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Post by mediadogg on Sept 21, 2019 12:37:26 GMT
I have a small 24V system that works well to catch the morning sun that is totally missed by my main system. It charges fast, because for a few hours, the sun and panels seem to be in a sweet spot - just sheer luck. The 24V is from two identical 22AH SLA in series.
I have a couple of small 12V loads that I would like to add, without going through the trouble of rewiring the batteries for 12V parallel. Does anybody have any experience / advice on the idea of running a 12V load across only one of the batteries in a (2 x 12V series) 24V system? The 24V battery is being charged by a 20A Rover MPPT. Will the batteries equalize naturally? I realize I am putting more stress on one of the batteries - I could switch batteries every month or two maybe.
By the way, the panels are 3x100W Renogy mono. I know overkill for the battery size, but I like the fact that it charges fast, and the batteries stay at a relatively high SOC, even under load, and by early afternoon I've lost the sun anyway on that side of the house.
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Post by tattoo on Sept 21, 2019 13:27:47 GMT
I have a couple of small 12V loads that I would like to add, without going through the trouble of rewiring the batteries for 12V parallel. Does anybody have any experience / advice on the idea of running a 12V load across only one of the batteries in a (2 x 12V series) 24V system? The 24V battery is being charged by a 20A Rover MPPT. I'm not sure it can be done so I will be watching this thread for an answer.....
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Post by mediadogg on Sept 21, 2019 13:28:47 GMT
I have a couple of small 12V loads that I would like to add, without going through the trouble of rewiring the batteries for 12V parallel. Does anybody have any experience / advice on the idea of running a 12V load across only one of the batteries in a (2 x 12V series) 24V system? The 24V battery is being charged by a 20A Rover MPPT. I'm not sure it can be done so I will be watching this thread for an answer..... Aw man, I thought it was gonna be YOU to deliver the goods ...
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Post by bupkis on Sept 21, 2019 14:15:44 GMT
A step down transformer like this is the way to go!
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Post by tattoo on Sept 21, 2019 16:20:16 GMT
^^^^ Well there you go.....^^^^^^^
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Post by tattoo on Sept 21, 2019 16:20:59 GMT
Aw man, I thought it was gonna be YOU to deliver the goods ... LOL Hell I don't know anything about stuff like that......
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Post by iamsoinsane on Sept 21, 2019 17:03:26 GMT
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Post by mediadogg on Sept 21, 2019 17:55:06 GMT
A step down transformer like this is the way to go! Doh! Of course, I even have some in my parts drawer. The high power buck converter that I have might not be the latest generation and certainly not as pretty as that one, but good enough to test the implementation without spending more money! So, thanks for that!
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Post by mediadogg on Sept 21, 2019 17:58:08 GMT
Yes, thanks. I have a bunch of those too. I need a higher power unit, but yes, that concept is definitely the way to go.
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Post by mediadogg on Sept 23, 2019 19:15:27 GMT
It did not go as well as I had hoped. I bought the 240W version of the aforementioed buck converter, but the Lycan somehow is not compatible. Its charging input shows 10.5V at 6.1A, or about 65 Watts. My battery was well over 25V at the time. I would think that a 22AH battery could easily deliver 10A (that would equal 12V x 2 x 10A = 240W). So any ideas why I got only 6.1A from the transformer that is supposed to be 96% efficient?
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Post by bupkis on Sept 23, 2019 20:57:48 GMT
are you attempting to use a 24v battery, tranform to 12v, another tranfform to charge the 48v lycan?
what happened to the 'couple of small 12V loads'?
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Post by mediadogg on Sept 23, 2019 21:31:52 GMT
are you attempting to use a 24v battery, tranform to 12v, another tranfform to charge the 48v lycan? what happened to the 'couple of small 12V loads'? I might have used a confusing discussion. The Lycan has its own internal charging circuitry of course for the 48V Lithium-iron battery. But, externally, you can charge the Lycan from either a 12-14VDC(car) input, a proprietary AC adapter, or solar. It turns out that the solar input and the 12VDC share the same sockets (Anderson power pole). Admin answered my question about this, saying that the Lycan will switch from DC charging to MPPT solar, by monitoring the input. So, anything above 14.4V, it assumes is solar, and switches in the MPPT, otherwise, it uses the DC input to supply its internal charging circuitry. One of the 12V loads I was thinking about was possibly to use a small cheap (12V) inverter to run the Lycan AC charging brick (100W max). This way, I could use the PV for charging the battery in my garage, and run the Lycan charger simultaneously. But after the combination of the transformer suggestion, and the Admin answer, I said: "why not just charge the Lycan using 24V transformed to 12V thru the DC port?" This would accomplish the same purpose using the PV to charge both the garage battery and the Lycan at the same time. I can't use the 24V directly because the Lycan will switch to MPPT mode and try to manage a DC input as though it were PV. Not sure what would happen there. Sorry for the contorted explanation. But that's the story. Well actually there is more. The AC charging adapter is only 100W. The solar input will take up to 300W of solar. I am not sure about the DC input, but since it is shared with solar, I am assuming that it will take more than 100W. That's why I thought using the 12DC input instead of the AC charger would be better. The Lycan would charge faster. The PV can connect to only one CC at a time, so I either have to connect the PV to the garage CC and use that system to charge the Lycan, or connect the PV to the Lycan and use it to charge the 24V garage battery. I just don't have things wired to be able to do that at the moment, but that would charge the Lycan faster, and also free up the Rover CC that I am using in the garage. Fun!!!!!
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Post by tattoo on Sept 24, 2019 0:11:41 GMT
^^^^^^^^ That's to damn complicated for me.....^^^^^^^^^ No wonder it doesn't work.......
But I wish you the best of luck...........
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Post by mediadogg on Sept 24, 2019 12:43:32 GMT
^^^^^^^^ That's to damn complicated for me.....^^^^^^^^^ No wonder it doesn't work....... But I wish you the best of luck........... Cheap shot. "It" works just fine, depending on what you define as "it." I don't need advice on the simple stuff. I come to you guys when I can't figure it out by myself.
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Post by tattoo on Sept 24, 2019 12:51:28 GMT
Cheap shot. "It" works just fine, depending on what you define as "it." I don't need advice on the simple stuff. I come to you guys when I can't figure it out by myself. Cheap shot? ? ?
Didn't you say, {It did not go as well as I had hoped.}?
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