Ready For LiFePO4 - Options?

HighClouds

Senior Member
Joined
Mar 13, 2023
Messages
135
HEPL!
Ready to pull the trigger on Li batteries.
Looking for my optimum/best set up.
We plan to expand it later. So…

1) The Installed Gear
Jaboni Charge Controller, 50 Amp
WFCO Converter WF-9855-AD, 55 Amp
WFCO Inverter WF-5220, 2000 Watts
2 Solar Panels, 670 Watts Total

2) The Power Sponges
A/C Main, 15k (Soft Start)
A/C Bedroom, 15k (Soft Start)
A/C - Heat Pump, 15k (Soft Start)
Residential Fridge - Samsung
The usual - Microwave, TV (2), Furnace (35k btu), and Fireplace

3) My Battery Ideas (LiFePO4)
12v, 100Ah (2) (BMS w/ Shunt)
12v, 200Ah (1) (BMS and Bluetooth)
12v, 270Ah (1) (BMS w/Shunt)

I want my Fridge to keep things cold/frozen on our (generally) 2 day drives to location.
Also, would like to run an A/C for a bit to cool down during our 1 overnight stop.
Optimally, would like the same during a 2-3 day boondock.
(Not interested - yet - on a generator)

Thought on the batteries? Recommendations on others? Other observations?

THANKS IN ADVANCE
R/
 
I wouldn't get too set on running A/C units with a small setup like you are looking at. Running a typical A/C unit for just one hour will deplete about 130AH out of the battery.....and that is JUST the A/C unit by itself.....and not counting any other DC loads you have on the system....like lighting/etc. Also, you more than likely aren't going to be able to power an A/C unit AND the fridge at the same time either, not with a 2000W inverter. The A/C unit by itself will be pulling at an almost 1700W rate, which will also peak much higher than that at the time the A/C unit starts.
 
Like [MENTION=21739]xrated[/MENTION] said, a lot more batteries and more inverter power will be needed to achieve even the modest end of your stated goals.
 
I wouldn't get too set on running A/C units with a small setup like you are looking at. Running a typical A/C unit for just one hour will deplete about 130AH out of the battery.....and that is JUST the A/C unit by itself.....and not counting any other DC loads you have on the system....like lighting/etc. Also, you more than likely aren't going to be able to power an A/C unit AND the fridge at the same time either, not with a 2000W inverter. The A/C unit by itself will be pulling at an almost 1700W rate, which will also peak much higher than that at the time the A/C unit starts.

I’ve seen 300W inverters. Are there higher ones more suitable to the Fridge - A/C potential combo use?
 
I’ve seen 300W inverters. Are there higher ones more suitable to the Fridge - A/C potential combo use?

I'm assuming you meant 3000W, not 300W inverters.....and yes, there are larger ones than 3000W. Here's something to remember though, and I'll use a 3000W inverter for the example. That unit would require battery power in the neighborhood of just under 230 amps at 13.2 Volts, which is the nominal voltage of a LiFePO battery. That would entail 4/0 cables to feed it, so you can imagine what something like a 4000W or 6000W inverter might draw. So the workaround is to have either a 24V system or sometimes even a 48 volt system. When the voltage is doubled, the current value is cut in half....which makes the cable size requirement less. Volts x amps = power. So if the amount of power.....say 3000W divided by 13.2 = 227 amps adn 4/0 gauge wire, then 3000W divided by 26.4 volts (nominal for a 24 volt system) would equal 113/114 amps and a much smaller cable.

So in the above example of a 3000W inverter, yes, it would be large enough to run one A/C unit and the fridge at the same time......but you are talking about having a battery to feed it that can give you some number of amps that is higher than the draw from the inverter, as well as the battery's BMS allowing for that higher number also......it just gets more complicated from there, as you also have to calculate inverter losses or calculate the known/published efficiency of the inverter, wire size, voltage drop, total load, etc, etc.

And that is why you don't see many rigs out there with solar/LiFePO setups that have the ability to run A/C units. I'm certainly not saying that there aren't some....because there are. But when you build or have a system like that built, with that kind of capability, the $$$$$ signs just start stacking up, and up, and up. I've never priced or looked into solar, as I pretty much have zero interest or need for it because of our camping lifestyle, plus I have an onboard 5500W generator.....but suffice it to say, something that has that kind of capability for running A/C units, tons of solar panels for help with recharging 1200...maybe 1500 AH of battery.....could be in the $20K range I'm guessing....and certainly more, depending on just how much you want and how long you want it to operate without any kind of assistance from either shore power or generator power.
 
