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Post by papaof2 on Nov 10, 2023 21:06:45 GMT -6
www.amazon.com/dp/B07GTH79JPIf you need a 50 watt or so solar panel, this is a very good price - it's less than half price (currently cheaper than the 30 watt Renogy panel). Lots of small "solar generators" charge at 50 watts or so (the FlashFish 200 I reviewed earlier this year). Two of these would give you 100 watts for $59.98 instead of the current $69.99 of the 100 watt Renogy panel. If you're looking for semi-portable solar, two of these weigh less and are easier to place than one 100 watt panel. No idea how long this price lasts. I noticed it on Amazon tonight when I was looking for something else. I think that's called serendipity - or is that Zipity-Doo-Dah?
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Post by feralferret on Nov 10, 2023 23:23:28 GMT -6
I'm watching an "ECO-WORTHY 100 Watt 12 Volt Solar Panel Kit for RV Battery Boat Trailer Cabin Garden Shed Home: 100W Solar Panel + 30A PWM Charge Controller + Tray Cable + Z Mounting Brackets" at auction, closing next Tuesday evening.
I've already picked up three of the 100 watt panels at auction, although one has shattered glass from freight damage. I plan to seal that one with clear vinyl and set it aside for when I need a separate lower output panel such as for charging a car or mower battery. Due to the light diffusion caused by the cracks, it won't be as efficient as the undamaged panels. I might set it up to keep the motorcycle battery charged that I use for backup power for my radio equipment. I may use the 30 amp charge controller from the one at auction if I win it, then buy a larger controller for the good 100 watt panels.
I already have a separate 35 watt panel setup for charging a car or mower battery.
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Post by papaof2 on Nov 11, 2023 17:58:20 GMT -6
For a while, I had a power meter on the pair of leads coming in from whatever solar panel I had outside under test at the time. That power meter needed 12 volt power for its microprocessor so I had a 20 watt panel leaned up against a bucket outside the garage door to keep its 7AH battery charged. That was another "put it together and forget it" design because the power meter needed just a few milliamps at 12 volts and even "Partly Cloudy" was enough sun to have the battery fully charged after an hour or two of daylight.
Most car batteries have ratings that would allow several hundred watts to be used for fast charging. If using an MPPT charge controller, 300 watts / 13 volts = 23.07 amps so about a third of the "65 amp" alternator that was once standard on many GM engines. Using a PWM controller, a 100 watt panel has a short circuit current of about 5 amps and three of those panels in parallel would be a 15 amp charge; 15 amps * 13 volts = 195 watts. If you can work MPPT controllers into your solar budget, they do provide more power using the same panels. At the 10 amp level (130 watts to a "12 volt" battery) the EPEver MPPT controllers are $50 shipped at Amazon. Previous versions of those controllers had a "Maximum power output" rating and a "Maximum solar power input" which was 3 times the maximum output: the 30 amp controller listed 390 watts input/output at 12 volts but a max of 1170 solar watts on the input. The newer controllers don't have that "Maximum solar input" column but I'd guess all of them would be OK at maybe twice the solar input: 200 watts of panels on the 10 amp (130 watt) unit because you won't have continuous full sun, the size of their heatsinks and their ability to throttle down the power going through them.
35 watts is, at most, a 3 amp charge so safe for all but the smallest UPS batteries.
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Post by papaof2 on Nov 24, 2023 18:41:17 GMT -6
As of this post, the Renogy 50 watt panels are still $29.99 shipped.
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Post by papaof2 on Nov 30, 2023 4:08:55 GMT -6
They're up to $49.99 + tax & free ship
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