Battery questions?

[k_allison510]

So our new 372rd came with 2 batteries. I have noticed some things lately that trouble me. One, my battery disconnect switch does not kill the power. It does kill the power to the slides, but thats about it. lights and other stuff still have power. The second battery is not affected at all by the switch. I have to pull the cables off to disconnect it. ( could I just switch the inverter off instread?) Shouldn't my batteries be wired together? MY residential fridge only runs off one of the batteries. When I go to the control panel in the rv, it will say my batteries are at %100,(not plugged into shore power) but the battery running my fridge will be low? I also figured out that my truck is not charging both batteries, nor will my solar port. The only way to charge the second battery is to hook my solar directly to it via alligator clips, or to run the generator or shore power. On our DP, when I would hit the disconnect switch, it killed the power to everything. That is how I would like this setup to be.

[Kirk S]

Nice rig!

Normally I wouldn't comment since I don't own a rig like yours but I see you asked 2 days ago with no response. If someone with your model has different ideas they may be a better source of help than me.

First, be absolutely certain there is no reason your batteries are connected separately. If there is I would like to know as well.

It is possible that the batteries were installed improperly by the dealer and Forest River would have no idea.

If you discover the current configuration is incorrect and new means still under warranty you should get your dealer to connect your batteries properly. If you are not close to your dealer you should get Forest River to authorize another dealer to do it, if they will agree to it.
If you are sure you know how, you could do it yourself but if something went wrong it would be on you.
You would need to disconnect truck, solar, shore power, inverter and both negative cables to be sure everything is off before reconfiguring.

I can't think of a reason your batteries would not be wired together in parallel. This still gives you 12 volts but doubles your capacity. Your disconnect switch should shut off most 12 volt items, your truck and solar should charge both batteries.

If you are connected to any charging source it's likely your battery level monitor will always show 100 % so it's best to check it when not connected to shore, truck or solar and a simple digital meter set on DC volts would show you actual voltage at the battery posts.

Goid luck and please post your solution when you find it.

Diagram attached.

[wahoonc]

Not familiar with your specific unit, however it sounds like something isn't wired up quite right. Typically the dealer installs the batteries not the factory. Battery disconnect switches typically don't disconnect everything. On my unit the various detectors like CO and LP bypass the disconnect switch along with a couple of lights.

Aaron

[pgandw]

Missing some critical information to help us provide a good solution.

In the meantime, I offer the following:

On paralleling 12V batteries, the result from outside the battery box is a single larger battery. For successful paralleling the batteries have to be very close equal - capacity, charge state, age, number of cycles, etc. If they are not equal, the higher voltage battery tries to charge the lower voltage battery up to its level. The current involved can be cable melting if the mismatch is severe enough - don't ask me how I know.

A reason (not very good) for not paralleling in your case is the residential fridge. I don't know how much power the fridge takes, but I'm guessing at least 180 watts - which equals 15A at 12V. If there is not power coming into the batteries, this could draw them flat in less than 6 hours of fridge run time. The previous owner may not have realized this, and found himself out of battery to operate the slides. But to fully understand what is going on we need to know the size and type of batteries you have, as well as the power requirements of the fridge.

I will not try to explain the miswiring of the disconnect switch. I agree, I like my disconnect to kill all battery connections - period. But because the slides and inverter and tongue jack (and leveling system and solar if equipped) are wired directly to the battery, the disconnect has to be located at the battery, and not at the panel.

Since my A-frame didn't come with a disconnect, I installed my own on the outside of the battery box, which is located on the tongue.

The panel lights require understanding to interpret correctly. The panel lights are a poor excuse of a voltmeter. When you are plugged into shore power, you are reading the output voltage of the converter, not the state of the batteries. And it takes a few hours of no charge being applied for a voltmeter to give a reasonable approximation of battery state of charge.

Another question pertains to your inverter. Does it charge batteries as well as provide power to the fridge? I'm guessing so, with your converter charging the other battery. If the inverter is also a battery charger, how does it get 120V power to charge batteries?

I'm sorry I'm not much help. Without knowing some of this information, there are just too many possibilities to provide you with good info.

Fred W
2019 Flagstaff T21TBHW A-frame

[k_allison510]

Originally Posted by pgandw

Missing some critical information to help us provide a good solution.

In the meantime, I offer the following:

On paralleling 12V batteries, the result from outside the battery box is a single larger battery. For successful paralleling the batteries have to be very close equal - capacity, charge state, age, number of cycles, etc. If they are not equal, the higher voltage battery tries to charge the lower voltage battery up to its level. The current involved can be cable melting if the mismatch is severe enough - don't ask me how I know.

