Anyone install a full inverter/charger system in their Minnie or Micro Towable?

[from1985]

Originally Posted by ScopeDope

I love my installation, it gives me a lot of flexibility when I go out in the boonies. It was a bit of a job to get everything installed, but it sure is nice. I would not recommend this layout if you have no understanding of electrical, volts, amps, and wiring.

Thanks for this write up, it answers a lot of the questions I have about putting a very similar system in my 2019 2401RG.


Regarding not running the A/C on the inverter power, could you elaborate? When you say the batteries would only last 30 seconds, is that an exaggeration, or is the discharge rate too low to support he A/C? The reason I ask is the system I'm thinking about using would include a 12v 300AH battery(ies), LiFEPO4. The max discharge rate would be 200AH (~2400W). A 3000W interverter typically will have a 5000-6000W surge capability to easily start the A/C, and my 13.5kbtu A/C needs about 900-1100W to run after that.


Sure, it'd only last a couple hours with 300AH, but I don't see how it would ruin the batteries (lithium iron phosphate). Maybe it's a limitation of the golf cart batteries?


(Also, I know this thread is a bit old, but it's full of useful info - thanks all)

[ScopeDope]

So, as I understand it, your battery bank would consist of (3) 100-AmpHour capacity Lithium-Ion-Phosphate Batterie$. The max discharge rate would easily handle the Air Conditioner. Actually, so will my Trojan T-145 batteries. Your batteries would be much better, spelled with some "$$" in the word "better." The problem is this: 300 amp-hours multiplied by 12 volts is 3600 Watts of power in those batteries when they are fully charged. P=EI, where P=Power in watts, E=Volts (electromotive force), and I = Amps (Current)..

Bottom line, you have 3600 Watts of power available. Typical Air Conditioners are 115 Volt machines, typically drawing about 13 -15 amps while running. I use a current meter and measured my unit at 13.8 - 14.1 Amps current while running... let's use 14). At 115-120 volts (let's use 120), that's 14 X 120 = 1680 Watts of power needed to run the Air Conditioner every hour.

Theoretically, you could run your Air Conditioner for 3600/1680, or 2.14 hours, then the batteries would have zero charge,

Your total storage in your batteries, when brand new and when fully charged is 3,600 Watts.... The inverter does not operate (convert DC to AC) for free, so you will lose some storage capacity to the inverting process.... I dunno how much. Your batterie$$ are much improved over mine....which are simple lead-acid flooded batteries. Not as many $$$$. So, yes, your batteries and system, with a good PURE Sine Wave Inverter would run your air conditioner for a while. I've never tried it on mine due to the limited time, but it would probably work.

Lithium batteries typically have self-protection built in,. but generally you should not discharge them to below about 10% capacity, so really, you probably have about 2700 Watt-Hours of real usable capacity.

My lead-acid batteries should NEVER be discharged to below 50% capacity, or they will be damaged to the point they will not produce as specified....they are sensitive to that requirement, and do not have a built-in protection circuit... you have to monitor that yourself. My fully charged capacity is 260 amphours, times 12 volts = 3120. Since I only have 50% of that capacity available, I really only have 1560 Watts available.... less than an hour of Air Conditioning run time. Also, my batteries will not hold the voltage up near 12 volts when discharging at a high rate... your batteries may, or may not do so. I don't know. If the big draw (high amps being drawn) causes the voltage to drop too low, the inverter will trip (go offline....stop inverting, etc.)

So, whlle I did exaggerate a bit, in reality I don't think 300 amphours of batteries is really enough to support the AC. Once you get to 600 or 800 AH of batteries, I'd bet the battery bank would support "some" running of the AC without the high current causing the voltage to drop so low as to trip the inverter.

Finally, remember...though the Lithium batteries will take a higher charge rate than lead acid batteries, you have to have a charger/system to generate that kind of power....and then it still has to be greatly reduced during the final charging to reach full charge. So, getting to full charge after one big use of the AC may be a challenge, as well.

