Solar, is it worthwhile?

[Kevin D Pem]

How much does your battery tend to drain overnight? Do you have a fridge that runs on 12V?

I’m trying to figure out if ours are running normally.

Is your fridge a compressor fridge?

 

[Buc]

Is your fridge a compressor fridge?

Yes. I seem to have maybe solved the issue we were having simply by adding some distilled water to the batteries (2 Interstate SRM-24 batteries). I unplugged the trailer before I topped the water up, and it’s sitting in front of t house in the sun. The battery level dropped to 2/3rds this morning (with the fridge running), and is back to 100% now (reading 13.4V).

 

[Diesel Pusher]

Batteries are usually at about 78 - 82% SOC in the morning. We use lights, the TV, Sat radio, water pump, Keurig (2 morning cups); pretty much anything we'd use if plugged in. I replaced the Norcold 1210 cooling unit with a JC Refrigeration Home - JC Refrigeration 12v compressor fridge and also have a 12v Dometic CFX50 in the basement we use as a freezer.

 

[Kevin D Pem]

How much does your battery tend to drain overnight? Do you have a fridge that runs on 12V?

I’m trying to figure out if ours are running normally.

Yes your system is running normally!!! Of course your normal may not be everyone's normal.

What is the amp hour rating of your bank? My guess is your fridge draws a minimum 45 watts, likely more. That's 4 amps drained from your bank at night per hour! So once again, how big is the bank? How long is the night? How many times do you open the fridge for a cold one? How many people stand in front of the fridge with door open trying to choose what to snack on!

Being over generous 650 amp hours might be available with1800 watts of panels in the winter months, and only if the panels are not flat on the roof. This may work out if your day light usage offers charge capacity!!!

Once again normal is a very personal thing!

As an example:

Today I woke up before daylight. I put the tea kettle on my induction cook top at 1000 watts I turned on my espresso maker at 800 watts both units did their jobs in roughly 8 minutes each. The breakfast I cooked on the butane stove top. Later in the day while under full sun, I turned on the induction cook top to boil/ rinse my rice before cooking. Roughly 10 minutes at 1000 watts. Then cooked the rice in my rice cooker, 450 watts roughly 15 minutes. Then add ingredients for my casserole for enough time to warm it all up, another 6 minutes.

My fridge and freezer pumping away when needed during this time!!!

I didn't expect to have my 400ah (12volt equivalent) battery bank to be topped off today,but my voltage is sitting at 25.4 volts 4 hours after the sun set(24 volt system)!!! I run 3000 watts of solar. Today could not be considered my normal, however, the bank seems to be telling me it is doable. My battery bank is carbon lead thin plate battery technology. Before the sun rises I will know better if my batteries took a hit after today's splurge!

 

[Kevin D Pem]

Update!
This morning the batteries sit at 25.1 while still dark out! That means the surface tension is gone, and for those using 12volt systems 12.55 volts. Yes my inverter runs 24/7 !!! Made my coffee this am, same process as yesterday, with the electric tea kettle instead of induction cook top 1200 watts. Still in the dark!!!

The sun peeks over the horizon, panels producing under 5 amps and freezer kicking in, batteries holding at 24.8 volts. That means under load the 12volt equivalent is 12.4 volts. For reference the freezer draws 2 amps or 240 watts! With the math 10 amps at 24volts. More draw than the panels are producing.

Although lithium has a slight advantage in internal resistance. These lead carbon batteries are much better than other AGM products, with a much higher cycle life than lithium.
The question then is, is 1000us a good price to pay for 400ah of lead carbon 7000 cycle life batteries??? Guess you know my opinion!!!

 

[TheLooks]

This discussion is between people talking about PV energy and generators. I don't see how making hot water helps top off any type of battery. Other then not needing electrical energy to produce it(hot water). Still has the storage and transporting it around gracefully issue.....so where did you want this discussion to go Kevin? No one is going to bolt a box filled with pex and covered with an old window to the top of their class A. And run the lines down thru the roof also? Well, most won't....
I considered doing this years ago at my sticks and bricks in Maine. I instead watched what others had done and experienced in my particular climate/area and stayed conventional. Much like wood heat, there is no free lunch. The amount of labor(yours) in wood heat in a cold climate is usually underestimated by novices. Storage, quality(type of wood and dryness), access to heated areas and ash dumping along with chimney fires/appliances to burn it make wood heat less then ideal for many people. But I digress....lol

 

[Kevin D Pem]

This discussion is between people talking about PV energy and generators. I don't see how making hot water helps top off any type of battery. Other then not needing electrical energy to produce it(hot water). Still has the storage and transporting it around gracefully issue.....so where did you want this discussion to go Kevin? No one is going to bolt a box filled with pex and covered with an old window to the top of their class A. And run the lines down thru the roof also? Well, most won't....
I considered doing this years ago at my sticks and bricks in Maine. I instead watched what others had done and experienced in my particular climate/area and stayed conventional. Much like wood heat, there is no free lunch. The amount of labor(yours) in wood heat in a cold climate is usually underestimated by novices. Storage, quality(type of wood and dryness), access to heated areas and ash dumping along with chimney fires/appliances to burn it make wood heat less then ideal for many people. But I digress....lol

I reference stuff like that to help illustrate efficiency as well as help people think!!! Think in terms of parables! A story is like a picture!!! It captures the imagination.

I suspect you got the meaning presented. Who other than, well, someone like me, in my humble "trailer" would even think of such modification? However my 1800 dollar box Beggs for experimentation! As we speak I have drawings for solar assisted floor heat to keep me warm without using propane!

I like to believe that this is a site for more than high end MHs, I may be wrong!!

 

[TheLooks]

Hmmm, most are not set up semi permanently in one spot. And floor heat is another area I know enough about to be dangerous. As with other things, it depends.

 

[Kevin D Pem]

Hmmm, most are not set up semi permanently in one spot. And floor heat is another area I know enough about to be dangerous. As with other things, it depends.

Spent to many years as a nomad to understand what you mean by that! Your knowledge on oasis makes me wonder what you mean by the other!

For what it's worth my consideration of water as a heating medium is based on my desire to dump mass to keep me mobile. I have spent most of the last 20 years playing with ideas. No it's not what you think! I like projects, they keep me happy, and sane, if there truly is such a thing!

 

[TheLooks]

Radiant heat is much more difficult then just heating water and circulating it. Transfer rates, temps, and other factors make it tricky.