Noob here. I have a relatively new, OEM truck camper with 180W rooftop solar (plus 120W additional portable solar) and a Victron 15/75 MPPT controller. I added a 200Ah Lossigy LiFePO4 battery (LOVE IT!). I'm looking for a solution to charge the battery when solar is not available or ineffective (winter, snowy conditions, low sun angle, long storage, etc.). The use case is primarily winter camping for extended periods away from civilization. I need a fast-charge solution that allows me to fully recharge the 200Ah battery in 6-8 hours of leaving the truck plugged in somewhere at a coffee shop / gym / Maverick's while I'm working, in between stints deep in the mountains. AND/OR a fast-charge solution that takes full advantage of my truck's dual-alternator, dual-starter-battery setup and draws high current while driving.
The issue is that the camper OEM never intended there to be a Lithium battery as far as a I can tell. It has a "power center" that takes AC shore-power and makes it available both in the camper over AC outlets (Some WFCO unit), and converts it to 12V to charge the battery. The built-in "battery charger" is designed for led acid/agm with suboptimal charge profile and a 15A limit. My (custom added) Victron SmartShunt shows that the battery never gets more than 150-180W charge power from this when plugged into shower power, and most of the time sits at 80W charge power. This is annoyingly slow.
There is also some kind of DC-to-DC system (unclear how this is wired by the OEM) that takes power from the vehicle's trailer plug and charges the battery while the vehicle is running from the vehicle's starter battery / alternator. This also seems limited to the same 15A or less and most of the time is drawing / charging the battery at 80-100W or less. Admittedly this may be a limitation of the trailer plug itself since I doubt the 20ft of OEM wiring to the back of the truck are high enough AWG for higher current. Anyway, I can fix this limitation myself.
My question is ... what's the ideal non-solar battery charging setup?
PS: I'm aware that I could upgrade the WFCO unit to a Lithium compatible unit. This would solve the shore-power / AC problem, but would not solve the DC-to-DC problem. I may still upgrade the WFCO unit, but would love to learn more about ideal overall system topology for a future camper build.
The issue is that the camper OEM never intended there to be a Lithium battery as far as a I can tell. It has a "power center" that takes AC shore-power and makes it available both in the camper over AC outlets (Some WFCO unit), and converts it to 12V to charge the battery. The built-in "battery charger" is designed for led acid/agm with suboptimal charge profile and a 15A limit. My (custom added) Victron SmartShunt shows that the battery never gets more than 150-180W charge power from this when plugged into shower power, and most of the time sits at 80W charge power. This is annoyingly slow.
There is also some kind of DC-to-DC system (unclear how this is wired by the OEM) that takes power from the vehicle's trailer plug and charges the battery while the vehicle is running from the vehicle's starter battery / alternator. This also seems limited to the same 15A or less and most of the time is drawing / charging the battery at 80-100W or less. Admittedly this may be a limitation of the trailer plug itself since I doubt the 20ft of OEM wiring to the back of the truck are high enough AWG for higher current. Anyway, I can fix this limitation myself.
My question is ... what's the ideal non-solar battery charging setup?
- AC to DC: something like this (https://www.amazon.com/gp/product/B08B4Z6GMM) charger? Run an extension cord from outside, wire direct to battery, be happy. Looks like my Lossigy battery would be happy at 40A charge current which meets my use case well.
- DC to DC: something like this (https://www.amazon.com/Renogy-Battery-Batteries-Multi-stage-Charging/dp/B07Q4SVX3M) wired from the truck's second starter battery (or direct from the second alternator?) directly to my Lossigy battery.
- AC to DC to DC: to avoid option one, but also have AC-to-DC capability, do option 2 (Renogy DC to DC), then also get a generic high-amperage AC-to-DC converter plugged (and isolated/switched) into the Renogy?
PS: I'm aware that I could upgrade the WFCO unit to a Lithium compatible unit. This would solve the shore-power / AC problem, but would not solve the DC-to-DC problem. I may still upgrade the WFCO unit, but would love to learn more about ideal overall system topology for a future camper build.
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