Amps are analogous to travel speed and heat increases with speed
30A = 3,600W | 15A = 1,800W
Watts / Volts = Amps
Amps X Volts = Watts
Watts / Amps = Volts
Notes and Tips
- First get a label maker. Mark all wires at both ends, possibly near middle. Label anything that is DC as "DC" and anything AC as "120V" to avoid confusion with AC as Air Conditioner.
- Don't use wire nuts or fork terminals because they come loose in a moving vehicle and don't allow full contact of all strands. Use only closed end terminals.
- 2ga (not 2/0) stranded wire recommended for primary battery and associated high amp component cables.
- 12ga (12/3) wire is recommended for most 120V wiring, depending on amps expected.
- 30amp service wire is 10ga wire that goes from the 30amp service to the EMS and/or breaker box.
- Circuit breakers are only rated to handle 80% of the rated capacity (20A breaker can handle 16A continuous)
- Consider making all 120V and DC wire colors consistent to avoid errors:
- Positive > Red (connects to black 120V appliance wires / inputs)
- Negative > Green
- 120V Neutral > stays White
- Make sure the master cutoff switch / type III breaker is easily accessible (see center batteries of photo).
- As opposed to name brand RVs, I desire to keep the major electronics components as close together as possible for best performance, minimal transmission loss, reliability and safety. I installed the electrical center over and next to the driver's side wheel well because it is "crap" real estate / hard to get to area which makes working on it hard, but not planning to have to work on it due to great install to begin with. Frees up prime real estate for frequently used items. Better center of gravity over drive wheels.
Confusing Problems with RV Electronics and RVs
- AC stands for both alternating current and air conditioner. You have to know which someone is referring to. Be sure to abbreviate air conditioner as A/C rather than AC to allow for some difference. You can also call / label AC power as 120V to eliminate any confusion.
- 120V hot wires are black, DC ground wires are also black. This can cause electrocution, smoke and/or damage if you don't pay attention.
- 2/O (ought) wire is much larger than 2/GA (gauge) wire
- Household breaker boxes connect ground and neutral, but in RV breaker boxes they must be separate.
- 120V amps are much lower than DC amps. Always signify whether the amps are DC or 120V.
- You have to pay most attention to DC amps, but many electronics don't let you know, but rather watts, etc.
- An inverter converts DC battery power to 120V. A converter (converter-charger) converts 120V power to DC and also provides 120V shore power to the 120V breaker box and thus 120V receptacles.
- AGM, Gel and Deep Cycle batteries refer to lead acid batteries, not lithium, even though lithium batteries are deep cycle.
- 6 volt batteries must be connected in series to form 12 volts. Two 100 aH (amp hour) 6 volt batteries in series creates 100 aH 12V (not 200 aH). 12V batteries must be connected parallel. Two 100 aH 12V batteries in parallel creates 200 aH.
- "Shore power" means campground, etc. power and is a term taken from boating.
- RV is a misnomer. They should be called something like VH for vehicular home.
- RV class order is illogical / out of order. A class A is largest, B is smallest, C is intermediate. Many other types of RVs are not issued a class such as slide-ins, trailers, etc.
Components are suggestions and may differ from install photos. Not for a tight budget, but substantially less than buying a pre-made / name brand RV, especially Class B or tiny home.
DIY Universal Power System
for Off Grid & Shore Power
Applicable for vans, tiny homes, RVs, etc.
for Off-Grid, Boondocking, Camping & Bug-Out
Electrical Control Center - Applicable for most vans and Tiny Homes. Between wheel well for better handling and traction; out of way from prime real estate. The 2 Gauge wire goes from the isolator, under the metal frame beside the hand brake, trough a metal shroud to the starter battery which has a 5/16" connector lug (Sprinter).
Recommended Components, Appliances, etc. with Tips
In order of recommended install sequence; no sales tax in Oregon and Montana; if no Costco, etc. near you, try Amazon.
- Fire Extinguisher, Small - can mount anywhere, but I prefer behind passenger seat next to sliding door.
- Vacuum,Cordless Trigger - Costco - keep work areas clean from the start.
- Basic Electrical Components - Harbor Freight - Extension cords, power strip, 16 gauge red & black wiring, wire straps, red and black electrical tape, liquid black rubber, connectors, wire nuts, grommets, etc.
2 gauge red copper wire 10' - eBay or Amazon (black and red) - Make only long enough to be able to keep out of the way and slightly move things.
2 gauge 1/4" copper ring terminals pack of 10 - Amazon.
2 gauge 5/16" copper ring terminal single - Amazon - use from to connect from battery isolator to main battery (on Sprinter).
- A/C LED lights - your preferred hardware stores, etc. - A/C preferred over D/C to take advantage of shore power and they are cheaper with better selection. High priority so you can see what you are doing!
- 150 Amp switchable circuit breaker - Amazon - fire, smoke and component protection. Highly preferred over the types of fuses you have to replace. West Marine sells this, but more expensive.
- Fuse Block (DC) with LEDs, quick connect / disconnect - Amazon - For DC auxiliary loads.
- (Shore) Power Inlet Receptacle, Weatherproof - Amazon
- 120 VAC (Breaker) Load Center - Home Depot - buy 20 Amp breaker Air Conditioner and heater; 20 Amp other loads.
- Air Conditioner, 6,000 BTU -
- Diesel Heater, 2,000 Kw - eBay / Amazon - [I installed the 4Kw version which seems to work too good / gets interior hot rapidly] Reason over electric: Don't have to run generator or depend on campground shore power. Reason over propane: Safer / no fumes, does not create moisture, but rather dries the air. Can tap into existing diesel fuel tank (if you have a diesel engine) for convenience. If not, can install a diesel fuel tank for this. Most units are sold with a fuel tank (not used in this case). Requires drilling hole in floor. Connect directly to battery bank. Install wired remote for easy access from both bed and living room (somewhere in middle). Since I had excess wire, I cut and used to extend the remote since the remote wire is too short.
- DC fan, Metal Blade - Camping World - even though you'll have a roof vent, this is still nice to have to blow directly where you need it. May help prevent need for running air conditioner. Cut off the end plug and wire into fuse block.
- Roof Fan - Camping World - by MaxxFan. Rainproof even when open.
Butyl tape - Camping World. Necessary to install ventilation roof fan.
- Aluminum Box - eBay
- Weather Station - Costco - with outdoor temp & humidity. Use A/C power cord in addition to batteries.
Fuel Powered Generator? Special Situations
- Noise and air pollution; loss of stealth
- Inconvenience of getting in and out of vehicle to turn on and off
- Theft risk
- Eliminate dependency with energy efficiency, insulation, large battery bank, maximum solar panels - park in sun
30A Service In - amazon
Allows up to 300A / 3600W DC power from shore power. Requires twist on type 30A extension cord. Requires drilling hole in vehicle body. Avoid plastic because it cracks, fades and the threads strip.
Recommended DC Electrical Accessories Powered by Main Starting Battery
- Backup camera (if not factory installed)
- Dash cam
- Aux horn with alarm remote (mount remote by bed). Allows scaring away would be criminals before having to confront them. Also makes horn louder when tied into factory horn.