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I'm assuming you meant 3000W, not 300W inverters.....and yes, there are larger ones than 3000W. Here's something to remember though, and I'll use a 3000W inverter for the example. That unit would require battery power in the neighborhood of just under 230 amps at 13.2 Volts, which is the nominal voltage of a LiFePO battery. That would entail 4/0 cables to feed it, so you can imagine what something like a 4000W or 6000W inverter might draw. So the workaround is to have either a 24V system or sometimes even a 48 volt system. When the voltage is doubled, the current value is cut in half....which makes the cable size requirement less. Volts x amps = power. So if the amount of power.....say 3000W divided by 13.2 = 227 amps adn 4/0 gauge wire, then 3000W divided by 26.4 volts (nominal for a 24 volt system) would equal 113/114 amps and a much smaller cable.

So in the above example of a 3000W inverter, yes, it would be large enough to run one A/C unit and the fridge at the same time......but you are talking about having a battery to feed it that can give you some number of amps that is higher than the draw from the inverter, as well as the battery's BMS allowing for that higher number also......it just gets more complicated from there, as you also have to calculate inverter losses or calculate the known/published efficiency of the inverter, wire size, voltage drop, total load, etc, etc.

And that is why you don't see many rigs out there with solar/LiFePO setups that have the ability to run A/C units. I'm certainly not saying that there aren't some....because there are. But when you build or have a system like that built, with that kind of capability, the $$$$$ signs just start stacking up, and up, and up. I've never priced or looked into solar, as I pretty much have zero interest or need for it because of our camping lifestyle, plus I have an onboard 5500W generator.....but suffice it to say, something that has that kind of capability for running A/C units, tons of solar panels for help with recharging 1200...maybe 1500 AH of battery.....could be in the $20K range I'm guessing....and certainly more, depending on just how much you want and how long you want it to operate without any kind of assistance from either shore power or generator power.

I Shoulda bought a tent… ��
Thanks for the info. Sounds like I’m gonna stay light on the solar.
Will see how that works for.
R/
 
I Shoulda bought a tent… ��
Thanks for the info. Sounds like I’m gonna stay light on the solar.
Will see how that works for.
R/

Well, to put things into perspective, there are a lot of folks that do not know the ins and outs of solar/battery storage/equipment needs, so you are certainly not by yourself. And for further perspective, I'm not a solar guy and there are many out there that know 10 times more than I know about the subject. I am an Electrician by trade though, and let's face it, solar/battery storage/etc is just another category/branch of the electrical trade and the same electrical formulas and theory of operation prevail throughout......the difference is the source of energy for producing the power.....sunlight vs. coal, vs hydro vs nuclear and so on. When I first bought our present trailer, the Momentum Toy Hauler, I had thoughts of getting into solar and starting down that road. It didn't take long for me to realize some of the things I mentioned above about the cost of the equipment if it were to be large enough to do things like run A/C units, microwaves, and other high power consuming devices that you find in camping trailers. Since we rarely if ever boondock, it totally didn't make sense for me/us, especially with the onboard generator that came with the trailer. I would however, never try to talk anyone out of pursuing the solar route if their needs warrant it, they can afford it, and when complete it satisfies the goals that they have set for the system.....but it's just not for me.
 
Welcome, Bob. We started down this road a year ago, doing a LOT of research and asking even more questions. Others know quite a bit more than I do, but I'll share what we've learned so far.

First of all, figure out what you really want to run all the time (the must-have list). Then add to that the things that would most likely be needed, but you could do without or won't be using them at the same time as something else (electric skillet and microwave, for example). Try to figure out your maximum draw.

With 12V batteries you can use a very rough conversion: 1A at 120V = 10A at 12V. This ignores the losses in the inverter, but will be close enough. Now, a bit of math, since things are labeled with different units. Watts = volts x amps. (Electrical engineers, please don't confuse us with power factors, etc. This is simply rough calculating.)

Now you have all you need to calculate your system. You may well find that building the whole system at once will cost more than the CFO will allow you to spend. That's okay, just plan on doing it in stages. Keep in mind that sales do happen. I bought a pair of 24V 200AH Redodo batteries during their Black Friday sale for just over $1,000 each. Right now those same batteries are $1300 each.

