electrical usage when boon docking/charging batteries

[moonlitcoyote]

We are really starting to think about how we are going to survive boon docking this winter as we make our way VERY slowly south and then west and have come across some questions.

#1 We have 2 coach batteries installed and am wondering how many hours they would normally last while boon docking before we have to re-charge them? The plan is that we will try only running 1 light, a 12v inverter running an i-pod and the furnace. I heard the furnace will kill my batteries very quickly though.

#2 What is the "best" way to recharge the batteries? My on board generator does not work but I have another generator that we will be bringing. Should I charge the batteries off the generator or run the homebago every day?

[Oz]

Question 1 depends on a few things.  What type of batteries are they?  How old are they?  What are the ratings?  Are they automotive?  Marine deep cell?  Gel?  What do you know about them.  Unless you know they're pretty new and are deep cell at least, you could run into waking up very cold, in the middle of the night.  And yes, the furnace will drain your batteries quickly. 

Question 2.  The "best" way to charge them would be to use a solar charger.  However, if there is a constant draw,

[moonlitcoyote]

question #1 I really dont know anything about the batteries, guess I'll have to look come daylight.

question #2.. I would love to charge them with solar but since I don't have solar panels.. What other option do I have?

[Oz]

There are no other options except running your generator, running your RV, or solar (unless you have the know how to build, or the money to buy, a wind powered generating system). 

The "best" way would be to use your generator since it would use the least amount of fuel.  The least expensive way would be to use solar with an occasional boost from either running your generator or the RV.  You don't need to run the RV everyday to recharge them.  That would eat fuel like you wouldn't believe but, once a week would be very good for the RV.  I used to run mine once a month, once every 2 weeks in the dead of winter.

For solar recharging, I'm not talking about some large, permanent, elaborate roof set-up.  I just did a quick web search and found some systems like what I mean...

http://www.campingworld.com/search/index.cfm?Ntt=solar+battery+charger&N=0&Ntx=mode+matchallpartial&Ntk=primary&Nty=1&Ntpc=1

http://www.radioshack.com/search/index.jsp?kwCatId=&kw=solar%20charging&origkw=Solar+Charging&sr=1&utm_source=Google&utm_medium=PPC&utm_term=solar%20battery%20charger&utm_content=Exact&utm

http://www.basspro.com/12Volt-Solar-Battery-Charger/product/5196/54308

Many of these are portable kits.  Even augmenting with the simple, dash lighter plug-in one would help.

I ran my RV on battery power for 10 days with no problems BUT... that was running the fridge on propane and powering the lights and the water pump only.  No furnace running and I was using 2 large, 6v forklift batteries.  You can imagine how much power and electric powered forklift uses so these batteries had some serious capacity.  To recharge them, I ran the RV since it needed to be run too anyway (and I didn't have a generator as an option).

Whatever you do, you need to have batteries which are in good condition.  Buying a couple of deep cycle, marine batteries from Wal-Mart or other battery place would be a very prudent idea... and one for your chassis too if you don't positively know the ones you have are in good shape.  You should be able to find the date codes on top and at least know how old they are. 

The grounds and connections to the batteries as well as the battery isolator etc. should all be cleaned as well since bad grounds account for the majority of electrical faults.

[ClydesdaleKevin]

Look into the Buddy Heaters while you are at it.  They run off the small propane cylinders, but you can get an adapter hose and run it off a large propane tank.  Just put it up on a counter or table out of the baby's reach.  They are very safe, and VERY efficient.  We use one for boondocking in the winter and they use very little propane and put out a LOT of heat.

Our eventual plan is to install a catalytic heater somewhere in the RV, as its the same principle as the Buddy Heater but is "built in"...even think we have the location picked out...but they aren't cheap.  A Buddy Heater will run you about 75 bucks, although I've seen them on sale as cheap as 50 bucks.

Kev

[85winnerb]

First find out what size/condition your batteries are. Make sure your engine charging system is charging your house batts. If you are going to charge them with a gen set put in a 3 stage converter charger. A solar panel would also be a big help. Forget the inverter for the Ipod get something that uses 12v for it. The buddy heater is a good idea. For your one light use a led. I found out last winter just how little battery power I had and how long it takes to recharge them.

