Newbie Question on Battery Charging

[David007]

We just bought an E-Pro 2019FBS and I was wondering what is charging the battery when plugged into shore power and when unplugged as well. I think the solar system may do some charging, but is it responsible for all the charging? Sorry if it's a stupid question, but I am learning a lot on this fourm as this is my first camper. Thanks for your time and enjoy your day!!
David

[Rover Podder]

Your camper has a converter behind the electrical panel. The converter charges the battery when the camper is plugged into shore power.

[Mr. Dan]

When you’re plugged in to shore power, your CONverter charges your battery.
I don’t have a solar setup so I’ll let others answer.

[Tabasco_Joe]

Originally Posted by David007

We just bought an E-Pro 2019FBS and I was wondering what is charging the battery when plugged into shore power and when unplugged as well. I think the solar system may do some charging, but is it responsible for all the charging? Sorry if it's a stupid question, but I am learning a lot on this fourm as this is my first camper. Thanks for your time and enjoy your day!!
David

Your TT should have a convertor which not only suppliers 12VDC for your camper but also charges the battery when connected to shore power.

When you are towing your TV is providing 12VDC which charges the battery.

And to supplement this your solar does as well.

[David007]

Thanks for all of your replies as I've learned I have a converter! We didn't get an owner's manual as I think it is online.......I think I should be having a look at it real soon? Thank you again-what a great place and way to learn!

[wmtire]

David, we have a thread aimed at new RV owners like yourself that hopefully explain a lot of things. Here is a link to it and there is a link there explaining a converter.

Hope it helps and welcome aboard

https://www.forestriverforums.com/fo...d.php?t=157524

[David007]

Originally Posted by wmtire

David, we have a thread aimed at new RV owners like yourself that hopefully explain a lot of things. Here is a link to it and there is a link there explaining a converter.

Hope it helps and welcome aboard

Well a big thank you for this information!! I'll bookmark it now! I've learned more on this forum in 2 days than in all my google/you tube searches!!
Thanks so much for sharing and have a good day!

[jimmoore13]

This is long, but you're new...and this is info you need.

Your solar charges all the time the sun is up...plugged in or not. The solar charge controller regulates the solar charging output based on the state of the battery's charge.

Your shore power feeds through a Converter (as others said). A converter is actually an assemblage of things:
1) It feeds 120 volts to the breaker panel (breakers are only for 120 volt circuits).
2) It feeds 12 volts to two places: the 12 volt fuse panel and the battery charger.
3) A multi-stage 12 volt battery charger. This charger is sophisticated enough to detect the battery's state of charge and charge in several steps: "bulk" (high rate of charge), "absorption" (moderately high rate of charge...used most of the time at the initial point of charging), "float" (trickle) mode to keep the battery topped of. Float mode can run essentially indefinitely...which means you can leave your rig plugged into shore power 24/7 whether you are using it or not. You probably have a WFCO brand converter in your rig.

Charging via converter and solar are NOT in conflict in any way. Think of this like jump-starting your car. You connect to the running vehicle with jumper cables. Once your car starts, your alternator also supplies charge current to your battery. There is no rush to disconnect the jumper cables, because both charging circuits (the one in your car and the one in the "donor" car) work in harmony, and both regulate charge output based on feedback from the battery or batteries. This is a perfect symbiotic relationship.

Obviously something can go wrong with either charging circuit...and the charging control can go haywire, but this is VERY unusual...so much so that I haven't heard stories of "runaway" charging.

In this (and all FCLA battery - flooded cell lead acid) scenarios, you have two key responsibilities.
1) Maintain the electrolyte levels in the battery by adding distilled water to the cells as the electrolyte "boils off"...evaporates.
2) Do NOT, under any circumstances, consume more than about 50% of the battery's total amp-hour capacity. In your case, there's a better than good chance that you have one puny "Group 24" "marine" battery that has a TOTAL amp-hour capacity of about 70. You get to use half...35 amp hours.
That's a LOT less than you think.

You also have a 1000 watt inverter that can eat that battery alive in no time flat.

