Re: Solar panel selection
Posted: Sat Aug 11, 2018 9:07 am
My 2 cents worth:
You probably don't need to have solar capacity to replace 100% of your daily power consumption each day. Let's say you have 400 Ah of house bank storage capacity. Assume that you use 100 Ah of electrical power each day when cruising. Since you would not want to drain your battery bank below 50% capacity, you would need to re-charge your house bank in 2 days. If you add solar panels that replace 80% of your consumption each day, you are only losing 20 Ah each day. With 200 Ah of useable capacity that would be 10 days before needing to re-charge via other means. Most of the time We are ready to move on (meaning motoring as we always seem to be headed into the wind) by that time.
In our case we have 3 pairs of 6V golf cart batteries in our house bank that total around 690 Ah of capacity when they were new. Our average daily consumption when cruising is around 125 Ah/day. The big power drain is the fridge. Although we have replaced the cabin lights and anchor light with LEDs. The cabin lights have little effect as they are only on for short periods of time, however the anchor light is a bigger drain as it is on all night (sometimes all day if I forget to turn it off). We have 2 Kyocera 140 watt fixed panels over the bimini that replace about 90% of our consumption on most days. I find that we need to defrost the fridge about once a week when cruising and have found that the easiest way to do that is to simply turn it off overnight for one night. It warms up enough to do a partial defrost without getting so warm that the frozen food is thawed. This gives the solar panels enough relief that they can re-supply power lost the rest of the week. Last spring, we took a 3-week cruise on the west coast of Florida and I don't think our house capacity was ever below 85%. I haven't put the portable Honda generator on the boat since we added the panels about 2 years ago.
Good Luck
You probably don't need to have solar capacity to replace 100% of your daily power consumption each day. Let's say you have 400 Ah of house bank storage capacity. Assume that you use 100 Ah of electrical power each day when cruising. Since you would not want to drain your battery bank below 50% capacity, you would need to re-charge your house bank in 2 days. If you add solar panels that replace 80% of your consumption each day, you are only losing 20 Ah each day. With 200 Ah of useable capacity that would be 10 days before needing to re-charge via other means. Most of the time We are ready to move on (meaning motoring as we always seem to be headed into the wind) by that time.
In our case we have 3 pairs of 6V golf cart batteries in our house bank that total around 690 Ah of capacity when they were new. Our average daily consumption when cruising is around 125 Ah/day. The big power drain is the fridge. Although we have replaced the cabin lights and anchor light with LEDs. The cabin lights have little effect as they are only on for short periods of time, however the anchor light is a bigger drain as it is on all night (sometimes all day if I forget to turn it off). We have 2 Kyocera 140 watt fixed panels over the bimini that replace about 90% of our consumption on most days. I find that we need to defrost the fridge about once a week when cruising and have found that the easiest way to do that is to simply turn it off overnight for one night. It warms up enough to do a partial defrost without getting so warm that the frozen food is thawed. This gives the solar panels enough relief that they can re-supply power lost the rest of the week. Last spring, we took a 3-week cruise on the west coast of Florida and I don't think our house capacity was ever below 85%. I haven't put the portable Honda generator on the boat since we added the panels about 2 years ago.
Good Luck