Please explain the jump in reported AC power usage when plugged into shore power?

DIY
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1

I have a 24Vdc/690Ah lithium batteries managed by a Quattro inverter/charger with a Lynx shunt and a Cerbo GX in my Ford Transit conversion van. The system is updated with the latest firmware.

I have an induction cooktop appliance powered by 120Vac. With every other AC breaker off except the one for the cooktop, the Cerbo GX shows 26W AC power draw when unplugged from shore power. But when I plug into shore power, it jumps to 340W. Though plugged in, the cooktop is off in both cases. Why the jump from 26W(unplugged to shore power) → 340W(plugged to shore power)?

2

Maybe your batteries being recharged?

3

Thanks, but that’s not it. Two things.

  1. This happens even if my batteries are at 100% and my Quattro is at “Float” state
  2. If I turn off the breaker for the cooktop, I read 0W, as expected.
4

My first suspicion would be the AC Out 2 …

What else have you connected to your system?
A small diagram would be great …

5

Thanks for taking the time to respond @Netrange. I don’t have anything connected to AC Out 2 since I want to be able to use ALL my AC appliances all the time.

I’ll try to post a simple diagram soon, but it’s nothing complicated. Maybe this simple text layout will help

Car alternator/battery → Renogy 3000 12Vdc/120VAc inverter → Quattro AC1 In (Primary)
Shore power → Quattro AC2 In (Secondary)

Quattro AC1 Out to AC breaker panel, which then feeds my AC circuits. NO connection to AC Out 2

Quattro 24V DC out to Lynx Distributor
Lynx Distributor connected to Victron Power In
Victron Lynx Power In connected to lithium batteries (which are fused at terminals)

Victron Lynx Distributor goes to DC panel, which then feeds my DC loads.

6

I don’t know how the Quattro works, but for the Multiplus, the AC IN 2 goes to AC OUT 2 circuit. So maybe it is looking for something that isn’t there? Wouldn’t explain the 0W is you turn off the cooktop.

7

I don’t think the Multiplus has 2 AC inputs, which is why I chose the Quattro.

8

Does it stay at 340W? Or just jump up and then settle down? I assume the latter?

If so, a few thoughts. Could be a grounding issue? Using the vehicles built in Inverter a second input to the Quattro is a cool idea I haven’t seen before. But, that alone makes me question the setup. Does this occur if the Vehicle inverter is disconnected? Not just off, but disconnected?

9

It stays at 340W.

I don’t use my Ford Transit (in USA) built-in inverter. Instead, I use a Renogy 3000 inverter, like this

12Vdc alternator/battery → Renogy 3000 12Vdc-to-120Vac → Quattro AC1 input

So it’s essentially a generator. It’s a common practice from what I gather, at least to the Ford Transit van conversion community.

My Quattro’s AC2 input is connected to shore power. I will soon switch the 2, so AC1 input will be shore power, and AC2 input will be the Renogy 3000.

When this happens, my AC1 input (currently the Renogy 3000) is not powered on. The Quattro is only receiving input from AC2, currently shore power.

10

Not an answer but observations/questions:

  1. I guess 12 vac is a typo and that should be 12vdc/120vac?
  2. Where are you reading the cooktop draw values: on the Cerbo, on VRM or both?
  3. What do you see when both AC in-1 and AC-in 2 are off, if you have that option?
11

Hmm Okay. I slightly strange wiring scheme, but it should work all things considered. Maybe next time look more into an Orion XS? You probably did, but that my thought.

Regarding the AC Loads changing after plugging into Shore, my thoughts still land on a grounding issue. I think @Fideri has the right idea to troubleshoot that. Turn off/disconnect both AC Inputs, then connect 1, then the other, then both, and record the Load draw. Also, knowing how you are recording this could be helpful too.

12
  1. Yes, 120Vac (I corrected it)
  2. I’m reading the AC out draw from the Cerbo GX via Touch 50
  3. When not connected to any AC input, either AC1-in or AC2-in, I see 24W AC draw.
13

How is it strange? Different maybe. I chose DC->AC->DC instead of DC->DC charging to utilize my Quattro’s 2 AC-ins and built in transfer switch.

14

You just lose a lot of power going between AC and DC. So its just inefficient is all. Hence the strange. But it’s not a problem if you’re willing to burn a little extra gas.

15

I have a dual alternator/battery setup in my Ford Transit designed specifically for this purpose. So the DC->AC->DC charging system is only utilized while I’m driving. But you’re correct, the DC->AC Renogy inverter operates at 90% efficiency (as most inverters do).

16

@ZillaG62 I read your original post again. I had missed a few things which might help isolate the issue:

  1. If I understand correctly, AC in 1 = batteries/alternator → Renogy inverter → quattro → cooktop
  2. AC in 2 = shore power → quattro → cooktop

So the quattro is not connected to the batteries without going through the Renogy inverter? It has no DC power? So what’s its use? Or the Renogy is only connected to the car battery and the Quattro to the lithiums?

I would expect the cooktop to use about 1000 watts when it’s on. What does your quattro output say when the cooktop is on?

I suspect there is something wrong with the cooktop and/or your wiring. Why don’t you test with another load?

As I understand it, the quattro only passes through AC in 1 and AC in 2 as is. So it’s unlikely to be the problem.

17

My Quattro supports BOTH AC and DC loads, so yes it is connected to a 24Vdc/690Ah lithium battery bank also via Lynx Distributor. However, the cooktop is an AC appliance. I only use the AC1 output of the Quattro, which goes through a circuit breaker panel, which then distributes the loads, one of them being the cooktop. You’re correct, I don’t believe it’s the Quattro.