RE: Batteries
Your available energy capacity will depend mostly upon the weight of the batteries, not the brand or voltage.
Trojan batteries last no longer than any other if properly managed and used. (see Az WindSun FAQ). It is the proper management and use of the batteries that makes the difference, not the trade name.
The trade-offs you will find in any particular manufacturer's line are primarily on cost, capacity, and 'ruggedness' and the variances aren't really all that much for any batteries you can find for RV service.
RE: 12 volt confusion
Battery storage is indeed a problem with many converters.
For best life, your storage plan needs to both insure a top charge and inhibit sulfation.
The least expensive thing to do would be to disconnect the batteries from your converter and use a BatteryMinder to keep it in good shape when on grid. That device has a desulfation technique that is supposed to work well.
The Power Dynamic Charge Wizard or WFCO converters both use a periodic bump to bulk charge voltage for a few minutes every now and then to assure top charge and keep the electrolyte stirred (which inhibits sulfation).
A trickle charger can keep a top charge but you need to be careful it doesn't 'trickle' sufficient current to cause water loss. Since it doesn't do any charge bumping or similar things, it doesn't help inhibit sulfation.
Sulfation is the buildup of lead sulfate crystals and is the primary cause of battery aging. It will happen and your goal is to slow it down through proper exercise and diet ;=)
RE: What's the difference in 12-v monitors?
Voltage is probably the easiest and most convenient way to determine the state of charge of your battery if appropriately measured and interpreted. For instance, measure the voltage after the battery has been quiet (no significant loads or charging) for a half hour. Don't worry until the voltage gets down to 12.4v, start thinking charging (as noted above) when it gets down to 12.2v and put charging as a priority if it starts getting towards 12.0v.
Electron counters, like many of the $200 battery monitors are fun but need to be set with the proper numbers. Modern ones are beginning to account for such things as Peukert compensation but they still miss on aging and the inherent variations in battery capacity from cycle to cycle. (i.e. the precision of the measure is misleading about the accuracy they measure)
Then you have monitors like the smartgauge that determine battery state of charge by observing battery behavior. This is much like the old timers who noted their battery status by watching how the light dimmed when the furnace or water pump came on.
Do keep in mind that state of charge is not the same as state of health. You have to do a load or conductance test to get a state of health measure.
RE: What is hiway 395 like in Nov-Dec
When traveling in western mountains, especially the Sierras and Cascades, your best bet is to not be in a hurry. Most of the time, a storm will bolix things up for only a day or two and if you can sit it out and stay warm, you can have good roads to travel.
RE: Yep...Another Battery Question
Your usable battery capacity will be about 10 watt hours per pound. It don't matter the voltage of the components of the bank! 12v as good as 6v. The battery trade-offs are cost, durability, and capacity and the differences in a line, say between a Trojan T105 vs T145 or SCS200 vs SCS220, really won't be significant due to all the other things that influence your battery.
AGM batteries are very nice, especially for high current needs, but don't provide a life expectancy matching the price premium.
There is good reason to run your batteries together in a bank rather than isolated one at a time. See the smartgauge web site for some good explanation of why.
See Basic battery guidelines for some rules of thumb and links to where they came from.
RE: What is hiway 395 like in Nov-Dec
Be prepared. But the odds don't get significant until after Thanksgiving. January and February provide the highest risk of weather related road problems.
RE: How do I figure out power consumption and battery life?
The only solid way to figure out battery consumption is by trial and error.
If you get into loads such as a furnace, you start to deal with its duty cycle and that can vary by 5:1 or more over the range of temperatures normally encountered by most folks in casual camping.
What causes people problems with the 'not enough battery syndrome' are constant loads that run more than the 20 hour rate (5 amps for a typical 100 AH battery). For instance, watching one DVD movie will take just about as much energy as you'd want to take from a typical 60# battery before giving it a charge. If the weather is sub freezing and you like it warm in your RV, then one night will also take about one standard battery's worth of energy. And, if your batteries are outside, then you can reduce that by quite a bit.
You just need to go camping and see what works. Adjust between your lifestyle and your battery bank size so you can have a good time in your RV outings.
RE: Depth of battery Discharge, and battery break-in
oh boy, I just love the augmentative nitpicking these things get into (pse pardon the sarcasm). Now it turns out that "quiet period" and "100% full" are being defined for me - despite what I said - it seems only in order to pick nits. Does that really help?
The battery voltage reads 12.8V. This , of course is incorrect.
If you measured the voltage then it is most likely correct unless your meter is broken. What is incorrect is how the measure is interpreted.
As I said, what you are looking for when you are out using your RV is a voltage below about 12.4v down to about 12.0v after a half hour or so when you haven't been working your battery. As I also said, looking for an excess of accuracy is a fool's errand. Whether your battery is at 75% or 80% DoD is irrelevant to the question about how urgent the need for a charge may be.