Best of luck in your endeavors...great to hear of your project.

Doug

[Marine359]

Originally Posted by from1985

Thanks for this write up, it answers a lot of the questions I have about putting a very similar system in my 2019 2401RG.


Regarding not running the A/C on the inverter power, could you elaborate? When you say the batteries would only last 30 seconds, is that an exaggeration, or is the discharge rate too low to support he A/C? The reason I ask is the system I'm thinking about using would include a 12v 300AH battery(ies), LiFEPO4. The max discharge rate would be 200AH (~2400W). A 3000W interverter typically will have a 5000-6000W surge capability to easily start the A/C, and my 13.5kbtu A/C needs about 900-1100W to run after that.


Sure, it'd only last a couple hours with 300AH, but I don't see how it would ruin the batteries (lithium iron phosphate). Maybe it's a limitation of the golf cart batteries?


(Also, I know this thread is a bit old, but it's full of useful info - thanks all)

Running your A/C off your inverter/charger will not ruin your batteries. It will simply drain them quickly. If you have lead acid, and allow DoD to go below 20% you’ll shorten their life. If you have LiFePo4, no harm; the BMS just shuts it down when SOC reaches zero. I installed a 2000w inverter/charger when at the same time I installed my LiFePo4. They work great together, and charging time is ridiculously low at 80amp charge setting. This setup WILL run the A/C for a short period. Although we hardly ever use any ac power when boondocking, it’s nice to have when principessa wants it. I have actually run down my battery while driving because I forgot to turn off the A/C after we disconnected from SP. My inverter will automatically turn on when there is an ac load with no SP present. To solve this problem, I installed an additional disconnect switch for the inverter/charger. So part of my departure routine is now to disconnect the inverter from the dc circuit. You can also avoid this issue by wiring your inverter to a separate ac circuit from the A/C, but I didn’t want to do that.

[creativepart]

Originally Posted by from1985

Sure, it'd only last a couple hours with 300AH,

In your dreams! Maybe an hour and then you’d have empty batteries.

Get 3 of those 300ah batteries if you want to run the A/C for maybe 2.5 hrs and still have power left for other uses.

And you’ll still need a way to charge them back up. 1.2 kWh of solar would be good… but only if it’s sunny and during the day. Otherwise you’ll need a generator. But if you’re going to run a generator you might as well just run the A/C on generator in the first place.

Of course, with a large enough expenditure RVs can run A/C units. But with current technology there are limits to practicality. We’re getting there, just not yet.

[Fred 2106DS]

Originally Posted by Marine359

Running your A/C off your inverter/charger will not ruin your batteries. It will simply drain them quickly. If you have lead acid, and allow DoD to go below 20% you’ll shorten their life. If you have LiFePo4, no harm; the BMS just shuts it down when SOC reaches zero. I installed a 2000w inverter/charger when at the same time I installed my LiFePo4. They work great together, and charging time is ridiculously low at 80amp charge setting. This setup WILL run the A/C for a short period. Although we hardly ever use any ac power when boondocking, it’s nice to have when principessa wants it. I have actually run down my battery while driving because I forgot to turn off the A/C after we disconnected from SP. My inverter will automatically turn on when there is an ac load with no SP present. To solve this problem, I installed an additional disconnect switch for the inverter/charger. So part of my departure routine is now to disconnect the inverter from the dc circuit. You can also avoid this issue by wiring your inverter to a separate ac circuit from the A/C, but I didn’t want to do that.

I agree with Jim's assessment of running the A/C off LiFePo4 batteries. We have a 13.5 A/C with a soft start installed and can run it off a 2000W Renogy inverter for 1.5 hours and still have around 25% of our 200ah LiFePo4 batteries remaining when the outside temperature is 85-90 F.

I like the idea of having the option of running the A/C off batteries, especially when we stop to have lunch while traveling. We have the option to go inside the MM, turn on the air have lunch and allow our cats to stretch their legs.