Some simple math: https://www.rapidtables.com/calc/ele...alculator.html
If you plug 1000 watts and 12 volts into the calculator - note that your ultimate power source is the battery, so always use 12 volts, not 120 volts - you are pulling 83 amps. 83 amps for an hour = 83 amp-hours. But you have only 35 USABLE amp-hours. Get the picture?

If you have "more battery," terrific. A great setup that your rig could handle would be 2 x 6 volt golf cart batteries in series to make 12 volts rated at combined output of 230 amp-hours...with a USABLE output of 115 amp-hours. (When you connect two 6 volts in series, the voltage doubles...the amp-hours do NOT double.) Even with that dramatic improvement, if you run that 1000 watt inverter for 90 minutes, your battery bank is tapped out completely. AND YOUR SOLAR ARRAY (190 watts) CAN'T PRODUCE 115 amp-hours on its very best day. To replace 115 amp-hours with 190 watts of solar will take, at minimum, more than two bright, sunny days...AND ABSOLUTELY NO 12 VOLT POWER CONSUMPTION AT ALL.

If you boondock, off the grid, you must be very frugal with power use. Use the calculator and plug in your loads, and do the math. A 500 watt appliance will consume over 40 amps. Run it for 15 minutes, and you've consumed 10 amp-hours. If you're starting with 35 amp-hours, you can see where this is going in one helluva hurry.

If you boondock, you need a generator for your 120 volt appliances...forget that inverter except for VERY short bursts. This brings us full circle to the fact that plugging your rig into the generator is no different than shore power, and your generator and solar will work in harmony with no special attention required.

As an aside, can you charge your battery bank with the generator? Yes, but it takes FAR longer than you think it might. If you want to add 35 amp-hours to a small, group-24 battery, the converter will regulate power to the battery in a manner that it may take 6 hours of generator time to fully charge the battery!! (Re-read the WFCO article.) On shore power, who would notice? But listening to a generator for 6 hours is the last thing I want to do when camping.

Now the kicker...as in kick in the teeth. Your rig is probably equipped with a 12 volt fridge (rather than a proper camper 2-way "absorption" fridge that runs on shore power or propane). 12 volt fridges are power hogs (about 35 amp-hours or more per day!!), and that 190 watt solar array output will largely be consumed by the fridge. If you're going to boondock, you would do well to add more solar and add more battery. Otherwise, you'll need to be VERY careful with 12 volt power. Run your furnace? Yours eats 4.2 amps. On a cold night, let's assume a 50% duty cycle (on half the time), and running 8 hours. In that scenario, your furnace will consume nearly 17 amp-hours!! But what about lights, the water pump, the power awning, the tongue jack, and, and, and??? Forget the TV and stereo.

The good news is that most brands of solar are compatible. You could probably add 2 x 100 watt Renology monocrystaline panels in parallel with your 190 watt array without much trouble. Forest River doesn't spec the solar charge controller installed on your rig, but most basic controllers can handle 30 amps (400 watts of solar panels) with no problem. You also have a "solar on the side" feature, so you can have panels with their own charge controllers on the ground. Again, all can run simultaneously with no problems.

Frankly, sticking a 1000 watt inverter in a rig with only 190 watts of solar is a dumb idea...and it invites abusing the battery bank. If you're going to boondock, I urge you to educate yourself about solar output, battery capacity, and loads. Especially get a clear grasp of how much power that 12 volt fridge is using. You'll soon see that you need, as Tim the Tool Man Taylor says, 'MORE POWER."

Your full enjoyment of your rig depends on you having a solid understanding of 12 volt power generation and consumption and being properly equipped for how you plan to camp...unless you want to listen to your generator droning on for endless hours.

P.S. My rig has 400 watts of solar and 2 x 6 volt golf cart batteries (a DIY labor of love) and an absorption fridge. I have a 500 watt inverter I use to run a 360 watt electric blanket for 20 minutes to take the chill off the bed (during quiet hours)...or to run my stepson's CPAP...one or the other. In sunny Colorado, I can boondock essentially endlessly with frugal use of 12 volt power. But that Rapid Tables calculator is a trusted aid for planning power consumption.

Good luck and enjoy your new rig.

