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Old 02-13-2009, 07:07 AM   #1
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I understand that batteries should be given a equalizing charge periodically. The chassi batteries are of the sealed lead acid type and the house are the regular golf cart lead acid.
Should I turn off the chassi disconnect switch or will it make a difference? Or maybe I should forget the whole process? I don't need any more problems this trip.

05 Alpine 36MDDS, 09 Subaru Forester, no animals.
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Old 02-13-2009, 07:16 AM   #2
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Chassis batteries typically don't require equalizing. Coach batteries, on the other hand, do because of the deep cycle demands put upon them over time. Also, only flooded batteries should be equalized, not AGMs.

When you do equalize the coach batteries you need to be sure that everything that's connected to them is shut off. On many coaches the entire electrical system is not switched off whenthe disconnect switch is thrown. I'd do a quick walk-around and see if anything else is hot before performing the equalize procedure. You may need to disconnect something or pull a fuse or two temporarily. Better safe than sorry. The higher voltages present during equalization can damage the house electrical systems. Your chassis batteries are a separate system so it really won't matter if they are disconnected or not. Equalizing flooded deep cycle batteries can be beneficial and you may indeed recover some extra runtime if this procedure hasn't been done for a while.

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Old 02-13-2009, 07:21 AM   #3
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Notwithstanding all the issues with battery charging as of late--for the purposes of equalizing, the chassis and house bats are seperate entities. Depending on how much you dry-camp [number of deep recharge cycles] you should probably equalize your bats atleast 1-2 times a year. The equalizing process knocks the sulfides off the bat plates [wet cell] to improve bat efficiency/ extends their life. The Xantrex inverter has a default of 1 hour equalizing duration so you may have to re-initiate the process 1 or more times to completely equalize yr bat bank.
Higher DC voltage during the process could be an issue but there is no single switch that I know of to completely shut off all yr DC equipment. Also not sure whether simply turing off DC equipment means its isolated from the higher voltage. Ive equalized my bats with the Xantrex several times with no "apparent" impact on "turned-off" DC equipment.
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Old 02-13-2009, 08:08 AM   #4
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With modern batteries and a good charging and maintenance system, a full blown, honest to goodness, actual equalization process usually isn't necessary. IMHO of course (and I do know that them are fightin' words for some as I seem to stimulate the angry, gotta' fix the world, from other's opinions types).

An equalization does not "knock off" sulfides - nothing can do that (go see batteryuniversity.com for one source). Your best means of assuring battery longevity (which is shortened by sulfation) is to inhibit sulfation in the first place. That is done by full and proper charging coupled with a storage maintenance program that keeps the battery at top charge and keeps the electrolyte mixed. The only mechanism I have seen to date to recover sulfated batteries is the technique used by the BatteryMINDer(tm) or found in some build your own circuits.

The purpose of equalization is, as its name states, to equalize all of the cells in a battery bank. This does implicate sulfation but only in (IMHO) a minor way. If you charge the batteries properly and have them properly wired (see the smartgauge site) and maintain them properly, the equalizing will be handled as a matter of routine procedure.

Note that the term 'equalization charge' is somewhat misused in marketing. The PD+CW or WFCO converters use this term for a top charge and mixing technique that isn't really an equalization charge (although it does provide a somewhat equivalent long term effect. See the Trojan maintenance documentation for a description of the old time actual equalization process.

As Old Scout notes, a proper equalization charge uses voltages that are higher than that you normally want applied to RV appliances, even when you think they are turned off. That means you should not equalize batteries unless they are disconnected from everything except the charger.

Another consideration in this is that the RV use profile is a bit different from the alternative energy bank. Most of the battery advice you see is not really tailored to RV use and is aimed at solving problems different from that seen by most RV batteries.
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Old 02-13-2009, 09:04 AM   #5
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For Vansco sufferers (Alpines 2004 and later, maybe some late 03's), there are 3 battery voltage monitor inputs on the rear multiplex module (VMM). These 3 inputs don't have an LED "input" showing, but are active if the VMM is "on." When house batteries reach a certain level, the VMM sends 12V to the charging solenoid (the much vilified antagonist in many iRV2 threads regarding batteries & charging) and lights LED#19 Output on the rear VMM. This indicates that house & chassis battery banks are connected thru the solenoid and its fat red cables.

If you are equalizing, I'd check to see that #19 stays off. Easiest way to do that is switch off the chassis battery disconnect, which kills power to the VMM system while equalizing. Now the charger cannot attempt to equalize your chassis batteries. Remember to turn it back on after equalizing.
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Old 02-13-2009, 02:03 PM   #6
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Thanks to all!
If it wasn't so difficult to get the battery fill caps off, I would check them with a hydrometer.
Thanks again,
05 Alpine 36MDDS, 09 Subaru Forester, no animals.
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Old 04-14-2009, 08:40 PM   #7
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Cruser said it very well.
Old Scout the same and on both of my Alpines, the house and chassis switches did disconnect all that is important. The inverte/charger is never disconnected w/o taking off the cables and is obviously needed for the equalizing charge.
BryanL, If you always have your coach plugged in when you are not driving it, then I would say OK other than that I will have to beg to differ.
Mike, good note for Vansco owners.