[moonlitcoyote]

Thanks Mark, I just looked at those links and I had no idea they made such things. How does it work plugged into your cigar lighter? I thought they would have to be hooked to the battery itself to work.

My batteries are deep cycle marine/rv batteries, cranking amps 690, reserve capacity 140. The date was not punched out on them but they look pretty new.

Kev.. I am going to look into the buddy heaters but my only concern with them is that the baby's door will be closed until I go to bed at night, so not sure how cold his room will get. But maybe I could run the furnace for the couple hours each night... BTW we had a catalytic heater in our 69 terry trailer and it was the bee's knee's. If I had ANY wall space to put one I would get one for the homebago.

[Oz]

Honestly, I have no clue how the ciggarette lighter plug-in ones work either.  That one stumped me as well as I thought the same as you... the thing pulls electricity, how can you send it back through it?   Hm?   But, others have used them to keep their chassis battery charged.

It's great that you posted the info on what batteries you have.  To give an educated guess on how long they would last, I will turn it over to the electrical gurus for an answer.

   I may have a workable suggestion for when you close the door to the baby's room...
another "cold spot" in any RV of that era is the bathroom.  Oh, what a dread it was to sit down on the commode in winter!  Well... I came up with a solution which made the bathroom nearly as warm as the rest of the RV.  Not as warm, but much more bearable. 

I cut a large vent hole in the lower portion of the door and a smaller one at the top.  This at least allows for some natural flow of warm air in which didn't exist before.  Now, to optimize the ability to get warm air in there, you'd need a small fan to draw the warm air in at the top but that would also increase your electrical usage.  Hopefully, you or others may come up with some more ideas to improve on this.  It's very easy and cheap.

Cut the holes in the door                                                 Screw in the vents 
                                                           (one on the inside and one on the outside, top and bottom)

     

Top vent

[moonlitcoyote]

HM, I like what you have come up with, with the vents. I am going to have to put some thought into doing something like that.

It's great that you posted the info on what batteries you have.  To give an educated guess on how long they would last, I will turn it over to the electrical gurus for an answer.

My main concern is whether the batteries will last through the night. I could add 1 more battery to the bank if I need to. I figure if they will last through the night, I will have a 12v solar charger running during the day to hopefully charge them back up before nighttime. That being said, if I have 2-3 batteries would I need more than 1 of those solar chargers?

[gadgetman]

SOLAR ! its all about the amp hours you use. You have to understand how many amps a item will use. A amp hour meter helps for that. For example.a 1156 12v bulb draws about 1.3 amps or 1300 mili amps. A small 12v fan like the old style chrome metal ones is about 2.5 amps, a walmart 12v plastic cig lighter fan uses  .8a/800ma.

12v computer fans use about 150ma to 800ma depends on the cfm of the fan.

The best thing you could do is to use 12v items that draw very low amps. Lights are a huge issue and LED lighting will fix that issue. The easiest and brightest way to do it is to use the LED dome/panel bulbs they sell and install them in your fixtures. The 36 to 48 led ones are very bright and draw 265 ma.
So the math is like this. If you have a ligh on for 1 hour that draws 3 amps you have uses up 3 amp hours of your battery bank.

Run everything you can off of 12v and avoid inverters for 110v usage. They eat up amps quickly.

You only have about 70 amp hours out of each of your batteries. So if you have 2 you have 140 ah before they are DEAD. Rule of thumb is never exceed 50%, but its best to not exceed 70% so that gives you 30% to use each NIGHT which is about 45ah. That's not a lot. So you can see its all about battery storage. Pushing that to 50% will give you 70 ah to use but your battery life will be shorter.

With solar you want as much wattage as you can afford because you still want charging on a cloudy day. I run 500 watts and that a lot of panels but it gives me about 40 amps on a perfect day and 10 amps on a very dark cloudy day. That's only because of the area/size of the panels I have. Its 4 panels that are 24in x 56in.

Another thing is, if you use 30 ah at night you really need a solar system that can put out at least 60 ah during the sun period so you can still use 12v stuff during the day and still put ah back into the battery bank.

