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#11
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On 03 Jul 2009 13:11:05 GMT, terryc newssevenspam-spam (AT) woa (DOT) com.au> wrote: On Fri, 03 Jul 2009 07:44:32 -0400, kony wrote: While you have a point, I don't necessarily agree the battery has to be oversized by 2X. Given 48 hours of runtime there is some margin already, more a matter of having the solar panel amply sized so that it provides enough recharge power even on overcast days. Totally irrelevant. You can not run lead acid batteries flat*. It permanently screws them about. It isn't my recommendation, but all the old farts who have worked with these things for decades. You wouldn't be running them flat. Remember, the suggestion was 48 hours of _reserve_ capacity, the average current plus some margin has to be supplied by the solar panel(s) either way. |
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Generally what this means is at most the pack is powering the cells from evening until dawn, perhaps 14 hours in the winter out of 48. |
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Further, the step-down supply for the cam can be selected with a cutoff at a threshold above the minimal desired battery pack voltage, |
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amply sized solar panel(s) that threshold should never be reached. |
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There is a Bill *arden Lead acid FAQ floating around somewhere on it all. |
#12
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On Fri, 03 Jul 2009 16:08:03 -0400, kony wrote: On 03 Jul 2009 13:11:05 GMT, terryc newssevenspam-spam (AT) woa (DOT) com.au> wrote: On Fri, 03 Jul 2009 07:44:32 -0400, kony wrote: While you have a point, I don't necessarily agree the battery has to be oversized by 2X. Given 48 hours of runtime there is some margin already, more a matter of having the solar panel amply sized so that it provides enough recharge power even on overcast days. Totally irrelevant. You can not run lead acid batteries flat*. It permanently screws them about. It isn't my recommendation, but all the old farts who have worked with these things for decades. You wouldn't be running them flat. Remember, the suggestion was 48 hours of _reserve_ capacity, the average current plus some margin has to be supplied by the solar panel(s) either way. Umm, do you actually have any experience with this type of kit? And I'll say again, 48Ah of deep discharge lead acid battery capacity is not 48Ah of usable capacity. Read it and learn http://www.batteryfaq.org/ |
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Generally what this means is at most the pack is powering the cells from evening until dawn, perhaps 14 hours in the winter out of 48. Do you have any experience to backup your previous claim that the solar panels will produce some meaningful amount of power every day?. Which is the fundamental shaky claim you are now making. |
| Further, the step-down supply for the cam can be selected with a cutoff at a threshold above the minimal desired battery pack voltage, Yep, absolutely necessary. Do you have a device recommendation for the original poster or a circuit for the constructor? How does it affect efficency? |
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amply sized solar panel(s) that threshold should never be reached. Aah,"amply sized". A vague quantity that means absolutely nothing. |
| There is a Bill *arden Lead acid FAQ floating around somewhere on it all. This looks like it. http://www.batteryfaq.org/ |
#13
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I never suggested it was. The 48Ah is to take this into account, that it is already more than needed. Let's look at it the other way, instead of saying we need to double the 48 hours, what the 48 hours is, is double 24 hours. |
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Generally what this means is at most the pack is powering the cells from evening until dawn, perhaps 14 hours in the winter out of 48. Do you have any experience to backup your previous claim that the solar panels will produce some meaningful amount of power every day?. Which is the fundamental shaky claim you are now making. Solar panels will product some meaningful power every day, unless you know of days the sun doesn't rise in the sky. |
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