Simple solar question

[nevadatear]

Solar question: I want to get a portable/folding solar panel to recharge my 72000mAh/266Wh power supply battery that I use for my CPAP machine. It needs at least a 15 V panel. I am looking at 60w or 100.w Cost and size are a factor, however, I don't understand solar enough to know the difference in charging time. The info on my battery says a 100W panel will recharge in 4-6 hrs. How much longer do you folks who know solar think it would take to recharge with the 60W?

[flboy]

If this is true for 100W , roughly Divide 4 to 6 by 0.6.

About 6.6 hours to 10 hours.

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[TimC]

I'm afraid I can't help with the charge rates but I can show an example of a solar suitcase I made for my son's teardrop. It is made from two Renogy 50w panels with a hinge on one end. Folds pretty small and keeps his 72aHr battery charged up very well. It requires an MC$ Y Branch connector to wire the panels in parallel.

It's shown about halfway down on this page. I modified it with a couple six inch MC4 extensions as mounting them on the hinge side of the panels was problematic for folding and unfolding.

http://tnttt.com/viewtopic.php?f=50&t=72877&start=60

[troubleScottie]

The average output for a 100W panel is 280-450Wh per day. There are lots of assumptions like charging time ( typically 6 hrs per day), etc. Obviously more in summer, less in winter. If the panel is not pointing at the sun (southerly, at the appropriate angle) or is shaded, you will get significantly less output. The 60W panel should be about 60% of the 100.

Assuming perfect conversion and 12V output, that is 23 to 40 Ah per day.

The other issue is how much charge do you need to replace. You should have a recharge need of 0 to 56 Ah (80%). So the answer is maybe on recharging it unless you are using multiple panels.