How to hook up battery to breaker Box

[Carmella & Kevin Byers]

 

Hello, I have been trying research this on the web but have been having a hard time finding direct answers to my questions.

We have a 12ft trailer that has had all the wiring pulled for a remodel however we left the breaker box. I would like to add 2 6v batteries to the trailer to run the few lights, outlets and an electric burner for cooking.

So my question is, how do you wire the battery up to the breaker box and still leave a plug in for when there is shore power?

What I do know is that we will need and inverter from the battery to make it A/C but the invertors that I see on-line all have a cigarette lighter hook up. Is there one that can be connected to the battery cables? Then how do I wire the inverter to the breaker box? Or is there a special inverter for just this need?

Lastly, how will the batteries re-charge, if I am hooked up to shore power will they re-charge?

Thank you

Carmella

[John "T" Nordhoff]

    Matthew,

    Yep the RV fridges are closed amonia absorption systems with no moving parts (notwithstanding the boiling, rise and fall of the gas) and certainly no energy hungry electric motor operated compressors, if properly used and maintained they can work for yearssssssssssss and require very little propane to heat the burner. However if operated using electricity to provide the heat they would drain even a large battery bank rapidly and do provide a good draw on an alternator if operated at 12 VDC while driving. Some of the Amish around here who dont use electricity have LP or even Kerosene fueled amonia absorption refrigerators and so long as theres no leaks and the burners and flues are kept clean they last like foreverrrrrrrrrrr.

 

 Ive never owned an RV that used engine coolant and a heat exchanger to heat domestic water as you mentioned, but that appears a good plan except for the maintenance issues.  I believe Travco was the first to use engine exhaust heat to incinerate toilet waste while driving down the road but the heat exchangers were prone to corrosion and problems.  PS I forgot I did own one that previously had such a system but it was removed due to leaks of coolant, I think thats the weak link in those systems, having to circulate engine coolant through the series of pipes hoses and heat exchangers. 

 

 I am a fan of rooftop solar panels as that can keep your house batteries topped off when dry camping and with sufficient wattage and sufficient house battery storage capacity (I currently have 375 Amp Hours) the system can pretty well sustain itself for extended periods. One thing that can really boost energy savings in RV is the use of LED lighting and I'm moving in that direction.

 

  If you wanna see some serious extended dry camping set ups you need to go to Quartzite in the winter where people camp months at a time with no utility services. They have some serious solar panel arrays and solar panel farms and battery banks.

 

 At the Busnuts Rally last January in Arcadia Florida a couple gave a seminar on their Lithium Ion battery bank and Smart Inverter/Charger system. They had 500 amp hours of electrochemical lithium ion battery energy storage in a compartment like 24 v 24 x 24 inches. They could even run rooftop AC a decent time when dry camping as the computer controlled system could draw higher initial current to allow the AC compressors to start. Their goal was to have 1000 Amp Hrs of energy storage and like a 3 or 4 K Inverter/Charger and something like 500 watts of rooftop solar NOW THATS SOME SERIOUS OFF THE GRID LIVING... HOWEVER they still use LP for refrigeration and heat and hot water as thats so much more practical and energy efficent for RV use as opposed to an "all electric" vehicle...

 Fun chattin with ya, Im still sticking with my combination LP and Electric set up

 

 John T in Indiana

[redwing]

and i bet you remember the cost of those lithium batteries as well, i am still waiting till they get the cost down on them before i venture them in my monaco, even with the factory solar set up and autostart on the genny, boondocking is still a viable thing for monaco

[harwood]

TRY GOING TO SAMS CLUB OR COSCO

I FILLED MY 40 LB THERE FOR 15.00

3.85 IS  REDICULUS

[Matthew Tritt]

$3.85 here in California is pretty average, and I run my house on propane as well - so I get something of a price break. You have to be in a a part of the country other than than the West coast.

