Batteries

It's a widespread misconception that 50% discharge is a magic number, and going past that will cause damage. The truth is that there's a nearly linear relationship between how far you discharge a battery and how many charge/discharge cycles (total battery life span) you can expect to get. This is best shown by the chart found partway down this page of Eureka! Live:
http://www.andybaird.com/Eureka/pages/batteries.htm
(Footnote: the chart is based on one I found on Concorde's website, and the original referred to their AGM batteries. Nevertheless, although the exact numbers may vary, the curve shown holds true for just about any lead-acid battery--flooded-cell, gel, or AGM.)
Looking at the chart, you can see that if you only discharge your batteries 10% (not that that would be practical), you can get 5,000 cycles out of them. If you go to 50%, you're looking at about 1,000 cycles. At 80% discharge, you're down to about 500 cycles. And so on.
The exact numbers may vary for different types of lead-acid batteries, but the point is that the relationship between discharge level and lifespan is a linear one: the lower you drain them, the fewer cycles they're good for. There's no "knee" in the curve, so there's no magic number (e.g., 50%) above which everything is fine and below which you cause permanent damage. It's a continuum, and it's up to you how you want to use your batteries.
Some folks choose to push their batteries hard in order to support the lifestyle they prefer, accepting that they will probably have to be replaced more frequently. That's a perfectly valid choice.
I tend to go in the other direction, rarely discharging my batteries below 80% charge (20% discharge) and almost always charging them up to 100% at least once every day. I can get away with that because I have 520 amp-hours worth of batteries, so I can pull 100 Ah out of them and still only have discharged them 20%.
But again, that's a personal choice I make, and it isn't the right choice for everyone. If you have the factory-standard 225 Ah batteries, limiting yourself to a 20% discharge (45 Ah) would probably put unreasonable limits on your lifestyle.
The moral is: understand what your batteries can do, and what to expect of them. Then use them as best suits your needs. They can always be replaced--and in the long run, they will have to be sooner or later; it's just a question of when.

From the Trojan web site:
*Discharging:*
1. Shallow discharges will result in a longer battery life. What they should add is "you'll get more cycles, but not more total amp hours over the life of the battery".
2. 50% (or less) discharges are recommended. Reasonable suggestion when you have no idea how well people are monitoring their batteries.
3. 80% discharge is the maximum safe discharge. I think this is sensible, as it corresponds with what I know about deep cycle lead acid batteries but requires more careful monitoring.
4. Do not fully discharge flooded batteries (80% or more). This will damage (or kill) the battery.
5. Many experts recommend operating batteries only between the 50% to 85% of full charge range. A periodic equalization charge is a must when using this practice. This is usually about charging efficiency, rather than battery life. It's how I do it when we use the genset to charge, because the last 15% of charge is done at a low rate and requires excessive genset running.
6. Do not leave batteries deeply discharged for any length of time. This is a real killer, worse than deep discharges followed by immediate charging.
/If you are using AGM batteries, be sure to check the manufacturer's data sheets. My experience with deep cycle AGM's is they are more tolerant of deep discharges than flooded batteries.

Buying new Trojan batteries:
- Each battery should have a voltage between about 6.2V to 6.4V.  This would be not connected and having been at rest for a while.
- Check the date code. All batteries have a manufacture date code on them. Trojan uses two codes: one on the positive and one on the negative terminals. One tells you the date of mfg and the other tells you when electrolyte was added and it shipped from the factory. They use letters and numbers. A-L represents the months Jan-Dec. On date of mfg they use two digits for year. On date shipped they use a single digit, so L3 would mean it shipped Dec. 2013.
- Be sure to follow proper, safe procedures: read the Lazy Daze Companion article on how to disconnect batteries.

Contributors: Andy Baird, Eric Greenwell, WxToad, Jim C.

Date revised: 16 Jan 2014

RV Power for Dummies

If you know much of anything about electricity, this article is not for you. You already know all this!

For the beginner, this will seem like a lot of info, but I've tried to keep it simple. Just read it over a couple of times and hopefully it will help you to begin to understand the electrical power in your RV.


Before I go any further, one note . . . If you are ordering a new Lazy Daze, I think one of the most important options you can pay for is to get as many 12-volt (Direct Current or DC) and 110 volts (Alternating Current or AC) outlets as they will give you. It's been my experience that they're never where you want them, so I like having them everywhere! We got all they would allow, and still had to put more in!


