Boondocking battery questions

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Timtimtim

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Apr 25, 2019
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Hello all! New here!

First off, I'm an electrical newb...

The wife and I are about to buy our first travel trailer and begin exploring! We plan on doing some Boondocking this spring after we get used to our rig a little at parks but do not know that much about battery capacities. While we are out we would primarily just be needing the bare essentials of the battery  (water pump, led lights, fans, radio). I know this is a difficult question to answer because each one may drain the battery a little differently. But does anybody have an estimate on how long you can go with just using those things on two 12V batteries? In the future I would like to pick up a solar panel or two to help recharge the batteries during the day. We live in sunny Colorado so there is no concern about having enough sunlight to replenish. The batteries would be the ones they supply from the dealer so they would most likely just be your standard 12V. The radio would probably be run most of the day, fans and water pump would be on and off throughout the day.

Also the second question would be the time that we do not have the solar panels to recharge the batteries how do you go about charging the batteries when you are back home? I have a small trickle charger I use for our car batteries, would this work to keep them always plugged in and topped off? Or do they do harm to your batteries?

I plan on getting a digital battery gauge before we go so I don?t have to guess as much also. Anyone recommend a decent one? Or just one off amazon?

Thank you all!
 

Gary RV_Wizard

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That's like asking "How long is a string?".  As you say, everybody uses power differently and what one person thinks is light use may in fact be huge. Most moderns are accustomed to [wastefully] using lots of lights and other devices, and bad habits are hard to break.  You also didn't mention the size of those two batteries, so we have no idea where you are starting from. Typical a small RV battery contains about 30-40 usable amp-hours of power, but they lose capacity as they age or are abused.


That said, the water pump uses next to nothing, and same for the circuit boards that control the fridge and the propane water heater. The furnace, however, is a major user (when the fan runs). Lighting is the major variable, with each light bulb using 1-2 amps, so an hour of time on one light is one amp-hour.


The RV will have its own built-in charger that recharges batteries whenever the RV shore cord is plugged to power. You can also use your portable charger if you like.  It takes many hours to fully charge a battery.
 

Drewd

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76
Yep, can't answer your question.  It is like asking how long does one paycheck last. Your paycheck is two 12 volt batteries that have about 100 amp hours each with 50% of that useable meaning 100 amp-hours of power before you should recharge.    For us, that would last us about 24 hours because we consume a lot of electricity especially at nite when our heater is running to keep us warn as temps in the mountains often are in the high 30's to low 40's even in the hottest month of summer.

Your best bet is to purchase a small inverter generator.  If you do not need airconditioning when you camp, then a 1600 watt continuous (2000 watt surge) generator is your best bet.  No need to go crazy and purchase an expensive Honda.  There are many reliable alternatives that are much more affordable.  Plus, many of these generators can be wired in parallel with another generator if you decide you need more power for air conditioning.

Here are a couple of suggestions: 

https://www.homedepot.com/p/Champion-Power-Equipment-Champion-2000-Watt-Parallel-Ready-Portable-Inverter-Generator-100565/306113176

I love my 3000 watt champion generator and has been very reliable though since going solar, don't use it much anymore.

Harbor freight 200 watt parallel generator is another good option.

Inverter generators are typically quieter when not run at full load than a regular generator.  Since you'll be running mostly your converter to charge your batteries, you won't even be bothered by the noise since you will running it at a max of 2-3 hours a day to recharge your batteries.  A long cord, 20 to 30 feet also helps and makes the noise a non issue.

 

John From Detroit

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The answer to "how long" depends on how loud the radiol Are the lights LED or regular and how many, And so on on the "More you eat the sooner you need a recharge"  V/s How much batter (The more the longer you can hang in there) and are they MARINE/deep cycle or DEEP CYCLE (GC-2 for example) with  no mention of Marine or Cold Cranking Amps.  Believe it or not.. I was reminded just the other day of something I learned a long, long time ago.... Even what radio station you listen to (AM takes less power than FM and "Low frequency" less power than "High end of the dial")

I won't even guess how long your batteries will last.


MARINE/deep cycle should be held to a minimum State of Charge of 75-80%
DEEP CYCLE can go to 50%

RECHARGE.. assuming your converter can put out about 1/3 the number of amps as the 20 hour (C/20) Amp hour capacity of your batteries. is about 6 hours for full charge.

If you plan to do lots of boondocking consider adding more battery
 

Gizmo100

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What this guy said....We also went with a inverter Generator as a backup to run AC -microwave - And AC side of water heater. I also added some solar panels to maintain and top off the batteries.

Drewd said:
Yep, can't answer your question.  It is like asking how long does one paycheck last. Your paycheck is two 12 volt batteries that have about 100 amp hours each with 50% of that useable meaning 100 amp-hours of power before you should recharge.    For us, that would last us about 24 hours because we consume a lot of electricity especially at nite when our heater is running to keep us warn as temps in the mountains often are in the high 30's to low 40's even in the hottest month of summer.

