I’m dreaming about the possibility of doing a full-size (28+ foot) cargo trailer to travel trailer conversion in a few years. A few reasons would be to build quality from scratch, better insulation, reduce likelihood of problems (solid water connections that are accessible, etc), no delamination to worry about, and to build split ductless ac, solar and LiFEPO4 batteries into the trailer without having to scrap some of what I paid for w/ rv purchase.
The purpose of this post is not to debate the wisdom of doing that, but to ask: What pros or cons am I missing of building a 120V-only system?
For my notional build, I would go with a 48V nominal LiFEPO4 battery pack to reduce inverter amp draw for major appliances (AC, Fridge, water heater), so adding 12V would require a 48V to 12V converter, adding another piece of hardware. Items that would typically use 12V (lighting, water pump) are readily available in 120V (can pick up lighting at any big box building supply store), so I’m struggling to come up with a solid reason why I would need 12V in the trailer (other than separate 12V tongue battery outside the trailer to power trailer brakes, brake and running lights, and jack). My build would not have powered levelers or slides.
Pros of 120V only:
- Less complexity in electrical system (no 48V to 12V converter or 12V distro panel)
- Lower gauge AC wiring possible vs 12V DC
- 120V components (particularly lighting fixtures, bulbs, outlets) readily available at big box stores
- USB charging outlets can be integrated into AC outlets (install AC outlets that include USB charging ports) vice separate i.e. not using 12V for USB
- Does not add significant sizing issue for inverter, as added 120V appliances (lighting, water pump) are not large draws
Cons of 120V only:
- Will need to up-size AC distro panel for a few more circuits
- Requires inverter to always be on, even for lighting (mitigated by fact 48V to 12V converter would have to be on to operate lighting on 12V, and fridge will be 120V and require inverter to be on anyway)
- Single source of failure for all electrical vs lighting and water pump separated on 12V (can mitigate by carrying a backup inverter and installing a few battery-powered lights for emergency use)
- Trades 48V to AC inversion loss in place of 48V to 12V (does not seem to be significant since inverter will be on anyway when trailer is in use)
What pros or cons of 120V-only am I not thinking about? Appreciate your thoughts, and huge thanks to all the contributors on this forum who have helped me envision this build as a real possibility--particularly DIY LiFEPO4 and split-ductless AC. Comfort of AC off-grid may give me a chance of actually selling this to my spouse over a pretty-looking purchased travel trailer with all the warts hidden from sight (and waiting to emerge after you drive it off the lot).
Hi from DiyGuy
The purpose of this post is not to debate the wisdom of doing that, but to ask: What pros or cons am I missing of building a 120V-only system?
For my notional build, I would go with a 48V nominal LiFEPO4 battery pack to reduce inverter amp draw for major appliances (AC, Fridge, water heater), so adding 12V would require a 48V to 12V converter, adding another piece of hardware. Items that would typically use 12V (lighting, water pump) are readily available in 120V (can pick up lighting at any big box building supply store), so I’m struggling to come up with a solid reason why I would need 12V in the trailer (other than separate 12V tongue battery outside the trailer to power trailer brakes, brake and running lights, and jack). My build would not have powered levelers or slides.
Pros of 120V only:
- Less complexity in electrical system (no 48V to 12V converter or 12V distro panel)
- Lower gauge AC wiring possible vs 12V DC
- 120V components (particularly lighting fixtures, bulbs, outlets) readily available at big box stores
- USB charging outlets can be integrated into AC outlets (install AC outlets that include USB charging ports) vice separate i.e. not using 12V for USB
- Does not add significant sizing issue for inverter, as added 120V appliances (lighting, water pump) are not large draws
Cons of 120V only:
- Will need to up-size AC distro panel for a few more circuits
- Requires inverter to always be on, even for lighting (mitigated by fact 48V to 12V converter would have to be on to operate lighting on 12V, and fridge will be 120V and require inverter to be on anyway)
- Single source of failure for all electrical vs lighting and water pump separated on 12V (can mitigate by carrying a backup inverter and installing a few battery-powered lights for emergency use)
- Trades 48V to AC inversion loss in place of 48V to 12V (does not seem to be significant since inverter will be on anyway when trailer is in use)
What pros or cons of 120V-only am I not thinking about? Appreciate your thoughts, and huge thanks to all the contributors on this forum who have helped me envision this build as a real possibility--particularly DIY LiFEPO4 and split-ductless AC. Comfort of AC off-grid may give me a chance of actually selling this to my spouse over a pretty-looking purchased travel trailer with all the warts hidden from sight (and waiting to emerge after you drive it off the lot).
Hi from DiyGuy