I too embarked on a hybrid Lithium installation. My goals were a bit different than some others, as I wanted to have the AGM system and the Lithium system primarily isolated from each other: “two is one and one is none.” In this way, the vehicle can be used in Winter Mode using the AGM bank, and in Summer Mode with the Lithium Bank. A Blue Sea Marine A-B switch (make before break) installed in the passenger seat pedestal allows switching between modes. Because the Lithiums are installed inside the vehicle, when it is warm enough for me to be comfortable inside the vehicle it is warm enough to utilize the Lithium bank.
AGM System: The AGM install consists of two new Lifeline GPL-31XT 125Ah batteries (total 250Ah) installed under the body in the stock Winnebago boxes. Blue Sea terminal fuses were added at each location. These charge from the stock 45A converter/charger when on shore power or from the Onan generator.
Lithium System: The Lithium install consists of two new Victron LiFePo V4 200Ah batteries (total 400Ah), installed under the starboard bunk. It is a tight squeeze, requiring removal of one drawer and adding a ventilation grille (for air flow and to camouflage the hole where the drawer was). A battery tray was welded up from angle stock, and through-bolted to the floor for crash-worthiness. A new Victron MultiPlus 12/3000W PSW inverter/charger keeps these charged when on shore power, and feeds inverted AC to the [almost] entire stock AC load center when on battery power (to retain the automated load shedding capabilities Winnebago built in). (The AC input to the stock 45A converter/charger that charges the AGM bank was removed from this load center, and instead is fed through the AC-2 output of the Victron inverter (which only passes AC and is never inverted), to avoid a death-loop. Thus, the AGMs only charge from shore power or the Onan generator, never from the inverter or the Lithium batteries.)
A Nations 280XP 280A alternator was added under the hood, and wired to the Lithium bank via 4/0 cabling. A dash switch allows you to turn the alternator off or place it in low-power mode, and dash indicators monitor its state.
The entire mess was terminated using two Victron Lynx Distribution panels with requisite fusing. Because I apparently suffer from an obsessive/compulsive disorder, each input and output is separately fused and runs through a manual Blue Sea Marine disconnect switch, as well as through automated relays getting instruction from an AM Solar BMS, to control appropriate charges and loads based upon Lithium battery temperature and other operating conditions. [Shout out to AM Solar, who patiently endured countless idiotic questions from me and supplied much of the hardware at competitive pricing.] There is a fairly complex Lithium qualification loop I created, which is probably clearer from the schematics than text will allow here.
AC Management: The stock ATS toggles between shore power and the stock Onan generator, and then feeds a new Progressive Industries hardwired EMS (with remote display) to monitor and qualify incoming AC power, before it is routed to the AC systems. These each run through Blue Sea circuit breakers too. When the Onan generator is running, its trigger output is fed to the Victron inverter signal inputs to automatically limit maximum current usage accordingly.
Solar: The stock Zamp single channel solar controller was replaced with a dual channel model, which isolates its two outputs and feeds each bank separately while never allowing cross-talk. I recognize that the Zamp is only a PWM controller, and is somewhat less efficient than a comparable MPPT controller. However, given the massive charging sources we have from the Victron inverter/charger and the Nations alternator, solar is merely an afterthought – primarily coming into use when the vehicle is parked somewhere off-grid while we are hiking. We generally do not boondock for extended periods, instead moving around frequently, allowing the underhood generator to quickly provide most charging we need. This is especially true given that Winnebago installed only 200W of solar panels, and littered the roof with things in an aggressively-haphazard topography that leaves very little room for more panels. Finally, the new Zamp controller was able to fit in the old panel cutout perfectly, making it the clear choice!
Monitoring: A Digital MultiControl GX panel and pair of Victron BMV-712 battery monitors (with separate shunts on each of the AGM and Lithium banks) allow me to keep an eye on everything.
Miscellaneous: I deemed the stock Start-Assist (a/k/a Boost) switch inadequate for our split system, so a new circuit and switch, using a second relay, was crafted. Flyback diodes were utilized on all relays. A Trik-L-Start was added, with a cutout switch and separate fusing.