Your best bet is to purchase a small inverter generator.  If you do not need airconditioning when you camp, then a 1600 watt continuous (2000 watt surge) generator is your best bet.  No need to go crazy and purchase an expensive Honda.  There are many reliable alternatives that are much more affordable.  Plus, many of these generators can be wired in parallel with another generator if you decide you need more power for air conditioning.

Here are a couple of suggestions: 

https://www.homedepot.com/p/Champion-Power-Equipment-Champion-2000-Watt-Parallel-Ready-Portable-Inverter-Generator-100565/306113176?cm_mmc=Shopping%7CG%7CBase%7CD28I%7C28-7_GENERATORS%7CNA%7CPLA%7CFixed%7c71700000041074939%7c58700004719988916%7c92700039996193494&gclid=EAIaIQobChMI-p2LnN7z4QIVB7XACh3h9QSFEAQYASABEgLxB_D_BwE&gclsrc=aw.ds

I love my 3000 watt champion generator and has been very reliable though since going solar, don't use it much anymore.

Harbor freight 200 watt parallel generator is another good option.

Inverter generators are typically quieter when not run at full load than a regular generator.  Since you'll be running mostly your converter to charge your batteries, you won't even be bothered by the noise since you will running it at a max of 2-3 hours a day to recharge your batteries.  A long cord, 20 to 30 feet also helps and makes the noise a non issue.
 

Gizmo

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To tag along with previous posts, more info is needed and impossible to say how long the batteries will supply your power demands.  To get a better idea you can do an energy audit by looking up the amp draw for each device you plan to use.  Then add it all up factoring in time used to determine how many amps per hour, not much fun and time consuming but gives a ballpark figure to work with.  An easier approach, is first thing, install a quality battery monitor, then when you take your rig to a RV park, don't plug in, use it like you are boondocking, keeping an eye on your monitor as you consume power.  Understand if your batteries are lead acid or AGM, you should not let them fall below 50% capacity.  If you do this over several outings, it will give you a real world idea of your consumption and you will have shore power available to charge your batteries if they start to get close to the 50% threshold.
 

Gizmo100

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Gizmo said:
then when you take your rig to a RV park, don't plug in, use it like you are boondocking, keeping an eye on your monitor as you consume power.  Understand if your batteries are lead acid or AGM, you should not let them fall below 50% capacity.

You can also do this at home....Charge you battery first. Then unplug and camp in the backyard. Take showers, cook dinner and spend the night in the RV. If you run out of power you can always plug back in.

Of course you could also turn things on during the day and keep a closer eye on the voltage.
 

Gizmo100

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Gizmo said:
This is true and an option for sure brother Gizmo, but more fun going someplace with the rig.

Let me set the scene for you..........

We arrive at the campsite and I have setup the TT...As soon as the TT is stable my loving wife gets started on dinner. I continual to setup the TT and get the TV's programmed with local stations. After a wonder dinner and a few hours of sitting by the campfire we turn in for the night.
Around 3 AM my wife's TV shuts down because the batteries are to low to run the inverter. Now she NEEDS that TV for several reasons. So Now I have a choice to make. I can get out of bed and go plug in the RV....OR.....I can tell her to go sleep in the house.


We did have something similar happen on our trip to AZ. We had stopped for the night and the batteries were full. My wife had decided to make some tea using her coffee maker. She thought she was so smart using the outlet in the bedroom. (inverter powered). When I realized what she had done. I told her we better turn in for the night because we would be getting up early. And sure enough right before 3 AM the alarm for the inverter went off.
 

Timtimtim

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Apr 25, 2019
Posts
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Thank you so much for all your replies! Y'all are really helpful on here! I totally understand that it is very hard to decipher what my actual length of stay can be without knowing anything about the batteries or my usage. I guess I was kinda hoping there was a rough estimate on what people have done running on their battery on just the stereo and lights. I guess my question is, does a standard stereo that comes in the RV require a lot of battery? If being run all day? We have yet to purchase the RV so I'm not sure what the stats are on all those but I kind of was wanting to go off grid the 1st couple times. Now that you guys have stated all this I think it's not a good idea and I should hook up for the 1st couple times. I like the idea of being able to set up at a park and not hook up until I really need to. That I actually sounds like a really really good idea.

In order to hook up at my house do I need to have a special plug or can I plug directly into a standard outlet and have a conversion plug?  Our camper would be parked in a community lot that we have for our HOA so you don't have to have your RV on the side of your home so I'll have to leave it in the street in front of the house with a big extension cord to it from my yard! But whatever works works!
 

Gizmo

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Gizmo100 said:
Let me set the scene for you..........

