Considering Adding a Second 12-V Battery in Parallel

[MJMCCAND]

We've not done any boondocking in our 2020 230RL Reflection Fifth Wheel, and will be going out to Cades Cove in May for four nights. I don't even know if our TCL TV works off of the battery system, but assuming it does and assuming we want to use a DVD player, should I add a second battery in parallel to the original to increase the available amp-hours or is a single one sufficient?
Some data:

• Just the wife and me
• The unit came with an Interstate battery, I assume it is a deep cycle, but will need to verify that.
• We have a Honda EU2000i 2,000 watt generator and will charge battery(ies) during the day (quiet hours begin at 8:00 PM)
• While on battery power only, we'll likely use the RV interior (LED) lights on a limited basis, the fridge (though I don't think it has much of any electrical load when running on propane), the water pump infrequently, and a TV and a DVD player for a few hours each night. I'm sure there are other parasitic electrical draws that I am not listing, but I don't imagine these amount to much.

I did a search, but didn't see direct answers to my specific questions.

Thanks in advance for your advice.

[xrated]

We've not done any boondocking in our 2020 230RL Reflection Fifth Wheel, and will be going out to Cades Cove in May for four nights. I don't even know if our TCL TV works off of the battery system, but assuming it does and assuming we want to use a DVD player, should I add a second battery in parallel to the original to increase the available amp-hours or is a single one sufficient?
Some data:

• Just the wife and me
• The unit came with an Interstate battery, I assume it is a deep cycle, but will need to verify that.
• We have a Honda EU2000i 2,000 watt generator and will charge battery(ies) during the day (quiet hours begin at 8:00 PM)
• While on battery power only, we'll likely use the RV interior (LED) lights on a limited basis, the fridge (though I don't think it has much of any electrical load when running on propane), the water pump infrequently, and a TV and a DVD player for a few hours each night. I'm sure there are other parasitic electrical draws that I am not listing, but I don't imagine these amount to much.

I did a search, but didn't see direct answers to my specific questions.

Thanks in advance for your advice.

Almost all TVs in campers are 120VAC, not 12VDC systems. If you are referring to the DVD player in the trailer, that is a 12V unit....but if your TV isn't available because of it being 120VAC, then it's useless for watching TV. As far as the Interstate battery, it is likely a "Deep Cycle/Marine" battery.....which is really just a multi purpose battery that is just mediocre at both things.....Kind of like a "jack of all trades, but Master of none". Current draw for the fridge, while running on propane is certainly one thing to consider, and that of course is the 12VDC provided by your battery system.....or the converter if you are either hooked up to shore power or running the converter from the supplied 120VAC from the generator. Hope this helps a bit

[Bungy]

L

We've not done any boondocking in our 2020 230RL Reflection Fifth Wheel, and will be going out to Cades Cove in May for four nights. I don't even know if our TCL TV works off of the battery system, but assuming it does and assuming we want to use a DVD player, should I add a second battery in parallel to the original to increase the available amp-hours or is a single one sufficient?
Some data:

• Just the wife and me
• The unit came with an Interstate battery, I assume it is a deep cycle, but will need to verify that.
• We have a Honda EU2000i 2,000 watt generator and will charge battery(ies) during the day (quiet hours begin at 8:00 PM)
• While on battery power only, we'll likely use the RV interior (LED) lights on a limited basis, the fridge (though I don't think it has much of any electrical load when running on propane), the water pump infrequently, and a TV and a DVD player for a few hours each night. I'm sure there are other parasitic electrical draws that I am not listing, but I don't imagine these amount to much.

I did a search, but didn't see direct answers to my specific questions.

Thanks in advance for your advice.

The tv will definitely not work, it requires ac current, not dc.

[BreakfastinAmerica]

I needed to get a new battery last year. Went to Costco and got 2 golf cart batteries to increase amp hours. We are able to go several days and recharge with a honda in the evening while watching tv.

[boyscout]

should I add a second battery in parallel to the original to increase the available amp-hours or is a single one sufficient?

Others have answered your question about TV watching without AC power. However none have mentioned the possibility of an "inverter", a device that converts DC power to AC power.

