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I've used the MK3-USB with an Android phone, a Mac laptop, and a Windows PC. VictronConnect on the Mac laptop never felt like it worked well to me, it would disconnect while I was editing settings. This was several years ago, so maybe things have changed. The Android phone and Windows PC worked...

If you're looking to save costs, it is helpful to know how much power use. Things like lights are easy, if they're on, they're likely using the watts they say on the label, other equipment is harder. A residential refrigerator typically runs the compressor for a while, then is mostly dormant...

I wish inverter companies would stop recommending this paired wired thing. IMO, substituting a pair of wires is asking for trouble. If one of the pair (on + or -) has a problem (loose crimp, bad connection at one end, etc) the other wire in the pair will have to handle the (at worst case) full...

Are you looking for a pre-built solution or are you looking for advice on how to build your own? If you want to build your own (please be careful, inverters have high voltage components!) here are some ideas. You'll probably need an MCU (like an Arduino) or maybe a Rapsberry Pi. This would...

Ya, each mfg seems to have their own idea of configurability. I was surprised my VW eGolf had the following: - Set immediate charge level (go to X% as soon as you plug in) - Set recurring schedule for "be charged to X% (typically 90% or 100%, but could be something X) by 6AM M-F. I could have...

Yep, Level 2 charging is 240VAC (single phase) or 208VAC (three phase) and a min of 6A. But at that 6A min, you're at ~1.4kW, which you could also get from L1 charging on 120VAC. Finding a 24V inverter that will do ~220V/60Hz for the US may be tough, if you find one, post here! Many modern...

Wire gauge vs current is really about heat dissipation. For wiring in a bundle or enclosed space where shedding heat may be a problem, current ratings are typically lower. I typically use the recommendations on this chart: https://www.powerstream.com/Wire_Size.htm On that chart "chassis wiring"...

It seems like you're asking too much of the batteries and the wires. For the wires: are they 5mm diameter (about 4AWG) or 5mm^2 cross section (about 10AWG)? I mean only the conductors, not including the insulation. The size should be marked on the jacket. Depending on the jacket, 4AWG can...

There are a few different ways. The easiest for you would be something like the Victron battery monitors. Look for Smart Shunt or BMV-702. The former has no display, you connect to it from your phone via Bluetooth (so limited range). There are cheaper shunt-type monitors, but the Victron ones...

I'm going back to the OP's statement about "double conversion UPS" having to worry more about ripple. I can only guess this is because the AC->DC converter/charger is always on, vs AC going directly to the load through a transfer switch like a standby UPS. How is this any different from a...

Thanks! I'll check those out. The varying duty cycle of MPPT feels similar to what is needed for switch mode power supplies. Double conversion isn't required, it's just what I did with external gear because it was easy. If I can find a component that act as a fast enough transfer switch (it's...

Heh. Agree. In fact the DIY (putting together lots of components, but not building your own PCB) is my current level of DIY when it comes to electronics. But, I guess I want to "dig deeper" as you say. So, I guess I'll spew out notes here, but any suggestions or help is appreciated. I've been...

Thanks for the reply! To be clear, I am not asking: "Can you help me get to a bigger UPS?" I have something working based on a separate converter/charger and inverter. It's been running since July. I've posted about it in a few threads here. The batteries are sized to power the needed load for...

@JoseMR I also recently hacked together a "big UPS" and I was missing the "notify something else so it can shut down" functionality. I solved this with an Arduino running this library: https://github.com/abratchik/HIDPowerDevice and my own code. I needed some extra hardware to do AC on/of...

Ya, that's a thing I've thought about. It's not as trivial as I'd like. I've got two groups of devices - Things that take DC-in (via wall warts): ISP gateway, router - Things that have multi-rail AC/DC: NAS and POE switch. The first group is pretty easy. Just provide DC-DC converters for the...

Ok, I bumped the peak bulk voltage up a bit, tested with the inverter to check the OVP wouldn't trip, then just let the Powermax charger/convert run with only the batteries as a load (inverter turned off). Since I thought the battery was nearly full before this, I was hoping to see if the...

I know it's tough showing up here and asking questions as a beginner. Glad you're here! The reason everyone keeps harping on "what do you need it to do" is that enough new people have shown up here asking for help that we've seen that there isn't a good "average case" for how much people need...

