Battery Chargers Feature Set Power Ease of Use Value 4.5 Final Thoughts The Optima Digital 400 battery charger is full of features, less than $100, and it’s small enough to fit in one hand. Great for a compact shop charger, or for someone on-the-go. Sending User Review 0 (0 votes) Optima developed the first maintenance-free lead-acid … Continue reading Optima Battery Charger Maintainer Digital 400 Review