- My new fifth wheel RV delivery is 2 weeks out and it will come with one 320 Watt Renogy Solar panel and a Renogy Rover 20 Amp mppt charger.
- Let me begin by saying I am not trying to build a system to boondock off grid for days.
- What I would like to do is have enough battery and inverter capacity to run my 12 volt 10 cubic foot fridge and make coffee in the morning and run one 13,500 btu A/C unit in bedroom (with soft start installed at night) if I stop for 1 or 2 nights at a Harvest Host or Walmart etc when traveling. So cooling will be at night when sun is down.
- Eventually I will probably add 2 more panels and larger solar charger.
- The RV Solar prep package only runs a single 15 amp outlet circuit to a junction box in the battery compartment for future inverter connection. So my plan is to not even use it and instead take the inverter output and the shore power connector to a 50 amp manual transfer switch. This way if I want to stop for a night with no power hookups all I need to do is turn off one of my two A/C units at the breaker panel or thermostat then throw the manual transfer switch to inverter and I should be able to run outlets, along with a single A/C (with soft start to reduce startup load) , or a coffee pot.
- I do realize if I will probably only be able to sustain 1 or maybe 2 nights like this with my limited single solar panel with out hooking up to power to help recharge my batteries. Again, in future I will add probably two more panels and larger solar charger.
- Does my fusing make sense?
- All components will be ground to negative buss bar which will in-turn be grounded to chassis.
- Thoughts? Feedback?
New Fifth Wheel RV Solar Plan
- Thread starter mwhittak
- Start date
sunshine_eggo
Happy Breffast!
Your MPPT charging current will not be measured by the shunt. It is connected to the bus bar between the shunt and batteries.
The only thing your shunt will measure is discharged current. It will go to 0% and stay there.
Both battery (-) should be connected to shunt battery side and shunt system side should be connected to bus bar.
Is the DC fridge also propane, or pure electric? If propane, it must be run on propane.
You can run a typical rooftop A/C for 4 hours before the batteries are tapped out. Recommend you install the soft start and leave it in place - not just for nights. Even with soft start, not sure that inverter will start it.
It will take you about 5 days of using no power whatsoever to completely recharge your batteries.
Your fuses should be sized for 1.25X wire rating.
The only thing your shunt will measure is discharged current. It will go to 0% and stay there.
Both battery (-) should be connected to shunt battery side and shunt system side should be connected to bus bar.
Is the DC fridge also propane, or pure electric? If propane, it must be run on propane.
You can run a typical rooftop A/C for 4 hours before the batteries are tapped out. Recommend you install the soft start and leave it in place - not just for nights. Even with soft start, not sure that inverter will start it.
It will take you about 5 days of using no power whatsoever to completely recharge your batteries.
Your fuses should be sized for 1.25X wire rating.
the one thing you are missing on fusing is the three lines going to solar charge controller, 12v house power, and battery monitor. Each of those needs a fuse - the fuse is protect the wires from the massive amps the batteries can provide. Fuses protect wires not components.
You really need more solar 20amps of solar with good sky’s will give you about 5 hrs of full power - so 100ah - if you drain the batteries it will take a week to recharge.
Also - is the 120v converter lithium compatible?
There are a few issues with the converters.
You really need more solar 20amps of solar with good sky’s will give you about 5 hrs of full power - so 100ah - if you drain the batteries it will take a week to recharge.
Also - is the 120v converter lithium compatible?
There are a few issues with the converters.
Thanks,
1. I think I corrected the shunt mistake.
2. Fridge is just 12 volt DC
3. I plan on leaving soft start installed 100 % of the time, I was just making point I am only concerned with inverter A/C at night when stopping.
4. I have read numerous forums where people are running 13,500 or 15,000 btu A/C units on 2000 watt inverters with soft start so I was hoping if I went to 3000 watt I would be ok, Guess time will tell on that one.
5. My Converter is lithium capable.
6. I only need to get 1 or 2 nights of inverter power, 95% of the time only 1 night then I will be hooked up to power to help recharge, at least for now.
7. I assumed the solar charger which will be wired by factory will be fused but I will confirm.
8. As far as fusing on the battery lines, I assume 4/0 is oversized especially from battery to buss bar, do those really need to be 1.25% of the rating of the wire, if the battery bms limits to 200 amps should i just do 250amp on the battery lines to be a bit over BMS?
1. I think I corrected the shunt mistake.
2. Fridge is just 12 volt DC
3. I plan on leaving soft start installed 100 % of the time, I was just making point I am only concerned with inverter A/C at night when stopping.
4. I have read numerous forums where people are running 13,500 or 15,000 btu A/C units on 2000 watt inverters with soft start so I was hoping if I went to 3000 watt I would be ok, Guess time will tell on that one.
5. My Converter is lithium capable.
6. I only need to get 1 or 2 nights of inverter power, 95% of the time only 1 night then I will be hooked up to power to help recharge, at least for now.
