I'm interested to find out if you find any large differences in their internal resistance.
Ray Builds Cool Stuff's videos on the Apexium 280 battery box and other battery builds have been very helpful to me. I just got some MG 847 in the mail, and plan to use it to reduce resistance in the...
Maybe, if I don't understand you correctly. Higher temperatures cause increased pressure in a closed system.
Argon with at least 32% helium works with graphite heating elements (see study at https://www.sciencedirect.com/science/article/abs/pii/S0008622317301689).
@Fluff34567 I recommend you ask Jenny Wu directly at jennywu896@gmail.com, for 2 reasons:
1. She gave me multiple options for the cell quantity, capacity, manufacturer, and chemistry (she offered sodium batteries), and the case, BMS, and cables she provided are designed for the cells I...
If you purchase this kit with the Seplos 10E BMS, Andy at the Off-Grid Garage on YouTube has a series of videos about configuring that BMS which I'm finding very helpful; I'm working through this one right now:
The whole battery kit is working quite well for me, but I'm uncertain whether it's...
Here you go. https://www.ebay.com/itm/196652863982. But it's only rated up to 2000C or so, because it's silicon-based. The best things in life can't be bought.
Perhaps the same process () could be used with carbon fiber to withstand higher temperatures, or a carbon aerogel could be fun...
I'm designing a solar power system for my trailer, to permit me to power my computers during work hours and travel with my family. I want to insert an all-in-one and LiFePO4 battery into my RV's existing electrical system, which includes an AC to DC converter, but I'm not sure about the precise...
To make a 48V battery with at least 17.9 KWh of capacity, I intend to buy 5 packs of 4 Lishen/Eve 3.2V cells, which is 20 cells. I can make a 48V battery using 16 cells in series, making a 16S1P battery, but then I’ll have 4 cells left over, unused. I want to use those 4 leftover cells in...
Thank you for this feedback; I need it. I have not bought the cells yet. My goal is to have a battery with at least a 16.1 kWh capacity, to have 3 days' worth of capacity to handle a 5.38 kWh/day load. 20 3.2V Lishen 280 Ah cells would provide that capacity, but I've been unsure whether there...
I've made a diagram of the system I'm designing at https://diysolarforum.com/threads/5kw-48v-system-sizing-circuit-safety-check.23725/. I've found physical locations for each component to be mounted in the trailer.
I haven't bought the AIO yet, but would like to buy an MPP Solar LVX6048...
Monomer
Here is a helpful etymology and definition of the word "monomer."
The "monomer" voltages in the app are in the normal range for single LFP cell voltages. So in the BMS Bluetooth app, it's pretty clear "monomer" means a single battery cell. I see the word "monomer" is used online...
He does exist. He was right to caution me that I needed to be sure the all in one has adequate ventilation to dissipate the heat it will produce; I think that was the main point he was making.
Thank you. The manual at https://watts247.com/manuals/mpp/PIP-LVX/LVX6048%20split%20phase%20manual-20210312.pdf?x65773, p. 28, says the LVX 6048's "Max. Input voltage (Maximum PV open voltage)" is 450 VDC. So I believe the 260 V the arrays I'm planning could produce should be far enough below...
In every shading scenario except where the last panel in a series is shaded, the TCT interconnects permit the voltage of each series to be equal at the point where their positive output wires are joined in parallel; bypass diodes in a SP configuration don't. I'm not sure whether that will...
My 11 year old son figured out how to isolate faults like this in the array. See his diagram at https://www.facebook.com/photo/?fbid=10160460204840847&set=pcb.10160460235695847 and the broader context at .
As I mentioned at ,
Our panels are in a 7 series 3 parallel array, labeled 1-7 and A-C, respectively. We tried shading various panels in the array to see how it affected the whole array’s open circuit voltage, so we can discover if a total-cross-tied configuration produces more power under the...
Bricks vs. rocks vs. sand vs. water vs. LFP.
Here's how I'm sorting this out.
My goal: I want to store excess solar PV power & heat collected from my solar panels as high-grade heat in a sand battery, to use directly as hot air to cook & heat. To store the most heat, I'd like to use graphite...
You're right! I see graphite insulation exists and is stable up to 3000C in a vacuum/inert atmosphere, but it looks very expensive. Graphite is not expensive. Perhaps there's a way to make graphite foam cheaply.
You're correct I have not calculated the insulation thickness yet.
Interesting. This sounds like real top balancing, because I would still actively and personally monitor each cell's voltage. The fact that it uses the BMS's active balancing to accomplish the goal of top balancing does not obviously show me that it is anything different than real top...