Our 3 stage chargers are designed to help with the need for equalization. The problem is that many of you only have your AGS set to "Absorb off" which means that the gen shuts off after the bulk charge and you don't get the true advantage of having the 3 stages.

From AM Solar @ AM Solar - Batteries in reference to charging, gassing and equaliztion, "if you don't push the batteries to their gassing threshold, you will leave some of the sulfur behind on the plates. This sulfur will begin to form a sulfate crystal which will eventually grow to cover a substantial part of the lead plate. Once this happens, that part of the plate can no longer interact with the electrolyte solution and the capacity of your battery diminishes. You will know your batteries are sulfated when you find that they don't last as long as they used to before they need recharging. An equalization charge can drive some of this sulfate crystal back into solution if it hasn't hardened into a rock like crystal yet.
An equalization charge is a planned overcharge. As discussed above, overcharging (equalizing) a battery is not good but then neither is allowing sulphate crystals to grow. Equalization, however, is a lessor evil than sulfation. Pushing the batteries up to 15 to 15.5 volts for 3 to 6 hours occasionally (once when you put your RV into storage and once when you take it out) will help knock loose hard rock sulfation and allow weaker cells to come up to a full charge. If you recognize that you will have to replace the water that 'boiled' off during this planned overcharge, you can extend the life of previously sulfated batteries.
Another method that works satisfactorily is to allow a once-daily climb to between 14.5 and 15 volts for a short duration (half of an hour). This has proven to eliminate the need for true, long duration equalization charges. This short duration, daily "equalization" also keeps the battery from losing excess water and overheating, both of which are potentially harmful to your battery."
The last paragraph refers to the likes of the absorption stage of our charge.

From Xantrex application note @ http://www.xantrex.com/web/id/257/DocServe.aspx
An equalizing charge is a controlled overcharge cycle that performs several actions within the battery and provides certain benefits. During equalization, the voltage is raised to approximately 2.7 volts per cell, or about 16.2 volts for a 12-volt battery. The current output of the charger should be limited to about 5% of the battery's capacity. In other words, a 200-amp hour battery should be allowed to accept no more than about 10 amps of current. This will help prevent overheating. The equalize cycle is timed to be between 4 and 8 hours depending on the features of the charging source, but the cycle can always be terminated early if necessary. The particular battery manufacturer's recommendations for equalization time should be followed. This elevated voltage results in a vigorous charging action to take place within each cell that has several effects on the battery. First, much of the residual sulfate is forced to re-combine with the electrolyte in the form of sulfuric acid. Crystallized sulfate that will not re-combine is broken loose from the plates and falls harmlessly to the bottom of the battery. Deep cycle batteries have additional space beneath the plates intended to collect this material. This action cleans the plates exposing fresh lead to the electrolyte and restores battery capacity."

Good information about deep cycle batteries.
Deep Cycle Battery FAQ

While trying to fine tune my battery monitor, I used a hydrometer and found that my batteries were far from fully charged, even after a full 3 stage charge. This is after I had done many charges that went thru a majority of the absorption charge. I did about 4-5 one hour equalizing charges and brought them up to almost full charge. I am still looking into how to get the AGS to shut off after doing most of the absorb cycle, but not all. The full absorb charge takes too long and wastes fuel.
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Old 04-14-2009, 11:16 PM   #8
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To terminate the genset charging prior to achieving float level (absorb cutoff), you could:

Set the Stop BattV trigger lower, or

Set the Maximum Run Time to the point at which your battery normally achieves the charge you want. It'd take some trial and error to achieve the right number of minutes and that, too, would need to increase as the batteries deteriorate.

Just a couple ideas.
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Old 04-15-2009, 08:55 AM   #9
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I did try the stop battV, but found the voltage the charger was going to during absorb varying. The max run time was my next move, but I am concerned about how much the bulk portion might vary, which will affect the amount of absorb it gets. I will play with it next time I get to dry camp.
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Old 04-15-2009, 11:08 AM   #10
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FWIW, our batteries are about 4 years old. We full-time w/a some dry-camping, have never equalized and they are still working fine w/minimal decrease in charge hold time but they still last throughout a normal quiet time (11 p.m. - 7 a.m.). We do have the residential frig as well.

I ensure the leads are kept clean and the batteries kept full of water. I check this at least monthly or more frequently when we're dry camping.

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