I have already prepared how much battery capacity I need and I am going to buy four 100AH lithium batteries to connect in series. I found that Amazon now has Bluetooth batteries and even batteries with displays. Bluetooth may be a useful feature at the moment?
How should I choose an RV battery?
- Thread starter Ricardo L
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Q-Dog
¯\_(ツ)_/¯
BMS controlled batteries in series can be problematic and difficult to keep balanced ... not really what you want in an RV I would think. Much better to use batteries at your system's native voltage.
timselectric
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Yeah, don't put BMS controlled batteries in series.
Always build for success, not regret.
Always build for success, not regret.
chrisski
Solar Boondocker
IME, 48 volts is too high for an RV. Not much can run off 48 VDC except the inverter. Victron makes balancers, but you’d need to purchase 3 for a 4s battery pack.
If you must stack in series, recommend a battery balancer. Just like your BMS balancer for cells except does this between batteries.
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I have 24 volts feeding a 12 volt DC converter. I can get all RV appliances at 12 volts, 24 volts fewer are available, and at 48 volts almost none.
The 24 volt appliances I have are lights, quick chargers, and the tire pressure management system. I could also get a 24 VDC fridge. Those aren’t available in 48 volts.
Also, IMO solar panels on an RV is limited to running 3 kW and inverters with between 500 watts and 3 kW of panels. A 24 VDC inverter will handle that. Going bigger than 3 kW get to the point you’re running more high wattage items than solar production can keep up with.
I have 1650 watts of panels on the roof of my fifth wheel and 1200 watts of ground mount panels with a 3 kW inverter and I can run 2 kW when the sun shines and still charge my batteries a little. My max production would be around 20 kWh a day. That’s not enough power to run one of my two AC units 24 hours.
If you must stack in series, recommend a battery balancer. Just like your BMS balancer for cells except does this between batteries.
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I have 24 volts feeding a 12 volt DC converter. I can get all RV appliances at 12 volts, 24 volts fewer are available, and at 48 volts almost none.
The 24 volt appliances I have are lights, quick chargers, and the tire pressure management system. I could also get a 24 VDC fridge. Those aren’t available in 48 volts.
Also, IMO solar panels on an RV is limited to running 3 kW and inverters with between 500 watts and 3 kW of panels. A 24 VDC inverter will handle that. Going bigger than 3 kW get to the point you’re running more high wattage items than solar production can keep up with.
I have 1650 watts of panels on the roof of my fifth wheel and 1200 watts of ground mount panels with a 3 kW inverter and I can run 2 kW when the sun shines and still charge my batteries a little. My max production would be around 20 kWh a day. That’s not enough power to run one of my two AC units 24 hours.
I have a 48 volt battery in my RV. The lack of components that work with a 48 volt environment sucks.
The 48-12 converter produces a lot more heat than I expected. The 12 volt DC refrigerator keeps the converter busy.
The 48-12 converter produces a lot more heat than I expected. The 12 volt DC refrigerator keeps the converter busy.
If you go with 48v in an RV, you'll either need a higher cost, high amperage 48-12 converter to run your 12v components, or you'll need to keep a smallish 12v lifepo4 or lead acid battery just for the 12v system with a smaller 48v to 12v charge controller of some type to keep that 12v battery charged off the 48v system. Same if you go 24v, though there are more options for 24v -> 12v converters.
In any case, buy batteries rated for the voltage you're after, and stack multiple in parallel to increase capacity keeping the rated voltage. Don't series connect them, increasing voltage.
Yeah, bluetooth can be handy for monitoring the batteries' health, state of charge, etc.
I would try to choose batteries from companies that have been known to ship acceptable quality units. Will seems to do pretty honest tear downs of a number of them on his youtube channel: https://www.youtube.com/@WillProwse/videos
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I wouldn't have a LiFePO₄ battery without Bluetooth.
Can you explain this?
personably I would connect them in parallel that will give you 400ah and will give you more than enough amps to power a 3000 watt inverter if you so chose. the problem with going with 48V setup or even a 24V setup over a 12V is you have to get different equipment for charging to that 24 or 48V then you have to get more to convert it back down to 12V to power your RV and if you can put the inverter right beside your batteries thee is not realy any cost savings in the wiring which would be small compared to the components anyways.