Note also that there is a difference between measuring state of charge and answering the questions an RV faces when using his battery. My focus is on the latter.
As with any measure, it is the _interpretation_ of the measure that counts. Even if you used a device to actually measure SoC it won't help you much until you interpret that measure in the context of your energy use patterns, battery bank size and type, battery age, and other matters.
For those who are not willing to use a modicum of common sense in interpreting battery behavior (or in trying to understand messages in these discussions), check out the smartgauge web site. That device has the 'smarts' built in so you don't need any. Better yet, the technical information has some easy to read information about how the device interprets its observations of battery behavior to provide its conclusions.
What I suggest may be "unwise" (I'd rather see differences of opinion rather than judgments) but it works and it is easy, in my experience, to teach the concepts to others so they can be more effective in their battery management in their RV.
RE: Depth of battery Discharge, and battery break-in
One of most misunderstood task is how to measure battery voltage. Battery surface charge can easily fool one into believing the battery is full when it's not. Surface charge will accumulate (even with a near dead battery) and give the wrong message.
and near everything else battery! - what I see is folks trying to re-establish laboratory conditions and then failing to consider the underlying accuracy of the measures. Very precise but not very accurate because batteries can vary by 20% or more from cycle to cycle and also by a large number of variables.
For most of us, we want to get an idea about our battery when we are in the field. That means the battery is in use and the question is whether we'll have heat in the morning with the furnace or to plan a charging session. The easiest way to gain this information is by a proper interpretation of the battery behavior. That is why the 'quiet period' voltage check is suggested as it is something easy to do, simple, and will usually yield sufficient information for an effective decision.
re the posted chart: it is missing so much necessary data as to be nothing more than an indication of the shape of the curve. (see batteryuniversity.com for a similar result with better provenance). My query was about a specific battery and how we could apply a specification to RV needs. I think there is a reason why you do not find life cycle ratings on commonly available spec sheets but that reason is not explicit. Instead you have to infer from warranties and comparison, for instance, of automotive SLI, RV, and commercial application warranties.
IMO what shortens the life more than hard usage is not getting back to 100% periodically or letting the battery run down while in storage.
I'd only add electrolyte stratification when in storage. That is why the PD+CW or WFCO converters or the Battery Minder Plus can be so effective in prolonging battery life.
The title subject of "battery break in" has not been beat to a pulp yet. That's a curious one as I have seen several comments from reputable sources that you need to cycle a battery a few times before you can realize its full potential. I haven't seen any measure of what this difference is or why it would be so - yet, still looking.
RE: Depth of battery Discharge, and battery break-in
I'd like a reference to that chart that says 80% DOD with 500 cycles - that is at the extreme edge, I think. The definition of 'cycle' is rather 'pure' in these specs so they can't be easily applied to typical RV service. Also note that very few RVers are going to cycle a battery more than a 100 times or so in the expected 5 year life of a typical lead acid battery.
Usually there are quiet periods in your power cycle when the battery isn't charging from the sun or other source and you aren't running any significant loads. If you measure the voltage after a half hour or so of a quiet period, you can get a very good measure of the current charge status of your battery bank. I'd suggest the 50% DoD to be your target or keeping the battery bank above 12.0v after a half hour or so of quiet.
If you never run your batteries below about 12.4 volts then you have too much battery and they don't get exercised properly. If you find them below 12.0v a lot then it is likely you don't have enough battery.
Perhaps the biggest drain on the life of a battery bank is not getting them fully charged. Serious full-timers often handle this by using a genset in the morning to get the bank up to absorption levels then a solar system to finish the charging during the day. For the weekenders, the primary battery killer is storage - batteries need a good maintainer and charger on them when not in use to keep the charge up and sulfation down.
RE: tires
The first step would be to get reliable data on RV tire failures, their frequency and factors related to potential failure causes such as loading, type, inflation pressure, history, and so on.
I think that one of the problems is that there are very many RV's compared to, say, antique cars and these RV's often cycle between long periods of sitting and medium periods of hard use. - but we won't know for sure until we get good data.
What I see is an awful lot of RV's that run around with ancient tires, underinflated tires, and tires not rated for the load they are carrying or the speeds at which they are used. From that I am rather amazed that there aren't more tire problems than what I actually see.
I also note a conflict between the perceived tire failure rate and basic business practice. The liabilities involved in tire failure even from basic warranty much less incidental damage do not seem to be an inhibiting factor in tire availability or options. If indeed RV tires were as much of a problem as it sometimes seems, their price would go up and their availability (and warranties) down, especially compared to other similar tires. That doesn't seem to be the case.
RE: More Arizona speed camera's
It is interesting that this is in Az which has one of the best rundowns on speed limits at its DOT site.
I also see we have a number of folks who 'drank the kool-aid' on the 'speed kills' and related myths - to the point of proselytizing their beliefs.
