Battery Tender 4 AMP Battery Charger and Maintainer - Automotive Switchable 12V or 6V Smart Automatic for Cars SUVs and Trucks - Lead Acid, AGM, Gel, & Lithium Battery Charger - 022-0209-BT-WH

Works great. Keep on my car in storage all winter without worry.

We already own several Battery Tender products and when we needed one for our new Lithium Ion batteries, we knew we couldn't go wrong purchasing another Battery Tender charger. They build quality products that are easy to use to keep your batteries charged during the winter months.

Love my battery tender. I dont ever have to worry about my battery not being charged. The design is amazing and size feels like great quality. Its a great value for the money since it keeps my battery charged all the time. Plug and forget. Very durable product.

I have two of these 4 amp chargers on a couple cars stored in my barn, and a few smaller ones on my 3 motorcycles, on my ATV, and one on my 12,000 watt gas generator. Batteries are always charged and it gets to -40F here in the winters. All are permanently connected, no glitches or any problems at all, everything starts right up!!!

An outdoor version of the excellent Battery Tender smart charger design.

This Battery Tender has been working great thus far. I primarily use it to keep my RV Batteries charged when stored throughout the winter months. I will occasionally use it for my lawnmower battery. I docked it 1 star simply because it wouldn't charge a Lithium Motorcycle battery. I connected it and after powering on the Tender, it automatically selected AGM. I tried to manually switch it to Lithium, but it wouldn't switch. After doing some Google research, I found that many people have issues getting the Tender to charge Lithium, even though it clearly says that it can charge it. It may have charged it on the AGM setting, however I didn't want to risk it on such an expensive battery. This Tender works great for most applications, but if you're looking to charge Lithium, I would go with a Lithium specific charger for it.

The Deltran “Battery Tender” is a lifesaver. The service advisor at our local dealership told us that he uses this exact charger for his old BMW that he never drives. We are in a similar situation, and I wanted something that I knew is safe for the complex batteries they put in newer cars. Since one of our cars sits in the garage for 90% of its life, maintaining a full battery seemed impossible. The Deltran solved the issue. I think the biggest thing I like about the “Battery Tender” is it is a smart charger. Once the battery charges to full, it turns into a trickle charge to maintain the battery power level. Having a smart system keeps the charger from overcharging your battery. The new car batteries are not inexpensive, so protecting and maintaining them is a must. I love the fact that it is easy to connect and use, and as long as you know the positive and negative terminals for your battery (and don’t mix them up), this charger is pretty idiot-proof. Highly recommended! Pros: Easy to use, recommended to me by a car expert, and priced well for what you get. The “smart” charging function is fantastic. Cons: None!

Seems to work well. It's a handy gadget for rarely used vehicles, vacations, etc.

Used this to charge my Lithium battery. Works well.

Excellent charger....put in sae port for easy plug in...very nice quality. Works great!