110 volt power is what you have in a regular house. It comes from the power poles that feed your home. You access it via through those familiar 3-prong plugs.


12 volts is what is supplied to your RV from your battery bank. In your RV, if you're sitting out in the middle of nowhere, you're running off of 12-volt power supplied by your batteries. Think of the plugs that go into a cigarette lighter. That is a 12-volt outlet.


The 12-volt plugs cab dash are powered by the cab battery located under the hood. The house batteries, which power the lights, etc. in the living quarters of the motor home are located somewhere in the body of the motor home.


One short note about house batteries. They come in two types, flooded cell and sealed (AGM or gel cell). If you have flooded cell batteries you must maintain them by checking that they have enough distilled water in them. If your batteries don't have enough water, they will die a premature death. There are many ways to water your batteries but that's another subject. Just remember that this is a crucial step in preserving your power. KEEP YOUR BATTERIES WATERED!!!
Tech Note: A Profill system is commonly used to keep the batteries topped off.


If you have replaced your flooded cell batteries with AGMs or gel cell, they are sealed and never need water. There are many advantages to sealed batteries, but they are considerably more expensive than flooded cells. Since most RVs come with flooded cell batteries, that's what I'm going to talk about here. [In 2010, AGM batteries became standard in Lazy Daze]


So here you are, out in the desert, relying on your batteries for power. You can only use lights and appliances that are 12 volt; nothing that uses a 3 prong plug (ac) will work.


If you want to use regular 110 volt items (DVD players, some TVs, charge your computer, etc.) you need an inverter.


An inverter takes 12-volt power from your batteries and changes it into 110 volts. Inverters come in several models, portable and hard wired. A small portable inverter plugs into a 12-volt outlet and contains regular 3-prong house plugs.


Different inverters can handle different amounts of power, so before you buy one, you need to do a bit of research. We opted for a hard wired full house inverter, so with the flick of a switch, all the 110 volt outlets in Cholula Red are "live". When we don't need this feature, we simply turn it off. Tech Note: A 400 watt inverter is more than adequate for charging computers, phones, a DVD and other low power requirement devices. If you want to power something like a hair dryer, you will need a 2000 watt hard wired inverter. The price difference between a portable 400 watt and hard wired 2000 watt inverter approaches $2,000. Also the 12-volt outlets will supply, at best, 10 amps, less the more removed they are from the batteries. Short story, anything that needs more than about 5 amps will need a hard wired inverter connected directly to the batteries.


Charging the Batteries


Depending on how much power you consume dictates when you will need to charge your batteries. This can be done in one of four ways.


First, anytime you are plugged into shore power, the batteries are being charged by the converter/charger unit.


Second is the option of solar power. Solar is a great boon to RVers and we love having it on Cholula Red. We have four panels, giving us lots of power for the batteries, assuming we have the sun to power them. That said, solar is somewhat expensive, and not for everyone. While we often have hook ups, we have found that solar gives us the opportunity to camp at places with no power for extended periods of time. I look at solar as an addition that opens up options. It does a great job of charging the batteries, but since it's an option rather than a standard item, I'm only mentioning it here for informational purposes. Tech Note: The power from the solar controller is fed directly to the batteries, bypassing the converter/charger.


Third, you can run your cab engine. This will charge your batteries via the engines alternator, and it's fairly efficient. HOWEVER, it's noisy, it pollutes and it uses a good amount of gasoline, so it's really not the best option. Tech Note: The batteries are charged by the alternator controlled by the engine's voltage regulator. Not ideal as the chassis and house batteries are probably at different charge levels.


Fourth, if you have a generator, you can charge your batteries with it. It also uses gasoline, but not as much as running the engine (.6 gallons per hour under a low load), But, there's a catch to charging the batteries via the generator. In order for your generator to charge your batteries, it has to use a device called a charger. And chargers come in various models.
Most RVs come with a single-stage charger as part of the built in converter. It takes the power made by the generator and it stores it the batteries. But here's where it gets tricky. Your batteries are sensitive, and they can only go to 100% charged. If you continue to charge them, they will start to “boil”. [The water appears to boil, but it’s actually hydrogen bubbles you see.] When they “boil”, your batteries will lose water.


And remember, YOU WANT TO KEEP YOU BATTERIES WATERED!!!


Tech Note: The charging ability of factory supplied converters varies. If you have the original converter, the charging will be very slow in all coaches manufactured before November 2001; that's when LD started installing the more modern 7345 converter. The earlier model 6345 converters charge at an incredibly slow rate so don't attempt to charge your batteries by running the generator.