Generally, as was mentioned above, since higher voltage means lower amperage (and therefore smaller wires) it makes sense to put the inverter as close as possible to the batteries. If you choose to go that route, a Victron MultiPlus II is a good all-in-one device that will charge the batteries, provide the 12 VDC for running the trailer lights, and is an inverter to provide the 120VAC for the outlets.

I put three 365W residential solar panels on the roof that charge the two 24 V 200 AH Redodo LiFePO4 batteries. Yes, I had to add an Orion 24V to 12V converter. I did some other things that I wanted to do, but you may not need to do or want to do, so I'm not going to go into them here. We chose to do the whole package at once. We practiced boondocking while at our winter base, and found that, generally, we can be totally free of shore power for as long as we want. We can run one a/c for an hour or two should we arrive and the trailer is really hot inside. We did two nights of real boondocking last week without any a/c and all was good. We're going to boondock Monday and Tuesday nights this week, so we'll see if our experience so far holds true.

I think, if I were to redo this project, I'd opt to stay with a 12V system. The few dollars the 4/0 wire would cost over the 2/0 I used would be far less than the cost of the Orion. In my case my batteries are a few feet from the MultiPlus II, so the wire cost wouldn't be much more.

Hope this helps.
 
HEPL!
Ready to pull the trigger on Li batteries.
Looking for my optimum/best set up.
We plan to expand it later. So…

1) The Installed Gear
Jaboni Charge Controller, 50 Amp
WFCO Converter WF-9855-AD, 55 Amp
WFCO Inverter WF-5220, 2000 Watts
2 Solar Panels, 670 Watts Total

2) The Power Sponges
A/C Main, 15k (Soft Start)
A/C Bedroom, 15k (Soft Start)
A/C - Heat Pump, 15k (Soft Start)
Residential Fridge - Samsung
The usual - Microwave, TV (2), Furnace (35k btu), and Fireplace

3) My Battery Ideas (LiFePO4)
12v, 100Ah (2) (BMS w/ Shunt)
12v, 200Ah (1) (BMS and Bluetooth)
12v, 270Ah (1) (BMS w/Shunt)

I want my Fridge to keep things cold/frozen on our (generally) 2 day drives to location.
Also, would like to run an A/C for a bit to cool down during our 1 overnight stop.
Optimally, would like the same during a 2-3 day boondock.
(Not interested - yet - on a generator)

Thought on the batteries? Recommendations on others? Other observations?

THANKS IN ADVANCE
R/

First, I would recommend you switch to Lithium batteries, their advantage over Lead Acid is significant and the Lithium prices have dropped to the point that it just makes sense to upgrade to Lithium batteries.

Second, I recommend you read the thread "Affordable Solar..." pinned at the top of the Solar and Generator forum. This will answer many of your questions about Solar, Lithium batteries, and energy requirements needed to, for example, run an Air Conditioner. This also gives you solid recommendations on how to design your system, but, to install it in phases (follow the link to: "Installing Your Solar System in Phases").

When looking at your list of batteries, it seems like you are looking at BattleBorn's catalog. I would recommend you consider the more value priced options available from Amazon. As an example: a couple of weeks ago, I priced 12v, 100ah, Lithium (LiFePo4) batteries and found several priced at $178 as well as one priced at $152, all of them included free shipping. As always, when shopping for value priced Lithium batteries, I recommend you search for a YouTube video showing a teardown of your prospective choices to determine if the brand meets your quality and power storage expectations. Also, I always recommend installing your batteries using a Buss Bar instead of simply wiring the batteries together.

Since you are looking at the higher amp hour batteries, I recommend you pay special attention to the rated power output of each battery's BMS. For the most part, the 100ah batteries are rated at 100 amps of continuous power output, consequently, if you install 4 batteries, using the Buss Bar method, your maximum power output would be 400 amps. On the other hand, if you chose a pair of 200ah batteries, and they were only rated for 100 amps continuous power output, you would be limited to only 200 amps of maximum power output. 200 amps of power is not enough energy to feed a 3,000 Watt Inverter, whereas the 400 amps from the 4, 100ah batteries would be able to power that Inverter.

