How To Size Your Inverter, Battery Bank, And Solar Panel System For Your Trailer

Published 10/02/2024

Question:

First of all I will have help doing this project since I'm not close to being a electrician. I have a enclosed 16ft cargo hauler used to take my golf cart and misc. items back and forth from Ohio to FLA. In the process of turning the back into bonus space once I get to FLA (man cave) I purchased the trailer with a electrical package that includes (1) AGM battery that is being charged when connected to tow vehicle. This is only for low voltage LED lights but not the standard outlet throughout the trailer. There is 50amp service with a breaker box and 4 breaker inside the box. Coming from the breaker box is a 20ft RV cord with 50amp on the end. Now that you have a idea of what I have this is what I'm looking to do. Keep a small frig and small freezer plugged in while driving plus extra power in case I add small mini split type A/C I figure about 500 watts (is that close) but there could be more for start up? I'm okay going overkill but not crazy just smart. Would like to have the invertor being charge from tow vehicle if possible? Solar option would be consider in case a RV resort tells me only 1 vehicle plug into shore power I would have back up plan. Would go with AGM or Lithium battery, what is your suggestion. Note will be park in FLA for 4-5 month in heat. How many and type of battery do you suggest. Hope this makes sense to you , it starting to make more sense to be typing it. Patrick

asked by: Patrick

Expert Reply:

Hey Patrick,

In order to power both the fridge and freezer while on the go you'll need an inverter that has a high enough capacity to handle their demand, especially if you'll be in a hot area where they'll run more. You'll also need a battery bank that's big enough to handle the demand for the time you'll be with out a power source or add a solar system to help extend the time you can go without.

You'll need to look up the wattage draw for the fridge and freezer to size the inverter and the amperage draw per hour to size the battery bank. Lithium batteries are going to be the better choice if you're wanting a large amp hour rating in a more compact and efficient package. Lithium can be drained down without being damaged like an AGM would be, which would protect the battery if you're not getting shore power or solar power to recharge the battery for an extended period.

For the solar the demand will need to be calculated first and we'll need to know how large of a battery bank you're going to go with to decide how many panels will be needed to keep your battery bank charged. We have a solar calculator that I've attached a link to below that you can enter in your demand for each item and it will give you a recommendation on what size system would work. I can help you as well if you can give me some figures on the demand.

expert reply by: Kevin C