Electrical Mod -- Feedback Requested

[howson]

A post on TDR of the Victron Multiplus 12/3000/120 caught my eye:
"This is pretty sexy. You can hook up to it with a laptop and configure it to do things such as bring the genset automatically on/off based on power needs or even if say the temp gets to a certain level while you're gone and you want the A/C on. It can also aggregate multiple power sources and use them each individually or consecutively based on a priority you set. I've also read of people for instance running a 15k BTU A/C with only a 2k genset. So when the A/C kicks on, it will pull as much power as you set (say 1,500 watts) from the genset, and supplement that with the inverter/batteries. When the compressor kicks off, it can run straight from the genset....then boom, compressor kicks on and it pulls from both sources again. Pretty cool. Ain't cheap, but the chicks dig dudes with the cool toys:"

VEConfigure is what they are referencing. A Victron MK3-USB interface is required (AMSolar sent one in their kit) so all I had to do was connect an ethernet cable from the MK3 to the MultiPlus.

I haven't gone past the very basics. Too much else to learn and play with right now.

[howson]

Howard,

Do you have any idea about how much charge to expect from the tow vehicle in terms of alternator output to the trailer and charge duration based on that output/input?

Thanks!


Sent from my iPhone using Tapatalk

I didn't want to send this thread off in another direction, so see the 2017 Ford F-350 Not Charging RV Batteries thread to read how I (finally) figured out how to get my '17 Ford SuperDuty to charge my batteries while towing.

-Howard

[jh.xsnrg]

Howard, 0 load watts is listed as 20w for your 3000 Victron inverter. (https://www.victronenergy.com/upload...120V-US-EN.pdf)

20w would be under 2 amps of no-load power usage by the Victron directly. Assuming the Victron is working according to spec, you have some other loads to discover to make up the difference.

Glad to see you were able to figure out the TV charging. Any additional sources help.

Jim

[howson]

Howard, 0 load watts is listed as 20w for your 3000 Victron inverter. (https://www.victronenergy.com/upload...120V-US-EN.pdf)

20w would be under 2 amps of no-load power usage by the Victron directly. Assuming the Victron is working according to spec, you have some other loads to discover to make up the difference.

Glad to see you were able to figure out the TV charging. Any additional sources help.

Jim

What's interesting is the CCGX shows 0 AC load with the refrigerator off. I know that's not quite true since the microwave's clock is on. I think the SmartATS draws power, too, as it constantly monitors the circuit. The only voltage going into the SmartATS is AC but the CCGX doesn't register the load. I may dig into the details further some day with all the tools Victron has available.

Plus--I'm hoping you and @Nomado, or any other Victron owners here, reveal some tricks I haven't figured out yet.

[jh.xsnrg]

With the Victron saying 0w on the AC side, I would suspect it is actually quite close to that. A couple LEDs here and there won't draw much at all. That would leave the various DC loads.

Either way, now that you have power coming from the tow vehicle as well, you should be good. I cannot wait to get mine hooked in and run some of the same tests.

Jim

[howson]

@Jim, @Gene, @Rob, and anyone else still following along;

I methodically powered up the trailer today and monitored each change in the load on the batteries. The PDF (attached) I *hope* explains itself.

Remember that the grounds for the trailer are connected to the BMV's shunt--every load on the trailer goes through the shunt--which means that every electron moving is getting measured. (At least in theory!)

If the ARP reference puzzles you, here's the related thread: https://www.mygrandrv.com/fo...-2019-315RLTS)

I really think the drain on the batteries from the first test is due to a refrigerator that cools well, but doesn't hold it's cool very well (if that makes sense). In other words, the refrigerator is actively running much more than anticipated.

As always, I encourage a critical review and invite feedback.

-Howard

[Cate&Rob]

Hi Howard,

Your logic on a "poorly insulated refrigerator that cools well" makes sense . . . but, if this is the case, this is going to compromise your overall plan of running the fridge off the batteries. An inexpensive way to confirm your numbers would be to use a Kill-A-Watt meter (inexpensive tool that plugs into the outlet and then the fridge plugs into it). You should see the same kind of kWh usage on shore power. Comparing kWH through the middle of a hot day vs through a cool night should help to prove/disprove the poor insulation theory.

I'm having trouble with the idea that my $300 residential fridge (on the boat) with about the same inside and outside dimensions as my RV fridge (ie: similar insulation thickness) is twice as well insulated. I know that it runs about a 50% duty cycle even on a warm day.

Well . . . you asked for feedback .

Rob

[howson]

Hi Howard,

Your logic on a "poorly insulated refrigerator that cools well" makes sense . . . but, if this is the case, this is going to compromise your overall plan of running the fridge off the batteries. An inexpensive way to confirm your numbers would be to use a Kill-A-Watt meter (inexpensive tool that plugs into the outlet and then the fridge plugs into it). You should see the same kind of kWh usage on shore power. Comparing kWH through the middle of a hot day vs through a cool night should help to prove/disprove the poor insulation theory.

I'm having trouble with the idea that my $300 residential fridge (on the boat) with about the same inside and outside dimensions as my RV fridge (ie: similar insulation thickness) is twice as well insulated. I know that it runs about a 50% duty cycle even on a warm day.

Well . . . you asked for feedback .

Rob

I could have doors with leaky door seals and don't know it. I'm going to put a bright light inside the fridge at night (with all the interior trailer lights off). If a seal is not right I'll be able to tell immediately.

Edit (6 May): I did the test last night with super-bright LEDs--the seals are fine.

I have a Kill-A-Watt (I'm sure you're not surprised) so I'll check and compare the usage as you suggest.

You know I appreciate your insightful feedback, Rob.

[Cate&Rob]

I could have doors with leaky door seals and don't know it. I'm going to put a bright light inside the fridge at night (with all the interior trailer lights off). If a seal is not right I'll be able to tell immediately.

I have a Kill-A-Watt (I'm sure you're not surprised) so I'll check and compare the usage as you suggest.

You know I appreciate your insightful feedback, Rob.

The "dollar bill" test is good for fridge seals too. If the closed door won't clamp the paper, there is a gap that you might not be able to see.

Rob

[howson]

The "dollar bill" test is good for fridge seals too. If the closed door won't clamp the paper, there is a gap that you might not be able to see.

Rob

I think Fran hit on the answer. When she asked what was going on (not knowing what the Kill-A-Watt was) I explained what it does and also about the duty cycle issue. She looked at me (with that look all wife's have perfected) and said, "That's because you didn't have enough in the refrigerator. If you put more items in it the refrigerator will stay colder longer." When I did the original how-long-will-the-batteries-last test I had maybe six cans of soft drinks in the 'frig. Doh!

The Kill-A-Watt test results are as expected (shore power):





-Howard