It's also handy when we reach our destination and it is hot inside the MM. We can turn on the air and let it run off of batteries until we get things setup. Then run off our generator after that, unless it is one of those rare occasions when we have shore power.

Like Jim, we also have the ability of recharging our LiFePo4's rather quickly at 80 ah.

Additionally, to protect the A/C and the other AC circuits, our inverter and shore power/generator outputs enter a WFCO T-30 transfer switch. The T-30's output then enters a PI hardwired EMS before going to the breaker panel and out to the A/C and other AC circuits.

[ScopeDope]

Really awesome that you can get 80 amps per hour back into the batteries! Just curious, how do you do that...what is the source pushing out 80 amps?

[Marine359]

Originally Posted by ScopeDope

Really awesome that you can get 80 amps per hour back into the batteries! Just curious, how do you do that...what is the source pushing out 80 amps?

Xantrex XC2000 is programmable for battery type and charging amperage up to 80amps. The Xantrex will charge my 170AH LiFePo4 from 20% to 100% SOC in less than two hours. Victron’s 2000w inverter/charger will do this too.

[Fred 2106DS]

Originally Posted by ScopeDope

Really awesome that you can get 80 amps per hour back into the batteries! Just curious, how do you do that...what is the source pushing out 80 amps?

We use two Progressive Dynamics PD9145ALV lithium chargers wired in parallel.

[Marine359]

Originally Posted by Old Navy

Pulling romex through the frame rail would be ideal, but pulling the chloroplast/plasticore wouldn't. There is a nice channel along the outside of the the frame rail, above the "outrigger" support arms that seems ideal to run the 10/2. It's pretty well tucked up and protected, but still exposed. Anyone tackle a similar project in their trailer and have tips or lessons learned?

Sorry I’m late getting back to the OP on this particular question.
Fred2106DS and I have both done this project. I learned it from him. You don’t have to drop the corroplast. If you’re mounting inverter/charger and the batteries in the pass through, just drill down through the floor of the pass thru on the inside of the frame rail, and drill up through the floor near your distribution panel. Run your ac wiring along the frame rail. Fred ran romex through conduit. I chose to run 30 amp rv shore power cable without conduit. I just bought a 50ft shore power cord and cut it in half. Fred and I have both posted photos of the project in our albums. Either of us would be happy to assist you or answer any questions.

[from1985]

Originally Posted by ScopeDope

So, as I understand it, your battery bank would consist of (3) 100-AmpHour capacity Lithium-Ion-Phosphate Batterie$. The max discharge rate would easily handle the Air Conditioner. Actually, so will my Trojan T-145 batteries. Your batteries would be much better, spelled with some "$$" in the word "better." The problem is this: 300 amp-hours multiplied by 12 volts is 3600 Watts of power in those batteries when they are fully charged. P=EI, where P=Power in watts, E=Volts (electromotive force), and I = Amps (Current)..

Bottom line, you have 3600 Watts of power available. Typical Air Conditioners are 115 Volt machines, typically drawing about 13 -15 amps while running. I use a current meter and measured my unit at 13.8 - 14.1 Amps current while running... let's use 14). At 115-120 volts (let's use 120), that's 14 X 120 = 1680 Watts of power needed to run the Air Conditioner every hour.

Theoretically, you could run your Air Conditioner for 3600/1680, or 2.14 hours, then the batteries would have zero charge,

Your total storage in your batteries, when brand new and when fully charged is 3,600 Watts.... The inverter does not operate (convert DC to AC) for free, so you will lose some storage capacity to the inverting process.... I dunno how much. Your batterie$$ are much improved over mine....which are simple lead-acid flooded batteries. Not as many $$$$. So, yes, your batteries and system, with a good PURE Sine Wave Inverter would run your air conditioner for a while. I've never tried it on mine due to the limited time, but it would probably work.

Lithium batteries typically have self-protection built in,. but generally you should not discharge them to below about 10% capacity, so really, you probably have about 2700 Watt-Hours of real usable capacity.