[mmartin_tdc]

Jim, thanks for that detailed and educational description of how all the systems play together. This will come in handy as I ponder adding solar to my 5er.

[mnoland30]

Great writeup! You'll need to send this to every new RV owner.

[David007]

I appreciate the detailed information! That's a lot to take it for sure! I don't see us boondocking a great deal, but I'm sure my 12V battery is not anything to of the line. I'm not very battery savvy, so would need to try and understand the 6V batteries in series?

That said, could you recommend a better replacement 12V battery that you might know of. I would imagine the battery I have came with the camper from 2019 and I'd like to replace it with something more substantial? Thanks for any thoughts you might have.

I'm gonna print your comments out and keep them as it's a great tutorial for someone that knows little about what he's doing.....LOL

Thanks again Jim, I greatly appreciate it! have a good day and weekend!
David

[njfishing]

The key to a good battery for an RV is making sure it's a true deep cycle battery. Most of the 12 volts you'll find that are labeled Marine or RV are not true deep cycles, they are dual purpose, the tell tale is they have Cold Cranking Amp ratings (CC) which means how much power they have to crank your starter which is meaningless in an RV since you're not starting anything... In contrast your looking for AMP hours which means how much power the battery can supply over time, rather then in short bursts.

This is why many people use two 6 volt golf cart batteries and wire them in series which makes them operate like one 12 volt. They are designed to tolerate more deep and frequent discharges which makes sense when you think about how a golf cart is used and how you'll use them in your RV.

[David007]

Thanks as this helps me understand a bit better. I'll be looking into the golf cart batteries for sure, as I would bet there's something on you tube about it. I appreciate the info. and nice fish too! Have a good weekend!
David

[njfishing]

Originally Posted by David007

Thanks as this helps me understand a bit better. I'll be looking into the golf cart batteries for sure, as I would bet there's something on you tube about it. I appreciate the info. and nice fish too! Have a good weekend!
David

You're welcome David and here is a article and video that goes into more detail https://www.rvhometown.com/6-volt-vs...-rv-batteries/

I will say that if you intend to be plugged into power all the time you probably don't need to upgrade to two 6 volts... They provide the most benefit if you intend to camp in places that you can't plug in, also know as "dry camping" or "boon docking"

Think about it this way..... A 12 volt car battery is fine in a car since once the car is started your alternator is supplying power to all your accessories and recharging the battery.... In an RV, if you are plugged in, your converter act's like an alternator, it does 2 things, it runs all of your accessories so that battery doesn't get depleted and if the battery happens to get discharged it charges it back up...

[jimmoore13]

Originally Posted by David007

I appreciate the detailed information! That's a lot to take it for sure! I don't see us boondocking a great deal, but I'm sure my 12V battery is not anything to of the line. I'm not very battery savvy, so would need to try and understand the 6V batteries in series?

That said, could you recommend a better replacement 12V battery that you might know of. I would imagine the battery I have came with the camper from 2019 and I'd like to replace it with something more substantial? Thanks for any thoughts you might have.

I'm gonna print your comments out and keep them as it's a great tutorial for someone that knows little about what he's doing.....LOL

Thanks again Jim, I greatly appreciate it! have a good day and weekend!
David

In basic batteries...as in affordable for someone who doesn't plan to boondock often...a BCI group 27 or group 29 or group 31 (and other sizes) FCLA (conventional lead acid) battery is bigger, and it has more capacity. These are modest but valuable jumps.

Here's the "all you need to know" source...brace yourself: https://www.batterystuff.com/kb/arti...ry-basics.html

You want a "deep cycle" battery over a "marine" battery or car battery. The deep cycle battery suits the application. You're not asking the battery to deliver a huge burst of power for a few seconds (CCA or cold cranking amps), you want a battery that can deliver a modest amount of amps for a LONG time...a deep cycle battery. Marine batteries, what came with your rig, are kind of jack of all trades...good to start your boat engine and good to run accessories while the engine is not on. Not great at either job.

You'll probably have to buy a new plastic battery box for your larger battery...$35 or $40.

