Peer Review Schematic for Alternator Charging of Lithium Battery
Please peer review the following schematic with constructive comments. See photos: After six months of pondering, below is my proposed solution for charging a big 400AH lithium engine battery using the alternator:
1. Dedicated alternator battery; a small lead AGM battery, 35AH. Weight 23 pounds.
This was chosen since the stock alternator was designed to charge lead batteries and there are no fully-engineered, low-cost lithium compliant regulators. Plus, lead batteries can charge in colder or hotter temperatures than lithium and can take more charging abuse, which alternators are famous for.
2. Diode isolator, similar to the stock isolator. The Schottky diodes reduce voltage loss to about .4 volts.
Here are the pros and cons:
PROS
1. Worry-free charging of lithium engine battery using stock Foretravel alternator.
2. Uses BMS (Battery Management System), the iCharger 4010.
3. Multiple charging sources: alternator, shore or solar power.
4. Battery minder ensures full charge of lead AGM alternator battery.
5. Simple operation. No computers.
6. Low-cost. About $100.
7. Maintenance-free AGM and Lithium batteries.
8. Gained about 250Amp-Hours of usable capacity and house battery back up capacity.
9. Battery minder keeps small lead battery at 100% charge, which limits inrush current after engine is started. The large alternator could easily dump a lot of current into the small 35AH lead battery, causing damage.
CONS
1. Manual intervention before and after charge.
2. Complication of additional circuitry, lead AGM battery and related parts.
So, I would appreciate constructive comments.