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opinion:frater_secessus:cheap_build

a longer-form answer to this thread

frugal camper builds

Building a functional camper on a big budget is easy - pay someone to do it. Doing it on a budget requires research, patience, and work.

> Tips and tricks to being a cheap o?

tl;dr

If you read nothing else:

  • avoid flexible solar panels, AGM batteries, and solar generators. They are all niche products with niche (ie, doubled) prices, and very few vandwellers need them.

expectations

It is cheap to think of the camper as a camping tent on wheels. It is expensive to think of it as a mobile apartment.

Pre-van experiment: read the product label to see wattage draw before operating or plugging in any appliance in your home. The object is to learn how much power things really consume.

power

Reducing your power use will have far-reaching effects, simplifying the system and reducing costs for batteries, panels, and charging equipment.

Timing your power use can also make a tremendous difference. Example: Charging the laptop while driving (or after the house batteries are charged) is a “freebie”. Running a laptop at night directly affects the system because there is no charge coming in then to help support the load.

loads

  • avoid heating/cooling with electricity you make offgrid. Use propane or similar for heating and cooking.
  • avoid using power-hungry PCs or laptops. Use a tablet, chromebook, phone, or other low-power device.\
  • run discretionary loads when you have excess power

solar

  • Buy larger/higher-voltage panels which are cheaper by the watt.1)
  • if you are using PWM controllers, choose poly panels vs mono – they are typically less expensive and actually perform better with PWM due to their higher Imp rating. When choosing between poly panels at the same price point, pick the one with the higher Imp (and thus lower Vmp)
  • if you are going to be deep-cycling the batteries every day2) consider using a dirt-cheap shunt controller rather than PWM.
  • overpanel your MPPT controller; +10% is optimal, and 20% is reasonable in challenging insolation.

charging

alternator charging

  • do add an isolator to your solar charging system; it is cheap “horsepower”
  • don't assume alternator charging alone will keep your deep cycle batteries happy. Augment with solar or with charging at home.
  • don't pay extra for voltage-sensing or DC-DC isolators if you already have solar. Exception: DC-DC chargers with the solar controller built in.

batteries

  • generally speaking, use the smallest battery bank appropriate for your use and apply maximal charging to it.
  • avoid convenience items like “solar generators
  • use 6v deep cycles in series rather than 12v singly or in parallel
  • use flooded rather than AGM. If you need massive current, use lithium rather than AGM. LFP lithium and 6v deep cycle have very similar costs in the long term. AGM costs 2-4x as much per lifetime kAh.

sourcing

Buy used from craigslist, thrift stores, etc. when possible. Know the internal dimensions of your van and carry a tape measure with you. Buy used/open-package from Amazon.

Use pricewatch tools like camelcamelcamel to get alerts when prices drop on items you need.

1)
this will require MPPT controllers for nominal 12v banks
2)
like to 50% DoD
opinion/frater_secessus/cheap_build.txt · Last modified: 2020/10/11 19:48 (external edit)