Living full time in suburban - solar advice needed

malt

New member
Well, that was an interesting discussion in the finer points of amps, amphours, draw, current and coulombs, which I might remember from high school physics...

I think we're going to forgo solar and stick with topping off the battery bank through a wall charger. Looking at the it's because they seem universally recommended.

So, can they be hooked up to the 6v gc batteries in series?
 

dwh

Tail-End Charlie
A 12v battery is 6 x 2v cells in series. A 6v battery is 3 x 2v cells in series. Two 6v batteries in series is 6 x 2v cells in series.
 

malt

New member
I got that bit, not familiar with how the "smart" chargers work and if they'd bug out with two 6vs rather than an actual 12v. Got it though.

Thanks.
 

freedomrider

Ordinary average guy
Your still yet to explain why current * time / time is not equal to current. As you correctly point out - the Ampere already has time in the denominator, which is also why you don't need to multiply it by time then divide it by time to get the rate of consumption. In physics this a basic technique called dimensional analysis.

I agree amps per hour makes no sense, that is why the correct unit is just Amps which was my point all along and is why the current draw of electronic devices is specified in amps.

Ampere hours per hour is not totally incorrect, it is just an unreduced fraction. It would be like using a unit such as ampere pounds per pounds (also just amps).

Anyway, this has run its course - you can use what ever units you would like.

I think you're both right because you're describing two different things (at least that's my take). Per john61ct's post (#22 in this thread), the Engel rating is a typical total energy use per hour that the fridge is on. "Amp hr/hr" may be a scientifically-unsatisfying unit but it's useful for the average consumer who just wants to calculate how much battery to buy to run his fridge on his camping trip. For the person who knows the compressor's cycling characteristics during his specific use, having the compressor's amp draw spec is sufficient (and hopefully Engel provides that number too). Sure, they could just say that the fridge has an average amp draw of 1-2 amps but some people might mistakenly think that 2 amps is the maximum amp draw, which is not true.

And if I'm totally off, it's the Pizza Port IPA talking. :beer: :snorkel:
 

dwh

Tail-End Charlie
I got that bit, not familiar with how the "smart" chargers work and if they'd bug out with two 6vs rather than an actual 12v. Got it though.

Thanks.

Nah, no worries - the voltages are the same either way. Only thing is if the charger puts out enough amps to charge big batteries in a timely fashion.
 

DLTooley

Observer
A good charge controller helps max out a panel. I also like the Victron. I recommend disconnecting the fridge during the absorption phase of charging, the first 2-3 hours of full solar. A daily drive would reduce or eliminate that. 24 volt panels or a 2 panel series wiring is a benefit. The Dometic cc40 is the cheapest 12v fridge - $335 at Dyers.

I have one 100 watt on my hood which looks cool. The 50 that I upgraded from is used as a portable for max absorption charging usually leaning on my canoe or the front windshield

Cheap rv living including the forums is another great resource for full timers.
 

dwh

Tail-End Charlie
I recommend disconnecting the fridge during the absorption phase of charging, the first 2-3 hours of full solar. A daily drive would reduce or eliminate that.

Did you mean bulk stage? First few hours would be bulk. Absorb comes after.
 

DLTooley

Observer
Bulk is just what happens until it gets bright enough to reach the absorption voltage. At l ast that's how I understand it. The absorption algorithm is the most crucial and varies - including by user program.
 

southpier

Expedition Leader
not to be cruel, but if you're living full time in any vehicle shorter than about 80 feet, solar advice is probably the least of your problems.
 

john61ct

Adventurer
That's just, like, your opinion, maan.

Not just cruel but ignorant!

I'm confused, nothing mobile is that long.

So are you putting down all full-time nomads?

I've got a friend worth $50mill lives full-time on his 70' racing yacht, except for flying to visit his grandkids a few weeks at a time.

Is he a sad case too?
 

dwh

Tail-End Charlie
Bulk is just what happens until it gets bright enough to reach the absorption voltage. At l ast that’s how I understand it. The absorption algorithm is the most crucial and varies - including by user program.

Bulk is constant current - running wide open, no voltage regulation (battery is the voltage regulator), current limited to charge controller' max capacity - until battery voltage rises to the programmed set point (mine is set to 14.7v), which triggers a shift to absorb mode.

Absorb is constant voltage (voltage is regulated by charge controller to hold battery at specified absorb voltage (mine is set to 14.7v). Absorb ends when the amperage flowing drops below a set threshold (mine is set to two amps), or a timer elapses, or the sun goes down. Whichever comes first.

The only "absorption algorithm" is that used to set the timer. My Victron times the bulk stage and sets the absorb timer to a multiple of that. Most charge controllers aren't that sophisticated.

Absoption isn't critical with solar - it'll end when the sun goes down regardless.

It is critical with shore powered chargers - if they stay in absorb too long they can severely overcharge a battery.
 

malt

New member
Thanks all for the advice - we built out the suburban last week and ended up not addressing power needs. He spent a year in a truck without power previously, will spend the next winter without it as well. He has a small goal zero, sherpa I think it's called, that he uses to power lights and that's about it.

suburban.jpg

Came out looking nice, hoping we can do solar in a few months when money is replenished.
 

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