7. I assumed the solar charger which will be wired by factory will be fused but I will confirm.
8. As far as fusing on the battery lines, I assume 4/0 is oversized especially from battery to buss bar, do those really need to be 1.25% of the rating of the wire, if the battery bms limits to 200 amps should i just do 250amp on the battery lines to be a bit over BMS?
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sunshine_eggo
Happy Breffast!
Yes.
Good.
I figured. I was making a bad joke.
Soft starts reduce, not eliminate, surge. Startup depends on the inverter. The cheap one you have shown doesn't have a meaningful surge rating. It claims 2X, but what they don't tell you is that it's only for 20ms. A legit surge low frequency inverter of 1500-2000W+ will probably start it with a soft start.
Again, if A/C is important, you have about 4 hours of use before the batteries are completely tapped out.
No. They need to be fused.
2000/.85/12 = 196A. 250A is good.
I purchased two 280ah Lithium batteries so far to start out.
Thanks, i will research a better Pure Sine wave inverter.
Does your “lithium” compatible converter have different levels of charging…
When in bulk - charges at 14.4v
Then holds at 14.4v for a time period -1/2hr or an hour.
Then drops to 13.5v as it goes into float or turns off.
Some devices advertised as lithium compatible are not very good for lithium batteries. You need to dive into the specs on your unit and understand how it will operate.
When in bulk - charges at 14.4v
Then holds at 14.4v for a time period -1/2hr or an hour.
Then drops to 13.5v as it goes into float or turns off.
Some devices advertised as lithium compatible are not very good for lithium batteries. You need to dive into the specs on your unit and understand how it will operate.
I have a RV with a Victron Multiplus 12/3000 inverter and 544ah of lithium battery. I can start and run the air conditioning.
With the soft start (Micro Aire Bluetooth) it takes 15.3amps of 120v power to start. Down from 27.4amps without the softstart. So they are needed.
Like I said I can only run the air conditioning for about an hour, before I need to decide to shut if off or start the generator. Otherwise I may not make it through the night.
One other item you may want to consider…
I added a Victron Smart battery protect (BP65), on the line going to my rig’s fuse box.
This is so if the battery gets low it will shut off all the lights,etc in the rig. It is much easier if the battery never goes into critical mode to get it recharged. It also acts as an easy on/off switch when I need to reset my furnace.
With the soft start (Micro Aire Bluetooth) it takes 15.3amps of 120v power to start. Down from 27.4amps without the softstart. So they are needed.
Like I said I can only run the air conditioning for about an hour, before I need to decide to shut if off or start the generator. Otherwise I may not make it through the night.
One other item you may want to consider…
I added a Victron Smart battery protect (BP65), on the line going to my rig’s fuse box.
This is so if the battery gets low it will shut off all the lights,etc in the rig. It is much easier if the battery never goes into critical mode to get it recharged. It also acts as an easy on/off switch when I need to reset my furnace.
Yes, my converter has multiple modes.
PD4500 - The full rated load is available for load, battery
charging or both. When functioning as a regulated battery
charger the converter has a nominal voltage output of 13.6
VDC. The system is designed to sense voltage on the battery
and automatically selects one of three operating modes
(normal, boost and storage) to provide the correct charge level
to the batteries.
BOOST MODE: If the converter senses that the battery
voltage has dropped below a preset level the output voltage is
increased to approximately 14.4 VDC to rapidly recharge the
battery.
NORMAL MODE: Output voltage set at approximately 13.6
VDC.
STORAGE MODE: When there has been no significant
battery usage for 30 hours the output voltage is reduced to
13.2 VDC for minimal water usage. When in storage mode,
the output voltage will periodically increase to 14.4 VDC to
help prevent sulfation of the battery plates.
I will look into that BP65, good thing to think of. I also have a generator if i need it, just sometimes harvest host wont let you run one after certain hours, which is why i figured i could make it so i can run A/C in the evening in bedroom off inverter. Should be no sun load and should not need to run much to cool just one small room with door closed.
Thanks for the input.
OTRwSolar
Solar Enthusiast
- Joined
- Apr 5, 2021
- Messages
- 208
What's your a/c's continuous current draw? Are you calculating a/c runtime based on a 100% compressor duty cycle?
We use a 12v Multiplus II 3000 to power the a/c in our small RV with a 304ah lifepo4 battery. A/c's continuous current draw is approx. 8.5a/120vac (approx. 85-95a of 12vdc). LRA/inrush current is 32a (no soft/easy start installed). The Multiplus handles the 32a LRA with no issues. Strangely, the manufacturer doesn't spec the a/c's BTU rating. I'd guess-estimate it to be 7000-8000 BTU. With a 100% compressor duty cycle, the 304ah lifepo4 will run the a/c for slightly over 3 hours. 50%, slightly over 6 hours.
I might add, the LRA/inrush current for most 13,500 BTU RV roof-mounted a/c units is approx. 55-65a (15,000 BTU 60-70a). A Micro Air Easy Start will typically reduce the LRA 55-65%---a very significant reduction. Most lower-tier, 2000w high-frequency inverters can start a 13,500 BTU a/c with a MAES installed---without one, nearly impossible.
