House/solar battery opinions

I received info today that the Duracell AGMs are available in a Dayton, OH Sam's Club for $179.73 for either 12V or 6V.

HTH;
John

Fortunately the Deka/Duracell AGMs charge at essentially the same voltages as flooded batteries.

Charging specs on page 11

Lol piano tuner. You're not going to let me forget! And your coffee arguments are getting to me...

Almot - its not really about cost, though I don't want to needlessly throw away cash. The panel smkettner suggested would be about 1/4 the cost of the panels I mentioned, though. I'm going with the mppt either way, but even if I weren't, the mppt and the one panel would still be cheaper than the four 100 watts.

I'm looking for upgradable efficiency, and I think the higher voltage panel and mppt controller will help offer that. If I'm understanding things correctly.

My concern with the one panel is it will be flat mounted - would like some 'extra' to make up for the loss of power from a flat mounted panel. Any thoughts?

Just got the battery monitore and wired it to the shunt. Tomorrow I'll cut the negative battery cable and insert th e shunt. Néed to get a fuse for the monitors power line.

Maybe then I'll install the new garbage disposal.

Priorities...

John - thanks for the info on the Duracells.

seraphim wrote:
I'm looking for upgradable efficiency, and I think the higher voltage panel and mppt controller will help offer that. If I'm understanding things correctly.

MPPT will get more than PWM out of the panel area, but only 8-10% more. So 235W with MPPT will be as if it were 260W with PWM. Many people here will disagree and tell you that they don't believe in MPPT and it won't give any "boost" over PWM at the given panel size :) ... Anyway, the "efficiency" of MPPT vs PWM will not be too significant.

seraphim wrote:
My concern with the one panel is it will be flat mounted - would like some 'extra' to make up for the loss of power from a flat mounted panel.

Yes. This is why flat 4*100W with PWM is better than flat 235W with MPPT. Because 400W is more than 260W. Total cost of such a system will be higher than one 24V panel with MPPT controller, but you will get more watts in the end.

seraphim wrote:

I'm looking for upgradable efficiency, and I think the higher voltage panel and mppt controller will help offer that. If I'm understanding things correctly.

The MS MPPT 15 will be maxxed out with any array over 200W. It will keep working but discard any charging Amps over 15A. So NO, not expandable. Not every MPPT is that smart. Some will shut down and others may even burn up if overloaded by the array.

Go larger with the MPPT controller if you plan on expanding the array Watts.

In my case, the 200+ panel would take all my roof real estate leaving no possibility of expansion.

HTH;
John

I really doubt much will be lost with the 15 amp controller limit driven by a 230w panel. Maybe if you have thick clouds and a near dead battery when the sun suddenly pops out at 11:30 am. Otherwise by the time you get 230w the battery voltage will be above 14 and 15a would be 210 watts or over 90% efficient.

You can expand with a second 15 amp controller. Or if you know you are going larger I recommend Rogue for 2 of these panels, MS-MPPT-45 for 3, and MS-MPPT-60 with 4 panels.

He's only got 96x44" space. It will be hard to find 2 x 24V panels that fit in there.

Hi seraphim,

Another possible route: http://www.eco-worthy.com/catalog/

And here is a thread that is germane to MPPT: Tristar MPPT 60

I think I need to buy a trailer with a long wide roof lol