Power supply disconnect sequence?

Autosnap · 07-01-2024, 09:14 AM

2024 2720QB New owner here, trying to learn. I tried boon-docking this last weekend in GSNP to try and learn my limits on battery power, and water tanks. I have a few questions. It didn't go well. Stupid issues aside...

I have the Ford tuck that has a generator on-board. so we used that to great effect during the day. I don't expect to do this all the time, but the trial on this part went swimmingly.

However, upon disconnecting the truck for quiet hours, we had no battery power. I had checked the panel before shutting the truck off and it said the battery was full. When I say no power, I mean, nothing, no lights, no water-pump, no info board, not even the gas sensor. TM was dead in the water. I checked all fuses, and breakers. There was no reason for it.

After thinking about it overnight, I decided to change the disconnect sequence. Well my 13y/o came up with this and I agreed as it is troubleshooting 101. So proud of him. He said, disconnect the trailer from the cable first as I had disconnected the truck first. It seems to have worked. I haven't had a chance to repeat this though.

My question is this, should this happen? I do have a soft start "Acustart".

Would the TM Board possibly see the capacitor in the soft start as the best source and negate the battery even after disconnected. Because I did disconnect the cable form the TM to store just after I disconnected it from the truck.

I'm pretty confused ATM... Thanks in advance for your replies.

Best,
Autosnap

**Bill** · 07-01-2024, 07:34 PM

Is your truck an EV or hybrid, or a conventional gas engine?

The generator on board the truck produces AC (household) power, right? My guess is that it has a second engine-powered alternator to produce AC power. Confirm?

How many watts is it rated to produce?

How do you connect the generator power in the truck to the TM? Can you plug the TM's big black power cord directly into it in some way?

Is the generator tied into your house system in some way? Not that you were trying to do that here, but some of the ads I see suggest that this a relatively complex system.

Your complete lack of 12-volt battery power suggests that the main battery fuse popped at some point. It is located in the positive wire coming directly off the TM battery, within a foot of the battery post, rather than within the breakers/fuses in the converter. If the fuse is blown, the TM battery would not get charged, of course, but all of your 12-volt stuff would still work (including the control panel lights), powered by the TM's built-in battery charger, which in turn was powered by the truck's generator.

To address your original question, I can't see how the disconnect sequence, whatever it is, would make any difference.

Tell us more.

Bill

Autosnap · Yesterday, 08:14 PM

Hey Bill,

Thanks for your reply, i hope i can provide the info correctly. Again, I'm still learning.

I know it sounds odd; it makes no sense to me either.
It's the 2024 F-150 hybrid with the 7.2kw generator. The way I understand it... It uses the truck's 3.5L powerboost to charge the hybrid battery that powers the inverter. Yes, ac power supplied. The motor doesn't run all the time. However, it only gives 7.2 over one cable if it combines both side a and side b which is 220v and a big no no. So, I was using "A" side at 120v. 2.4kw 20A. And is a standard US 3 prong plug. Yes, household type AC.

Connection was this. Dog bone 3 prong ->30amp soft start -> TM factory supplied cable ->TM

If it didn't work after I disconnected the TM first, I would be inclined to agree about the fuse. But even now the panel and solar panel work and shows 100% charge...

Best,
Autosnap

Autosnap · Yesterday, 08:32 PM

By the way, it does the same thing when I have the TM plugged into the house. If I pull the extension cord out of the socket first. The only common denominator is the dog bone, and soft start/ surge protector.

**Kidkraz** · Yesterday, 10:13 PM

Autosnap, are you using this?

https://softstartup.com/

Autosnap · Today, 06:26 AM

I tried to post the link but it needs mod approval. Which I fully understand.

If you search for this. ActiveStart SoftStart 30 AMP - ACS30P

You'll find it. It's made by Active controls, which I assume is one guy in a garage, but from what I've seen is a nice product. Unless it's a problem... lol

**rickst29** · Today, 01:17 PM

We might gain insights by keeping Issue #1, no '12 volt DC power to anything!' separate, even though the issue only appears after some odd situations happening on the 120-VAC main power input.

Here is why I suggest that: There are only two kinds of 'interconnects' between the TM's 120-VAC power wiring and the "12V" system (powering overhead lights, water pump, and other things).

The first is the "power converter", which can generate 12-VDC power when both 120-VAC is available on its hot versus neutral wire AND the converter "thinks" that power is needed to charge the batteries or run 12V loads. It makes that decision (often badly) according to the output voltage it "sees" while sniffing the voltage it sees on it's output wire into the 12-VDC fuse board. Those decisions can be unreliable when the when the batteries have been disconnected by a fuse failure (flying up or down according to whether loads are present). Some smarter power converters actually refuse to run at all, when they can detect that no battery is connected. Start with Bill's suggestion - check that battery connection through BOTH of its fuses.

If there is no 12-VDC on the fuse board (because the battery connection is failed), the ceiling lights will only run while the "power converter" converter has "decided" to create 12V output power. Fix the battery connection first - the lights should still work (and the water pump,. and other "12v"-powered things.)

Only then consider problem #2, weirdness when you connect or disconnect 120-VAC from through the 30A "softstart device".
- - -
The other 'interconnect' between the 120-VAC electrical system and the 12-VDC system is a single wire, interconnecting the TM frame "DC ground" to the 120-VAC safety grounding bus (the 120-VAC set of green and bare wires, NOT the white 120-VAC current carrying "neutral" wires.)

Your soft-start device might be introducing a GFCI/AFCI - like "management problem", disallowing current on the "hot" and ""neutral" wires when they are unbalanced. Many RV power converters are incompatible with the use of sensiitive AFCI/GFCI within the upstream power supply circuit.

The 120-VAC plugs provided by the F-150 might have that issue, and the soft-start device might introduce it part way through a connection from ANY source, and your house outlet (if not 30A using old-style breakers) might have it as well.

The fact that F-150 provides only 20A, while the "soft-start" might assume that 30A is available to fill its own capacitors, might be an issue as well: If your soft-start supports parameter setting from a cellphone app, please check if it can be configured to pull less power from lower-powered input ports.