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    PV Hot Water Heating--Why Not Skip The Charge Controller?

    @efficientPV thank you, that is very helpful! Actually, I think the most useful bit may be the chart I found in the paper where your center image came from: So if I understand this correctly, with the panels hooked up directly (without charge controller/battery/inverter) to a resistance...
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    PV Hot Water Heating--Why Not Skip The Charge Controller?

    Part II: Here's where I may go off the rails even more. If I hooked a solar panel up directly to heating elements--no charge controller, no battery, no nothing--then the resistance I chose would impact the current. And the current would, in turn, impact the voltage and, thought the IV curve...
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    PV Hot Water Heating--Why Not Skip The Charge Controller?

    Thanks @Quattrohead and @Bobert OK, so if I'm understanding yall correctly--and I hope this isn't gibberish--the issue is that increasing the resistance of the solar panel's circuit, which is necessary to use that power, changes the...current?...put out by the panel. And the change in current...
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    PV Hot Water Heating--Why Not Skip The Charge Controller?

    Huh. I thought that the maximum power point of the panels was kind of in-built. In other words....I thought the panels put out what they put out. They're set to put out a certain voltage but that voltage is, in practice, modified by the temperature of the panel. And the maximum power point...
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    PV Hot Water Heating--Why Not Skip The Charge Controller?

    I'm wondering about hooking up a PV panel directly to a water heating element. I'm 99.9% sure that this is a dumb idea and I've been told that it will often be inefficient, however I'd like to understand why that is. PV and Direct Heating Of Hot Water I've seen some folks talk about using...
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    LiFePO4 Cell Balancing Hardware

    Maybe I'm using the wrong word. So let me back up and ask: What is the advantage of getting the DCC add-on? Because my existing plan doesn't have a "relay delay time board" that I know of. Unless it's built into some other piece of hardware? Is this something that I need? Here's my...
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    LiFePO4 Cell Balancing Hardware

    One final thing: @Steve_S I'm looking at the chargery store and I see the options for the DCC um, add-on I guess. I found your thread on the topic but some of it is still greek to me. But I gather that it's good to have because it protects from surge currents? Does that mean I don't need a...
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    LiFePO4 Cell Balancing Hardware

    OK, thanks yall. So I guess I'll go without an active balancer for now and then see if I need something further down the line. This is my first build, and I think the simpler the better. And I'll watch the cells as time goes on. Good way to learn!
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    LiFePO4 Cell Balancing Hardware

    OK, so I'm sure this conversation has been had before but...I just watched the Prowse Video where he says "don't use an active balancer" unless and then he lists a few situations where it might matter, including if the cells are mismatched (because you didn't buy the highest grade of cells) and...
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    LiFePO4 Cell Balancing Hardware

    Thanks Steve, I guess I'll ask Jason about the Balance Charger. Hopefully he'll get back more quickly than he did last time (it took a month)!
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    LiFePO4 Cell Balancing Hardware

    @Steve_S I know it's been a bit--been dealing with getting booted out of the campground I was going to spend winter in because of a lockdown--but now I'm back to the project, and I've got a follow up question: Any reason not to use the Chargery 5008B Balance Charger instead of the QNBBM active...
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    Portable Battery Bank Concerns

    For now. She may add solar later.
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    Portable Battery Bank Concerns

    Interesting. Any idea why it did that? And other than "being quick about it" is there a way to avoid this? Like, I don't know, using a disconnect switch?
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    Portable Battery Bank Concerns

    I've got a friend whose van/trailer build I'm helping with. She wants to hook her battery bank up to a Sterling Power DC-to-DC charger thing (so it's powered off the van's alternator). However the catch is that in the winter, the trailer will be heated but not the van (unless she's driving it...
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    Best Practices For DIY Battery Connections

    I have actually never done this one and kind of want to now.
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    Best Practices For DIY Battery Connections

    Thanks @Steve_S ! Hmm.. If I don't use the vinegar+baking sodia mix, what should I use? Also, wouldn't mixing vinegar with baking soda (in a 1:3 ratio no less) leave us with something a bit basic? I honestly don't understand the idea of mixing vinegar and baking soda to clean metals--I did...
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    Best Practices For DIY Battery Connections

    Great, that makes things simpler! Thanks. Hah, to me serrated washers are a kind of lock washer, "toothed lock washers" to be exact. Which I was planning on using. Probably should have been more precise :) Once again this is great and makes my life much simpler. OK, so from this my...
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    Best Practices For DIY Battery Connections

    I'm gathering the stuff to put my battery bank together. I've got the 280 AH LiFePO4 cells sold through @Michael B Caro, and that includes enough tinned copper bussbars to almost cover all the connections if I double them up (I need to double them up so I get enough amperage). The right-angle...
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    LiFePO4 Cell Balancing Hardware