My lead-acid batteries should NEVER be discharged to below 50% capacity, or they will be damaged to the point they will not produce as specified....they are sensitive to that requirement, and do not have a built-in protection circuit... you have to monitor that yourself. My fully charged capacity is 260 amphours, times 12 volts = 3120. Since I only have 50% of that capacity available, I really only have 1560 Watts available.... less than an hour of Air Conditioning run time. Also, my batteries will not hold the voltage up near 12 volts when discharging at a high rate... your batteries may, or may not do so. I don't know. If the big draw (high amps being drawn) causes the voltage to drop too low, the inverter will trip (go offline....stop inverting, etc.)

So, whlle I did exaggerate a bit, in reality I don't think 300 amphours of batteries is really enough to support the AC. Once you get to 600 or 800 AH of batteries, I'd bet the battery bank would support "some" running of the AC without the high current causing the voltage to drop so low as to trip the inverter.

Finally, remember...though the Lithium batteries will take a higher charge rate than lead acid batteries, you have to have a charger/system to generate that kind of power....and then it still has to be greatly reduced during the final charging to reach full charge. So, getting to full charge after one big use of the AC may be a challenge, as well.

Best of luck in your endeavors...great to hear of your project.

Doug

Doug, thanks for your detailed response. It confirmed by suspicion, namely, that you can/could run the A/C on your T145 batteries but it wouldn't be the smartest or most efficient idea given the alternative of using a generator.


The A/C on my 2401RG uses about 1100-1200W while the fan is on high and the compressor is running (summer temps). Since I have a lot more [usable] AH on my Lithium batteries, I could run for a couple hours if needed.


I know in years past Lithium iron phosphate batteries were a lot pricier than FLA/Gel, but you might want to reconsider your T-145s. Here's what I mean:


300AH x 12V Lithium: About $1000 for a 12v x 300AH of excellent quality.


300AH x12v FLA (T-145 or Similar): 300AH 6V battery, roughly $350 (Trojan 305AH), times two = $700


Seems like a clear win for lead acid. But as you mentioned, your really only get 50% of that 300AH versus 80% (conservatively) with Lithium. So $/usable AH :


Lithium: $1000/240AH = $5/AH
Lead: $700/150 = $5/AH



So they're actually.... dead even on price.



If you factor in lifetime, which is THE most important factor for a travel trailer, a lithium battery will get at least 2x-4x the cycles of a lead battery. So then the $5/AH/deep cycle becomes:


Lithium: $5/ah / 2500dcycles =$.0020/ah per deep cycle
Lead: $5/AH/1000dcycles =$.0050/ah per deep cycle


Basically, lead becomes more than 2.5x more expensive over the battery lifetime. And part of that expense means replacing and reinstalling new batteries during the time your lithium system is still running strong. So even if you find a really really good deal on a lead based battery, it's not going to be worth it. And even if you don't keep the batteries for a long time, lithium are still the same "real price" as lead.



This also completely ignores another two critical factors with trailers - weight and weight distribution. 300AH of lithium batters weights around $75 whereas 300AH of 6V lead batteries weighs around 165. Plus, lithium can be relocated anywhere in the trailer, but with lead you're stuck with what you can fit in the battery box, right on the front of the trailer.


I know there are other considerations like charging and chargers, maintenance, etc, but these are relatively minor in comparison with cost/life/weight.

[from1985]

Originally Posted by creativepart

In your dreams! Maybe an hour and then you’d have empty batteries.

Get 3 of those 300ah batteries if you want to run the A/C for maybe 2.5 hrs and still have power left for other uses.

And you’ll still need a way to charge them back up. 1.2 kWh of solar would be good… but only if it’s sunny and during the day. Otherwise you’ll need a generator. But if you’re going to run a generator you might as well just run the A/C on generator in the first place.

Of course, with a large enough expenditure RVs can run A/C units. But with current technology there are limits to practicality. We’re getting there, just not yet.