A reason (not very good) for not paralleling in your case is the residential fridge. I don't know how much power the fridge takes, but I'm guessing at least 180 watts - which equals 15A at 12V. If there is not power coming into the batteries, this could draw them flat in less than 6 hours of fridge run time. The previous owner may not have realized this, and found himself out of battery to operate the slides. But to fully understand what is going on we need to know the size and type of batteries you have, as well as the power requirements of the fridge.

I will not try to explain the miswiring of the disconnect switch. I agree, I like my disconnect to kill all battery connections - period. But because the slides and inverter and tongue jack (and leveling system and solar if equipped) are wired directly to the battery, the disconnect has to be located at the battery, and not at the panel.

Since my A-frame didn't come with a disconnect, I installed my own on the outside of the battery box, which is located on the tongue.

The panel lights require understanding to interpret correctly. The panel lights are a poor excuse of a voltmeter. When you are plugged into shore power, you are reading the output voltage of the converter, not the state of the batteries. And it takes a few hours of no charge being applied for a voltmeter to give a reasonable approximation of battery state of charge.

Another question pertains to your inverter. Does it charge batteries as well as provide power to the fridge? I'm guessing so, with your converter charging the other battery. If the inverter is also a battery charger, how does it get 120V power to charge batteries?

I'm sorry I'm not much help. Without knowing some of this information, there are just too many possibilities to provide you with good info.

Fred W
2019 Flagstaff T21TBHW A-frame

Thanks for replies fellas. I will try and fill in some of the blanks. The trailer is brand new. We have had it for about 3 weeks now. We are about 4 hours from the dealer we bought it from but are taking it back in late October /early November for our 90 day shakedown work.

The only thing I know about the batteries right now is that they are interstate deep cycles. I will have to go get the actual specs off them. (trailers in storage). The dealer did install the batteries because when we looked at the unit initially, it didnt have batteries installed. The batteries are actually in 2 different locations. The one the fridge runs on is in the pod in the front of the trailer (under the pin box) The other is in its own pod on the side of the trailer at the front. They are not very far apart, by I figure it will take at least 5 feet of cable to attach them in parallel. But I figured that they both ran to a junction box of some kind to put them in parallel. Guess I am wrong about that. Our sales lady (i know I know) told us that the fridge would run for about 10 hours with out shore power, so I figured that both batteries were powering it.

Something that confuses me is that when the fridge battery starts getting low (about 10.5v) the inverter will start beeping and telling me that its going into shutdown to protect the battery. So I turned the inverter off. But even with it off, I still have lights. I didnt check if anything else will work but I suspect the slides and jacks will also work since I know they run off the other battery.

The battery disconnect seems to only shut off the 2nd battery. (the non fridge battery) I guess I can live with that if turning the inverter off will essentially do the same thing for the first battery.

Long story short, I am going to discuss these issues with the dealer but I wanted to be educated so I can argue if they say thats the way its supposed to be, and maybe it is? I guess if worse came to worse, I could just go buy another battery and wire it in parallel to the fridge battery.

Also, When I am completely disconnected from any power (shore, gen. solar) and my inverter is going into shut down,(fridge battery is close to 10.5v) the panel will show that my batteries are %100, which leads me to believe that only the 2nd battery is wired to that panel. And apparently it only powers my lights, slides, jacks, and awning. If I could only choose one battery for it to display, I would rather the fridge battery be on it.

Again, thanks for the replies, I really appreciate it.

[k_allison510]

Also forgot the mention that my inverter does charge both batteries when I am plugged into shore power or generator.

[Herk7769]

The reason the CONverter is not connected to both batteries and why the batteries are not connected in parallel is because the INverter used with the residential fridge is an INVerter/Charger.

One of the batteries is dedicated to the fridge and is charged when the INverter is connected to shore power (120VAC). The INverter goes into "pass through" mode to supply the fridge with 120VAC power. At the same time, while it is in "Pass-through", it charges the dedicated fridge battery.

The camper's CONverter charges the camper's dedicated "house" battery when connected to 120VAC shore power.

The two batteries are not connected to each other and serve two different purposes.

[k_allison510]

Originally Posted by Herk7769

The reason the CONverter is not connected to both batteries and why the batteries are not connected in parallel is because the INverter used with the residential fridge is an INVerter/Charger.