So here's where you might want to consider a smart multi-stage charger. Not only does it charge your batteries, but it communicates with them. It knows when the batteries are low and need a lot of charge and it pumps the power in at a fast rate. When it reads that your batteries are getting close to full, it backs off to a lower rate of charge. And when it reads that your batteries are near to completely full, it goes in to a trickle charge mode. Three stage "smart" chargers are a real boon to RVers and I think a necessary upgrade for many users.


Now I want to talk a bit more about the power in your batteries. Now that you understand that the power comes from your batteries to your appliances, the question comes up, how do you know just how much power is left in your batteries?

The answer is simple. You need a battery monitor.


IF YOU DRY CAMP, YOU NEED A BATTERY MONITOR!


Short story here …When we first got Cholula Red, I was truly clueless about RV power. I understood that I didn't understand, and I wanted to learn. But when people would try to explain to me about power, they would start talking amps, volts and watts, and honestly, my eyes would just glaze over.


But, I did know that I was using a lot of power and I wanted to know where I stood. After all, we were running lights, watching television, playing DVDs, charging phones, computers, you get the idea. I wanted to know when my batteries were getting low, and I was completely clueless about how to find that out. Several people had told me that I could get this information from my solar controller (the device that monitors/controls the power from your solar panels to your battery). The catch was this - it would only give an accurate reading when there was no power going into or coming out of the batteries. And when would that be? Yep, I would find myself getting up in the middle of the night, turning on my flashlight and sneaking up to the display, trying to figure out how much power was left in the batteries. [Tech Note: Equating a voltage reading to the amount the batteries are discharged is up to 25% off.]


Now, with the push of a button the monitor tells me that I have exactly 83% left in my batteries (or whatever the percentage is at any given time). For me, managing the power in the RV became pretty simple after I got the battery monitor. If you don't want to have to learn all the math, it's the easiest way to manage your power.


Tech Note: Battery manufacturers warn that discharging below 50% will shorten the life cycle of the battery. Most users consider 65% the low threshold.]


by Kate Klein

How to Disconnect a Battery

To disconnect the battery, open the house (or coach) battery door and look at the wires on the the terminals. All you must do is to remove the wire off of any one battery terminal to break the connection. However, it is much safer to remove the wire from the negative or ground terminal. Working on this terminal means that no damage will be done if you brush up against the door frame with the wrench as you remove the nut on the battery terminal.

You don't want the wire that goes from battery to battery. You are looking for the negative battery terminal and you may be able to read which terminal it is right off of the battery itself. In my coach it's the one closest to the outside door. The negative terminal probably will probably have only one big wire on it that goes off to a ground connection. However, that ground connection probably will not be in sight. The positive terminal will have a two or three big wires on it, one of which typically runs to a circuit breaker but, again, that circuit breaker may not be in the battery compartment.

Once you have identified the negative terminal, use a wrench (a small crescent wrench is good) to remove the nut on the terminal. Once off,just lift the wire up off of the terminal and wrap it in a piece of paper so it won't touch any other piece of metal in the compartment.

When you are done, just put the wire back on the terminal and replace and tighten the nut to about the same tension it took to remove it. If you disconnect the battery, you probably will have to reprogram the buttons on your radio.

Contributor: Linley Gumm

Battery Isolator Terminals

Here is another maintenance item for you.

Last week I was poking around under the hood when I noticed a lot of corrosion on the battery isolator terminals. Grabbing onto the wires, I could move them around. The nuts appeared to be tight and the studs themselves were moving. Using a multimeter I checked and found a small amount of voltage drop over two of the terminals, indicating a poor connection. I removed the screws holding the radiator reservoir in place and tied it back to provide access to the isolator's terminals. After disconnecting all power, the starting battery, coach battery, converter and solar panel, I removed the three nuts on the isolator and pulled the wires terminals off. At the base of each isolator stud, there is a thin nut. I snugged each of them up without over tightening since I did not want to break off anything inside the isolator.

The wire terminals were cleaned with a stainless steel brush and then everything received a coating of dielectric grease before reassembly. Checking afterwards, I found no voltage drop.

http://www.flickr.com/photos/lwade/sets/72157616714752420/

Contributor: Larry Wade

Battery Monitor

If you are going to dry camp more than a day or two every once in awhile, then you need a battery monitor that tells with precision the state of the charge remaining in the batteries. A battery monitor is a digital meter/computer that reports voltage, amp flow into and out of the batteries, amp hours remaining and operating time left. Without a monitor, you are shooting in the dark about not only the remaining charge, but how many amps different devices use. This is vital information to be able to dry camp for several days without damaging the batteries.

