Solar. What Can It Do?

Not sure why I'm having trouble posting to this thread...

Howdy cm11599ps, solar can do ANYTHING and EVERYTHING!!! :W

These types of questions are very difficult to answer as no information has been provided. Some thoughts for you to consider.

If you do not have a quality battery monitor (like Trimetric) you do not actually know the state of charge of your battery bank (unless checking specific gravity). Installing one of these is an excellent first step as it allows you to see/measure your actual power usage. Battery boltage is a very poor indicator of state of charge.

Many CPAP/BiPAP machines are 12 volt - but not all of them. If you haven't already, you might check yours. I have a BiPAP that is directly wired to the house 12 volt system (I do not use the humidifier). This may reduce your power usage to some degree (you would need to measure it to know exactly).

A 100 watt panel will produce approximately 7 amps of power at a battery charging voltage of 13.5 volts - under ideal conditions. Conditions are never ideal so assume 80% of that, at best - 5.5 to 6 amps. This is not a lot but it is more than nothing. Over the course of a day, it slowly adds up - possibly 30 Ah per day (5 amps x 6 hours).

Above all (in my opinion), adequate solar eliminates the noise, smell, and maintenance of your generator. I know... people argue that their little Honda is quiet. I've camped near people running them and I can assure you that they are NOT as quiet as my solar. I love listening to the breeze flow thru the trees, the birds, the stream, etc. - solar allows one to hear those things. Of course, with this point, people always start debating the cost of solar. Mine was inexpensive (details here) and paid for itself very quickly (details here).

Just a data point:
I have 2 100?W panels and 2 batteries; I have not used my genny ever since
I bought the solar panels. In winter, I'm usually hooked to shore power in
case it gets too cold.

100w might cover part of your day time use after the the Honda recharged the batteries
meaning you would start the night, with the batteries in slightly better state of charge, it will keep the batteries charged when the TT is in storage

it will NOT recharge the batteries to full during the day, after your overnight use

So, you run the gen all day, starting around 7:30? At what time do the batteries show full charge? With a dual battery setup, and using 2/3 in 9 hours overnight starting at 1030, you're likely looking a a pretty big system to go full solar. More reasonable might be to run the gen until the batteries are close to charged, let a small solar system finish the charge until the light goes away, batteries until say 9, then go back to generator to top up before overnight.

100 watts will reduce the generator time and extend the life of the battery. Make your coffee with the honda and let it run a bit to get 85%+ charged. Then the solar would finish the long absorption charge the rest of the day and provide power for the inverter as needed. This should allow you to head into the evening with a higher charge on the battery. In time you may find you need less generator time.

When not camping the solar will do an excellent job of keeping the battery in tip top shape. I think the minimal daily cycling actually helps for storage vs a continuous float.

Go LED lights if you have not already.

I found that One of these fits my needs,as I do about what you do with the same type camping and usage and it will bring my batteries back to a usable level until the next day.

5 days of dry camping and only used the generator to make coffee and some microwave use.

mike-s wrote:
How big is your battery bank, and how low does it drain overnight? Without knowing that, you can't know how much solar you would need to replace the charge.

Genny hours end at 8 or 9pm and the batteries are full. We use the led fixtures VERY sparingly then. At about 1030pm or so we'll get ready for bed and this is when I'll turn the invertor on, turn the convertor off and fire up the cpap and charge phone/tablets. By about 730am the batteries usually read 1/3.

Take a look at Jack Mayer and Handy Bob's web sites. People on here are going to get tired of me saying this but these guys have LIVED with solar for several years and know what they are talking about. A lot of what they say makes sense.

100W is not going to do much, especially in the East. You will be lucky to get 3 amps mid day without tilting the panel.

How big is your battery bank, and how low does it drain overnight? Without knowing that, you can't know how much solar you would need to replace the charge.