As kb0zke alluded to in his response, you can configure your system as 24 volts. There are other advantages to a 24v system versus a 12v system besides reduced cable size, the biggest advantage is when using your Inverter, the Inverter only has to increase the voltage 5 times with a 24v system, compared to 10 times with a 12v system. This gives you better efficiency when using your Inverter.

You already have a decent sized Solar system installed, if you installed a large battery bank (800ah to 1,000ah) and a Victron Multiplus II Inverter, you could achieve your stated goals with minimal cost and effort. This is what I recommend. With the Victron Multiplus II (with 2, 120v outputs) you can have 120 volts throughout your whole coach and with 800ah to 1,000ah of battery storage, you could run one Air Conditioner for a few hours whenever necessary. This system would easily meet your needs during your two day travels as well as meet your needs for a 2 to 3 day boondocking stay.

As a future upgrade, I might suggest you consider installing a DC-DC Converter in your Tow Vehicle if you wanted to extend your boondocking days, especially, if you were traveling every few days, this would allow you to top off your batteries since you only have 670 Watts of Solar.

Good luck and please let us know what you choose.
 
Welcome, Bob. We started down this road a year ago, doing a LOT of research and asking even more questions. Others know quite a bit more than I do, but I'll share what we've learned so far.

First of all, figure out what you really want to run all the time (the must-have list). Then add to that the things that would most likely be needed, but you could do without or won't be using them at the same time as something else (electric skillet and microwave, for example). Try to figure out your maximum draw.

With 12V batteries you can use a very rough conversion: 1A at 120V = 10A at 12V. This ignores the losses in the inverter, but will be close enough. Now, a bit of math, since things are labeled with different units. Watts = volts x amps. (Electrical engineers, please don't confuse us with power factors, etc. This is simply rough calculating.)

Now you have all you need to calculate your system. You may well find that building the whole system at once will cost more than the CFO will allow you to spend. That's okay, just plan on doing it in stages. Keep in mind that sales do happen. I bought a pair of 24V 200AH Redodo batteries during their Black Friday sale for just over $1,000 each. Right now those same batteries are $1300 each.

Generally, as was mentioned above, since higher voltage means lower amperage (and therefore smaller wires) it makes sense to put the inverter as close as possible to the batteries. If you choose to go that route, a Victron MultiPlus II is a good all-in-one device that will charge the batteries, provide the 12 VDC for running the trailer lights, and is an inverter to provide the 120VAC for the outlets.

I put three 365W residential solar panels on the roof that charge the two 24 V 200 AH Redodo LiFePO4 batteries. Yes, I had to add an Orion 24V to 12V converter. I did some other things that I wanted to do, but you may not need to do or want to do, so I'm not going to go into them here. We chose to do the whole package at once. We practiced boondocking while at our winter base, and found that, generally, we can be totally free of shore power for as long as we want. We can run one a/c for an hour or two should we arrive and the trailer is really hot inside. We did two nights of real boondocking last week without any a/c and all was good. We're going to boondock Monday and Tuesday nights this week, so we'll see if our experience so far holds true.

I think, if I were to redo this project, I'd opt to stay with a 12V system. The few dollars the 4/0 wire would cost over the 2/0 I used would be far less than the cost of the Orion. In my case my batteries are a few feet from the MultiPlus II, so the wire cost wouldn't be much more.

Hope this helps.

Where did you put all of this?
 
Well, to put things into perspective, there are a lot of folks that do not know the ins and outs of solar/battery storage/equipment needs, so you are certainly not by yourself. And for further perspective, I'm not a solar guy and there are many out there that know 10 times more than I know about the subject. I am an Electrician by trade though, and let's face it, solar/battery storage/etc is just another category/branch of the electrical trade and the same electrical formulas and theory of operation prevail throughout......the difference is the source of energy for producing the power.....sunlight vs. coal, vs hydro vs nuclear and so on. When I first bought our present trailer, the Momentum Toy Hauler, I had thoughts of getting into solar and starting down that road. It didn't take long for me to realize some of the things I mentioned above about the cost of the equipment if it were to be large enough to do things like run A/C units, microwaves, and other high power consuming devices that you find in camping trailers. Since we rarely if ever boondock, it totally didn't make sense for me/us, especially with the onboard generator that came with the trailer. I would however, never try to talk anyone out of pursuing the solar route if their needs warrant it, they can afford it, and when complete it satisfies the goals that they have set for the system.....but it's just not for me.