The fundamental principle guiding the federal manual for uniform traffic control devices (MUTCD), which states follow in order to be eligible for federal funds, is that most folks drive safely and the laws of the road should recognize and respect this fact.
Blind adherence to traffic laws such as promoted by automated enforcement means that conditions, circumstances, and individual judgment are ignored. That means that these cameras tend to promote poorer safety practices. This has actually be demostrated in studies. That doesn't stop the effort to use them though, and it is indeed cash flow for the government that seems to be the primary stimulus. That leads towards a cynical public distrustful of traffic enforcement and that is perhaps the real tragedy.
RE: does everyone want an Airstream?
Interesting 'tone' here. It didn't take long to hit the limited storage and low clearance canards, either.
When I compare a 29' Airstream to a 24' Holiday Rambler I find the Airstream has less trouble with gutters and tail dragging.
Interior storage is surprising to those who actually depend upon it. That rounded off corners thing isn't where it's at. I know many full timers who find their Airstreams have plenty of storage space for their needs. Those who need more space usually end up as Class A folks so they can take 5 tons rather than 1.
It is also interesting to see headroom mentioned as the shape of an Airstream often means a bit better headroom for tall folks than in other brands.
And also to hear about all the leaks and rot and such as that just isn't the case. Look at just how many older Airstreams are on the road (more than 60% of all sold if I recall correctly) and reconcile that with the claims about leaks and repairs and so forth. The fact is that Airstream repair is often more likely to be cost effective than in the repair of other brands.
The insulation thing is an inherent problem in RV's. Most, including Airstream, just have inch and half walls and that is not much. In severe temperature conditions you will always need to take additional measures (such as window insulation and skirting and even shading) to be comfortable.
I don't think everyone wants an Airstream - thank goodness for individual preferences and opinions! But I also don't think we need to spout myths trying to rationalize our own choices nor denigrate the choices of others.
RE: 2-12s vs 2-6's
You'll get about 10 watt hours usable energy per pound of battery for your RV no matter voltage or whatever.
The trade-offs are cost, longevity, and capacity. Manufacturers provide a line that express these trade-offs. See, for instance, the Trojan SCS200 vs SCS220 or the T105 vs T145.
Forget the arguments about 'true deep cycle' and other similar labels. They do not match anything you are going to find on a spec sheet and do not have objective definitions of any utility in RV applications.
Your battery life is going to reflect your use and maintenance. Other factors are minor in comparison.
RE: Batteries
The Smartgauge site has a good rundown on this at Splitting battery banks.
It is generally better to keep batteries together in one bank unless you have a good reason to keep them separate, such as for house and engine batteries.
RE: Advantage of Battery Banks
The available capacity will be about 10 watt hours per pound of battery no matter 6v or 12v or whatever.
The trade-offs are cost, longevity, and capacity. Voltage of the battery is a misplaced concern for these issues. All manufacturers have several models at each voltage that express this trade-off.
If you run significant loads, a parallel bank can be an advantage - think about why many diesel pickups have parallel 12v starting batteries. A significant load is one higher than the 20 hour rate used for most common AH ratings. Both Peukert effects and impedance effects tend to make a difference then.
The 'deep cycle' or 'marine' designations don't mean much as their is no reliable specification to define them.
Longevity or cycles is not really an issue in RV service. How long your batteries will last is going to depend more upon proper use and storage management.
RE: Who else has learned the hard way?
i'm constantly amazed at the number of people willing to risk their family by pulling a trailer with a minivan or small SUV.
that is because they don't!
There is no inherent safety risk that is caused by towing a medium sized trailer with a minivan or small SUV.
As noted, the biggest problem is uncomfortable handling. That tends to slow people down and, in effect, makes them safer drivers. i.e. less risk, not more.
There are many ways to improve handing of a trailer rig besides excessive tow vehicle. What you cannot improve is performance and that is what often drives folks to upgrade their tow vehicle, not safety.
RE: 77 Airstream 27 FT.
see price vs condition for some ideas about how to judge the value of older Airstreams.
As Ivylog noted, floor rot is perhaps the biggest issue to check for.
An older Airstream can be a very cost effective trailer.
RE: How to measure power usage??
There are things like the EML which will handle up to 60 watts. (the site has a bunch of interesting stuff as it is a power meter store!)
I have also seen one discussed on these forums that is a surge protector that provides measures similar to the Kill-a-watt but I can't find a link to it.
RE: New to RV'ing/Looking at airstreams
interesting the comments about Airstream pricing - if you want to gasp about prices, go look at decent class-A RV's.
Unless you have a lot of experience with small travel trailers of any type or do not plan to spend a lot of time with your RV, the under 20' idea needs a lot of thought. Towing a 30' isn't really that much different than towing a 20' and the livability is much much better. There is a big jump when you get to a design that has beds that are dedicated to purpose and don't have to serve as sofas during the day (this usually means 24' or larger).