If you upgrade your lead acid battery, just remember that you get to use 50% of its rated capacity before you need to charge it. So, if you have a battery rated at 100 AH (amp hours) you get to use 50.

If you change your mind about boondocking, the 2 x 6 volt golf cart batteries are a very simple solution for a substantial upgrade in capacity. They'll fit on the tongue of most rigs, and wiring them in series is easy: A jumper wire from the negative on one battery to the positive on the other makes them be in series. Then you connect the rig's positve wire to the positve terminal on one battery and the negative terminal on the other battery, and voila, you have a big ass 12 volt battery...good for a usable 115 AH or so. Some people prefer two 12 volt batteries in parallel...a bit less overall capacity, but simpler. In parallel, you join the two batteries by connecting positive to positive and negative to negative on the two batteries, and you hookup the camper to either positive terminal and either negative terminal. Easy.


There are, of course, lithium batteries...specifically LiFePo (Lithium, Iron, Phosphate)...the current gold standard. https://www.google.com/search?q=life...hrome&ie=UTF-8
These are very costly, but they allow you to use about 80% of rated capacity, they are light weight and so on. But if you don't boondock, they are a waste of money...and they are a bit more delicate. Most of the time, these get moved inside the rig...they don't live on the tongue.

So, after wandering all over the place, I suggest an upgrade to a group 31 lead acid battery and you'll have 50 usable AH, which means a super cold night running the furnace and fridge won't leave your rig dead. You could wait to upgrade until you (maybe) kill your original. You might get 3 or 4 years out of the original even if you abuse the hell out of it. You can always charge up with the genny in combo with the solar for the occasional boondocking trip.

All I do is boondock, so solar and battery capacites are very important. But if you mostly run on shore power, just know that you'll have to be VERY frugal with power when boondocking...but you can make it work. I got by for years with a single 100 watt solar panel and a group 24 (and an absorption fridge running on propane) by using portable lanterns, not using the stereo, and being careful with the furnace. OMG, we were camping!! If you know you have only 35 AH going in, just know the fridge will use most of that and, well, camp.

[trailerdude]

I installed one of these: https://www.amazon.com/dp/B088RG27LS...t_details&th=1
It's really nice having the amps in and out and %ah remaining. You can see what you are using and when it's charging or not.
I got this after ruining a couple batteries by deeply discharging them. Now have the 6v batteries too. I have 150 watts of portable solar that works great as long a I have sun. Lot's of good advice here.

[TitanMike]

Originally Posted by trailerdude

I installed one of these: https://www.amazon.com/dp/B088RG27LS...t_details&th=1
It's really nice having the amps in and out and %ah remaining. You can see what you are using and when it's charging or not.
I got this after ruining a couple batteries by deeply discharging them. Now have the 6v batteries too. I have 150 watts of portable solar that works great as long a I have sun. Lot's of good advice here.

The meter you linked, and other similar inexpensive meters, are fine if your loads are consistent and relatively low. Running the lights at night and furnace as needed, it will give a fairly accurate status of your batteries.

When you add an Inverter to the mix and there are periodic high current draws on the battery these simple "Fuel Gauge" meters lose accuracy.

Meters like the Victron Smart Shunt and the BMV-712 use a far more sophisticated circuitry that takes into consideration the varying loads and with Lead Acid batteries also takes into consideration that type of battery chemistry's inefficiency.

Yes, they cost more but you get more.

[jimmoore13]

Originally Posted by TitanMike

The meter you linked, and other similar inexpensive meters, are fine if your loads are consistent and relatively low. Running the lights at night and furnace as needed, it will give a fairly accurate status of your batteries.

When you add an Inverter to the mix and there are periodic high current draws on the battery these simple "Fuel Gauge" meters lose accuracy.

Meters like the Victron Smart Shunt and the BMV-712 use a far more sophisticated circuitry that takes into consideration the varying loads and with Lead Acid batteries also takes into consideration that type of battery chemistry's inefficiency.

Yes, they cost more but you get more.

