SmithsJunk
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I'll be printing out graph-paper today to do the solar schematic. I was waiting till I heard back from Mighty Max batteries cause I wanted to post the current draw in the schematic, but like I was thinking, these batteries don't have a set current output. So I'll just give the draw from the lights and post the chart M.M. sent me.
So here's the deal with the maintenance free lead acid (AGM) batteries...
They will pump out as much current as needed, up to 900A. As the discharge rate increases the lower the amp hour rate drops. The batteries are rated by how many amps they can produce over a 10hr period, ie 10A per hour for 10hrs = 100ah, but as the rate of discharge increases the Ah rate decreases, ie 75A per hour for 1hr = 75Ah. The way to solve this is to spread the discharge across a bank of batteries (12v parallel in my case), ie 5x 100Ah batteries = 50A per hour for 10hrs. Since discharging these batteries below 50% can severely reduce the life of the batteries from 5yrs down to 6mos-1yr, you'll want to make your calculations at 50% of the listed Ahrs. So a 100Ah battery is really only 50Ah. My 200w fixture is about 5.2A. It should run about 30hrs on 3x 100Ah batteries. By the time I need to add the single 100w CXB I'll have 5x 100Ah batteries. Altogether my fixtures will run 7.75A. That should give me 32hrs+ of battery time since the current spread across 5x 100Ah batteries in parallel is only 1.55A ea.
Here are some screenshots of the PDF Mighty Max sent me...
...of course, I have not have considered every factor so my battery life will vary from that simple calculation but it's a good starting point. I will know exactly what my current draw and battery life will be in conjunction with my solar panels once I've run tests using a killawatt meter.
(Also, it's nice n cool right now and the hot summer temps are going to decrease capacity and and slow recharge rates, not to mention decrease solar pv output. I'll keep track throughout the season and it'll give me a good overall picture to make adjustments from in the future.)
So here's the deal with the maintenance free lead acid (AGM) batteries...
They will pump out as much current as needed, up to 900A. As the discharge rate increases the lower the amp hour rate drops. The batteries are rated by how many amps they can produce over a 10hr period, ie 10A per hour for 10hrs = 100ah, but as the rate of discharge increases the Ah rate decreases, ie 75A per hour for 1hr = 75Ah. The way to solve this is to spread the discharge across a bank of batteries (12v parallel in my case), ie 5x 100Ah batteries = 50A per hour for 10hrs. Since discharging these batteries below 50% can severely reduce the life of the batteries from 5yrs down to 6mos-1yr, you'll want to make your calculations at 50% of the listed Ahrs. So a 100Ah battery is really only 50Ah. My 200w fixture is about 5.2A. It should run about 30hrs on 3x 100Ah batteries. By the time I need to add the single 100w CXB I'll have 5x 100Ah batteries. Altogether my fixtures will run 7.75A. That should give me 32hrs+ of battery time since the current spread across 5x 100Ah batteries in parallel is only 1.55A ea.
Here are some screenshots of the PDF Mighty Max sent me...
...of course, I have not have considered every factor so my battery life will vary from that simple calculation but it's a good starting point. I will know exactly what my current draw and battery life will be in conjunction with my solar panels once I've run tests using a killawatt meter.
(Also, it's nice n cool right now and the hot summer temps are going to decrease capacity and and slow recharge rates, not to mention decrease solar pv output. I'll keep track throughout the season and it'll give me a good overall picture to make adjustments from in the future.)
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