[Glen Olson]

the 3.85 is gallon not pound,  $3.85 X 5 gallons = $20.00 and I think you filled a 20# for $15.00 not 40#

[Tim Dailey]

I'm with Jimco on this one!  I also have a 3000 watt inverter, even heat my water and run my fridge on electric.   I run 4 golf cart batteries (66lbs each, 225ah each).   If I were to rebuild my Winnebago again, I would run with all electric appliances.   A few times I ran with 8 golf cart batteries, could run my overhead AC all night and still had enough power to make hot water and cook breakfast.  

[redwing]

well lets look at that, taking (8) 6 volt batteries at 225ah each and making 12 volts you get a total of 900 ah, a 3000 watt inverter running an ac by itself at at 8amps ac, or 960watts, not including start-up will last 4.68 hrs way short of a whole night. you would be at your 50% rate in 4 .68hrs and if you went farther you would litteraly kill your batteries and way before the night is over and shorten their life, or quite possibly just kill them.

8) 6volt 225ah = 1800 ah at 6 volts

convert to 12 volts that equals 1/2 the total of 6volt ah and is 900ah

normal ac roof air 8ah ac convertered to watts =960watts not including start-up

all the above says that nothing else including lights or a battery charger or any ac appliance is running you would have to add them up to be fair. and thats using a good inverter from zantrex.

http://www.ecovolt.ro/en/support/calcul_autonomie_baterii_en.html

 

[Tim Dailey]

Your close, but you forgot to factor a few things in, more than likely to keep things simple for some of the other folks that are still learning.

Because of the thermostat, an air conditioner doesn't pull a full continuous load, it cycles and it can vary a lot depending on the desired temperature and outside elements.   Using your math, if it cycled at 50%, we would see well over 9 hours before the battery bank got to 50%. (-blower fan) Also don't ever underestimate Peukert's Law, it sometimes even surprises me.

Now I do know better, but with lack of care I do run my batteries down to about 20%.  I started doing this with a set I bought about 4 years ago expecting to replace them every season and to my surprise, the set is still serving me well, but I don't camp nearly as much as the average camper.  I agree the batteries will last a longer not discharging them below 50%.

 

The biggest issue is getting the batteries charged back up the next day.

 

[redwing]

i just have to stop rolling on the floor to answer you, that amp rating was for ac small window unit, thought i would catch you so i posted that usage, the normal cooling cycle on a rv roof air unit is 1650 watts(lowfan) or more depending on if it is new or old the older it is the more it was designed to use. go insert that and even if you ran half the time on fan as you say its still only 5.44hrs yeah i caught ya like i thought i would. suprised you didn't catch that. by the way the figure above is with the fan on low, with the fan on high it jumps up to 1900watts here let me hit you with the specs for a new efficient unit specs for 13,000btu.

http://www.coastdistribution.com/PDF/Coleman%20Product%20Page.pdf

[Tim Dailey]

"i just have to stop rolling"

Your not coming across as very nice person.  This is a place to learn, share commen interest and make friends.  Its not a place to try to prove people wrong.  

And yes, my AC uses more than 8 amps, I have a kill-o-watt meter, I just didn't see the need to correct you.   In my world, 8 batteries lets me get a nice comfy nights sleep with my AC unit.  I don't need you to tell my how I'm wrong.  LOL

[John "T" Nordhoff]

     Cool Tim,

 

fun post, thanks, as an electrical engineer I can tell you with 8 six volt 225 Amp Hour golf cart batteries wired in series paralell to feed a 12 volt inverter, you could store 900 Amp Hours of energy. However no inverter is 100% efficient there are heat losses remember. If an AC requires 960 watts to operate (many RV rooftop units require more like 1400 watts??) that would be like 80 amps being drawn from the batteries but thats if the Inverter were 100% efficient, so figure more like around 87 amps. THATS ONE HECK OF A LOAD TO RUN ALL NIGHT OFF BATTERY POWER. Also, even though a battery can stand a certain degree of discharge (they can, they are deep cycle design) if you constantly draw them that far down (like the all night AC marathon use) you are using up their inherent number of "life cycles" you know... and once the life cycles (a finite and known quantity) are all used up THE EXPENSIVE BANK OF BATTERIES ARE SHOT. Lets see, if a Trojan T 105 costs $80 eight of them cost you $640 so Id be hesitant to deep discharge them (like all night AC use would) any more often then I had to