Excellent point...and I overlooked mentioning that a 1000 watt inverter inhales batteries more quickly than smaller loads will. It's not a linear relationship between amps drawn and power remaining. At 1000 watts, the inverter is drawing over 80 amps (assuming full load on the inverter...say a small microwave), but batteries are generally rated using 20 hour discharge time. Your group 24 is rated at about 70 amp hours (until totally dead and essentially ruined) over the course of 20 hours...at the rate of 3.5 amp hours per hour. If you accelerate that rate to 80 amp hours, you'll exhaust your battery far more quickly than simple math would imply. You won't get nearly the 52 minutes out of the battery the math would suggest...it will be significantly less. And since you get to use only half, you won't get to use anywhere near the 26 minutes the math would suggest. This means you must charge sooner to not kill the battery when you draw very high amps.

Want to nuke a cookie for 15 seconds? No problem. Want to run the micro for 10 minutes straight? You'd better be on generator.

https://www.batterystuff.com/kb/arti...ate-mean-.html

Once again, far mor than you asked for or may need to know, but here goes: https://www.progressivedyn.com/service/battery-basics/

PS. Like your car battery, draining your battery dead is not likely to kill it all at once. But it will shorten its life significantly, and repeatedly draining it dead will ruin it in less than a season...maybe just a few outings. Most batteries will recover a few times, but not many.

[MNtraveler]

Originally Posted by David007

Thanks for all of your replies as I've learned I have a converter! We didn't get an owner's manual as I think it is online.......I think I should be having a look at it real soon? Thank you again-what a great place and way to learn!

You should ask you dealer for the set of instruction manuals that go with every appliance and utility in the trailer. It should have been there in your trailer when you picked it up. If they don't have those for you, you should make a list of all the appliance numbers with their model numbers, then look them up online and download them. Some people put hard copies into a folder or a 3-ring notebook (which I use), but now some people take the downloaded files and put them on their laptop or notepad. In fact some dealers now give them out in a thumb drive you can carry with you. And maybe Forest River has more of the appliance manuals available on their web site than they used to.

Apart from gathering them up, it's best to actually read them and have a good working understanding of every system in the RV. It will really help when you are on the road because something always happens amongst all those systems.

[TitanMike]

Originally Posted by jimmoore13

Excellent point...and I overlooked mentioning that a 1000 watt inverter inhales batteries more quickly than smaller loads will. It's not a linear relationship between amps drawn and power remaining. At 1000 watts, the inverter is drawing over 80 amps (assuming full load on the inverter...say a small microwave), but batteries are generally rated using 20 hour discharge time. Your group 24 is rated at about 70 amp hours (until totally dead and essentially ruined) over the course of 20 hours...at the rate of 3.5 amp hours per hour. If you accelerate that rate to 80 amp hours, you'll exhaust your battery far more quickly than simple math would imply. You won't get nearly the 52 minutes out of the battery the math would suggest...it will be significantly less. And since you get to use only half, you won't get to use anywhere near the 26 minutes the math would suggest. This means you must charge sooner to not kill the battery when you draw very high amps.

Want to nuke a cookie for 15 seconds? No problem. Want to run the micro for 10 minutes straight? You'd better be on generator.

https://www.batterystuff.com/kb/arti...ate-mean-.html

Once again, far mor than you asked for or may need to know, but here goes: https://www.progressivedyn.com/service/battery-basics/

PS. Like your car battery, draining your battery dead is not likely to kill it all at once. But it will shorten its life significantly, and repeatedly draining it dead will ruin it in less than a season...maybe just a few outings. Most batteries will recover a few times, but not many.

Actually I can run my microwave for 10 minutes straight. It draws 1.35 KW and my Inverter draws around 125 amps to generate the 120 volts necessary.

The thing that's often overlooked is that 10 minutes is only 1/6th of an hour so the actual number of Amp Hours used (using my 125 amps as an example) are only 20.8 amp hours.

The real issue will not be the battery's capacity as it will be the battery's ability to deliver enough voltage while that 125 amp draw is taking place. Lead Acid's will 'sag' badly while under this kind of load yet when the load is removed they will recover voltage and they will still retain plenty of "amp hours".

LiFePo4 batteries have minimal 'sag" and can deliver high currents right down to the end.