Bluetooth is what I use to adjust my batteries
0truck0
Solar Enthusiast
I would not do 4 batts!
Keep it at 12 unless 24v just is needed. 12 makes everything RV in life so much easier.
Get two 200 amp/hr batts instead of your 4. The reality that one batt goes bad and you just have to replace 1/4 of your batts for 1/4 of the price is just not realistic and not worth the issues that will come with so many batts, and if you try to do 48v with 4 batts and one goes out then you are down to 36v and will that work still, can you convert on the fly? With 12v batts in parallel they are always 12 if you have one or 21 batteries....
Keep it at 12 unless 24v just is needed. 12 makes everything RV in life so much easier.
Get two 200 amp/hr batts instead of your 4. The reality that one batt goes bad and you just have to replace 1/4 of your batts for 1/4 of the price is just not realistic and not worth the issues that will come with so many batts, and if you try to do 48v with 4 batts and one goes out then you are down to 36v and will that work still, can you convert on the fly? With 12v batts in parallel they are always 12 if you have one or 21 batteries....
CommandoJoe
Solar Enthusiast
Have you tracked power consumption of the 12v fridge? My travel trailer came with a propane / 120v AC fridge that was a power hog when running on AC - 400w when running about 60% of the time. I replaced it with an apartment size unit from Walmart and can't even see it cycle on my power usage now. I would estimate the new fridge uses less than half what the old one did...
Have you looked into using a charge controller to convert 48v-12v? There's a Youtube video where someone used a Victron CC to do that and it was actually more efficient than a Victron DC-DC converter...
I don't have any big 12v DC loads, so I just rely on the built in AC to DC converter to keep a 12v battery going for lights, water pump, etc. The blower on my propane furnace was probably the biggest load, but I rarely use it since installing a diesel heater.
As others have said, series 12v lithium is not the best way to go.
Take a look at what you need to power - If you have mainly 12v DC loads, consider going with the batteries in parallel and a moderately sized 12v AC inverter.
If you have mainly AC loads like me, go with 24v or 48v batteries and larger inverter and keep the built in 12v system as is. This lets you use smaller gauge wire to the batteries and inverter and fewer batteries
No, I haven't tracked power consumption. I'm still trying to dial in where to set the refrigerator to keep my refrigerated items from freezing. The rated DC current is 11 amps, which isn't a small amount. Of course, it doesn't draw 11 amps all the time. The Orion Tr 48-12/30 is dumb (no Bluetooth) so I can't pull any usage data from it. It has an efficiency of only 87%. By contrast, the Orion XS (which I'm using) has an efficiency of 98.5%. I'm hoping that Victron will come out with a 48-12 version of the XS.
With regard to using a solar charge controller in place of the Orion Tr, I'll hold out for the Orion XS version.
RvNaut
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I disagree. I have 48v system in place for two+ years in my RV. Long term I will have 3200+- watts of solar up top, and I currently use around 3500 watts hours a day, and will likely double that in the next couple of years. Most of the usage is on the 110 side of the RV. Creating, storing and using this much power is way more efficient at 48v.
Up to 1000w of solar, 12v
1000-1800w of solar, 24v
1800-and up of solar, 48v
of course everyone has different needs and opinions... I live full time in my 32' class A... this is my home until I die or other... I am a power hog.. 42" screen and desktop computer, starlink, etc etc ...
So IME, 48 volt is the way to go if you intend to suck many electrons
YMMV IANAL CPBCM
your not disagreeing, you are the case where 48V makes sense, like he said most of your loads are inverter loads, which we have all been saying is the only reason in a RV to go over 12V.
for most people who are powering nothing but 12V loads it becomes inefficient and adds un necessary costs to go 48V as you are either running your inverter and converting the 120V back to 12V dc or using a buck converter to drop the 48V output of the batteries to 12V to power the rv systems. either way your converting twice and adding in efficiency's and more parts for no reason.
and basing it off solar is a bad way to do it also, that's about as bad as basing your battery bank capacity off the size of your solar in a rv. your solar should be sized to properly recover your overnight usage in short order the next day. I size mine to recover everything I use overnight (assuming I am at 100% when the sun goes down) by noon so that leaves the rest of the day to make up for bad solar days and power the loads during the day. the battery bank I recommend sizing to allow you to do your normal trip with out solar. so for my truck camper I have a 9 day capacity at my normal 24 hour usage rate with the furnace running. in my 5th wheel I sized it for 10 days. that way if something brakes down or I just run into a stretch of bad solar weather I don't have to worry about it. but the only inverter loads I use are in the 5th wheel and it is the coffee pot, the outdoor kitchen fridge, sometimes a tv show in bad weather, otherwise its all 12V. now if I lived somewhere where I had to say run the AC most of the day that would be different then I would be going 48V
I have serious doubts that "most people" are powering nothing but 12v loads today.
