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You are spot on with this assessment. I did the install and indeed found consumption numbers just like those you mention: Post in thread 'Hotspot Energy 48V DC air conditioners' https://diysolarforum.com/threads/hotspot-energy-48v-dc-air-conditioners.23937/post-550530 I ended up doing the...

Hah, good point, water tank is a type of battery :) I suppose there are differences in terms of space and energy loss over time, perhaps an electric battery would be smaller and lose less power when not being used, but definitely more expensive!

Any advance here? In the building science world (non RVs) there is a lot of effort around hot water heating. Yes, heat pumps are used (including split systems with the compressor outside), but a few people use electric tankless. Generally the problem here is that the electric demands are...

*somehow double posted, sorry!*

Do a manual J at coolcalc.com. That will give you room by room loads. Then you'll have some idea how much heating or cooling you need in each room. Compare that to the BTUs of the units you think you could fit. Otherwise everyone is just guessing.

I like the idea of flipping the cable! Would need a locking 30amp to locking 50amp, but that’s easy to get. And TT-30 female on the side of the RV somewhere. I don’t think I can use the second AC out in the Victron because AC-out-2 is always disconnected when grid power is not available on...

Yes, the generator interlock does this. The breaker for the generator inlet can’t be in the on position without turning off the main breaker to the grid. That’s all code compliant :)

Thanks. Confirmed we do not have any of these. House was completely re-wired a few years ago.

House has a generator inlet with interlock switch. RV has a 3000W Victron inverter with sufficient batteries/wiring to provide sustained 25amp of 120v. What do I need on the RV to enable connection to the generator inlet, to provide emergency power to the house? Two issues: 1. AC panel in...

FWIW, when my hotspot 48v system is running full tilt (like just after turning it on arriving at a campsite in 100°F weather (thanks texas), it does run at just over 1000W. So that is about 20amps (batteries are usually at ~51 or ~52v). Fairly quickly (20 minutes?) it scales back to running at...

Follow up to this. I re-torqued all the cells in the battery. There were quite a few that required substantial tightening (again, nothing physically lose but definitely below torque specs). I added the Nord Lock washers. Unfortunately that has not fixed the issue, Cell 04 is still...

Perhaps some useful ideas here: Thread 'Minimal system to charge 48v battery from 48v battery?' https://diysolarforum.com/threads/minimal-system-to-charge-48v-battery-from-48v-battery.65136/ Maybe the idea of a buck boost into an MPPT could give you the voltage needed to kick off the MPPT and...

What are the performance issues with the hotspot? Price I definitely see!

Right. I was thinking of that sensor, but working in reverse. But yeah, not thinking hard :)

Thanks. Makes me wonder, though, why don’t generators just use that technology, then no ATS no interlock etc.

I watched a youtube video from Germany about an Anker Solix "balcony" solar system. Anyone on here use something like this? https://www.anker.com/eu-de/products/b5143411?discount=WS24HES1 The manual shows that it is panels, connected to a micro-inverter, then plugged straight into an...

Yeah, review says they mounted it on a wall with no issues. Seems a goer.

Any know of a vent fan that can be mounted on the vertical section of the roof? Seems a shame to put it in the roof, stealing solar space (and creating unpredictable shade patterns). They also drive a lot of heat gain (unless mount under a panel, but then panel is so high!) Perhaps something...

To compare apples to apples, you have to look at things in watt-hours, not amp hours. or first half of this:

Pretty sure each of those options gives the same energy storage. Hence the same price. Watts = amps x volts. 48v just allows smaller wires, 12v needs such large wires for anything over 3000w inverter that it is said to be impractical.

For charge controller selection try the Victron mppt selector, can use the specs for other brands too. https://www.victronenergy.com/mppt-calculator You’ll have a total of 400 amp hours at 12v which is about 5KwH of energy. If your AC draws 1000W an hour that is 5 hours run time. But they often...

Yeah, I'm also not sure about "rated" vs "max continuous" vs "surge/peak". Or rather I think I understand "continuous" vs "surge" ("surge" or "peak" is for a very short time, Victron shows that time for each piece of equipment, but it's usually from less than a second to a few seconds). But I...

My impression is that "passthrough" means when the inverter is connected to the grid. It can "pass through" AC current, meaning that the inverter is not converting the DC power in the batteries to AC, but just passing through the AC current from the grid. Conversely, AC output power would be...

Jakiper has been great. They have consistently answered emails, made videos to show how to do needed service. You can see those videos on their channel. They sent a new individual cell to replace (although I'm hoping I don't need to). I mean better that no service was needed, but they've...

I think you just add their PV kit to each foot and then no strut needed.

My understanding of this is that you can't use voltage to see differences in charging (ie one cell taking more or less) until the very top/bottom. Because both cells could be at 3.2v but one have charged to 20% of capacity and one to 80% of capacity. Then the one with 80% of capacity will show...

When you say “top balance already done” what do you mean? What capacity is the battery showing? I had a similar experience and worried about it for quite some time. In the advice of Jakiper, I did use a torque wrench to confirm all connections were up to spec. That helped some. I’ve had to do...

Hmmm, learning over here. I thought lock-washers created tension, but now I read they just create additional friction with the cut edges. I think I'll explore the nordlock washers.

I just meant that perhaps some refridgerators have lower surge requirements, in the way that "inverter driven" AC units (e.g., mini-splits) don't have the same surge requirements as non-inverter driven AC units. So just spit balling by analogy :)

You might also check whether the equipment really needs that power draw, or whether it's being used to cover surge and inductive loads from the refrigerators/freezer compressors. You might be able to get those down using fancier inverter driven equipment, or explore the "soft start" (slight pun...

Interim follow-up here. We took the camper on the road, with both batteries in place. I had the problematic one turned off. After about two weeks, including national forest camping down a quite bumpy unpaved road (4 low gear) the other battery started showing issues. It would shut off under...

Yeah, I’m thinking this is a good application for an all in one solar generator as the truck/remote system. Plug the 30amp in, charge the RV batteries, all done. And then useful mobile system rest of the time.

True story. But also one would loose like 10-20%, on the trip from DC to AC to DC, no?

Ah, so the booster would always keep the voltage coming from the donor battery higher and therefore power would keep flowing. Got it, thanks!

Thanks! I’m not entirely following why a booster is needed? This is 48v to 48v (ie not boosting from 12 or 24). But is it to boost the voltage high enough (eg +5v or so) to drive the MPPT to charge the RV battery? Maybe that was obvious to others :)