Sanity check for a RV system (I'm a newbie and this is going on an older trailer)

[jpwic]

Hi!!

I was wondering if you could give me a sanity check for the following system.

This is going in a 2009 Jayco Jay Flight G2 (not solar ready), my main use case is to make sure I can run the RV lights, water pumps, slides, a bed side fan, a slow cooker, charge laptops/phones, run the RV stereo and make sure I have enough power to make sure the systems that require a trickle current are always powered, mainly thinking the propane/CO detector and possibly the fans of the heater if it gets cold, the dealer insists that the stove and fridge don't take any electricity are purely propane,)

Right now I'm looking at the (minus wiring, fuses, busbars and the like)

1 300ah redodo lifepo4 battery
1 victron phoenix inverter 12/1200
1 victron smartshunt (500a I believe)
1 victron mppt 100/50
3 220W panels (probably the Lumera panels made in canada)


My main concerns right now are the inverter; I want one that is inverter only, this trailer will NEVER be hooked up to shore power, so a multiplus or other similar charger/inverters would be wasted on me. I'll probably be running a cable from the inverter to the shorepower plug to power the RV until i can have the inverter hardwired to the distribution panel.

I'm also on a fairly tight budget, so I'm trying to build a basicish system right now for the first summer season or two, until I can upgrade and expand if needed.

 

[outsider]

That inverter is indeed an inverter only.

Your parts list seems fine.

My RV has a propane fridge, and, contrary to what your dealer said, mine does use a small amount of 12 V when it is on propane mode. It uses about 10 W, which is less than 1 A, but not zero. It needs to operate a solenoid valve, strike a spark to light the propane, and it has a small fan. This in addition to the lights inside the fridge when the door is opened. These loads are easy for the trailer battery to power, but they are loads.

I use the inverter to run the shore power. My inverter can't run the A/C, but it can run everything else, and this includes charging the trailer battery.

 

[jpwic]

That inverter is indeed an inverter only.

Your parts list seems fine.

My RV has a propane fridge, and, contrary to what your dealer said, mine does use a small amount of 12 V when it is on propane mode. It uses about 10 W, which is less than 1 A, but not zero. It needs to operate a solenoid valve, strike a spark to light the propane, and it has a small fan. This in addition to the lights inside the fridge when the door is opened. These loads are easy for the trailer battery to power, but they are loads.

I use the inverter to run the shore power. My inverter can't run the A/C, but it can run everything else, and this includes charging the trailer battery.

are there any changes I should consider? I was trying to stay within Victron as I keep hearing bad things about Renogy and I'm also trying to be super realistic with what I'm looking to get as well. When I first started speccing things out I was looking at 2000-3000 watt inverters, like 600ah hours of batteries and so on; and then went down from there...

I'm not going to be full timing in the RV, mainly weekends and a couple of weeks during the summer.
I had thought the fridge needed a trickle amount of battery but they insisted it was propane only.

 

[outsider]

One potential gotcha, if the trailer has a lead acid battery and a charger, but you have LFP batteries as part of the solar system, be sure that the lead-acid charger remains within the electrical system, possibly powered by your inverter "shore power", and that the MPPT is set to LFP and correctly charges your Redodo. Also, your LFP should probably come inside during winter, in which case the lead acid won't get charged, and so it would deep discharge over the winter, which is very bad for those types of batteries. So bring it in too.

 

[jpwic]

One potential gotcha, if the trailer has a lead acid battery and a charger, but you have LFP batteries as part of the solar system, be sure that the lead-acid charger remains within the electrical system, possibly powered by your inverter "shore power", and that the MPPT is set to LFP and correctly charges your Redodo. Also, your LFP should probably come inside during winter, in which case the lead acid won't get charged, and so it would deep discharge over the winter, which is very bad for those types of batteries. So bring it in too.

My plan was to replace the trailers lead acid and use the already installed house wiring for the 12v system?

Is that not doable?

