batteries n more

[zingaro]

Hello and welcome all:
heres my setup ive got 8 6v 12 ah sealed batteries wired up into 4 12 v wired in parallel to my bus.
My current panel is 40 w 18 v but im about to get a 100 w flexible to attach to the roof of my van (home)
can I wire the 100 wt into the controller on the 40 or will it need to be separate?
ALSO: ive ordered a 20 amp controller on epay mppt. will a larger than needed controller effect the outcome?
I bought that size as to expand in the future.

AND SO: while its on my mind. lets use the word OVERKILL. Is there a loss in current if you using a really large inverter, say a 1000w to charge your laptop or is it more efficient to use a say 150 w.

It would be nice to just have one inverter unless the demand for the larger to do a smaller job is ah expensive.

Just found this forum tonite and sure I have more questions than answers....thx ..z

[jony101]

since your panels are different sizes its best to keep them seperated.

having a controller larger than you need is no big deal. Its better than the other way around. But a ebay mppt controller might not be a true mppt. But it will still work with your 100 watt panel. mppt is usually for the high voltage panels 30 volts or higher to get best performance. if you paid more than 100 dollars, it might be mppt, the under 100 dollars are usually fake mppt.

A larger inverter will use more current when on standby, as long as you turn it off when not in use, you be ok. But your battery bank of 48ah is too small for 1000 watts of inverter. Myself i have a 150 watt pure sine and a 400 watt modified sine inverter. Some items only work with one or the other.

[zingaro]

thx for the info. So by keeping them separate you mean separate controllers or can I feed them both in parallel into one controller?
Yes my mppt was under a c note
My inverter is actually 175 wt but I do have a 2000 for my coffee pot but I hardwire it to the battery of the van and run it to brew. I have a 125 amp alternator so it works fine, even with the microwave.

I did see a 1000 wt inverter, mod sine. that had both cigarette plug and alligator and I thought it would be a good backup. its actually 1200 wt for 34 $ so it probably overrated. pullin that power out of my batteries would melt the terminals. I harvested them from some emergency lights from the flea NIB @ $6 each so it was a sweet deal. They were halogen lites and I converted them to 3 wt led.

If you find time to tell me if I can parallel them panels into a single controller ill thank u now!!!!

THX...z

[PNjunction]

Zingaro - to get serious stop buying stuff now even if it is cheap.

To do it right, one works backwards, ie measure how much current / power you need to draw over time in hours. Then find battery to support that. Then you size your solar array and controller appropriately, according to your geographical location and season (ie, "solar insolation" charts should be consulted.

Doing it this way guides your wallet properly. Doing it backwards, even if cheaply is a waste of money. For example, those batteries you bought have several major issues (aside from not knowing if they would even support your load if new!)

Take a breather, read some of the stickies here, but most importantly, close wallet for the time being.

[zingaro]

O the batteries worked fine last year, I just didn't charge them with solar. Im tring something new, although im one that likes to park n the shade.
I was looking for useful info, not how and where to spend my $.
Butt thx any way ...z