One of the batteries is dedicated to the fridge and is charged when the INverter is connected to shore power (120VAC). The INverter goes into "pass through" mode to supply the fridge with 120VAC power. At the same time, while it is in "Pass-through", it charges the dedicated fridge battery.

The camper's CONverter charges the camper's dedicated "house" battery when connected to 120VAC shore power.

The two batteries are not connected to each other and serve two different purposes.

My mind is literally blown.....Thanks you for clearing that up. So....still have a question. I have a xantrex freedom x 1200 in one of the front pods. That is what beeps when the fridge battery is getting low. Is that my INverter for the fridge?

Also, just to clarify, should my truck and solar port be charging both batteries? Or just the "house" battery?

[pgandw]

Originally Posted by k_allison510

My mind is literally blown.....Thanks you for clearing that up. So....still have a question. I have a xantrex freedom x 1200 in one of the front pods. That is what beeps when the fridge battery is getting low. Is that my INverter for the fridge?

Also, just to clarify, should my truck and solar port be charging both batteries? Or just the "house" battery?

I don't know whether the residential fridge was a dealer or factory installation - but it doesn't matter. As Herk pointed out, you have 2 totally separate electrical systems - one for the fridge, and one for everything else.

Which works well in the intended usage scenario - your camper is plugged in while in storage, you drive a day or less to your campsite, and your campsite has electrical service. The battery is only there to power the fridge while you are driving the less than 10 hours.

Whoever designed your system did not intend for it to run 24 hours + on a single 80AH battery. Because the fridge battery has already been taken down to 10.5 volts (dead battery) once or twice, putting that battery in parallel would be a mistake that will likely destroy the better battery in short order.

Before we can make recommendations for a better system for your usage, we need to understand how much power the fridge needs (should be a plate on the back or at least a model number), and how many hours/days between plugging in the 5th wheeler.

Charging batteries with your tow vehicle is the wild card that is hard to predict without you doing a series of measurements. But usually, the tow vehicle does far less battery charging than we would like it to do.

look forward to hearing the specs on the residential fridge and usage

Fred W
2019 Flagstaff T21TBHW A-frame
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time

[pgandw]

Originally Posted by k_allison510

My mind is literally blown.....Thanks you for clearing that up. So....still have a question. I have a xantrex freedom x 1200 in one of the front pods. That is what beeps when the fridge battery is getting low. Is that my INverter for the fridge?

Also, just to clarify, should my truck and solar port be charging both batteries? Or just the "house" battery?

The Xantrex is your inverter. It converts the fridge battery 12VDC to 120VAC for the residential fridge. The Xantrex may, but not likely, also power an AC outlet besides the fridge. Think of your residential fridge as a separate branch off the AC panel of your camper. The 120V power comes in when you are plugged in, and is distributed through the AC circuit breakers. One of these breakers powers the Xantrex which powers the residential fridge and has a battery it both charges and uses. The Xantrex draws from the fridge battery when there is no AC power coming in, and charges the fridge battery when there is.

It is a question worth asking - but I don't know if your dealer will know - whether or not the tow vehicle charge line also ties into your fridge battery. It probably does, but might not.

The rest of your electrical is RV standard 120V/12V with its own house battery and converter to charge it when plugged in.

Your tow vehicle - at very best, and could be 8-10 - might provide 15 amps to the trailer, but only when the engine is running. That 15 amps has to be take care of all needs in your camper while towing down the road, including the residential fridge, battery charging, running lights, all parasitic loads. The residential fridge sucks at least 15 amps at 12V, so you are depleting the fridge battery while towing. And even more so when you turn the engine in your tow vehicle off.

FWIW, your lights, thermostats, stereo, control boards in your camper are all 12V, not 120V. These operate off the house battery and converter.

Fred W

[CHICKDOE]

i just looked at pictures of your trailer. very nice! and very large! something just seems wrong. why are the two batteries in different places? on a trailer that large i would expect there to be room to install two (or more) batteries in a single battery compartment. if they were in a common compartment they would be connected and you wouldn't be having these problems. what i also don't understand is why you apparently have two converters (a converter and a converter / inverter). with all the penny pinching that the manufacturers and dealers do why would the spent a couple hundred extra dollars to have two? have you contacted forest river and asked them how this model is wired if it has two batteries? is there room for two batteries in the up front battery / generator compartment? running a residential refrigerator on a single battery is nothing but shortsighted. i suspect there is more to this story.