 

[outsider]

The charging profiles for LA and LFP are different. If you simply replace the LA tongue battery with LFP, it will be charged by the built-in charger as if it is LA, which won't charge it correctly. So either be sure to replace the LA charger with an LFP charger, not yet on your list in the first post, or keep both and charge the LA using the inverter. Maybe there's a third option, but I doubt it: adjust the charge settings on your built-in battery charger (that uses shore power to charge the tongue battery) such that it works for LFP. But your trailer build date is well before LFP batteries became common, I think, so it might not have that adjustability.

 

[SouthernSolar]

If you plan on using the Bluetooth to monitor the system via the smart shunt , get the battery monitor instead.
https://a.co/d/i8QwmzU

The Bluetooth range is a lot longer and it about the same price as smart shunt plus a Bluetooth dongle you would need to extend the range of the shunt.

 

[jpwic]

The charging profiles for LA and LFP are different. If you simply replace the LA tongue battery with LFP, it will be charged by the built-in charger as if it is LA, which won't charge it correctly. So either be sure to replace the LA charger with an LFP charger, not yet on your list in the first post, or keep both and charge the LA using the inverter. Maybe there's a third option, but I doubt it: adjust the charge settings on your built-in battery charger (that uses shore power to charge the tongue battery) such that it works for LFP. But your trailer build date is well before LFP batteries became common, I think, so it might not have that adjustability.

I thought the 100/50 MPPT was a charge controller?

 

[outsider]

I thought the 100/50 MPPT was a charge controller?

That's right. But if you simply replace the tongue battery with LFP, and then run shore power from the inverter, it might try to charge the battery with the built-in charger. (Because normally, shore power is used to charge the tongue battery.) So some other change, other than simply replacing the tongue battery, with LFP, is needed. Either keep both (and, charge the LFP with the solar, and charge the tongue battery with shore power and the built-in charger), or, remove the built-in charger so when the LFP is inverting, it's not trying to charge itself.

 

[outsider]

Incidentally, you would have more total battery capacity if you kept the tongue battery. But if you keep both, just be sure the two batteries are charged correctly and separately.

Solar -> Victron MPPT -> LFP -> inverter -> built-in charger -> tongue battery

 

[jpwic]

That's right. But if you simply replace the tongue battery with LFP, and then run shore power from the inverter, it might try to charge the battery with the built-in charger. (Because normally, shore power is used to charge the tongue battery.) So some other change, other than simply replacing the tongue battery, with LFP, is needed. Either keep both (and, charge the LFP with the solar, and charge the tongue battery with shore power and the built-in charger), or, remove the built-in charger so when the LFP is inverting, it's not trying to charge itsel

Ahh, I'm not planning on real shore power, my original plan was to to then off the converter on the RV and then either hard wire a shore power cord on to the inverter or to use a plug with a dogbone from the inverter to the shore power plug... From what I've seen and read that should be possible

 

[outsider]

I do that myself, using either an eco-flow or my own inverter to plug into shore power when boondocking. However, when I do that, the trailer's internal charger charges the tongue battery, which I still have installed, and which is lead-acid. (And the charger is made to charge lead acid.) What I haven't done is removed the tongue battery, replace it with LFP, and then plug in shore power using an inverter powered by that same battery. If I were to do so, the built-in charger would try to charge that same battery - wrongly, because of LA vs. LFP, and, in a perpetual loop, that would simply discharge the battery.

Normally, before one makes any mods to the trailer's electrical system, if you plug in shore power, the trailer tries to use that electricity to keep the tongue battery charged. But if the shore power is coming from an inverter that you are powering with a battery - and, in particular, using the tongue battery - then there is a problem which requires you to change things. Either have a separate battery that the trailer won't try to charge (which you hook up to your solar), or, with one LFP battery only in the tongue position, remove shore power from the trailer charger, such that when your inverter applies shore power to the shore power plug, it isn't trying to charge your LFP battery from it.

 

[J.H.]

had thought the fridge needed a trickle amount of battery but they insisted it was propane only.

It is run by propane …..but as the previous poster said it uses a small amount of dc to run the light and the brain unit so it can work on propane …. Mine is that way.. I think most all are..

