RV Parks with only 15 amps.

[Jeremy Parrett]

Going to Mexico again this winter.  
 I   have a 50 amp TRC Surge Protector fitted.
 The La Penita RV Park we are going to has a 15 amp 110 volt ac power supply.
  If I dont use the a/c, electric water heater,washing machine ,ice maker etc will the prosine keep the batteries happy? I have 2 x 80 watt solar panels fitted. I have LED G4 lights in the coach . I can use the Hurricane for hot water. Only other thing running will be the 12 volt demand water pump.
 Any input will be helpful.  Thanks, Jeremy
2000 Marquis Amethyst. C12  12 KW Gen.

[Bill Sprague]

Not only will it be maybe 15 amps, but the voltage will be all over the place.  

You can have all the Surge Guards and Hughes Autoformers money can buy, but you only get 15 amps at variable voltage.

Re-think it a little.  Buy a good $100 battery charger.  Plug it into the around 110 volts and maybe 15 amp power.  Attach the clips to your house batteries and it will provide a steady charge.   That's because the specs on the battery charger will have a somewhat variable input requirement and a steady output.   Read the label.

Then, you pretend you are "dry camping", except that you don't need the genset unless you need A/C.  The inverter powers almost everything except the A/C and propane powers the fridge.  You can use the TV, microwave and lights through the inverter.  The cheap battery charger keeps the house batteries working.

The all important ice maker will work, you will have to run the genset do laundry.

If a Mexican power anomaly floats down the grid, you will only fry a $100 battery charger, not your Marcus power system.  

15 amps and who knows what voltage can still be luxury living in a Beaver!

[Edward Buker]

15amps is enough to run the prosine as long as the batteries were fullly charged and no load was put on the AC side of things. If significant load was on the DC side of things that could draw the house bank down or have the prosine exceed 15amps of ac demand by itself. It just is not really sufficient amperage to do anything but maintain a charged battery bank. Bill's approach is good in that it isolates the coach AC system from brown outs and would be a more managable way to handle variable loads while living in the coach.
I would be careful as to the charger you buy.... it would have to not exceed 15 amps of AC use but you would want it to be close to that AC amp use for adequate DC amp capacity, it should have the ability to taper off the charge (smart charger) and be rated for continuous duty if you are going to rely on it. A marine version may be a good place to look and I would try a semi permanent installation using connectors that are bolted down to the appropriate battery posts if you wire direct. That avoids sparking disconnecting or reconnecting where explosive gasses could be involved. Consider mounting this charger in the bay near the prosine to avoid the battery compartment fumes and you could tap onto the Prosine DC leads for battery charging from your auxiliary charger.

Later Ed

[Jeremy Parrett]

Bill and Ed, thank you for your advise.  Sounds good to me.  I am going shopping for a charger today.
I have 6 brand new 220 amp/hr 6 volt batteries from Sam's Club.  They are Duracell at $89.95 each.  

[Edward Buker]

One last thing, whatever charger you buy, try your dry camp routine here letting your house batteries run down and then use the new charger to bring them back up. That should stress the new charger before you need to rely on it ln Mexico. This is to make sure that there are no inherent defects in it that would cause it to fail. If you stressed it 3 or 4 times with a low battery bank and ran it 40 hours or so that should be enough to assure the bugs are out of it.

It would be good to have a plug or perhaps a marine battery on off switch in the plus line where you can take the new charger out of the circuit when not being used for extended periods of time. This one is $26 on Amazon. The charger may have some small parasitic draw on the 12V system end when not powered up. Good design feature to be able to just take it offline.

 http://www.amazon.com/Blue-Sea-Systems-m-Series-Battery/dp/B00445KFZ2/ref=sr_1_1?ie=UTF8&qid=1344694659&sr=8-1&keywords=battery+switch

Later Ed

[Bill Sprague]

Ed,

Don't make this too complicated.  You don't need marine, hard wiring or switches.   Charging a lead acid wet battery has been around since just after hand crank starters.  

I use an off the shelf, charger that I got a Sears a long time ago.  I have a newer smart charger too, but have not used it in this application yet.