Solar can be hooked up anywhere but its best to go right to the battery bank with it to avoid and voltage drops in the vehicles electrical system wiring. You want all the solar you can get to GET to the battery bank.

you pretty much need a min of 200 watts of solar for it to really do much as far are running on solar and not just maintaining a battery. Solar is the way to go for boondocking !

[moonlitcoyote]

ok, so I understood VERY little about all that but what I did understand is that by using a 3amp light for 3 hours I would use up 9hours out of my available 45. Leaving 36ah for my furnace if I ran nothing else. SO would my furnace take more than those 36ah to run all night? How do I find out how many amps things take to run?

I did find a 12v charger that works for the i-pod speakers so I wont need the inverter except to charge the i-pod when it dies. Not sure how long its battery will last. I haven't tried yet.

As far as solar panels go, I have notice 2 sets of brackets on my roof that look like they may be or work for solar panels. But I am living basically on a zero income right now, so solar panels will have to wait until some power plant somewhere needs their pipes insulated and my husband can get back to work.

[gadgetman]

To test the fan for amps you need a amp clamp/meter to test it but............guessing I would say that fan would take at least 5 amps and maybe as much as 10. It all depends on the fan motor.


With no solar I wouldn't use the electric/propane furnace. I would do as others have mentioned with a propane radiant heater. Either a cat style or a blue flame style. Both of those are meant to be ventless but still need caution used, like having 2 windows open 1/4 in when the heaters are on.

[moonlitcoyote]

I think I am starting to get things straight in my slow and often unreliable brain....

Heat..
I did see a ceramic heater at wal Mart today, but the thing was "tiny" are we sure they put out some heat?
Looked for a propane buddy heater but it must be too early in the season as they didnt have any propane heaters out.

Lights..
I am going to install some battery operated lights that I also used in my terry trailer, they last for awhile before needing to change the batteries.
Check on installing at least 1 LED light.. Do these run off 12v?

Charging..
Order small (and probably inefficient) but cheap 12v solar charger.

Now with my battery (as in AA) operated lights and propane buddy heater. The only thing I "should be running is my water pump a couple times a day for shower/dishes and baby bath. (use baby bath water for toilet). .. HM, does the fridge use electricity? Oh and have to charge the laptops. Shoot, going to need the inverter after all. .. Can you take a guess at how much ah I will be using? I dont know how many amps it takes to charge a laptop.

[Oz]

Anything which requires an electrical motor to run is going to have a high amp draw (i.e. furnace & air conditioner and the refrigerator though it doesn't use an electric motor to heat but I won't go into that).

My main concern is whether the batteries will last through the night. ...

If that's all you're concerned about, I wouldn't be too concerned.  As long as you have a day's worth of charging time, you'll have no problem without adding an additional battery (although that would be a good thing to do).  You can run several lights, a TV and other things as well.  You'll be able to tell very quickly when the lights are starting to dim and you need to recharge.  It's the furnace which would be the biggest draw.  If you can use a low draw alternative to the furnace, you'll be just fine using a single solar recharger or running your generator for about an hour.  But, you may find the need to run a heating system 24 hours a day if you're not far enough south not to.  If that's the case, you will need to recharge more frequently.

The door venting will help but, you really should have a heat source adequate for the baby's area when the door is closed.

You can get all kinds of LED 12v bulbs but, they are expensive.  Your fridge uses very little electricity to run off LP.  If you run it solely on electricity, yes, it will use a lot so I'd avoid that for sure. 

Battery operated lights, unless they are LED ones, chew up batteries pretty quickly and you'd be spending a lot on AA batteries.  I bought an AA charger like 4 years ago which came with 4 rechargeable batteries from Wal Mart and have used them in my camera and optical computer mouse and they have saved me tons of bucks on regular, non-rechargeable batteries.  The charger and batteries only cost $15 at the time.

I'm not an electrical guru who can determine the numerical demand/supply equations.  I can only talk in common speak... what works without the technical data... based on experience.

And honestly, if you're planning to make this trip on a shoe-string budget... I'd seriously rethink it unless you have ample financial reserves to be fully prepared for daily operation as well as for emergencies.  We've followed more than one of these ventures and unexpected things happened which left the people stranded with no financial resources to make it through.

