Newbie

[Fuji]

Hey all. I’m new here and new to solar. I’m starting out with a simple 100 watt system for my cargo trailer conversion. I have a few questions.
first, can I use regular led acid car batteries or do I have to buy a sealed solar specific battery?
second, where do I find the blade type fuses that go at the battery connection and what size would they need to be?

 

[boondox]

You can use a regular flooded lead acid battery. However, especially if located inside the trailer it can make a mess. Most people opt to use a sealed or AGM battery. Many these days are going with lithium batteries but they are more expensive.

As to what size fuse, you have the cart way ahead of the horse. First step is to determine what you need to run and for how long. This is called an energy audit. Then you can size the rest of the system, which in turn will tell you what size fuse you need.

 

[Fuji]

You can use a regular flooded lead acid battery. However, especially if located inside the trailer it can make a mess. Most people opt to use a sealed or AGM battery. Many these days are going with lithium batteries but they are more expensive.

As to what size fuse, you have the cart way ahead of the horse. First step is to determine what you need to run and for how long. This is called an energy audit. Then you can size the rest of the system, which in turn will tell you what size fuse you need.

 

[Fuji]

Thanks for the reply. I have 2 folded LA Batteries mounted on the front (outside) Of the trailer so that shouldn’t be a problem. How do I go about doing said audit?

 

[boondox]

Thanks for the reply. I have 2 folded LA Batteries mounted on the front (outside) Of the trailer so that shouldn’t be a problem. How do I go about doing said audit?

Figure out the things you want to power and what they use. Here is an example:

You need to run a light that uses 10 watts for 10 hours a day. That adds up to 100 watt hours of power you need to provide. With your FLA batteries you don't want to discharge them more than 50%. So you need a battery that has at least 200 watt hours of storage. You need a panel that will provide at least 130-140 watt hours a day as charging isn't 100% efficient.

Do a search for amp hours, watt hours and sizing a solar system, lots of information out there. Make a list of what you want to power, how much power it uses and how long you want to run it.

 

[Fuji]

Ok, very interesting. I will look into what I need and try to calculate it. Thank you very much

 

[boondox]

You are very welcome. You will likely be surprised how much power we all use without being aware of it. Do some reading and roll on back here with questions.

 

[SolarQueen]

If you are installing a 100W solar panel, you need at least an 8A charge controller (Isc of the panel x 1.25). PWM is fine for that small of a system, and less expensive than MPPT. With just one panel, you don't have to have a fuse between the panel and the controller, but if you want a way to disconnect the panel when needed, a 10A breaker would do the trick. You do need a fuse or breaker on the output of the charge controller. The size of it depends on the size of the controller. For example, if you get a 10A charge controller, you need at least a 13A breaker (10A x 1.25 = 12.5A).

 

[Fuji]

I purchased a 100 watt panel kit on Amazon. Comes with panel, controller, cabling and mounts

 

[svetz]

If you plan on cycling the batteries a lot (e.g., daily) you might get more bang for the buck with LiFePO4. See How do I compare the value of two different battery chemistries?

 

[Fuji]

I really only plan on using the solar to power up a few things a few times a year. Most of the time I’d be on shore power.