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The problem with a simple priority system as I propose above is that the 3rd priority unit will be starved under extreme conditions. If the first two units call for cooling most of the time the temperature in the third will creep up over time and the temperature difference will grow...

Fairly trivial relay based HVAC priority circuit. Supports three AC units and three thermostats. The first and second control their respective AC units directly - their signals are passed through. The third only runs if 0 or 1 of the first two units are running. If both of the first two...

Design can be found here, should be easy and cheap to produce via jlcpcb, pcbway, or any similar service. Of course it could be easily hand wired as well. OSHW project: https://oshwlab.com/stienman/priority-hvac-cooling#P4 Open in editor...

This is a complicated problem, and there are several levels of solutions. The problem I have is that without knowing the worst case scenario for the home in question then we're all just shooting in the dark. Assuming these only provide cooling and not heating then it isn't as bad since you...

Regarding holes in bus bars: yes, they must be accounted for. There are design guides for that, and here is a general overview on how to go about dealing with busbar sizing in general, and how to use that general guideline to account for holes and tabs...

When discussing battery current you should look at the worst case scenario, which is usually the highest current at the lowest system voltage. If you're running LiFePO4, then the lowest voltage for a 16S pack is 40V. Assuming you don't take each cell below 3v (ie, set up the inverters to turn...

I've updated my post. Thanks for pointing out the error!

As soon as they pop up on the Amazon Vine review program, I'll snap them up and review them! [crickets]

Aw! My high school chemistry teacher would be yelling "REMEMBER TO WRITE THE UNITS CORRECTLY AFTER EACH NUMBER". Weeeell, adjust all my numbers by 1,000 in your head(s), I don't have time to fix it now.

A 50A semiconductor is cheaper and more efficient (less heat lost) than a 200A semiconductor. So higher voltages will always be preferred. Stronger magnetic fields with less copper, again another bonus. This on top of wires that are 1/10 the copper of our low voltage systems for the same...

Edit - reviewed and fixed due to cal vs kcal error. The reason we don't store energy overwinter like we store food is that there is a 10x difference in daily needs of food compared to electricity. We need about 2,500 watt hours per day of food, but our houses consume around 29,000 watt hours...

I was surprised during our snowstorm with 1"+ coming down per hour starlink stayed up. It wasn't great, but we still had 2-3 streams going at once and only saw buffering a few times. In the field of satellite communications, Starlink has an incalculable advantage in that they effectively own...

The OP is not wrong to complain. SS is not wrong in their fraud detection and notification strategy. We can hold both of these contradictory statements as true, and if we assume that both parties are doing their best to resolve a difficult situation then things will probably go better for...

The supposed EV that would be charged by their device and would undergo a test run for 12 hours without recharging externally doesn't work: They've cancelled the demonstration without a future attempt date, and without explaining what went wrong or what they're doing to resolve the issue...

Check the product specs of your fridge, but the one I looked up (CRD55) supports 12v and 24v DC, and on the solar input supports 12-50vdv. So the only thing you really need is a way to get the DC connected from the dewalt battery into the fridge, which already exists. Search for "dewalt power...

A pair of right angle needle nose pliers also works really well since you're able to pull in the same direction you're trying to disconnect the cable in.

There are too many preferred outcomes so there is really no universal rule. What do you mean by "cell death"? If not abused, then a LiFePO4 will continue to be useful long after it drops below 80% of it's design capacity, and that 80% figure is what most companies appear to aim for in their...

Can't trust the straightness of plastic rulers. Use a metal one to measure your terminals like that. ;) (I'd better put a disclaimer here - some people won't realize this is a joke. DON'T DO THIS. METAL CONDUCTS. BIG SPARKS AND LOUD POP. HOT.)

If it's going to be done, though, I think this is the way to do it - start with an existing, no-solar plant, and bring in a small amount of solar to supplement the heating system. Check the results over time to see what cost savings is acheived, and if good then expand. If not it's no big deal...

Except in very high current situations (ie, 1C charge/discharge) the only matching to be done is based on capacity. Individual testing is the go-to for capacity testing. If their capacities are close to each other (within 2-3%) then it doesn't matter how you gang them. The worse the match is...

Out of curiosity, since old, used 3 phase transformers are cheap in the US (ie, https://www.ebay.com/itm/334855546358 shows a $400 45kVA three phase) can a 3 transformer warpverter be made using a 3 phase transformer form? I suppose a 4th transformer could be added for the tiny one if THD was...

Just a quick note: MPPT controllers have a distinct advantage over this one, which is that users don't have to set them up, nor change their settings if their array is changed. Plug it in and then ignore it. As your data shows, once you're close to MPP rating of the panel string the power...

Given enough time every diysolarforum thread turns into a compression thread. Please consider taking compression discussion to one of the many, many, many threads dedicated to various aspects and assertions regarding compression...

Here are a few resources you might enjoy reading regarding positive ground electrical systems: https://diysolarforum.com/threads/what-is-a-charge-controller-with-a-positive-ground.7007/...

The technical standards are available. My question was more about whether a tesla would accept a charge from a low current DC source, assuming that all the protocol and other connector/communication requirements were met. It's still a 6kw DC solar array, so at 400VDC it would be about 16 amps...

Jim Cleaver is starting his attempt at a cross-country trip in an electric vehicle solely powered by solar panels he's carrying. Looks like a tesla, Sol-Ark, SOK 5kwh battery, and 64 100w flexible panels. Here's his first video: And here's a technical overview of the system hosted by Munro...

Each MPPT controller has a maximum of 12.5A input, so you definitely don't need 10AWG. Maximum current should be 9.4A per pair (short circuit panel current * 4). But you are correct - I did not take into account the fact that each combined string needs its own pair of wires, and that may result...

That is either 1) incorrect or, at best 2) misleading. MPPT charge controllers have a few ratings. - The maximum input voltage is the one which, if exceeded, will result in damage or malfunction. - The operating voltage is the range in which the MPPT will perform the MPPT algorithm and...

I agree. The four panel strings are about 370 VMP, and with a 20kW (effective - 80% of 128 panels) energy input it'll be 54A on the long wire. If converted to 240VAC before the long wire you'll be pushing 80A, with 50% more voltage drop, or 50% more copper at the same voltage drop. Further...

Well that's concerning. I suppose I'll need to examine my connectors to confirm they are in good condition and aren't leaking. I'm guessing they are leaking/corroded, though, because while the solarcity H6 inverter ran without issue the first year I used it when the panels were first...

On the connectors with the shrouded release tabs (where the plastic bar covers the entire release tab) I use the tool at an angle to go around the shroud, so the tool squeezes the shroud and the shroud presses the tabs in far enough to release. It's not a clear, quick, easy disconnect, I usually...

Our speeds slow down for heavy downpours, but I've been surprised at how well it handles weather. But here in Michigan we don't get rainstorms with so much water it hurts to be outside in them, so I'm sure it's worse in the south. I've never noticed handoff. My understanding is the dish is in...

In a roundabout way. Most inverters with internet connectivity have a way to change their settings, and you can change the settings so it would force the inverter on or off. Very few have an explicit on/off button in a remote app, though. You could always use a switchbot. I suspect...

Yeah, that's pretty terrible. Make sure the starlink is absolutely stable - if it's teetering on three legs and the wind can move it then you'll experience the problem you're describing. If you're in a windy place you may need to weight down the legs to make sure it doesn't move. Even a tiny...

Ouch. I assume that if you have air conditioning it's an inverter style AC, or you already have a soft start on it. I've wondered if adding an auto transformer to the system would take care of the start up surge for small motor loads like these for HF inverters. In my LF system (growatt 12k...