I should have mentioned, I have a Honda generator to run the A/C during the day at the campground. Some of the places I camp in the Sierra Nevada of California hit 100F+ so it's all but necessary. However, when quiet hours start (8-10PM in the places I camp most often), it can still be 85-95F so it'd be nice to use the A/C on battery for an our or two, or even during the day when you don't want to fire up the generator just for that purpose. Then, I can run the generator the next day to recharge and supplement the solar (thinking of 400W or so, no room for 1.2kw).

[from1985]

Originally Posted by Fred 2106DS

I agree with Jim's assessment of running the A/C off LiFePo4 batteries. We have a 13.5 A/C with a soft start installed and can run it off a 2000W Renogy inverter for 1.5 hours and still have around 25% of our 200ah LiFePo4 batteries remaining when the outside temperature is 85-90 F.

I like the idea of having the option of running the A/C off batteries, especially when we stop to have lunch while traveling. We have the option to go inside the MM, turn on the air have lunch and allow our cats to stretch their legs.

It's also handy when we reach our destination and it is hot inside the MM. We can turn on the air and let it run off of batteries until we get things setup. Then run off our generator after that, unless it is one of those rare occasions when we have shore power.

Like Jim, we also have the ability of recharging our LiFePo4's rather quickly at 80 ah.

Additionally, to protect the A/C and the other AC circuits, our inverter and shore power/generator outputs enter a WFCO T-30 transfer switch. The T-30's output then enters a PI hardwired EMS before going to the breaker panel and out to the A/C and other AC circuits.

Does your Renogy 2000W inverter handle the charging @80A as well or do you have a seperate charger? Does the 2000W handle your needs pretty well? I'm looking at either the 2000W or 3000W victron inverter/charger/auto transfer switch.

[Fred 2106DS]

Originally Posted by from1985

Does your Renogy 2000W inverter handle the charging @80A as well or do you have a seperate charger? Does the 2000W handle your needs pretty well? I'm looking at either the 2000W or 3000W victron inverter/charger/auto transfer switch.

We use separate components. That was my preference when I started putting our system together a few years ago. I liked the idea of having separate components, that way if one fails, it could be removed and we wouldn't lose access to the other components.

Currently, we use two Progressive Dynamics PD9145ALV lithium chargers wired in parallel with our two Battle Born batteries. Each charger is capable of outputting around 40 amps after AC to DC conversion loses. Also, I disconnected the onboard converter that came with the MM since it was programmed for lead acid batteries.

If I was doing it today, I would probably go the all-in-one route with power sharing, similar to Jim's (Marine359) setup. If I had the money and space, I would probably opt for a 3000W system, for the additional overhead in case we needed it in the future.

We find that the 2000W inverter works well for us. Though, we removed our microwave in favor of additional food storage and my wife doesn't use a hair dryer, curling iron or any other high current electronics. Besides the A/C, which has a Micro-Air Easy Start installed, the highest drawing electronics we currently use are all 700-800W. These are a 2 slice toaster, 4 cup drip coffee maker, a breakfast sandwich maker and a 3 quart Instant Pot.

[jwiebe]

Originally Posted by Marine359

Sorry I’m late getting back to the OP on this particular question.
Fred2106DS and I have both done this project. I learned it from him. You don’t have to drop the corroplast. If you’re mounting inverter/charger and the batteries in the pass through, just drill down through the floor of the pass thru on the inside of the frame rail, and drill up through the floor near your distribution panel. Run your ac wiring along the frame rail. Fred ran romex through conduit. I chose to run 30 amp rv shore power cable without conduit. I just bought a 50ft shore power cord and cut it in half. Fred and I have both posted photos of the project in our albums. Either of us would be happy to assist you or answer any questions.

I just got my hands on a Xantrex Freedom 2000W inverter as well and would like to replicate your project. Do you have a thread where you outlined what you all did that you could point me to?

[Marine359]

Originally Posted by jwiebe

I just got my hands on a Xantrex Freedom 2000W inverter as well and would like to replicate your project. Do you have a thread where you outlined what you all did that you could point me to?

