Battery Boondocking Question

[ptooti]

Wondering if anyone can give me some info I'm taking my camper to a 6 day festival and there is no Electrical hookups however water and sewer is provided via a suck and fill truck to keep the campers happy...anyway my question is I plan on running the hotwater and fridge on gas, I have a 100w solar panel I want to know if I would be able to use the led lights sparingly, charge my phone, and run the water pump occasionally to flush and a shower for 6 days and still have power enough to pull in the slide in at the end of it all? I have never used the solar panel before wondering if I should add another battery?

Also can someone tell me if the battery was dead and I hooked up the trailer wiring to the truck would that give me power to pull in the slide worst case should the battery be flat? I'm just not sure how it all works
Thanks

[Fishsizzle]

Couple things.... what is your current battery And or batteries?

Need to know “amp hours” on them

[MarkEHansen]

Make sure you don't tow with a dead coach battery. The battery is required to provide emergency braking in the event of trailer separation from the tow vehicle.

[spade117]

Charging your phone will not work in the camper when only using the battery as a power source. The outlets do not work off the battery.

[MarkEHansen]

I can charge my phone using a 12v charger - FYI

[Canonman]

Originally Posted by ptooti

Wondering if anyone can give me some info I'm taking my camper to a 6 day festival and there is no Electrical hookups however water and sewer is provided via a suck and fill truck to keep the campers happy...anyway my question is I plan on running the hotwater and fridge on gas, I have a 100w solar panel I want to know if I would be able to use the led lights sparingly, charge my phone, and run the water pump occasionally to flush and a shower for 6 days and still have power enough to pull in the slide in at the end of it all? I have never used the solar panel before wondering if I should add another battery?

Also can someone tell me if the battery was dead and I hooked up the trailer wiring to the truck would that give me power to pull in the slide worst case should the battery be flat? I'm just not sure how it all works
Thanks

Adding another battery is a good idea for sure. Your 100w solar will keep the batteries topped off assuming there is sufficient sunlight to use it and you don't deplete the batteries below 50%. Think of your solar as a battery charger. You don't really run your accessories off the solar directly but off the batteries.
If your TT is equipped with 12v SDI ports you can use those to charge the cell phone. We've gone over a week of dry camping with our solar and battery (2) set up. Should the batteries be to low to bring in the slide, just hook up the truck connector and with the engine running you can bring in the slide that way.

[Logan X]

I have USB ports in my trailer that are powered off of the 12v system so I can use those to charge my phone.

Regarding the breakaway brake system, I thought the 7 pin connector supplied power to the breakaway brakes in case the trailer battery was not operational? Am I just making that up or is that a thing? Of course if the trailer separates, it could pull out the 7 pin connector, however hopefully the safety chains would prevent that from happening. Either way, I agree towing with a dead battery is not a good idea.

I think the 100 watt solar panel should be able to keep the battery charged (if it is in the sun) if you are not using much power in the trailer. Just leave the solar panel connected all day.

[MarkEHansen]

The point of the emergency brake is to stop the trailer in the event of a separation from the tow vehicle - including safety chains - so there would be no electrical connection to the tow vehicle at all.

[Logan X]

Originally Posted by MarkEHansen

The point of the emergency brake is to stop the trailer in the event of a separation from the tow vehicle - including safety chains - so there would be no electrical connection to the tow vehicle at all.

Very true! Man, that would be a bad day! Your battery is dead, your trailer came uncoupled, and your safety chains failed.

[depush]

Originally Posted by ptooti

Wondering if anyone can give me some info I'm taking my camper to a 6 day festival and there is no Electrical hookups however water and sewer is provided via a suck and fill truck to keep the campers happy...anyway my question is I plan on running the hotwater and fridge on gas, I have a 100w solar panel I want to know if I would be able to use the led lights sparingly, charge my phone, and run the water pump occasionally to flush and a shower for 6 days and still have power enough to pull in the slide in at the end of it all? I have never used the solar panel before wondering if I should add another battery?

Also can someone tell me if the battery was dead and I hooked up the trailer wiring to the truck would that give me power to pull in the slide worst case should the battery be flat? I'm just not sure how it all works
Thanks

Your 100watt solar is gonna produce around 4 amp hours in full sun. Much less under less ideal conditions. Some clouds and you're down ~75% or more real quick.

Say you have a 12 volt, 100 amp hour rated battery. You're not supposed to draw down past 50%, so you use 50 amp hours. It'd take over 12 hours of full noonday sun to recharge fully if everything was perfect and 100% efficient. It's not.

It's about what you draw vs replenish per day. Making some assumptions here, each LED light you use is gonna draw just under 1/2 amp hour. You can replace ~4 Ah at best. It's conceivable with sparing use you could replace what you use everyday. Real world, not likely though. Your monoxide detector, your radio, water pump (6A), and your water heater and fridge that use DC every time they light will draw off and on all day.

