Review on ⚡ TecMate OptiMATE 1 DUO TM-409: Advanced 12V Battery Charger and Maintainer - Fast, Safe, and Efficient Charging at 0.6A by Chucky Hepler

Another winner in my stable version of Optimate. At the moment I have three different models that serve different purposes. I wanted one of these to keep my Optima Blue-Top in tip-top shape. While the AGM has very low self-discharge, mine is stored in a garage where temperatures typically top 100F in the summer. I'm tired of taking care of it every month for a fee and the Optimate 421 is perfect for the job. I have other service chargers but none of them do it right. What I really like is the 50% duty cycle while maintenance is 30 minutes maintenance and 30 minutes idle time along with other testing features. This helps ensure proper battery management instead of just draining an endless stream (even if it's low) like other chargers do. This is essential in my hot garage and gives the batteries a breather every 30 minutes. Common sense. While I could use it to charge the Optima Blue Top, I actually use another that's better suited to the job - the Optimate 6 - for most top-ups. The Optimate 2 is then used primarily for maintenance, freeing up the 6th for other loading duties. For lithium, I prefer the Optimate 5A dedicated lithium charger. Now that they have a newer, lower amperage lithium model, the "TM-471” model, I would use that instead of the extra features that are only available for lifepo4 .