[ClydesdaleKevin]

Hate to rain on anyones plans, but 2 Walmart deep cycles with no solar, or very little solar, is going to limit your power use severely.  No furnace for starters, that will drain the battery bank right quick!  Use the inverter as infrequently as possible.  Run the fridge off propane.  Use no more that one or two lights at a time.  Keep the TV time, which probably runs off the inverter, to a minimum, and shut the inverter off when not in use.  Get a catalytic propane heater like a Buddy Heater.  Train the baby to sleep with the door cracked open slightly so the heat gets back there too.

Whatever kind of battery you have, think of it like a gas tank.  Whatever you drain out of it, you have to put back in.  Even with a battery system like ours, and even following my own advice above, I still had to run the genny for 2.5 hours a night to bring my batteries back up to full charge, even with 85 watts of solar on the roof, aimed at the Arizona sun with no shade.

Actually, think of your battery bank more like a tire...and power use like draining the air out of it.  You have to pump air back into it when it gets low.  And the closer you get to full pressure, the more pressure you need to air it up.  Same with a battery.  The closer you get to full charge, the more power (voltage) you need to complete the charge, if you want to do it quickly...which is how a solar system works.  Sunlight hours are limited, and even in ideal conditions (ideal ambient temperature, minimal clouds, panels aimed right at the sun, panels clean, etc.), you need panels that put out sufficient voltage and watts to push the volts back into the battery as quickly as possible, and a good charge controller that will charge at a high enough voltage to charge the batteries in a short time.

So even with 4 golf cart batteries like we have right now, and 85 watts of solar aimed right at the bright Arizona sun all day, it still wasn't enough to fully charge our batteries from our minimal usage from the day and from the night before.  Thus the reason we had to run the genny at night for a couple of hours.  And that is with our stellar Powermax Boondocker converter/charger rated at 100 watts.  With a stock converter charger, you'd have to run a genny for way longer.

As Mark said, if you are going to go with battery powered lights, you'd be better off getting rechargable batteries, but now you have to consider how you would keep them charged...if you put the inverter on, you'll draw more juice charging them then you would running your regular RV lights.  A better investment would be to replace the RV light bulbs you use the most with LED bulbs, which draw a LOT less power.

Harbor Freight has a 45 watt solar system on the cheap, complete with charge controller, (on sale right now for 159 bucks...just go to their website), which will help tremendously...our friend Arlene uses that set up...she built a frame and sets it on the ground near her RV when she's parked, tilted to the sun, and runs the cables right to her batteries.  She still has to run her genny at night, but she runs her TV and whatnot often, charges her phones and laptops, and isn't as careful with power use as you'll have to be since you don't have a genny.  The Harbor Freight system is far from ideal, but with very careful power use it would work for you.  A little trickle charge solar panel isn't going to do squat though.  A trickle charger simply doesn't put out enough power to do anything more than maintain a charge on a battery that isn't being used, not a battery in use. 

So if you want my advice from experience, you'll have to invest about 250-300 bucks to get started on a boondocking adventure, and then be a miser with power use.  160 bucks for the solar system, about 75 bucks for the Buddy Heater (also available from Harbor Freight), another 20-30 bucks for the adapter hose that will let you use a BBQ tank for the heater since the little canisters will cost you a fortune, and another 30- 60 bucks for the LED light bulbs to replace the bulbs in your RV fixtures that you use the most.

You'll also have to start weaning the babe from some if his habits so you can keep the bedroom door slightly open so its stays warm enough back there for him.

Also remember that gas is expensive, and our rigs don't get the best fuel economy on the planet.  Its a LONG way from Maine to Arizona, but way closer to mid or southern Florida.  Yes you can find a lot more free camping in AZ and out west, but the gas to get there, over 2000 miles from where you are, is going to cost a small fortune.  Just all depends on your budget and your husbands future job prospects.  If you drive to Florida and run out of funds, at least you are a lot closer to home and the summer heat there isn't unbearable, especially in mid to north Florida.  Get stuck in AZ in the summer and you'll be hating life.  112 there right now in Apache Junction, and no shade to speak of.