[k_allison510]

Originally Posted by CHICKDOE

i just looked at pictures of your trailer. very nice! and very large! something just seems wrong. why are the two batteries in different places? on a trailer that large i would expect there to be room to install two (or more) batteries in a single battery compartment. if they were in a common compartment they would be connected and you wouldn't be having these problems. what i also don't understand is why you apparently have two converters (a converter and a converter / inverter). with all the penny pinching that the manufacturers and dealers do why would the spent a couple hundred extra dollars to have two? have you contacted forest river and asked them how this model is wired if it has two batteries? is there room for two batteries in the up front battery / generator compartment? running a residential refrigerator on a single battery is nothing but shortsighted. i suspect there is more to this story.

Thanks. And I have no idea why they decided to put them in 2 different places. I am pretty sure they designed it that way because there are battery boxes with hoses connected to vents to discharge any gasses from the battery. And there is a bunch of wiring under there to. The compartment on the side is barely big enough for one battery. The only thing I can think of is that the second battery in the front is only there if the trailer has the residential fridge. IE, wouldnt be there if it had a regular rv fridge.

I have not contacted FR, didnt really think I would get a response due to past experiences. But I will give it a shot to see if they reply.

There is plenty of room in the front for more batteries, even if I store my genset in there as well. I dont put anything else in there because of the pods in the rear.

Ideally, I would like to be able to get 15 hours out of the fridge. I think most of the time, 12 hours would be fantastic. (the 10 hour statement from my dealer may be a "tad" generous) My solar could help supplement during the day, and my generator could handle it at night as I usually have to run the ac at night anyway. I dont mind buying batteries to accomplish this, but I am kind of a over achiever and like to be prepared. So I might shoot for 24 hours or longer. I will figure how many batteries I can fit and still be able to store my genset. Off the top of my head I am thinking 5 more for a total of 6 for the fridge. All wired parallel should be possible with out causing problems?

[rk06382]

Originally Posted by k_allison510

Thanks. And I have no idea why they decided to put them in 2 different places. I am pretty sure they designed it that way because there are battery boxes with hoses connected to vents to discharge any gasses from the battery. And there is a bunch of wiring under there to. The compartment on the side is barely big enough for one battery. The only thing I can think of is that the second battery in the front is only there if the trailer has the residential fridge. IE, wouldnt be there if it had a regular rv fridge.

I have not contacted FR, didnt really think I would get a response due to past experiences. But I will give it a shot to see if they reply.

There is plenty of room in the front for more batteries, even if I store my genset in there as well. I dont put anything else in there because of the pods in the rear.

Ideally, I would like to be able to get 15 hours out of the fridge. I think most of the time, 12 hours would be fantastic. (the 10 hour statement from my dealer may be a "tad" generous) My solar could help supplement during the day, and my generator could handle it at night as I usually have to run the ac at night anyway. I dont mind buying batteries to accomplish this, but I am kind of a over achiever and like to be prepared. So I might shoot for 24 hours or longer. I will figure how many batteries I can fit and still be able to store my genset. Off the top of my head I am thinking 5 more for a total of 6 for the fridge. All wired parallel should be possible with out causing problems?

If you are going to add more batteries, check out Battle Born LiFePO4 Batteries.

I did the Total Cost of Ownership of LiFePO4 lithium batteries vs lead acid. LiFePO4 batteries do not have fumes or acid corrosion. LiFePO4 will recharge two times faster lead acid.

You can tell, I love my Battle Born LiFePO4 Batteries.

[CHICKDOE]

so you are saying that if you ordered a standard rv refrigerator you would get one battery in the small side compartment. with the residential you get that one and another one dedicated to the refrigerator in the larger front compartment. who installed the solar? it is only connected to one battery. factory or dealer? do you know who installed the residential refrigerator? did it come from the factory or by chance, did the dealer remove an rv refrigerator and install the residential one? i could see how this would happen if the dealer did it. he would also need to install an inverter so he just added the refrigerator, the front battery, and the converter / inverter for the front battery. he could do this without having to touch any of the factory installed stuff.

as far as your comment about adding batteries to get 24 hour run time on the refrigerator there are many options. six batteries for the refrigerator is a lot of weight. i think i would concentrate on getting you current situation resolved and get both batteries connected together in parallel with the solar connected to recharge them. get that going and then see how much run time you get out of it. (probably not 24 hours). one option for the future might be a large lithium battery as you seem to have the room for it.