100Ah batt means you could use ~16 Ah a day without recharging but be dead at the end. So 8 Ah per day and still have 50% batt left. Your solar is left to make up any difference beyond that.

I'm guessing you don't have battery monitor but if you can use a volt meter this chart will help you know what state of charge your battery is in.

[JRTJH]

Originally Posted by Logan X

...
Regarding the breakaway brake system, I thought the 7 pin connector supplied power to the breakaway brakes in case the trailer battery was not operational? Am I just making that up or is that a thing? Of course if the trailer separates, it could pull out the 7 pin connector, however hopefully the safety chains would prevent that from happening. Either way, I agree towing with a dead battery is not a good idea.
....

If you think about how the emergency braking system actually functions, there's a "perfect storm of events" that must occur BEFORE the brakes will activate. First, when the trailer separates from the ball, IF the safety chains hold, a SECOND event must occur. The plunger on the break-away switch must be pulled. Far too many people don't cut/shorten the plunger cable, so effectively, if the "OEM cable is used as supplied at delivery" chances are very good that it will not function as expected.

In theory (yeah I know) the way it's supposed to work is this:

The trailer separates from the ball.
As the trailer moves back, the break-away cable tightens BEFORE the chains reach full extension and the plunger is pulled.
The break-away switch closes, applying braking action using onboard battery power. The reason for this is that there is no assurance that the 7 pin umbilical will remain connected to the tow vehicle AND, if the safety chains do not hold, that connection will definitely be severed.
The brakes slow the trailer and prevent it from "overrunning the tow vehicle" preventing increased damage and helping to maintain control by not "banging into the back of the tow vehicle" as you attempt to slow/stop the rig.

If the safety chains are shorter than the plunger cable, the trailer brakes won't function. If the 7 pin umbilical cable is shorter than the safety chains, it will sever BEFORE the chains reach full extension and remove any power from the tow vehicle that might reach the trailer brakes. If the plunger cable is too long, you have an increased risk of the trailer slamming into the back of the tow vehicle, causing loss of control and increasing the chances for injury.

In the event of a separation, you want the trailer brakes to hold the trailer back from the tow vehicle as you slow to a stop. If it "works as planned" the safety chains will keep the trailer in line with the tow vehicle, but don't count on the 7 pin umbilical to remain connected.

In the event the safety chains fail, then you definitely want the onboard battery to power the trailer brakes to slow the "runaway trailer" before it slams into an oncoming vehicle or sideswipes a vehicle going in the same direction.

So, it may be a good idea to think through the actual sequence of events that occur, inspect your plunger/cable assembly to be sure it is shorter than the safety chains and that the system actually works as expected.

ADDED: While I'm sure there are "some" I've not yet, in 50 years of towing and being around RV's, seen a dealership that cuts/shortens the break-away plunger cable so it "fits" the tow vehicle/safety chain/hitch for that application.... My guess is that probably 50% of the break-away cables in use by members on this forum are 'too long to pull the plunger' if the trailer separates from the ball or from the fifth wheel hitch.

[Logan X]

Originally Posted by JRTJH

ADDED: While I'm sure there are "some" I've not yet, in 50 years of towing and being around RV's, seen a dealership that cuts/shortens the break-away plunger cable so it "fits" the tow vehicle/safety chain/hitch for that application.... My guess is that probably 50% of the break-away cables in use by members on this forum are 'too long to pull the plunger' if the trailer separates from the ball or from the fifth wheel hitch.

Good information, thanks John. Regarding the breakaway plunger cable, I put a small carabiner on the end of mine and loop it through the the hitch. I put a small loop in the cable, using a square knot, at the appropriate length and hook the carabiner into the loop I made. This way I can adjust the length of the plunger cable without any cutting or permanent alteration.

[JRTJH]

Originally Posted by Logan X

Good information, thanks John. Regarding the breakaway plunger cable, I put a small carabiner on the end of mine and loop it through the the hitch. I put a small loop in the cable, using a square knot, at the appropriate length and hook the carabiner into the loop I made. This way I can adjust the length of the plunger cable without any cutting or permanent alteration.

Your method is one of many ways to "shorten/adjust" the cable and works well.

Essentially, everyone "should" back their tow vehicle under the trailer hitch receiver (do not lower the trailer onto the ball), attach the safety chains by crossing them under the hitch, attach the break-away cable at their choice of locations (not on the hitch) and then have someone SLOWLY pull forward until the chains are tight. At that position (relative to the trailer safety chains) the break-away cable SHOULD have pulled the pin on the break-away switch. If not, then "braiding, tying knots, cutting the cable and re-swedging the loop or some other method should be used to make sure the cable is "shorter than the safety chains".