I appreciate that. I’m sticking with the solar route, but will limit to what I need for the few days of boondocks id like to get in during our trips. Definitely going to expand as I learn more about how it all goes together. Presently going to use my existing system set up and buy a single LoFePO, 280Ah with a BMS that lets me get 200Ah out of it. Again, thanks for the insight and comments!
R/
 
First, I would recommend you switch to Lithium batteries, their advantage over Lead Acid is significant and the Lithium prices have dropped to the point that it just makes sense to upgrade to Lithium batteries.

Second, I recommend you read the thread "Affordable Solar..." pinned at the top of the Solar and Generator forum. This will answer many of your questions about Solar, Lithium batteries, and energy requirements needed to, for example, run an Air Conditioner. This also gives you solid recommendations on how to design your system, but, to install it in phases (follow the link to: "Installing Your Solar System in Phases").

When looking at your list of batteries, it seems like you are looking at BattleBorn's catalog. I would recommend you consider the more value priced options available from Amazon. As an example: a couple of weeks ago, I priced 12v, 100ah, Lithium (LiFePo4) batteries and found several priced at $178 as well as one priced at $152, all of them included free shipping. As always, when shopping for value priced Lithium batteries, I recommend you search for a YouTube video showing a teardown of your prospective choices to determine if the brand meets your quality and power storage expectations. Also, I always recommend installing your batteries using a Buss Bar instead of simply wiring the batteries together.

Since you are looking at the higher amp hour batteries, I recommend you pay special attention to the rated power output of each battery's BMS. For the most part, the 100ah batteries are rated at 100 amps of continuous power output, consequently, if you install 4 batteries, using the Buss Bar method, your maximum power output would be 400 amps. On the other hand, if you chose a pair of 200ah batteries, and they were only rated for 100 amps continuous power output, you would be limited to only 200 amps of maximum power output. 200 amps of power is not enough energy to feed a 3,000 Watt Inverter, whereas the 400 amps from the 4, 100ah batteries would be able to power that Inverter.

As kb0zke alluded to in his response, you can configure your system as 24 volts. There are other advantages to a 24v system versus a 12v system besides reduced cable size, the biggest advantage is when using your Inverter, the Inverter only has to increase the voltage 5 times with a 24v system, compared to 10 times with a 12v system. This gives you better efficiency when using your Inverter.

You already have a decent sized Solar system installed, if you installed a large battery bank (800ah to 1,000ah) and a Victron Multiplus II Inverter, you could achieve your stated goals with minimal cost and effort. This is what I recommend. With the Victron Multiplus II (with 2, 120v outputs) you can have 120 volts throughout your whole coach and with 800ah to 1,000ah of battery storage, you could run one Air Conditioner for a few hours whenever necessary. This system would easily meet your needs during your two day travels as well as meet your needs for a 2 to 3 day boondocking stay.

As a future upgrade, I might suggest you consider installing a DC-DC Converter in your Tow Vehicle if you wanted to extend your boondocking days, especially, if you were traveling every few days, this would allow you to top off your batteries since you only have 670 Watts of Solar.

Good luck and please let us know what you choose.

Thanks very much. Encouraging that I can probably get where I want to be in stages. I think I’m gonna go with a 280Ah lithium with a BMS that lets me get 200Ah out of the battery. I’ll add to that afterward, building in stages. Pretty sure I want to stick with the 12v system as it looks like I can get where I want to be eventually - and not ok great a cost. Hoping to end up with 400Ah in batteries and related upgrades to peripherals to make it work for my goal of boondocks 2-3 days every now and again.

Thank you!!
R/
 
Everything is mounted in the pass-through under the front closet. There is an access hatch from the closet floor to the bay and the batteries are right there. I did divide the bay into two parts, with the electric stuff and the Nautilus on the street side (about 2/3 of the total) and storage on the curb side.

I should have mentioned that I also added a Hughes Power Watchdog. I relocated the shore power cord to be wired directly into the Power Watchdog, which goes less than a foot to the MultiPlus II. Doing that let me do away with the typical RV shore power connection, which was already showing signs of overheating, and gave me just one run from the MultiPlus II to the breaker panel. Had I kept the original connection location I would have had to run a cable from there to the front and another one back to the breakers. This way I have just one run.
 

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