It would not be simple plug-and-play. However you could pretty easily cobble together something to get 120VAC to your TV alone (run an extension cord into the basement where you've connected a small inverter to 12VDC power, for example). Or you could get ambitious and install a more-robust inverter that powered more or all of your 120VAC outlets.

A rough rule of thumb for power required is to divide the WATTS required by your AC load (the television) by 12 volts to get the CURRENT (amps) drawn from the battery by the inverter. So if your television needs about 30 watts of power, an inverter will draw a little less than 3 amps from your battery(ies). Not much. OTOH a 1,500-watt coffee maker would draw about 125 amps of current from the battery(ies).

With this information you can decide if you need more battery. Most of us do.

Another bit of advice about installing your additional battery "in parallel" with the original one. Some people literally install them "in parallel", with the second battery connected to the first battery, positive to positive and negative to negative, with the load connected to the first battery. It will work that way but the batteries will suffer for it, especially the first battery.

It's better to purchase high-quality heavy battery cable and terminal lugs and make two sets of cables that are the SAME LENGTH to connect each of the batteries individually to the load. These cables are connected to the battery on one end, and then the two positive and two negative are connected to the load on the other end. Your batteries will last longer if connected this way.

Good luck with your decisions.

[grumpypapa]

Hi boyscout,at the present time I have two trojan 6 volts I use in our 303rls reflection 5th wheel,both batteries are on the same side of the rv (left side in front storage)
I am concerned it is too much weight on the one side for the front legs.If I separate the batteries ,put one on each side of the storage by the front legs,can I just
run two 4 gauge battery cables about 6`long to join them.Negative to postive and negative trailer to one battery and positive to the other battery.

[RickLight]

When we first got our similar rig I immediately put 2 more batteries, cheapy Walmart 100AH. They did a great job letting us go 4-5 days with 4 people in the rig. No TV and no generator, but it did kill the batteries in one season.

Since then I've upgraded to lithium and bought a small inverter to run the TV. With 300AH fully usable, DW & I now go 5 days watching a movie every night.

[grumpypapa]

Ricklight,what size of inverter did you purchase and where did you install it ? Is it a sine inverter ?

[RickLight]

Ricklight,what size of inverter did you purchase and where did you install it ? Is it a sine inverter ?

I just got a cheap little portable one, 350W sign wave, on Amazon. It doesn't install, but uses a cigarette lighter port and sits on the counter. Auto part places have them too. I installed a multi USB-power port outlet near the radio. It's a really convenient spot for charging and has easy access to the wires. https://www.amazon.com/Magnadyne-Bla.../dp/B0814BT629

[MJMCCAND]

Others have answered your question about TV watching without AC power. However none have mentioned the possibility of an "inverter", a device that converts DC power to AC power.

It would not be simple plug-and-play. However you could pretty easily cobble together something to get 120VAC to your TV alone (run an extension cord into the basement where you've connected a small inverter to 12VDC power, for example). Or you could get ambitious and install a more-robust inverter that powered more or all of your 120VAC outlets.

A rough rule of thumb for power required is to divide the WATTS required by your AC load (the television) by 12 volts to get the CURRENT (amps) drawn from the battery by the inverter. So if your television needs about 30 watts of power, an inverter will draw a little less than 3 amps from your battery(ies). Not much. OTOH a 1,500-watt coffee maker would draw about 125 amps of current from the battery(ies).

With this information you can decide if you need more battery. Most of us do.

Another bit of advice about installing your additional battery "in parallel" with the original one. Some people literally install them "in parallel", with the second battery connected to the first battery, positive to positive and negative to negative, with the load connected to the first battery. It will work that way but the batteries will suffer for it, especially the first battery.

It's better to purchase high-quality heavy battery cable and terminal lugs and make two sets of cables that are the SAME LENGTH to connect each of the batteries individually to the load. These cables are connected to the battery on one end, and then the two positive and two negative are connected to the load on the other end. Your batteries will last longer if connected this way.

Good luck with your decisions.

Let me check for my own understanding here by way of a sketch; I think what you are describing is captured in the top sketch and what is commonly done (what I would have done) is in the bottom. Am I correct?