Got a choke point here somewhere.

[donelwell]

Hi folks,

Im new to this, so bear with me.

We live on a boat with a small solar system here in the Baltimore area, which at the moment consists of a windynation panel setup (2 X 100W panels, PWM 30A controller, and 6 35 AH deep cycle batteries).

Everything was just ducky until we added a small fridge to the setup. The Edgestar supposedly consumes 75W at startup and 35W running, but it's exhausting our system to the point that we can only operate it a few hours a day.

I'm a bit puzzled and trying to figure out where our choke point might be. The rest of our energy consumption is only the occasional run of a blender and charging a laptop, so it's not as if we were anywhere close on exhausting the system beforehand.

Ideas? Too few batteries? Too small panel setup? Laser deathray cannon consuming too many watts when blasting people who won't kill their wake?

Don

[Mike90250]

It's the laser death ray. It makes the fridge run all the time to provide coolant.

So your 35W fridge x 20 hours = 700 wh consumption

Your 200w of panels x 4 hours = 800wh harvest
See the problem ?

[donelwell]

It's the laser death ray. It makes the fridge run all the time to provide coolant.

So your 35W fridge x 20 hours = 700 wh consumption

Your 200w of panels x 4 hours = 800wh harvest
See the problem ?

Um....yep. sigh. That's rather what I figured.

[Sunking]

Simple you used Obama Math. You make $5/day but spend $7/day, you ran out of money. Or in technical terms everything you have is too small to support such a monster of a load. At 700 wh/day consumption minimum 12 volt battery is 300 AH and you only have 210 AH trying to run everything else on top of that. Panel power alone will take 400 watts minimum just for the fridge.

[donelwell]

electrical reaganlmics

Simple you used Obama Math. You make $5/day but spend $7/day, you ran out of money. Or in technical terms everything you have is too small to support such a monster of a load. At 700 wh/day consumption minimum 12 volt battery is 300 AH and you only have 210 AH trying to run everything else on top of that. Panel power alone will take 400 watts minimum just for the fridge.

I would have said voodoo math but your point is taken comrade.
Looks like I need anouter panel and at least another battery to make this system work
Thanks everyone

[mapmaker]

I would have said voodoo math but your point is taken comrade.
Looks like I need anouter panel and at least another battery to make this system work

Another battery? You already have 6 batteries. If they are 6 volt batteries and you have a 12 volt system voltage, that means you have 3 parallel 12 volt batteries (each 12 volt battery = two 6 volt batteries in series). If your 6 batteries are 12 volts each, that means you have 6 batteries in parallel.

Either of those is a poor design and adding more batteries in parallel makes it even worse.

My advice is figure out what your loads are, design a system on paper that will meet those loads, and then figure out how to get from where you are to where you want to be. Hopefully some of your existing system can be used in your properly designed system.

--mapmaker

[PNjunction]

The other thing to mention is to use the least amount of batteries as you can. Strive for a single battery, perhaps no more than 2 in parallel. Bad interconnects, high resistance wiring, and differing states of SOC on multiple batteries are a nightmare unless you are willing to add even more maintenance to the project.