Check these pages before and after:
https://www.winnieowners.com/forums/...290423-24.html
Hi jweibe,
I pretty much followed the lead of Fred 2106DS, except he used an inverter, transfer switch setup, and I went with the Xantrex XC2000. Try on these pages, I’ve slightly changed wiring to the bus bars, now having a dedicated disconnect for the Xantrex. That makes it real easy to just disconnect the Xantrex from the system, leaving my 12v system running. You can leave the Xantrex on, but it has a pretty hefty draw in Standby when there’s no ac loads. I prefer disconnecting it. There are more pictures, and more current photos in my mods photo album. Just click on my name and look at mods and upgrades. I can answer most any question you have on pm. I’m on a 2 month mostly boondocking trip now, so I may not be able to get back to you right away. Fred 2106DS will also be happy to help.

[jwiebe]

Originally Posted by Marine359

Check these pages before and after:
https://www.winnieowners.com/forums/...290423-24.html
Hi jweibe,
I pretty much followed the lead of Fred 2106DS, except he used an inverter, transfer switch setup, and I went with the Xantrex XC2000. Try on these pages, I’ve slightly changed wiring to the bus bars, now having a dedicated disconnect for the Xantrex. That makes it real easy to just disconnect the Xantrex from the system, leaving my 12v system running. You can leave the Xantrex on, but it has a pretty hefty draw in Standby when there’s no ac loads. I prefer disconnecting it. There are more pictures, and more current photos in my mods photo album. Just click on my name and look at mods and upgrades. I can answer most any question you have on pm. I’m on a 2 month mostly boondocking trip now, so I may not be able to get back to you right away. Fred 2106DS will also be happy to help.

That is helpful, thanks. Do either of you have a wiring diagram to approximate what you did?

[Marine359]

I was too lazy to make a wiring diagram, but here’s what I did:
On the ac side, bought a 50ft 30 amp rv cord and cut it in half. It’s insulated and rubberized enough that I bypassed using conduit. See pictures on my album with cable run through pass thru floor on curb side, and back along frame rail, then up through floor under sink. Short run to panel from there. You can also run the inverter Bluetooth remote panel wires along the same path and install the panel in the entryway. Connected inverter input to inbound shore power at the panel, disconnected charger, connected inverter output to panel powering all ac circuits. Some people use a separate circuit for the A/C but I didn’t because my inverter will run the air conditioner if given enough battery amp/hrs.
On the dc side, I just took the wires from the outside battery box and ran them back up through the existing loom that goes through the floor. I also disconnected 12v wiring from the tongue box and ran them up inside as well, reconnecting them to disconnect switch, so now when I shut down power, nothing can draw power. Inverter ground wired to chassis. I ran 1/0 cable from inverter to battery with positive cable through a separate disconnect switch so I can disconnect the inverter entirely from the 12v circuit. On the negative side, I installed a smart negative shunt battery monitor. Everything is connected to bus bars, making for a neater, and more secure connection.

[Fred 2106DS]

Originally Posted by jwiebe

That is helpful, thanks. Do either of you have a wiring diagram to approximate what you did?

Here's my diagram, I started putting it together after I initially built my system to document the key components I used. I've continued to update it as components have been upgraded. What I haven't completely documented are some of the wire gauges and lengths.

I also use a second battery monitor that's Bluetooth which isn't documented on the diagram. It's a Thornwave Labs - PowerMon.

[jwiebe]

Thanks again, Marine & Fred.

Just ordered a 200aH Renogy smart lithium battery – will do an similar approximation of your installs in a couple weeks (we just got a big dumping of snow which has delayed my plans).

My install will probably closely follow Marine's, but I do have a quick question for you. What is the benefit of your second disconnect switch? Is turning the inverter off not adequate?

[creativepart]

Originally Posted by jwiebe

What is the benefit of your second disconnect switch? Is turning the inverter off not adequate?

For many inverters, disconnecting power to the inverter before working on batteries - removing battery cables - is important to protect the inverter.