The general rule of thumb is you can do up to ~3000W (some say 2000W) on 12V. If you have a bunch of 12V equipment already, aren't going to exceed 2000W then that may be easiest. However, 48V systems are generally "the new hotness" so lots of gear is coming out to support 48V. If you have gear...

Thanks for the link, I'll check that out. Opening it up and posting pictures may be useful just for understanding what would be required if I decide to build my own from scratch

I guess I should have said: The other option would be an already built "UPS head unit" type thing that could handle 12 or 24V, was configurable enough for various chemistries, and could handle the >300W AC output. I don't think anything like that exists. I wish it did. That feels like a...

I've posted in other threads about a DIY UPS I have working. It's a collection of bought components (some I had on hand). It's an inverter, a charger, and a battery bank. Technically, this is an online double conversion architecture. The inverter is running full time. I've had this running...

Ya, if I'm going over $1000, I'd start looking at Samlex, Victron, etc. I have a Multiplus 24V 3000VA in a different project. For this, it's much less critical and sort of a passion project so I was trying to go cheaper especially since my power needs are so low. It looks like there just isn't a...

A 12V 800Ah battery has 12x800=9,600Wh (9.6kWh) of power capacity. A 48V 800Ah battery has 48x800=38,400Wh (38.4kWh) of power capacity. That's four times more. It will be roughly four times heavier and roughly four times more expensive. Think of a Wh (watt-hours) as similar to a gallon of...

Quick update: As of this morning. The voltage is at 12.91 under load, so it appears the Powermax stepped down to Storage Mode sometime overnight. But it's a bit lower than I'd like.

Ya, I guess maybe the size isn't so relevant. >500W more is fine. Price is really what I'm after, so I guess I should look at what is possible for pure sine wave inverter/chargers at <$350 and then maybe <$500? Dunno if anything reasonable exists at those prices.

With high gain directional antennas, you can overcome some of these, but not all. About 20 years ago, my home internet link was service from a neighborhood co-op ISP. Standard (2002 era) consumer 2.4 Ghz wifi radios with 24dBi parabolic antenna on one end and an 8dBi omni on another. I think the...

I don't quite follow. When you say "reduce the voltage and use what I have", what do you mean? Do you mean just accept the problem of the current inverter? Thanks, that's the default. I would still like to hear options for a small charger/inverter. It's not needed, but I'd be happier with a...

When I wrote the above, I had a vague memory of a few StackExchange posts talking about this. I went back and found a (new to me) post that does a pretty good job of explaining it: https://electronics.stackexchange.com/a/544036/20244

Just to be pedantic: USB-PD (USB Power Delivery) is not specific to USB-C. It is totally possible to do USB-PD over NON USB-C cables, it's just rare. USB-PD is spec which defines the protocol for source and sink to negotiate power over USB. It allows for more than the old 7.5W maximum, and...

Thanks for the reply! I agree the lack of flexibility isn't great. It was cheap and I knew it would likely handle 24/7 DC output because as you said, it's intended to both charge and power the DC side of an RV or boat from shore power for long periods of time. With my settings (14.4, 13.4...

I have built a DIY UPS for my home network rack. When I built it, I had an inverter already, found a good deal on the batteries, so I just bought a RV converter/charger to and build a double conversion-style UPS. It's been running fine since July and in the last few months I added an Arduino...

Following up with what I ended up doing: I stayed with the existing gear in my OP (separate converter/charger, inverter, Arduino inside the converter/charger). I really wanted voltage monitoring to give a rough estimate of remaining battery, so I added some more modules to sense the DC power...

TL;DR: For various reasons, I'm using 14.4V bulk, 13.4V absorb, and 13.0V float voltages for an AGM SLA battery bank. Is this ok? I'm concerned the batteries might never get fully charged. Full background and question below: Background I have put together a DIY UPS for my home network rack...

Mouser, Newark, and DigiKey have a ton of electronic components. Price of components in bulk is usually better than Amazon, but shipping is (usually) slower.

UPDATE: I thought Will did a video about this. Found it: Someone else will probably explain, but I'll give it my best here: The DC input of an inverter has a set of large capacitors. One great thing about capacitors is they can charge and discharge *REALLY* quickly. But, to the DC source...