If my wife asks, the system was quite economical.
For completeness, vehicle is a 2017 Winnebago ERA 70A (2016 Sprinter EXT chassis) fairly stock, which we purchased used in November 2018 with approximately 4K miles.
Thank you.
AGM System: The AGM install consists of two new Lifeline GPL-31XT 125Ah batteries (total 250Ah) installed under the body in the stock Winnebago boxes. Blue Sea terminal fuses were added at each location. These charge from the stock 45A converter/charger when on shore power or from the Onan generator.
Lithium System: The Lithium install consists of two new Victron LiFePo V4 200Ah batteries (total 400Ah), installed under the starboard bunk. It is a tight squeeze, requiring removal of one drawer and adding a ventilation grille (for air flow and to camouflage the hole where the drawer was). A battery tray was welded up from angle stock, and through-bolted to the floor for crash-worthiness. A new Victron MultiPlus 12/3000W PSW inverter/charger keeps these charged when on shore power, and feeds inverted AC to the [almost] entire stock AC load center when on battery power (to retain the automated load shedding capabilities Winnebago built in). (The AC input to the stock 45A converter/charger that charges the AGM bank was removed from this load center, and instead is fed through the AC-2 output of the Victron inverter (which only passes AC and is never inverted), to avoid a death-loop. Thus, the AGMs only charge from shore power or the Onan generator, never from the inverter or the Lithium batteries.)
A Nations 280XP 280A alternator was added under the hood, and wired to the Lithium bank via 4/0 cabling. A dash switch allows you to turn the alternator off or place it in low-power mode, and dash indicators monitor its state.
The entire mess was terminated using two Victron Lynx Distribution panels with requisite fusing. Because I apparently suffer from an obsessive/compulsive disorder, each input and output is separately fused and runs through a manual Blue Sea Marine disconnect switch, as well as through automated relays getting instruction from an AM Solar BMS, to control appropriate charges and loads based upon Lithium battery temperature and other operating conditions. [Shout out to AM Solar, who patiently endured countless idiotic questions from me and supplied much of the hardware at competitive pricing.] There is a fairly complex Lithium qualification loop I created, which is probably clearer from the schematics than text will allow here.
AC Management: The stock ATS toggles between shore power and the stock Onan generator, and then feeds a new Progressive Industries hardwired EMS (with remote display) to monitor and qualify incoming AC power, before it is routed to the AC systems. These each run through Blue Sea circuit breakers too. When the Onan generator is running, its trigger output is fed to the Victron inverter signal inputs to automatically limit maximum current usage accordingly.
Solar: The stock Zamp single channel solar controller was replaced with a dual channel model, which isolates its two outputs and feeds each bank separately while never allowing cross-talk. I recognize that the Zamp is only a PWM controller, and is somewhat less efficient than a comparable MPPT controller. However, given the massive charging sources we have from the Victron inverter/charger and the Nations alternator, solar is merely an afterthought – primarily coming into use when the vehicle is parked somewhere off-grid while we are hiking. We generally do not boondock for extended periods, instead moving around frequently, allowing the underhood generator to quickly provide most charging we need. This is especially true given that Winnebago installed only 200W of solar panels, and littered the roof with things in an aggressively-haphazard topography that leaves very little room for more panels. Finally, the new Zamp controller was able to fit in the old panel cutout perfectly, making it the clear choice!
Monitoring: A Digital MultiControl GX panel and pair of Victron BMV-712 battery monitors (with separate shunts on each of the AGM and Lithium banks) allow me to keep an eye on everything.
Miscellaneous: I deemed the stock Start-Assist (a/k/a Boost) switch inadequate for our split system, so a new circuit and switch, using a second relay, was crafted. Flyback diodes were utilized on all relays. A Trik-L-Start was added, with a cutout switch and separate fusing.
If my wife asks, the system was quite economical.
For completeness, vehicle is a 2017 Winnebago ERA 70A (2016 Sprinter EXT chassis) fairly stock, which we purchased used in November 2018 with approximately 4K miles.
Thank you.
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