Renogy 100watt 12v panel

[4johnny]

Can I expect this Renogy 100 Watts 12 Volts Monocrystalline Solar Starter Kit to fully charge a deep cycle marine battery? How long can I expect that charge to take in full sun?

Thanks

[SunEagle]

Can I expect this Renogy 100 Watts 12 Volts Monocrystalline Solar Starter Kit to fully charge a deep cycle marine battery? How long can I expect that charge to take in full sun?

Thanks

To be honest with you probably not.

Unless your battery is only rated 50Ah and you use 20% max you may not put back what you take out.

That 100 watt panel will probably put out about 5 amps max for (depending on where you live) 5 hours. Minus losses and efficiency you may not get the battery fully charged by the end of the day.

[4johnny]

Thanks for the info. Would 2 panels wired in series get that battery charged?

[SunEagle]

Thanks for the info. Would 2 panels wired in series get that battery charged?

Actually 2 of those panels wired in parallel will double your charging amps.

I can't tell you if that is enough since I do not know what that battery is rated but it is more charging capabilities.

[PNjunction]

4johnny - we need more info otherwise you'll just be winging it.

What exactly is your battery make / model and ah capacity? Is it a flooded wet-cell or agm?

Where are you located? - close is good enough. With solar, there is a thing called "solar insolation hours". These hours are different than just sunrise-to-sunset visibility hours, and they center around noon. Early morning and late afternoons are basically discarded when calculating what it will take - especially if you operate in winter. Most use the winter-hours for calculations. Nearly all solar projects that fail do so in part because they do not use solar-insolation, but mistakenly rely on sunrise-to-sunset hours.

Welcome to solar!

[4johnny]

Optima SC31DM Cold Crank Amp 900; Crank Amp 1125; Res. Capacity 155; Amp Hour 75; Deep Cycle, non-spillable
I live in CT and the Renogy 100 Watts 12 Volts Monocrystalline panel gets direct sun late morning to mid afternoon(maybe 4 hours/day).
I was hoping to fully charge this battery with the panel... or 2 panels if needed.

Thanks

[PNjunction]

Optima SC31DM Cold Crank Amp 900; Crank Amp 1125; Res. Capacity 155; Amp Hour 75; Deep Cycle, non-spillable

Minimum of 2 100w panels, possibly 4 if you are running in winter .. but be sure to read to the bottom so you don't paint yourself into a corner...

I have one of those about 10 feet away from me. The important value here for our use is the 75ah C/20 capacity. Normally to get any sort of decent cycle life out of them, only plan of having 35ah usable. That is, one normally doesn't cycle any deeper than 50% DOD. And yes, it is "deep cycle", but only so far as compared to starter batteries. What that obligatory opening out of the way...

Where you live you may have 4 hours of solar insolation in the summer. (I'm very glad you said "late" morning" to "mid" afternoon, because that is precisely about the range of solar insolation, and not just visible hours.)

If you want to run this battery down to 50% DOD, (about 35ah usable) and you plan to do so in winter, where you may only have 2 hours max of good solar insolation to recharge, you'll want to hammer the Optima.

Quick table for Optima Yellow/Blue light-case SOC's with minimum 4 hour rest:
12.9v + 100%
12.5v 75%
12.2v 50%
11.9v 25 % < -- don't go here unless you want to sacrifice cycle life. This is the "deep discharge" they are talking about. For us, go no lower than 50%.

Fortunately they can take a huge amount of inrush current, so it all depends on how much you want to spend and how critical this application is to you. Right now, you might be able to get by with only 2 panels with a large discharge and summer insolation to back it up. Take it up to 3 or even 4 panels if you plan on good recharging in winter.

Thing is, by the time you start thinking about 4 panels, you might want to look into using "grid-tie" panels with higher ocv voltages, along with an "mppt" controller to maximize output, especially in winter where you live.

The biggest killer of agm's is undercharging. Using an insufficient amount of panels to get the charge truly done daily will walk the capacity down over time. Since the Optima's have no reasonable input on current, don't be afraid to hit them hard with a large solar array.

For now, if you just want to experiment and have fun, then TWO of the 100w nominal-12v renogy panels will probably suffice in summer. It all depends on budget and how important this is for you since the Optima will eat up all you can give it.











I live in CT and the Renogy 100 Watts 12 Volts Monocrystalline panel gets direct sun late morning to mid afternoon(maybe 4 hours/day).
I was hoping to fully charge this battery with the panel... or 2 panels if needed.

Thanks[/QUOTE]

[4johnny]

OK, I will experiment with 2 panels.
I appreciate the info...Thanks for taking the time

[PNjunction]

No problem.

With solar doing the majority of the charge, if you are not using it full time, you may want to consider an ac-maintainer if your usage is not frequent.

I know I sound like a broken record or salesman around here, but my personal favorite for solely maintenance duty is an inexpensive Tecmate-Optimate 2. Without going into the whole thing, the biggest draw is the 50% duty cycle. That is, it only floats every other half-hour, giving the batts a break especially in warm/hot locations.

Guys that have run Odysseys (also pure-lead) have come back to cracked cases / warped plates even from small maintainers that never ever take a break from trickling. While that kind of heat can't be felt outside the case, over time internally, that does take a toll.