We arrive at the campsite and I have setup the TT...As soon as the TT is stable my loving wife gets started on dinner. I continual to setup the TT and get the TV's programmed with local stations. After a wonder dinner and a few hours of sitting by the campfire we turn in for the night.
Around 3 AM my wife's TV shuts down because the batteries are to low to run the inverter. Now she NEEDS that TV for several reasons. So Now I have a choice to make. I can get out of bed and go plug in the RV....OR.....I can tell her to go sleep in the house.


We did have something similar happen on our trip to AZ. We had stopped for the night and the batteries were full. My wife had decided to make some tea using her coffee maker. She thought she was so smart using the outlet in the bedroom. (inverter powered). When I realized what she had done. I told her we better turn in for the night because we would be getting up early. And sure enough right before 3 AM the alarm for the inverter went off.

That is exactly why a good battery monitor is a must, one would know if a charge is in order now or can wait.  Operating an RV without a battery monitor is like driving a car without a working fuel gauge, it can be done but usually not without some stress and possibly a bad event and certainly removes some of the fun.
 

Gizmo

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Gizmo100 said:
Let me set the scene for you..........

We arrive at the campsite and I have setup the TT...As soon as the TT is stable my loving wife gets started on dinner. I continual to setup the TT and get the TV's programmed with local stations. After a wonder dinner and a few hours of sitting by the campfire we turn in for the night.
Around 3 AM my wife's TV shuts down because the batteries are to low to run the inverter. Now she NEEDS that TV for several reasons. So Now I have a choice to make. I can get out of bed and go plug in the RV....OR.....I can tell her to go sleep in the house.


We did have something similar happen on our trip to AZ. We had stopped for the night and the batteries were full. My wife had decided to make some tea using her coffee maker. She thought she was so smart using the outlet in the bedroom. (inverter powered). When I realized what she had done. I told her we better turn in for the night because we would be getting up early. And sure enough right before 3 AM the alarm for the inverter went off.

That is exactly why a good battery monitor is a must, one would know if a charge is in order now or can wait.  Operating an RV without a battery monitor is like driving a car without a working fuel gauge, it can be done but usually not without some stress and possibly a bad event and certainly removes some of the fun. Oh and shame on you for telling your dear wife to go sleep in the house, that is not how us Gizmos were raised.
 

Timtimtim

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Apr 25, 2019
Posts
11
Very good point, I guess I kinda figured they had put some kind of low power unit in.

I have been searching for a battery monitor. Do you have to go ham on the $100 monitors or does a good $40 one work. I found this on Ebay and it looks like it shows other things besides %.

https://www.ebay.com/p/Battery-Monitor-DC-80v-50a-Auto-Car-RV-Motor-Boat-UPS-Lithium-Iron-Lead-acid-Ah/18019706033?iid=183236688659&chn=ps&ul_ref=https%253A%252F%252Frover.ebay.com%252Frover%252F1%252F711-117182-37290-0%252F2%253Fmpre%253Dhttps%25253A%25252F%25252Fwww.ebay.com%25252Fp%25252FBattery-Monitor-DC-80v-50a-Auto-Car-RV-Motor-Boat-UPS-Lithium-Iron-Lead-acid-Ah%25252F18019706033%25253Fiid%25253D183236688659%252526chn%25253Dps%2526itemid%253D183236688659%2526targetid%253D593772237533%2526device%253Dm%2526adtype%253Dpla%2526googleloc%253D1014526%2526poi%253D%2526campaignid%253D1689945013%2526adgroupid%253D69559042287%2526rlsatarget%253Dpla-593772237533%2526abcId%253D1140466%2526merchantid%253D101709870%2526gclid%253DCjwKCAjwwZrmBRA7EiwA4iMzBPwjnPGzHIKIS4kS4ycDQ8lXHs4zRQmEMEF8WeK4RAm6kcasqPPdgxoCyHMQAvD_BwE%2526srcrot%253D711-117182-37290-0%2526rvr_id%253D1952625823427%2526rvr_ts%253D6bb78e7016a0a861b5a43447ffef82fb
 

Willowflowage

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Ladysmith Wis
I bought a monitor like this a year ago and it does fine telling me my current battery voltage and how many amps are being used. You can turn your radio on and off and see in real time what it's drawing. While running things you get a lower than real voltage charge on your battery but you'll easily get a feel for your 50% battery level. Compared with a good digital volt meter it's right on.
About 18 bucks. There's quite a few prices and types but this works for me.

bayite DC 6.5-100V 0-100A LCD Display Digital Current Voltage Power Energy Meter Multimeter Ammeter Voltmeter with 100A Current Shunt https://www.amazon.com/dp/B013PKYILS/ref=cm_sw_r_cp_apa_i_DV7XCbYRJN3B4
 
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