz Battery Tender Plus 6V Battery Charger 6V 1.25A 4 Step STD & AGM 120 VAC, 60 Hz Battery Tender Plus 12V Battery Charger 12V 1.25A 4 Step STD & AGM 120 VAC, 60 Hz Battery Tender Plus 12V Battery Charger (Gel Cell) 12V 1.25A 4 Step STD & AGM or GEL 120 VAC, 60 Hz Battery Tender Twin 800 12V Dual Battery Charger 12V 0.800A 3 Step STD & AGM 100 to 240 VAC, 50/60 Hz Battery Tender 12V 2-Bank Battery Management System 12V 1.25A 3 Step STD & AGM 100 to 240 VAC, 50/60 Hz Battery Tender 12V 4-Bank Battery Management System 12V 1.25A 4 Step STD & AGM 100 to 240 VAC, 50/60 Hz Battery Tender 12V 5-Bank Battery Management System 12V 2.0A  4 Step STD & AGM 120 VAC, 60 Hz Battery Tender 12V 10-Bank Battery Management System 12V 2.0A  4 Step STD & AGM 120 VAC, 60 Hz *Note: All Deltran battery chargers will charge all types of lead acid batteries: either flooded (standard STD), sealed maintenance free Absorbed Glass Mat (AGM), or sealed maintenance free gelled electrolyte (GEL) batteries. However, for optimum battery performance in deep cycle applications (for example, running a trolling motor), it is best to chose the Deltran charger that has the charging software specifically designed for the battery type. Fortunately, since the technical staff at Deltran has developed charging software that works equally well for both STD & AGM batteries, the only choice to be made is between 2 models: either STD & AGM or GEL software. Five-year Limited Warranty Deltran provides a limited five-year warranty on its Battery Tender Junior 12V Battery Charger to the original purchaser based on defective material or workmanship. Warranty is void in cases of product misuse, disassembly or modification. Other details regarding warranty limitations and procedures are contained in the Deltran Battery Tender Charger's general limited warranty information sheet enclosed with this product.

Customer Reviews

The Tender Jr. Is Very Similar To The Tender Plus , Not Temperature Compensated, Less Amps!
In the analysis of buying a Tender Jr. vs. a Tender Plus, the main issues are time to full charge, battery size, & parasitic draw. The Tender Plus (1.25) will get the job done twice as fast as the Tender Jr. (0.75). Both now are similar architecturally, save it be the charging power & lack of temperature compensation on the Jr. They both are 4 stage, both have the same sophisticated computer chip technology running the charging process, etc... I spoke to The Deltran(The Manufacturer) customer service department on 3 different occasions, making sure I had the facts right. The first 2 times I was misinformed about the temperature compensation issue. I am editing this review to be accurate as of today's date of 12/01/10. Because The Plus will bring a battery to full charge twice as quickly as The Jr. will, The Plus has a much better chance at overcoming a parasitic draw on your batteries power. Modern cars have sophisticated electronics that require constant power 24/7. Check all your battery connections & your alternator belt!!! If the connections are not clean & tight, clean it with original coca-cola and a rag / brush, make sure they fit snugly. If your alternator belt is too loose it will not charge your battery properly. If you only want to buy one Tender, don't cheap out, buy The Plus if you have the money to do so. If you want to buy 2 or 3 Tenders to make sure all your batteries are fully charged, the Jr. will probably do just fine. I personally alternate The Jr. between 3 different cars, if I had it to do over again, I would buy The Plus instead as I am not a patient person. Both models will turn off in 72 hours automatically if a full charge is not reached, & neither will start charging without at least 3 volts stored in the battery before initiating a charge. If you left your lights on for 4 days like I did, get a jump, & drive your car around for 30 minutes before hooking up any Tender to charge your dead battery. Either of these 2 Battery Tenders are the best in the world, don't bother doing anymore research, I have done it all for you. Buy one or buy both!!! I bought The Plus model a few months ago also... These babies save you $$$, time & frustration!!! Get the 25 foot extension if you want to charge a car that sits in the driveway, it's only $12. You might also want to buy the Cigarette Lighter Apapter to charge cars that have the battery in the trunk, like the BMW E39 models. [...]

Not temperature compensated. (Watch out for old 3-step unit.)
January 2011 update: I've had one hooked up to my 2003 Chevy S-10 since July 2008 and another to my 2004 Kawasaki Z1000 since February 2008. The S-10 has an Optima battery installed August 2006 and the Kawasaki a Deka installed August 2008. Both of these batteries are premium quality and represent the finest in their class available to the average consumer. Nonetheless, I am certain the BT Jr. is the primary reason the Optima retains 81% of cranking health and the Deka 71%. (Search my other reviews for the Argus BB-SBM12 and BB-SBM12-PS Battery Bug monitors as to the source of those percentages.)

As for the 3-step model... It's doubtful you'll ever run into one of these now. Unless it's dust and grime encrusted, hanging on a hook in that truck stop 2 miles off I40 in Two Guns, AZ.

Temperature compensation doesn't seem to have been as critical as I might have expected.

ORIGINAL REVIEW July 2008:
There are two things you need to consider when purchasing this item.

First, unlike its big brother, the Plus, the Junior is not temperature compensated. To find out more about that, go to batterytender.com, click on the FAQs link on the left and read item #18: "What is Temperature Compensation and how important is it?"

I was concerned about this, as living in the desert as I do, the temperature in my garage is 90 to 130 degrees most of the year and can drop to the 50s in the winter. I inquired about this to Battery Tender support and received this answer: "The Junior is not a temperature compensating unit, however, when the temperature is hotter, the unit will actually charge the battery a bit faster and it will not harm the battery." I don't know what to make of this, especially since compensation is so important according to their FAQ.

The other is to make sure you get the 4-step Junior which replaced the 3-step over a year and a half ago. On the back side of the packaging on the left side look for the reference to "Complete 4-step."

That being said, I've been using a Junior for almost 6 months on my motorcycle so I can't post up my experience as well as others here. I'm hoping it will provide my batteries with more service than the 14-16 months I'm used to.

By popular acclaim and editorial content, the Junior and the Plus have garnered untarnished reputations and withstood the test of time. For maintaining your battery, there really isn't anything else out there.

excellent gadget & easy to use
The battery Tender Jr. comes with 1 set of permanent mount ring terminals & 1 set of mini jumper cable clamps so you can hardwire 1 car & use the clamps whereever they are needed.The 1-way quick disconnect on the cord makes things very easy to hook up & unhook. And it is maintaining my battery fine, no more dead car.