So not trying to rain on the parade, but giving you advice from experience...unless you have a decent reserve of money, take the southern route and not the western route.  And if you are going to attempt boondocking fulltime, you'll have to make the minimal investment I mentioned above to do it without draining your batteries and having NO power.  Without a generator, you'll have no way to charge your batteries without those solar panels (without burning a lot of expensive fuel), and even with those you'll have to be extremely stingy with power use.  With an external genny, you can plug the rig into it and charge the batteries with either the converter, or an external battery charger, but you'll have to run the genny for at least a few hours a night.  You can also start the engine to charge them off the alternator, but again, it takes time, and you'll be burning fuel which has to be replaced, and have to run the engine for at least a few hours.

Another good idea is to turn off your 12 volt water pump when not in use.  They tend to cycle on and off, so no point in leaving it on when you aren't using it.

Hope that helps!

Kev

[gadgetman]

And that is with our stellar Powermax Boondocker converter/charger rated at 100 watts. 

Did you mean 1000 watts ? 

Solar Rocks because its free and the goverment pays for 30% of it !!!!!!! Add more panels and run the gen less or not at all !!

[moonlitcoyote]

Thanks guys for your input, it is much appreciated. I mentioned in another thread but not this one. I did finally get my on board genny running. And I also have another genny I will be bringing. I am figuring to use the external genny as it will run 12 hours on 5gal of gas. Thats what we normally did when spending weeks at the lake in Colorado. The only reason I am "worried" about this trip is because we never had the baby when boondocking for weeks at a time before.

As far as warming the baby's room, thats why I asked if the ceramic heaters actually put out heat. I figure to run the genny for a few hours a night to watch tv, charge the batteries and run a ceramic heater in the baby room until I go to bed. At which point I will open his door and the buddy heater should warm his room since it will be placed about 5 ft from his door.

As far as solar goes, I'm sorry but I just cant wrap my head around how it works and such, I wouldn't mind spending a few hundred $$ to set up a somewhat small solar set-up but I just don't understand enough of it to even try it. Maybe someday I will run into someone that will help me set one up.

I also appreciate everyone's concern about my financial issues, I am making this trip out of necessity not want. I have the money to make the trip as far as Georgia to start with where I have found a campground for $280/month. And once my husbands retirement goes through we, well we are hoping the situation gets better. But we do know we cannot survive in a  winnebago in the -30 degree weather we will be hit with here in Maine this winter. If worse comes to worse, we can always park the winny and drive the toad to Colorado to stay with family. But keeping my fingers crossed that a job rears its ugly head before we have to head out.

[Oz]

Getting to Georgia will make a world of difference in the winter for sure.  It sounds like you have a good plan and many of us are in similar boats, so-to-speak, financially unable to see a way to live the now defunct "American Dream" of a house in the burbs with a white picket fence, yadda-yadda.  The need for "alternative housing options" is growing (full-time RV living) and I really don't see it getting better for many of us.  So, all of us here support you as we have supported one another over the years, with true desire to see you achieve your goals and help however we can when needed. 

A couple things you may want to scan over for the solar thing... Phred's Poop Sheets in the resources section and the topic, "everything solar".  I get swamped too with electrical testing and computations etc.  I thought it was just me but no, not all of us are that quick with the electrical stuff so, we're a club in our own - LOL!  That's why we rely so much on those who do know.

[vincewarde]

Here are my suggestions:

1) The largest and best batteries you can buy.  You can never have too much storage.

2) I definitely 2nd the 200w solar system.  I have 130w and it is not enough.  I am going to add another 80-100w.  Remember that the wattage rating is best case scenario.  This means with the panel pointed directly at the sun.  That never happens in a typical roof top install. My system puts out 4-5 amps at mid-day, the full rating would be 6-7 amps.  200w will get you something like 7 amps at mid-day 10am to 2pm, less before and after.  A good guess of what you can get out of a 7 amp max system is roughly 50 amp hours per day, during the summer with the coach parked in full sun.

3) Change ALL your lights over to LED lights.  I found mine for $4.95 each at amazon.  They draw .2 amps for 250 lumins - typical incandescent bulbs draw about 2 amps for maybe 50 lumins.  Do the math - LED bulbs are cheaper than buying more panels or running your generator.