 

  So, what source of energy (120 VAC or the RV's engine driven 80 amp alternator) and how long does it take to replenish the batteries after all that??? It probably takes about as long to recharge (as it did to discharge) depending on the size of the charger and the source of energy, so you use the stored energy all night and have to be plugged into shore AC power much of the day or else the RV engine (and its 80 amp alternator) could run all day to recharge so you can run the AC all night again the next night............

 

 Without doing the math Id prefer to run an onboard Onan 2500 genset (around 1.25 pint per hour of gas I believe???) to run a 960 watt AC unit versus using batteries and then have to take most of the next day to recharge them. Of course if the next 8 hours of AC power is "free" that can be used to recharge but if youre using the RV engines alternator to recharge thats using gas also i.e. theres no free lunch lol you either pay for the gas to run the genset at night or pay for gas to recharge the batteries (via RV engine alternator) the next day. Of course, if youre where you have AC shore power all the next day to recharge the batteries, Id just use the shore power to run the AC instead of the batteries at night myself.

 

 Its very fun to hear how different people store and use energy to operate their RV's, different strokes for different folks. I still prefer (and believe its more efficient and economical in the long run) to use the

 COMBINATION of:

    LP gas,,,,,,,,,,

    Onboard genset,,,,,,,,,,,,,,

    Battery storage and Solar

 

 THEN ANY ALL ELECTRIC METHOD (batteries only, no LP Gas for heat or hot water or run the fridge or a genset for the AC or wifes hair dryer or Microwave)

 

  If youre into extended dry camping (say at least a week with no AC available) and you dont have AC much of the next day to recharge the batteries and youre not willing to run the RV engine all day (it can supply 80 amps all day to replace what 80 amps all night depleted) and assuming you dont have 900 watts of rooftop solar panels (yeah right) YOURE DEAD IN THE WATER AFTER THE FIRST NIGHT while with my COMBINATION OF Onan Genset,,,,,,, LP Gas (fridge and hot water and furnace),,,,,,,,,,more modest 375 AH of Batteries and 100 watt solar panel,,,,,,,,,,I CAN PROBABLY DRY CAMP MORE LIKE AN ENTIRE WEEK   

   

 But God Bless all and they are entitled to their choices and I support and respect them to do that BUT THERES NO WAY IM GOING ALL ELECTRIC since I may dry camp (NO AC available remember to recharge batteries) an entire week with my COMBINATION of LP gas,,,,,,,Onan genset,,,,,,,,,Battery and Solar Power.........Three sources just gotta be better then one lol

 

 The MAIN LIMITING FACTOR when we dry camp is fresh water so I can store 110 gallons of fresh water and hold 70 gallons of gray plus 30 gallons of black and use a electric recirculating toilet (big water saver) so that coupled with LP gas for heat and hot water and 375 AH of battery storage and solar plus my genset COMBINATION SYSTEM is just so cool

 

 Im headed for a 6 week RV Western Natl Park Tour (and lots of dry camping in utah and Colorado) next week so my LP Tank is fulllllllllllll I will be checkin with yall now n then as net access is available

 

 God Bless, John T, retired electrical engineer and attorney in Indiana

[Tim Dailey]

John, your absolutely correct, its a big load for 8 batteries, and yes, charging them back up is the biggest issue I had, thats why I currently only run 4.  I actually took the idea from another member on another forum who runs his AC though the night on a battery bank of 8.  I have a 2nd 300 amp alternator thats connected to my house batteries, I did this so I can travel down the road with the roof air running on inverter.