That's how quite a few people are starting out. Once they get that working/stable, it's off to the Internet again to upgrade. I started out with solar and no inverter.
The higher system voltage allows you to purchase a smaller solar charge controller. A Victron 100/50 in a 12 volt system is 700 PV watts nominal while the same controller in a 24 volt system is 1400 PV watts nominal. 1400 watts of PV on a 12 volt system would require two solar charge controllers.
RvNaut
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I have lived off grid in an RV for three years and I have met a ton of other nomads living the same way... those in RVs use a lot of 110v power, those in cars and vans and other non-traditional living situations often use more 12v... but almost all of us use some amount of 110v devices on a daily basis.
RvNaut
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You take most of what i said out of my context.... but as I said.. we all have our opinions, your are right for you, mine are right for me. Going with large solar arrays is more efficient at higher battery voltages. This isn't basing anything else on it.. just stating a fact that if you have a large array, 48v is better. As for how I power my 12v, I'm not sure you have a good grip on my system or why I built it the way I did.. but again, you are free to have an opinion...
RvNaut
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I have occasional heavy loads on the 12v side, with the operation of the hyd leveling jacks and the slide motors, up to 48 amp at startup on the Hyd motor... I employed a 30 amp 48v-->12v converter and left a deep cycle battery in place to act as a buffer. The converter allows me to adjust the voltage and I have it set at 13.2 volts. This system has been operational for over 2 years with no issues... Given I was set on a 48v system, this was the best way to power the 12v side of my RV. ...and yes the Victron 30 amp 48/12 was not cheap, but was the best solution for *me* and my 48v system. I use 3500 watt hours a day, most of that is 110.
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I think the problem comes in as people that are in the southern USA can't fathom that most of us don't need a air-conditioning unit to camp. so any 120V loads are momentary and its not worth the extra cost to convert and reconvert and incur extra losses and such. my 5th wheel we do have a 2000watt inverter and I will turn it on for about 30 min in the morning to make a pot of coffee then turn it off. it might come on again later to use the microwave for a short period and then after supper to make coffee again. other than that everything is 12V loads and that has lasted us for 9 years now.
my truck camper there is no inverter at all, I may put one in, only because the wife wants to be able to use a hair dryer.. but thats the same it will be on for that then off.
hang on here, I am only talking about storage not the panel voltage haha. and there is no way in hell I would recommend some one getting a PWM controller.
I run 24V panels LOL well on the camper, the 5th is getting upgraded to 24V when I do that. it came with the 480 watt 12V setup which does work good, but I want to be able to run the refrigerator in the outdoor kitchen and it doesn't quite keep up, so I am going change the three 180 watt panels out for three 400 watt panels.
my 325watt 24v panel on a MPPT puts out the same amperage as the 480 watts of 12V panels on a PWM that is on my 5th wheel. I just wish I knew more about solar besides "I want it" when I bought the 5th wheel.
I'm not in the south most of the time. I certainly want A/C much of the summer. Pretty sure I'm not alone on this.
I think everyone else is talking about storage voltage too. For the same amp MPPT you can push more juice to a 48v storage bank than you can if it were 24v or 12v. So for larger solar arrays you can get away with fewer/smaller MPPT charge controllers when you increase your storage voltage.
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what I was replying to he was talking about panel voltage.
if you are not maxing out your MPPT then it doesn't matter, if you have a controller that will put out 1200 watts of 12V, 2400 watts of 24V, or 4800 watts of 48V, if you only have 600 watts it will output the same, the difference will be in the wire size you need to move it efficiently. yes higher voltage will have less transmission loss. when the 5th wheel is set up I might set it up for three 24V panels in series, just to reduce the wire requirement. the battery bank will stay 12V though as I don't want to have to buy a new inverter or converter and incur extra conversion losses.
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