If making a permanent cut in the cable, be sure to take into consideration the "growing length" required to make left/right turns when towing. You want the cable short enough to pull the pin BEFORE the safety chains reach full extension but not so short that the cable pulls the pin in a sharp turn (such as backing into a campsite).

[Hodgy]

.

To the OP, last August we dry camped for 4 nights with a 100 watt panel and a single 12 volt DC battery. Had lots of power for LED lights, water pump, furnace and yes charging electronics.

This year I added another 100 watt panel and went to two 6 volt GC batteries. The system works great, in bright sun I get 14.4 volts at the batteries and the other morning it was overcast and no direct sun and was getting 13.6 at the batteries.

.

[Hodgy]

.

To the OP, last August we dry camped for 4 nights with a 100 watt panel and a single 12 volt DC battery. Had lots of power for LED lights, water pump, furnace and yes charging electronics.

This year I added another 100 watt panel and went to two 6 volt GC batteries. The system works great, in bright sun I get 14.4 volts at the batteries and the other morning it was overcast and no direct sun and was getting 13.6 at the batteries.

.

[bbells]

Most of our campers come with fake deep cycle marine batteries that are only 65ah. That means you can only use half that, 30ah without killing it. That means only 360 watt hours total from your stock battery - volts times amps. My led lights are 2 watts each. My TV is 40 watts. My stereo is about 8 watts. my rv uses about 24 watts per hour just sitting there. Just do the math and you will know what you can do with your battery. In direct sun your panel when pointed at the sun will put out about a maximum of 500 watts a day. So, if you keep to your battery's specs your panel should be able to keep it charged. But, depending on the age of your battery it could store as little as 1/2 of the rated ah. Imho, 200 watts is the minimum for RV solar. You might want to get a second panel and a real deep cycle battery. Battery's plus has 12v golf cart batteries for $279. Or, better yet, 2 6v golf cart batteries in series.

[JRTJH]

In the US, COSTCO has 12VDC Interstate golf cart batteries for $229 and 6 VDC Interstate golf cart batteries for $94. I was looking at the 12VDC batteries in the store Monday, but can't justify the expense to buy two which won't give me the capacity of four 6VDC batteries. I walked away convincing myself that my two battery golf cart system is "good enough" for the rest of this year and I'll revisit an upgrade "maybe next spring"... It's hard to spend the money on something I haven't yet found to be a "need" more than a "want".... I guess I'm saying that so far, our two GC-2 batteries have provided us with 3+ days of dry camping without recharging and with the generator, we're limited more by holding tank capacity than by electrical conveniences.

[bbells]

Originally Posted by JRTJH

In the US, COSTCO has 12VDC Interstate golf cart batteries for $229 and 6 VDC Interstate golf cart batteries for $94. I was looking at the 12VDC batteries in the store Monday, but can't justify the expense to buy two which won't give me the capacity of four 6VDC batteries. I walked away convincing myself that my two battery golf cart system is "good enough" for the rest of this year and I'll revisit an upgrade "maybe next spring"... It's hard to spend the money on something I haven't yet found to be a "need" more than a "want".... I guess I'm saying that so far, our two GC-2 batteries have provided us with 3+ days of dry camping without recharging and with the generator, we're limited more by holding tank capacity than by electrical conveniences.

Costco charges a $20 core charge in my state. If that is also the case in your state next time around it may be cost-effective to get the 2 12v with your 2 cores. Just remember you can bypass the core charge at many retailers by saying it is a new install.

[JRTJH]

Originally Posted by bbells

Costco charges a $20 core charge in my state. If that is also the case in your state next time around it may be cost-effective to get the 2 12v with your 2 cores. Just remember you can bypass the core charge at many retailers by saying it is a new install.

That's "good to know" info.... I've got several old batteries around that are left over from buying ATV replacements on Amazon (cheaper than WalMart) and no core required. Costco and Sam's here (not sure about other places) will accept a "core return" of any wet cell battery for a wet cell purchase. So, I've got a few sitting around for future purchases.... But, if they'll delete the core charge on new installs, maybe that's a way of "getting the $15 credit" without turning in an old one......

[MarkEHansen]

Keep in mind that when comparing, you should compare 2 12V batteries with 2 6V batteries (not 4 6V batteries). It's easy to get 2 6V batteries which have more total AHs than 2 12V batteries - wired in each case to provide 12V.

A reasonable 12v deep cycle battery will deliver around 100 AH (at 20-hr rate). Two of these batteries give you 12V at around 200 AH.

However, a reasonable 6V deep cycle battery will give you around 250 AH (at 20-hr rate). Two of these batteries give you 12V at 250 AH.