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Post by Deleted on Apr 14, 2021 10:19:06 GMT
So can I ask- with a roof full of solar panels, how do you manage if/when you want to get on the roof and go forward? It hasn't happened to me often, but I do remember one or two locks where there was no lock ladder at my end, and I had to go forward over the roof to reach the ladder. Normally I can get onto the ladders directly from the stern deck, but not in this case. I guess I could have walked along the gunnels to reach the ladder, but in the narrow locks there wasnt a big gap, and the walls were slimy as hell, so I would rather avoid walking along the sides and getting my clothes 'slimed' if the boat moves close to the wall. Best to have panels that leave a little bit of room for roof walking (how much is an individual judgement). Unless you restrict yourself to locks where you can haul the boat in/out with ropes.
I've always treated the gunnels as the worst place to be in a lock - only bettering the water.
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Post by Deleted on Apr 14, 2021 10:25:36 GMT
I’m having to disconnect the solar at the moment, but I’m planing to be using more power soon. My problem or issue at the moment is setting the soc. so it reads correct. So all I’m doing is keeping them between 13.8v-12.8v I've lost track of my exact SoC tbh, although I have a reasonable idea. At some point you'll need to get them fully charged, right? If only so you can synchronise the BMV etc. So how will you know when you're at 100% SoC? Will the batteries just stop taking any further charge? Before I set the voltage limits I could tell they were approaching 100% SoC because the voltage started to rise sharply, but I've now set the max charging voltage to 13.9v and the relay disconnects at 14v. Nick was saying that they can still get to 100% SoC when charging at 13.8v, as long as you charge slowly. So with a charging voltage that wont go above 13.8v, how will know when you've reached 100%? I'm going to charge mine up some time soon so I can synchronise the BMV again, but I need to know when they reach 100% so I stop charging immediately. Wouldnt want to stress the little blighters.
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Post by Telemachus on Apr 14, 2021 13:03:28 GMT
I’m having to disconnect the solar at the moment, but I’m planing to be using more power soon. My problem or issue at the moment is setting the soc. so it reads correct. So all I’m doing is keeping them between 13.8v-12.8v I've lost track of my exact SoC tbh, although I have a reasonable idea. At some point you'll need to get them fully charged, right? If only so you can synchronise the BMV etc. So how will you know when you're at 100% SoC? Will the batteries just stop taking any further charge? Before I set the voltage limits I could tell they were approaching 100% SoC because the voltage started to rise sharply, but I've now set the max charging voltage to 13.9v and the relay disconnects at 14v. Nick was saying that they can still get to 100% SoC when charging at 13.8v, as long as you charge slowly. So with a charging voltage that wont go above 13.8v, how will know when you've reached 100%? I'm going to charge mine up some time soon so I can synchronise the BMV again, but I need to know when they reach 100% so I stop charging immediately. Wouldnt want to stress the little blighters. Yes in that respect it is fairly similar to lead acid, you hold the charging voltage until the current falls to some % of capacity. With Li, that % is a bit higher than with LA, maybe 5%. But it depends on the charging voltage, so 14.6v I would use 5%, at 13.8v it would say nearer 2%. But anyway, the clue is when the current falls of significantly with the battery terminal voltage up at 13.8v, it will be fully charged or nearly so, certainly more than 95% (and super accuracy isn’t needed).
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Post by Deleted on Apr 14, 2021 14:32:59 GMT
Yes in that respect it is fairly similar to lead acid, you hold the charging voltage until the current falls to some % of capacity. With Li, that % is a bit higher than with LA, maybe 5%. But it depends on the charging voltage, so 14.6v I would use 5%, at 13.8v it would say nearer 2%. But anyway, the clue is when the current falls of significantly with the battery terminal voltage up at 13.8v, it will be fully charged or nearly so, certainly more than 95% (and super accuracy isn’t needed). The complication I have is that I don't often charge at much above those 'tail' values anyway. When cruising there might be 45-50 amps from the engine and maybe 10-15 from the solar, so its easy to see when there is a drop from that sort of charging current down to 8 amps, which in my case would be about 2%. But a lot of the time I'm charging just from solar, so the charge current might be around 10 amps, or in good periods 25-30 amps. At those sorts of low charging currents, I think its harder to tell when it drops to 2%. And the solar often goes up and down between 8amps to 20 amps anyway, depending on the weather. So maybe the time to do a 100% charge is when cruising- that way I'll spot a drop-off in charge much more easily....
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Post by Telemachus on Apr 14, 2021 15:56:52 GMT
Yes in that respect it is fairly similar to lead acid, you hold the charging voltage until the current falls to some % of capacity. With Li, that % is a bit higher than with LA, maybe 5%. But it depends on the charging voltage, so 14.6v I would use 5%, at 13.8v it would say nearer 2%. But anyway, the clue is when the current falls of significantly with the battery terminal voltage up at 13.8v, it will be fully charged or nearly so, certainly more than 95% (and super accuracy isn’t needed). The complication I have is that I don't often charge at much above those 'tail' values anyway. When cruising there might be 45-50 amps from the engine and maybe 10-15 from the solar, so its easy to see when there is a drop from that sort of charging current down to 8 amps, which in my case would be about 2%. But a lot of the time I'm charging just from solar, so the charge current might be around 10 amps, or in good periods 25-30 amps. At those sorts of low charging currents, I think its harder to tell when it drops to 2%. And the solar often goes up and down between 8amps to 20 amps anyway, depending on the weather. So maybe the time to do a 100% charge is when cruising- that way I'll spot a drop-off in charge much more easily.... I understand the "vagaries" of solar, but I think you just have to take into account the voltage. Yes when the current drops it might be because the sun's gone in, or it might be because the batteries are approaching fully charged. The difference between those scenarios is that in the former, the voltage will also have decreased, whereas in the latter it won't.
If you've set up the BMV correctly then it will reset at 100% anyway, and if you have a relatively high tail current it will reset a bit early, before it is absolutely rammed full, which is probably a good thing.
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Post by kris on May 4, 2021 13:20:08 GMT
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Post by kris on Jun 27, 2021 12:59:28 GMT
Anyway here is an update, I’ve fitted isolation switches on the solar panels and I now have three controllers wired in. So I can harness the full potential of the panels. I’m going to sell the outback controller and replace it with another tristar so they can be wired to the same relay easily for hot water. Anyway so if anybody is interested in the outback let me know.
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Post by JohnV on Jun 27, 2021 13:11:47 GMT
good looking job kris
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Post by kris on Jun 27, 2021 14:32:51 GMT
Thank you.
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Post by Deleted on Jun 27, 2021 14:35:02 GMT
And I was like "god what an awful bodge" isn't it.
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