 

[HarryN]

The phoenix inverter is not nearly as good of an inverter as the other victron products. If you can find something else, I would.

 

[jpwic]

I do that myself, using either an eco-flow or my own inverter to plug into shore power when boondocking. However, when I do that, the trailer's internal charger charges the tongue battery, which I still have installed, and which is lead-acid. (And the charger is made to charge lead acid.) What I haven't done is removed the tongue battery, replace it with LFP, and then plug in shore power using an inverter powered by that same battery. If I were to do so, the built-in charger would try to charge that same battery - wrongly, because of LA vs. LFP, and, in a perpetual loop, that would simply discharge the battery.

Normally, before one makes any mods to the trailer's electrical system, if you plug in shore power, the trailer tries to use that electricity to keep the tongue battery charged. But if the shore power is coming from an inverter that you are powering with a battery - and, in particular, using the tongue battery - then there is a problem which requires you to change things. Either have a separate battery that the trailer won't try to charge (which you hook up to your solar), or, with one LFP battery only in the tongue position, remove shore power from the trailer charger, such that when your inverter applies shore power to the shore power plug, it isn't trying to charge your LFP battery from it.

Sorry! I was a little slow on the uptake! I get what you mean now!!!

So if I understand it right now; Solar charges lifepo4, from the batteries it goes to the inverter which will plug into shore power, the converter at the electical panel changes it to 12v which then charges the lead acid battery on the tongue!!! So the RV's 12v system is powered off the lead acid battery AND the lifepo4 as I can still run 12v through the shore power as well!. I'm sorry it took me that long to figure it out!!!


I'd definitely want to look at a way to hardwire the inverter to the panel eventually as I'd like to have the fridge going on days I'm not at the RV (it's going to be staying at a fairly secure boondocking site on private land); I've seen solutions where people have put a hole in their passthrough door, but with winter storage I'd rather not do that.

Also, is it worth it to add a Cerbo GX so I can monitor the system when I'm not at the trailer?

 

[jpwic]

The phoenix inverter is not nearly as good of an inverter as the other victron products. If you can find something else, I would.

The Multiplus is $1000+ more and has functionality I don't need..

My other choices were like a Renogy or BougeRV inverter but I figured that the Victron would still be better quality and that one matched my needs exactly

 

[scrubjaysnest]

Forget the lead acid battery. Ditch the converter. Power the DC distribution panel from the lithium battery (s) via a properly sized breaker. For us it's 50 amp.
Power the AC distribution panel from the inverter. Wire it to the 30 amp breaker.
Get a good quality inverter, low frequency, of 2000 watt 4000 to 6000 watt surge. I use Expertpower, half the price of a Sungold and 1/3 the price of an Aims. The Expert power appears to be the same as Sungold/Aims. A 2000 watt will run a crock pot all day. It barely starts our 15kBTU roof air-conditioning.

I recommend 400 Ah battery bank to get you through a cloudy day or two.
Our off grid set up is 1060 Ah of batteries, 2000 watts solar, and a 3000 watt Expert power inverter. The TT is a 32 foot Jayco. The 12 volt DC refrigerator draws 3.5 amps when it cycles on.
Here in the AZ 2 to 3 fans 24/7. A/C is run 3 to 6 hours about 6 days a year. Heating is propane.
Mppt's and shunts are Victron with Bluetooth.

 

[wme]

Ferget about the inverter, everything on your power list is available as 12v DC.
Also make sure all of lights are LED. Led lights draw 10% of what an incandescent bulb draws

 

[jpwic]

Ferget about the inverter, everything on your power list is available as 12v DC.
Also make sure all of lights are LED. Led lights draw 10% of what an incandescent bulb draws

Possibly so, but then I need to wire outlets and the like all over the place don't I? Right now the only outlets I have are all 120v

 

[wme]

Just leave the 120v AC sockets alone just in case you have shore power. There are scads of 12v outlets, 12v to USB outlets, 12v fuse panels on e-bay/Amazon.
A little DIY will greatly simplify your life