I'm assembling a Apexium 280 battery box I got from Jenny Wu / Docan Power. Its build quality seems excellent. I noticed there is a small gap between the left group of cells and the central metal frame member. The gap is about the thickness of the foam pads provided in the kit. The assembly...
Just for reference, in case someone wants a text description rather than just a diagram, I described the idea in the original battery layout above at https://diysolarforum.com/threads/mixing-12s1p-4s2p-to-stay-at-48v-but-increase-capacity.23215/, and asked if it would work.
https://diysolarforum.com/resources/top-balancing-lifepo4-cells-using-a-low-cost-benchtop-power-supply.65/ includes "Appendix B: Step-and-Pause top balance" and "Appendix D: Top Balance using an active balancer," which are basically the same as some of the recommendations here which are not the...
Ray Builds Cool Stuff's videos on the Apexium 280 battery box and other battery builds have been very helpful to me. I just got some MG 847 in the mail, and plan to use it to reduce resistance in the connections. I plan to sand the contacts WITH the MG 847 to prevent any new oxidation from...
The fellow behind the counter at a solar store gave me some good advice, but stated a few things on which I'd like to get a second opinion. Here's one: The MPP Solar Hybrid LVX 6048 all-in-one inverter will waste excess power coming from the solar panels by burning it off as heat.
Is that...
The fellow behind the counter at a solar store gave me some good advice, but stated a few things on which I'd like to get a second opinion. Here's one: 8 AWG wire could handle 9.6 A over 40 feet if there were only 1-3 panels put in series (creating 37 - 111 V), but since I plan to put 7 panels...
I got the slightly more expensive Eve 304Ah cells, expecting their actual capacity would be higher than the 280Ah cells, but says the 280Ah (version 3, 8000 cycle life, actual capacity 315-316Ah) is actually better than the 304Ah (version #?, 6000 cycle life, actual capacity 316-320Ah). Oh well!
I purchased 16 LFP cells and an Apexium battery box kit which includes a BMS from Jenny Wu. Everything seems to be in perfect condition. I am very pleased.
On my first voltage test after opening the boxes, 12 of the cells each have 3.256 volts. The other four cells vary by only one millivolt...
I set absorption, float, and inverter cut-off values in the LVX6048 all-in-one, rather than in the BMS. It appears this is the correct place to put those settings. So that satisfies my main concern. I still want to know if I should change any of the settings in the BMS; I'm not sure what they...
I assembled the Apexium 280 battery box, and am trying to set the charge profile in the BMS Bluetooth app. Here are the default settings that appeared when I opened the app.
https://photos.app.goo.gl/XksgCUqSC4hkMQ9q6
I want to set this charge profile, taken from...
I appreciate your taking the time to give me your opinion and recommendation regarding a better way to go.
How are you arriving at that that conclusion? If that conclusion is correct, then I can see my original question is not worth answering. However, that conclusion does not appear to be...
I appreciate the recommendation to favor parallel strings. That requires buying more wire. Space and weight are at a premium on a camping trailer, so some might welcome a 10% performance improvement from a TCT array. The increased cost and complexity of a passive TCT configuration amounts to...
Hm. https://www.mobile-solarpower.com/design-your-own-12v-lifepo4-system.html says "Inverter Cut-off: 42.8V-48V." I didn't know whether to pick the high or the low end of that range, so I picked the low end. But looking closer at the voltage curve and charts, I think 3.0V (48V pack) is as low...
Background info
I have an MPP Solar Hybrid LVX 6048, which uses Maximum Power Point Tracking (MPPT). TCT refers to a "total cross-tied" panel array wiring configuration, like the configuration pictured at https://www.researchgate.net/figure/Total-Cross-Tied-TCT-configuration_fig2_316359468...
Thank you for this warning. I considered it as carefully as I could and so did some more research to verify whether your concerns are a reason to change the TCT design I'm proposing and testing here. Your concern is that too many amps could flow through one panel, and so burn up its diode or...
The shading scenario I have in mind is an array on top of a camping trailer which will be in many different shaded environments, like forested campsites.
Hi,
I'm designing a 5kW 48V system to upgrade my camping trailer from having 12V batteries and a 120VAC to 12VDC converter to having 5kW of solar panels, a 48V MPP Solar Hybrid LVX 6048 all-in-one, a 17.9 kWh 48V battery, and a 48V-12V DC buck converter. My current design is attached. Did I...
It appears I was wrong to think this BMS has active balancing. Rather, it appears it uses passive balancing. I've corrected my posts above accordingly.