Best UPS for H2D

[NeverDie]

At least initially I’m using the DJI 1000, which can deliver up to 2200w continuous. It was $379 on amazon from Black Friday through Christmas, though it has bounced up since then. It can be limited to not charge faster than 600w.

It’s not truly ideal though, as I think it’s not likely to engage unless the mains voltage to it fails, which is what I want to avoid. So, for my purposes, I disconnect it from mains while heating the H2D to temperature, then reconnect. This is seamless, and at that point, the circuit has plenty of headroom.

More ideal would be a double conversion power source, where the input watts can also be rate limited. This way the H2D would only draw upon battery power at all times, and the battery just acts as a buffer during the initial power up of the H2D to temperature.

In general, the batteries on a double conversion type probably doesn’t last as long as the kind that switches over only when needed. However, given the large number of charge-discharge cycles most LiFePO4 batteries now claim, that may not matter from a practical standpoint. More than likely most quality LiFePO4 batteries, especially if of the EV type and so built to automotive standards, will age out before they wear out, at least for anything I’m likely to use them for.

Of course, all this may be overkill. I’m just being extra cautious at the beginning, until after I collect my own measurements. Thus far, according to my emporia smart plug energy monitor, H2D draws a peak of 1469 watts while running the calibration from the console. That’s higher than the 1320w peak for 110v in the H2D spec sheet:

My 1469w measurement was with no AMS connected. This peak lasted for less than 30 seconds. Emporia states that their smart plug energy monitor accuracy is within ±2% of actual energy usage. Go figure. It probably pulls more than the rated power since my mains voltage is probably closer to 115 or 120vac than to 110.

Regardless, the DJI has enough amp hours that it will sail through just about any non-catastrophic blackout without pausing for even a moment, which is nice belt and suspenders.

Anyone else have a preferred UPS or other power source that they like to use for H2D?

[jspikeball123]

Yeah, I was using a 1500w UPS from like 20 years ago and the cable was getting pretty… melty. I would certainly recommend a newer +2kw on 120v at least. This thing peaks in power similarly to my welder. I don’t have a UPS anywhere near that level.

[mscott]

The DJI 1000 doesn’t appear to be a true UPS, however. It says to unplug it when it’s charged so it would appear to require a fair bit of manual intervention. Although it could be used with a source transfer switch, I suppose, like the Eaton Pulsar STS line (but the 120V version seems to max out at 1400W, which isn’t enough).

I’ve been investigating UPS options, and there are a lot more options with 240V equipment, but you can’t get a 240V H2D in the US. Finding a UPS that can handle 1500W is pricey. Finding one that isn’t meant for a server room (i.e., reasonably quiet) is even harder.

[krellboy]

@NeverDie

It’s not truly ideal though, as I think it’s not likely to engage unless the mains voltage to it fails, which is what I want to avoid. So, for my purposes, I disconnect it from mains while heating the H2D to temperature, then reconnect. This is seamless, and at that point, the circuit has plenty of headroom.

Does it have a solar input? I don’t know how these work, but if you feed it 500w solar can’t you still draw 1000w ac out?

[NeverDie]

@krellboy

but if you feed it 500w solar can’t you still draw 1000w ac out?

Good point. Unlike most power stations DJI requires an add-on dongle to charge from solar or DC, but with that add-on you’re exactly right. Yes, that should do the business. And it should be able to draw the full 2200w output continuous–not that it would ever need to go that high–since it would be pulling from the battery rather than a pass-through. With the 12v adapter, it can charge at up to 1000w (meant for charging from a direct connect car battery with the engine running, without stalling the engine, but any sufficient DC power source should do just as well), which I’m fairly sure is well above whatever worst-case average the H2D might ever draw. The 1000w adapter is effectively like an MPPT controller: it will take whatever power it can without crashing the input DC voltage below some minimum threshold. So, if I wanted to charge it at a lower rate, I should be able to simply supply it with less power, within reasonable limits, and it will adapt accordingly.

Usefull workaround! Effectively converts my DJI into a double conversion topology, giving the option for the best of both worlds. In so doing, it eliminates any switchover time as well. That being the case, whether it’s advertised as UPS or not, in this configuration I don’t see why it wouldn’t qualify as one, at least for this application.

[NeverDie]

Just now started my first print from the slicer, and initial power draw is 1575w according to my emporia smart plug energy monitor, maybe (?) because I increased the heated bed temperature to 70C from the prior default of 55C. Go figure. I wonder if there are settings which will drive the initial power draw even higher?

So far I have adequate headroom as long as I’m not running any other high current draws during that roughly 30 second time period. Most often I’ll probably run from a UPS anyway, though, given its other advantages, and that will render it moot.

Maybe someone with a kill-a-watt meter, or similar, will want to confirm and post their finding?

[krellboy]

@NeverDie

With the 12v adapter, it can charge at up to 1000w (meant for charging from a direct connect car battery with the engine running, without stalling the engine, but any sufficient DC power source should do just as well), which I’m fairly sure is well above whatever worst-case average the H2D might ever draw.

12V 1000W is a very thick cable. Doesn’t it have a higher solar input voltage?

[NeverDie]

@krellboy

Doesn’t it have a higher solar input voltage?

Good point. Yes, looks as though it can accept an input voltage anywhere in the range from 12-45v:

The full device listing itself is: Buy DJI Power 1kW Super Fast Car Charger - DJI Store

I bought one purely for emergency backup purposes, and it’s still sitting in its unopened box. I’ve not even tried it yet, but maybe now I have a reason to.

I think it may be at least marginally better than just a brainless boost converter that will try to pull 1000w from anything it’s connected to, even if it means bringing the power source to its knees. I say that because not all car alternators can provide that kind of continuous wattage without overheating and burning up in the process, and it’s presumably designed to avoid that kind of catastrophic outcome. Ecoflow was the first to market with an 800w version, and not long afterward others, like DJI, followed with what I presume are similar offerings.