[k_allison510]

Originally Posted by CHICKDOE

so you are saying that if you ordered a standard rv refrigerator you would get one battery in the small side compartment. with the residential you get that one and another one dedicated to the refrigerator in the larger front compartment. who installed the solar? it is only connected to one battery. factory or dealer? do you know who installed the residential refrigerator? did it come from the factory or by chance, did the dealer remove an rv refrigerator and install the residential one? i could see how this would happen if the dealer did it. he would also need to install an inverter so he just added the refrigerator, the front battery, and the converter / inverter for the front battery. he could do this without having to touch any of the factory installed stuff.

as far as your comment about adding batteries to get 24 hour run time on the refrigerator there are many options. six batteries for the refrigerator is a lot of weight. i think i would concentrate on getting you current situation resolved and get both batteries connected together in parallel with the solar connected to recharge them. get that going and then see how much run time you get out of it. (probably not 24 hours). one option for the future might be a large lithium battery as you seem to have the room for it.

The 2nd battery for the residential fridge theory is strictly a guess on my part. The residential fridge was factory installed. It is listed on my spec sheet as being delivered that way. I also did a quick search of other 2018 372rd's for sale and everyone I looked at had the same fridge as mine. As a matter of fact, I could not find one with out a residential fridge. So my "2nd battery as an option theory" might be a bust.


I have a solar plug on the side of the trailer. I bought a simple solar kit to experiment with. When I plug it into the solar port, it only seems to charge the "house" battery. Thats not a big deal since I can charge the fridge battery with the alligator clips that came with the kit.

[CHICKDOE]

this one is above my pay grade. it just doesn't make any sense. i can't believe, or more properly stated, i don't want to believe that the factory would ship a unit with a residential refrigerator with only a single battery. but why would they put in two with each one with its own charger? every day we read posts about them trying to save a few cents per unit. two chargers? two separate 12 volts systems? solar only on one? especially when you say there is plenty of room to add multiple batteries?

i have read a lot of posts about batteries, converters, chargers, etc but i have to admit i have not ever heard of this before.

[clr]

I have a friend with a Ceder Creek 5th wheel and it came with 2 12 batteries. One of the batteries was for the residential fridge only and the other was the house battery for every thing else. There was a battery wiring diagram on the inside of the battery compartment that clearly showed how to connect the batteries. So this arrangement was OEM per design. My unit a Sanibel 5th wheel came with only 1 12 volt battery for the fridge and everything else. So not all units are wired the same here.

[pgandw]

Originally Posted by k_allison510

Ideally, I would like to be able to get 15 hours out of the fridge. I think most of the time, 12 hours would be fantastic. (the 10 hour statement from my dealer may be a "tad" generous) My solar could help supplement during the day, and my generator could handle it at night as I usually have to run the ac at night anyway. I dont mind buying batteries to accomplish this, but I am kind of a over achiever and like to be prepared. So I might shoot for 24 hours or longer. I will figure how many batteries I can fit and still be able to store my genset. Off the top of my head I am thinking 5 more for a total of 6 for the fridge. All wired parallel should be possible with out causing problems?

Knowing how much power your fridge needs to run is critical to the calculations. My assumed 160 watts (180 after inverter losses) is just a guess, and is likely low given the size of your RV and fridge. 180 divided by 12 gives 15 amps at 12V when the fridge is running. And assuming a 50% duty cycle - could be a lot more if you open the fridge door a lot, travel in hot weather, or use the fridge to cool stuff down instead of pre-cooling your food and drinks - that's 180AH from your battery in 24 hours. You need a battery bank of 360AH to avoid destroying your battery investment by keeping them above 50%. 4 6V golf cart batteries should get you there.

Even if the solar panel is wired to charge your fridge battery, that's about 40AH per good day from a 100 watt panel on the roof - might push 50-60 AH per day in the SW. If you add multiple panels, the OEM wiring isn't good enough to support the currents - just like the OEM wiring on your tow vehicle limits the battery charging from that source.

Keep in mind, unless you have heavy wiring and high current converter and inverter, it's going to take a full day to recharge your fridge battery bank after a day on the road.

Fred W
2019 T21TBHW A-frame
camping Colorado and adjacent states one weekend at a time
2 golf cart batteries from Costco, no solar, no generator, and a propane fridge

[k_allison510]

So I actually got a reply from Forest River. They said the the batteries ARE supposed to be wired together in parallel. And that the battery disconnect is only wired to one battery but should kill the power to everything once it is turned off. I asked for a wiring schematic but they said they did not have one. I think the dealer will make it right. They have been great so far.

[CHICKDOE]

That makes more sense, with the exception of where did the second converter come from? In parallel you would only need one. If wired properly in parallel a single battery disconnect is all you would need. If you have it rewired double and triple check it afterwards.