Here are two manufacturers:


Xantrex LinkLite and LinkPro
TriMetric

Contributors: Don Malpas


Return to FAQ Index

12-Volt Electrical System

General
The electrical system in your Lazy Daze is a little more complicated than that of your home. Basically there are two major systems in your LD: a 110-volt AC system that is similar to your house and a 12-volt system that provides power when you are not plugged into the electrical grid, either at home or in a campground. The 12-volt system allows you to boondock without utility hookups and enjoy most of the conveniences of home. Check out the 110-volt AC System FAQ for more details on that.

The 12-volt system, as built by the factory, is powered from two different sources. The heart of the system is two Trojan T-105 6-volt batteries wired in series to provide 12 volts of power when not connected to shore power. Trojans are known for their durability and longevity, provided they are properly maintained. When connected to shore power or the generator, the 12-volt system is powered through the converter that is standard on all Lazy Daze motorhomes. On the front of the converter is a 12-volt panel with a number of fuse positions for the various 12-volt circuits in the coach.

As noted in the Battery Maintenance FAQ, it is important to keep your batteries as charged up (full of power) as possible, especially when boondocking. The batteries can be charged in four ways: running the generator, plugging into shore power, running the LD's engine, or optionally with solar panels.
When boondocking, it also pays to be aware of the current draw of lights and appliances, so you can make the available power in the batteries last as long as possible. Some folks have replaced the incandescent and fluorescent bulbs in the fixtures with LED bulbs that draw significantly less power. Many folks install a battery monitoring system, such as the Link-10, LinkPro, XBM or TriMetric that keeps track of battery use. Its computer keeps a running total of every milliamp that goes into or comes out of your battery bank. If you're a frequent boondocker, you might consider adding more batteries for storage of power and more solar panels to feed them.

There should be a matching of battery capacity to power needs.  In general, it is considered bad form to repeatedly draw down the batteries too far.  How much is too far?  Some say 50%.  Some say more, and some say less.  It seems clear that the less you draw down your batteries, the longer they will last.

Trouble-shooting
12-volt appliances or lights fail to operate:
The obvious place to start is to check the fuse. The 12-volt panel uses standard automotive flat-blade fuses of varying amperage, depending on the circuit. You should keep a supply of spare fuses handy.

Caution: If a fuse keeps blowing, do NOT replace with a higher-amperage fuse - find the source of the problem and repair it. Otherwise you may face a hazardous fire situation.

The entire coach 12-volt system is inoperative:
There is a 12 Volt 100 Amp manual reset circuit breaker located typically on the back wall of the battery compartment. There is also a 12 Volt 50 Amp manual reset circuit breaker located inside the coach very close to the enclosed battery "box". The location varies with the floor plan. On the RB, it is under the forward dinette cushion and u have to remove the screws from the plywood cover over the battery box to get to it. Some rigs may even have two of these. The "inside" breaker is a small gray plastic box about 1.5 inches by 1.5 inches by about 3/4 inches with a tiny black reset button. If you lose ALL 12 Volt power, this is the one to look for. On one new rig, a "run-away" ShurFlo 5.7 water pump caused this breaker to trip (50 Amps!!!!!!).
Contributors: Terry Tanner, WxToad
Return to FAQ Index

Pro-Fill Battery Watering System

Maintaining the proper water level in your batteries is crucial for their long-term health and ability to provide maximum power output. It's possible to do this fairly cheaply, using a turkey baster and a small mirror. But it is hard to get the level exactly right, especially for the cells near the back of the batteries. The battery tray only pulls out so far.

Many RV'ers have opted to install a Pro-Fill On-Board Battery Watering System, which makes the job much easier. To quote from the manufacturer's web site:

• Fill up to six batteries in seconds from a single fill point
• Fits all standard 6V lead acid batteries
• Eliminates need to remove vent covers to fill
• Automatically sends water to low cells only
• Installs in minutes, no tools required
• Safer and more accurate than conventional filling
• Improves battery life and performance
• Hard to reach batteries are as simple to fill as batteries on a workbench
• Several batteries can be connected and filled at the same time
• Automatic shut-off prevents over or under watering
• Simple hand pump operation
• Use with any distilled water container
• Quick disconnect feature allows supply to be attached in a snap
• No need to remove vent covers

The Pro-fill system consists of a set of battery caps connected by a series of tubing and a hand-squeeze bulb pump.