4) Get a good voltmeter so you can see the status of the battery and an ampmeter with a 10 amp scale to see what you are getting out of your panels.

5) Check the output of our charger/convertor.  Mine is 3 amps.  I got one that does 2-10-50 (I have a very big battery, so I am OK with brief charges at 50 amps).  You don;t want to run your generator longer than absolutely necessary.

That's my .02 worth

[moonlitcoyote]

Thank you for your 2¢

I had decided to go with solar, BUT, after reading everything I could find about it. I have decided that it is just WAY too complicated for me. I get lost as soon as you start talking about watts and amps and no matter how much I read I just cant understand it. Which is not easy for me to admit since I thought I knew everything with my college education and all.  . I am hoping someday I will run into someone that will tell me ok buy this this and this and I will help you hook it all up. I might be dreaming but that is the ONLY way I am ever going to get solar going on my home.

[jkilbert]

Here's one thought that could kill 2 birds with one stone for you. Many "vintage" rv's had a single propane light inside as either standard or as an option. I can remember 2 of the trailers that my family had  when I was a lad had one in it and my grandparents trailer had one. All this is , is a single mantel light that is wall mounted. I can say that when we would go to camp in the winter, the first thing dad did was to crank up that light and it would take the chill off until he could get the furnace going.  I just did a quick search and one popped up on eBay. Something like this might help out for you.


John

[jkilbert]

One more tidbit. Ther company that makes these lamps is still around and they have a website. Humphery gas products...    www.humphreygasproducts.com


John

[ClydesdaleKevin]

Nope Gadgetman...I meant 100 amp converter/charger.  Its the Powermax Boondocker, three stage charger, designed to charge the large battery bank we have at a higher than normal charge rate when the genny is running and the batteries are low, then drops down, then goes to a 13.2 float charge.  We got the 100 amp model, the biggest one they make, to handle our boondocking needs.  The hundred amp model easily handles 6 golf cart batteries, while still having enough power to run the 12 volt system in our RV.  Last year in Arizona, with just a single 65 watt solar panel and crappy charge controller, and only 4 golf cart batteries, the Powermax Boondocker would bring the battery bank all the way back to a full charge running the genny for only an hour and a half to two hours a night.

I'm guessing that our new 705 watt solar system with the Morningstar Tristar MPPT 60 amp charge controller, and 6 golf cart batteries, will virtually eliminate the need for running the genny at all.  Really heavy cloud cover or thunderstorms might force us to fire it up, so we'll keep it as a backup and keep it tuned up, but I'm going to guess that we'll now have more than enough solar power to boondock as long as we want to. 

Got the Powermax Boondocker 100 from Best Converters.  They are on the resource page. 

Kev

[vincewarde]

If you can keep positive and negative wires straight, you can hook up a simple solar system - which is all an RV needs.
Let's start with the charge controller.  Get a 12 volt, 10 amp controller (think of it as doing the same thing your cars voltage regulator does - prevent over charging).  The controller will have positive and negative terminals labeled "Battery"  - just run wires to the positive and negative terminals on your battery.

Next you need panels.  Most are rated to charge a 12v battery, which means without a load they will put out at least 18.5 volts.  Just buy 200 watts worth of panels.  It doesn't matter if you use 4 x 50 watt panels, or 2 x 100 watt panels.

Each panel will have - you guessed it - a positive and negative connection.  The controller will have a positive and negative connection marks 'array" or maybe "panel(s)".  Just connect the panels up to the change controller.  Each panel gets connected to the controller.

That's it.  You now have a functioning solar system that should generate about 7-8 amps with the rig parked in full sun.

Of course you need to secure them to the roof and water proof any holes you punch through the skin or roof - but that's pretty basic handy man stuff.

Now, if you want to get fancy, you can put in an ampmeter and a voltmeter so you can check the performance of the system.
It's really not that hard

[moonlitcoyote]

You made that sound so easy that as soon as we have some extra cash we are going to buy the 12v 10amp charger and 2 panels. I dont know what I can run off the 2 panels but who cares they got to at least keep my batteries charged right.