    Oh, ok. So FET vs relays/contacts are just two ways that BMS' cut off the battery from the rest of the system when certain conditions are met. And probably it doesn't matter to me except that it might be hard to find certain sizes of the FET-based one. The chargery you mentioned looks good...
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    LiFePO4 Cell Balancing Hardware

    Is it any different from a disconnect switch? I'll have a big bluesea 300A disconnect switch between the battery and the positive buss bar.
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    LiFePO4 Cell Balancing Hardware

    Thanks @Steve_S Hmm... -I don't need bluetooth monitoring. Just need to be able to plug something in. -Hah, I don't even understand the purpose of the relay. Is that the thing that would let me shut down the inverter/charger if the BMS shuts down so that way I can plug the inverter/charger...
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    LiFePO4 Cell Balancing Hardware

    So what BMSs (or BMS/ battery balancer pair) should I look into if I want A) Something that'll give me 200 A of continuous discharge current capacity for my 24 V 280 AH LiFePO4 battery bank? B) Something that'll keep said bank reasonably balanced. I don't care if it's balanced actively or...
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    Fuse Sized For Wire Or BMS?

    For what it's worth, Samlex just put the 175A breaker size in a table and didn't provide context regarding whether it was the minimum or exact size needed. Plus they had a diagram with a breaker coming off the DC positive post of the inverter/charger, and they never specified a size for that...
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    Voltmeter Help

    Yup. You were dead on @Bob B, mystery solved!
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    Voltmeter Help

    I bet you're right!
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    Voltmeter Help

    The answer to this is probably quite simple but I thought I'd ask since I've never used a voltmeter before: When I use my voltmeter (multimeter, actually) to measure the charge on my battery's cells, the voltage basically climbs up and then drops down to zero, all in the space of maybe half a...
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    Fuse Sized For Wire Or BMS?

    Oh, I didn't know that...and I've already bought the Eaton MRBF fuse, I thought I was fine since the Samlex manual specifically said they were ok! Could you explain a bit more about this? I looked up the interrupt capacity for the MRBF fuses, it seems to be 5000 A @ 32V (my system is 24 V...
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    Buying An Extra Battery Buss Bar

    Ah, so this would be why when I double the cross-sectional area of the bar by increasing the lesser of the dimensions (say increasing a 1"X1/8" bar to a 1"X1/4" bar) the ampacity increases but doesn't double! Always great when stuff makes sense.
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    Fuse Sized For Wire Or BMS?

    Talked to Samlex this morning, they were really helpful. Thanks @Dzl I honestly didn't know I could use them as a resource, that'll be great in the future. They said that I DON'T need the breaker near the positive inverter/charger terminal because if the EVO detects a short while it's...
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    Fuse Sized For Wire Or BMS?

    Thanks @Dzl that makes sense. OK, so I'll bring my fuses a bit little under what the perfect temp rating of the wire is to make sure they blow first. And of course I'll make sure the fuses stay above 125% of the expected load. Great!
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    Fuse Sized For Wire Or BMS?

    I vaguely recall reading this too...but yeah, hopefully someone more confident will chime in. Better safe than sorry, at least with electronics. Hah, that is an important consideration. So I guess it's just between 200A and 175A. I've got a Samlex EVO 2224. 24 Volt, 2200 watts inverter/charger.
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    Fuse Sized For Wire Or BMS?

    OK, a second one: The manual for my inverter/charger specifies a particular size of breaker that should be on the line between the inverter and the positive buss bar. It wants a 175 A breaker. However, that line will also be using 1/0 AWG wire with, in a perfect world, 300 A of capacity...
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    Fuse Sized For Wire Or BMS?

    Thanks @Zil One follow-up question: If the actual capacity of my wires will sometimes be lower because they'll be in an RV without air conditioning...I can still size my fuse for the rated wire capacity, since the fuse (I'll be using an MRBF one) will be similarly effected by the heat and thus...
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    Buying An Extra Battery Buss Bar

    Right, but the numbers don't match up with that in any way I can see. Other than that the value given does get larger in proportion to the actual dimensions. For example, a 1/2" wide and 1/8" thick buss bar has a cross section of 0.5" X 0.125" = 0.0625 square inches. Converted to square cm...
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    Buying An Extra Battery Buss Bar

    Thanks Chrisski. That's a really interesting table...but now that I'm trying to use it, I admit that I'm a bit confused. What does it mean by "cross-section area"? It doesn't seem to be a reference to the bar's cross section...or at least a bar that's 1/2" wide and 1/8" thick does not have a...
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