To install, first remove the stock battery caps from each cell. Insert the new set of caps with their tubing. Install so that the quick-connect fitting is near the front of the batteries. That's it.

To use, insert the intake-end of the tubing from the hand pump and put it into the container of distilled water. While holding the other end of the tube up, SLOWLY squeeze the pump until the water has risen to the upper end of the tubing. Fasten the tubing to the quick-connect fitting on top of the batteries. Now squeeze the pump to force the water into the cells. Keep pumping until the bulb becomes hard to squeeze, the indication that the cells are properly filled. Generally it shouldn't take more than 1-3 squeezes under normal conditions.

When finished, disconnect the pump tube and drain the water from it. You can either drain the water back into the container, or, if you're concerned about contaminating the water in the container, merely discard the water from the tube.

Trouble-shooting

Occasionally, especially with an earlier version of the squeeze bulb pump, the valve ball will become lodged in the valve and will not allow water through the bulb. This happened to me a few years ago. A call to the company resulted in their sending me a new pump, free of charge, which has worked fine since then. I found Flow-Rite to be very customer-oriented.
Web Site: www.flow-rite.com

Here's another solution: On-line sources provided only a full pump system (bulb/check vales/tubing) replacement for $$. Email requests to Flowrite for guidance/assistance went un-answered. A trip to Walmart's "marine" section provided the solution for $6 and change.

Attwood Primer Bulb (with installed check valves)
Universal - 3/8ths
PN 9362LP7
UPC 0 2269793628 8

Remove tubing from both ends of Pro-Fill bulb and place on the Attwood bulb paying attention to the water flow direction as marked on the new bulb.

The Attwood bulb appears to be of much stronger construction than the Pro-Fill.

Another problem may be the check-valve at the coupler end, which won't allow water to pass through to the batteries. A very simple fix is to wiggle the plunger in the middle of the coupler; this might be enough to free it up.

Contributors: WxToad, George, Mike Lewis

Revised 25 Jun 2013

Return to FAQ Index

Maintaining Coach Batteries

If you have your coach plugged in most of the time, the converter that LD installs will slowly boil the batteries. This causes the acid to vaporize and to come out of the vents at the top of the batteries, and corrode EVERYTHING that it contacts. Proper water level will help greatly, but to fix the source of the problem replace the converter. Do a search on this Group and you will find lots of info on converter replacement.

One tip that may be handy for some: In a few aircraft, there will be a vent line from the sealed battery compartment that is routed through a container of baking soda before exiting the ship. Most planes don't have this, so some will solve the problem by mixing as much baking soda as will stay dissolved or suspended in water. Then soak paper towels in the solution. Fold the wet towels into a thick strip of appropriate dimension that will lay on top of the battery vents. Microwave this strip until dry. Place on top of battery to neutralize any acid fumes. Replace baking soda towel every few years or on condition.
Periodically clean all battery connections.

Consider the use of the Pro-Fill battery watering system. It greatly simplifies maintaining the battery water level at the proper level.

Care of your battery when the coach is not is not in use is also very important. As noted above, the stock converter/charger used by Lazy Daze will "cook" your batteries over time if left plugged in while in storage. One solution is to plug your coach into a timer that allows the charger to come on only for an hour a day. Another is to use a multi-stage battery charger/ maintainer, such as the Battery Tender by Deltran. This is more than a simple trickle-charger.

From the horses mouth: The Trojan Battery User's Guide. Load it, Print it, Read it, File in a handy place.

Trouble-Shooting

Batteries charge only when engine is running:

You need to find out if the 120 Volts is getting to the converter. If you have AC power in the coach, and the breaker to the converter is not tripped, then most likely the converter has failed.

There is a "Main" breaker. Is there AC power to the rest of the coach. For instance, does the microwave have power (light in the timer window, door light when the door opens)? Does the refrigerator operate on AC or the air conditioning fan work?

If not, check the supply to the coach and the 30 amp breaker in the coach. Breakers themselves do occasionally go bad and need replacing. See if 120 Volts is making past the breaker.

You could have a loose connection. Any chance some of the wires need to be torqued down at the terminal strip?

If everything is OK but still no power, the generator automatic transfer switch (ATS) may have failed.

Contributors: bumper, WxToad, Linley Gumm, Alex Rutchka

Revised 6 Jun 11

Return to FAQ Index