The one I have looks about like this:  http://www.amazon.com/Schumacher-SE-5212A-Automatic-Handheld-Battery/dp/B0009IBJCQ/ref=sr_1_9?s=automotive&ie=UTF8&qid=1344702093&sr=1-9&keywords=battery+charger

To avoid the sparks, the written instructions will tell you to connect the battery clamps first and plug in the charger second.

Part of what makes it work so well is that normal car chargers only draw about 8 amps of 110.  They aren't intended for more than that.  During the day, and especially evening with TV and lights, my batteries do draw down a little and the charger needle will go to max rate.  And, it does not keep up.  Then, while sleeping, with the lights and TV off, the charger will catch up.  In the morning the needle on the charger will be showing a very low charge rate.

I prefer to leave it out where nothing matters if it fries from bad juice or overwork.

Besides Mexico,  this works well when "camping" in front of a friends house or at my kids.  Genset noise might be OK in campgrounds, but not Sunday morning in a quiet residential neighborhood.   The best "hookup" might be a 50 foot 14 ga orange cord to the garage.   Another use can be dry camping on a near silent, fuel sipping red Honda generator.  

[Edward Buker]

Bill,

Sounded to me like Jeramy was spending the winter basically living off a battery charger. That is a little different application, in my opinion, from buying a 10 amp charger at Sears.  I'm not for or against a portable or an installed option, just for having enough of a reliable and capable charger to last the winter and not be trying to hunt something down in Mexico.

I suspect you are lucky to have an old 5-10 amp charger from Sears which will probably run forever.  The newer less than intermittent duty ones that you would get today are less than reliable which was why I was thinking of a Marine charger. A Marine charger is built to bring up discharged batteries when back at the dock and handle 100% duty cycle for months. They also handle harsh environments.

 I also do not know Jeramy's habits and how much electricity he would be using but with the capacity of six 6 Volt golf cart batteries and all the electric options that you can be running in these coaches, you can quickly add up a lot of 12V amp hours. I would probably be looking at something like this 30 amp model. Two year warranty and made in the U.S. If it did fail they would ship you another even in Mexico.

http://www.defender.com/product.jsp?path=-1|328|985|316470&id=537990

Bill, I like your external lower current charger approach for the 15 amp AC service we are faced with from time to time or for this case where you are living on it for months. I envisioned installing that as a system for use whenever and however long you chose to use it.  The other thing I like about your approach is that while at home or in storage you could leave the AC to the coach disconnected and use this sytem to maintain the battery banks. That keeps all the coach electronics isolated from spikes, lightning issues when the coach is not in use or while camping with a limited AC supply.

Different approaches, temporary charging, or a more permanent system. Not one size fits all, I just wanted to offer up another choice for those that want the full Monty to live on for extended periods.

Later Ed

[Jeremy Parrett]

Great discussion !!   Here is a link to  a possible solution.   http://www.12voltpowersupplies.us/
 Marine chargers are more  spendy. but probably the best choice. Here is another link http://www.ebay.com/itm/320580964757?_trksid=p5197.c0.m619 .
 I lean towards a more sacrificial solution in a lower priced charger I wont mind loosing if it gets fried.

[Edward Buker]

Jeramy,

The units that are power supplies like in the first link are basically set up to maintain a voltage and are not tailored to the bulk, absorbtion, and float charge that batteries require. They are set up to run electronic devices with a constant voltage.

If you want to keep the price down just get a basic 10 amp charger and let it run until it croaks and then go get another one. By keeping the charge current capability low vs the battery capacity capability you can just continually charge and not worry much about over charging and multi stage charging. Give it a shot and if it works well for you then you are home free.

If later you want something that handles the load well and automates the charging cycle you can always spring for that later.

Ed

[Jeremy Parrett]

Ed, as usual I tried to complicate things.  Your advise is well taken.  Thank you.  Jeremy

[Edward Buker]

Jeramy, I don't think you complicated things, if anything I did.

 It was a good discussion in that these coaches are really not set up to handle a 15amp AC source. You could look at that as something I do often or for extended periods and then might then consider having in place a permanent built in charging system to handle that. If not then grab a couple of 10 amp chargers and see how they do. Either way you will be warm in Mexico and having some fun this winter.

Later Ed