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Discussion Starter · #1 · (Edited)
i have been looking at several versions of these for comparison and evaluation. This is the best one so far.

For Lead Acid batteries. Reaches 14.4 V peak, then automagically switches to maintenance mode. Designed to prevent overcharging.

See a manual at YUA1AMPCH-MANUAL-English
• Charge & Maintain - Automatic Charge: on power up, the charger will automatically go to charging system, then could be left unattended and never overcharge your batteries.
• Charge & Maintain - Automatic Maintenance: When the battery is charged to "full" state, the charger automatically switches to maintain the battery. It will monitor the battery voltage and continue to peak performance to the battery.
• Short circuit protection: The charger will automatically turn off when an output short circuit occurs to prevent any damage.
• Output overload protection: The charger employs the use of a ‘Solid State Circuit Interrupter’ that opens under severe overload. This condition may occur if attempting to charge any severely discharged or heavily sulfated battery. Once the Interrupter opens, the charger will stop charging for a short period and then resume charging automatically and the yellow. L.E.D. will be OFF, until resume charging. Overloading could be due to an external load, remove the load condition prior to attempting to recharge the battery.
• Reserve Battery / Overload Condition: The charger has reverse battery and short circuit protection. If a reverse battery condition exists (white L.E.D. will turn RED, while output leads are connected backwards), simply unplug charger from AC power and properly remake the connections as described in this manual.
• Internal overheat protection: The charger has internal overheat protection. The charger will turn off power until the temperature is down to a safe level and start charging again. All LEDs will be off.

The Nissan Leaf DC converter only holds the 12V aux battery at 13.1, and the batteries tend to die early due to sulfation of the plates. For a good service life the lead acid battery must be kept 100% charged at all times. Permanent damage can result in as little as 3 days if stored at a low state of charge.

Just out of curiousity i'm hoping there is a way to read the firmware in the STM8 microcontroller. It would be interesting to understand the details of the charging and maintenance schemes for educational purposes only.



1,078 Posts
Re: 12V Automatic Battery Chargers & Maintainers

Every single charger worthy of the name does this.

Ideally setpoints for both Absorb / CC setpoint and Float V are user-custom adjustable.

Note that, if the target batt is not being deep-cycled, just used as Starter, just Floating is fine, might need to replace every 3-4 years rather than 5-6. Cheap lead anyway.

Usually a DCDC charger, or simple converter does the job, sourcing off the main bank, rather than using a separate shore power unit.
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