I need educated about my inverter/charger

[Jack Mayer]

 

I went back and re-read a couple charger manuals and I think I did get the last bit wrong, from what I see in current charging systems they either use a timer of some sort or monitor the amps for the absorption / float transition, not the voltage.

Right Stan. They now generally time out on the absorption stage. One thing to watch for in considering different chargers is the ability to set that absorption time. Some will time out before a full charge can occur. In other words the timer expires BEFORE the current flow reduce to the appropriate level.Others allow a longer charge by default, etc.

 

The battery voltage on wet cells to trigger absorption should be 14.8 if your charger will do that. Most experts that have done testing on batteries recommend that as the setpoint. MANY chargers do not come set that way, but can be increased. Trojan was the first battery manuf. to recommend 14.8 (to my knowledge), but many others have done so. The experience of the off-grid battery guys is that 14.8 is correct for all wet cells and will provide the best charge and battery life. UNLESS there is a special circumstance that requires differently. There are some weird batteries out there in use off-grid....they may be the exception.

 

Note that some charging systems now do not float continuously. They will float - then STOP - and only start a float again if they detect a load or other trigger event. Then they will float again using various algorithms. I consider this a superior charge profile.

[oldjohnt]

Yo Stanley and Jack, gotta love this sparky chat even if were boring all the rest.

 

Regarding the transition between Absorption and Float you gentlemen are discussing, here's what I found at least one charger manufacturer had to say:

 

"The transition from absorption charge mode to the next stage is determined either by a timer, or by the charger sensing the value of charge current and then switching over when the charge current drops below a certain threshold. For example, the Battery Tender? Plus (part of a different product line) switches out of absorption mode when the charge current falls below 100 milliamps (or 0.1 amp) or when the absorption mode has lasted for 8 hours. With properly set timers or charge current switch thresholds, the battery should be charged to more than 95% at the end of absorption mode. Ideally it would be at 100%, but there are some practical limitations that usually prevent full recharge."

 

NOTICE TO ALL: Im not saying the above is good or bad, I'm not defending nor recommending it, it's their words NOT mine, I'm ONLY the messenger, do with the information as you please........................

 

Looks like different manufacturers have slightly different theories and charging algorithms, plus of course, the cost comes into play. I prefer a full 100% charge myself. I've had such good results with Xantrex and Progressive Dynamics I see no reason to run out and spend big bucks at the present time. My friend has the same Xantrex I own and his six deep cycle golf cart batteries lasted over 8 years which is certainly reasonable.

 

Best wishes to all and God Bless and safe travels.

 

John T

[Yarome]

The experience of the off-grid battery guys is that 14.8 is correct for all wet cells and will provide the best charge and battery life.

 

Agreed.

 

You guys are fun to read.

 

Now that you've got all that settled.. let's talk about shunts and temp compensation!! Ready... GO!!

[oldjohnt]

Yarome,

 

Here's some good reading regarding Temperature Compensated Charging by Xantrex, looks like a good start at least, and not too technical I didn't think and a PDF file for easy addition to your digital library.

 

http://www.tekrispower.com/pdfs/xantrex/Batteries%20-%20Temperature%20Compensated%20Charging.pdf

 

 

John T

[Yarome]

Yarome,

 

Here's some good reading regarding Temperature Compensated Charging by Xantrex,

 

John,

 

I'm got all my ducks in the pond in that regard. Just you folks were getting a little deeper into the mechanics of the charge algorithms and thought I would "stir the pot". Makes for good sparky talk when what you 'set' may not actually be what you 'get' at the terminals without a properly shunted and temp compensated charge profile. Adjustments may need to be made to the blanket 14.8v and subsequent settings.

 

Might as well get it all out there.

[Randyretired]

I prefer to float sealed batteries at 13.2 volts. Higher voltages seem to shorten battery life significantly. I also float the wet cells at 13.4 volts. Higher float voltages cause the batteries to need water more often. I also charge the wet cells at 14.8 volts and if the batteries are just resting at float it helps to reinitiate a charge at least once a week to stir things up.

[oldjohnt]

Yarome,

 

The more I dig the more DIFFERENCES I see concerning charging voltages. Trojan talks about 14.8 volts,,,,,,,,,,,,,,,,,,, the Rolls Surrette Website talks about 14 to 14.2 volts,,,,,,,,,,,,,,,,,,,,,Some share the opinion to use 14.8 volts,,,,,,,,,,,,,,,,,,,,Many so called Smart Chargers (120 VAC or Solar) use a BULK rate of 14.2 to 14.4 (perhaps they can be adjusted up???).

 

As you brought up TEMPERATURE AFFECTS THAT ALSO.

 

Same as Rif and I discussed above, different manufacturers of so called 3 or 4 Stage Smart Chargers use different charging algorithms, different voltages, different say timed versus current measurement to switch from Absorption to Float, different float voltages (Ive seen 13.2 up to 13.6 or even more).

 

BUT THEY ALL CLAIM TO BE BEST IF YOU LOOK AT THEIR LITERATURE LOL

 

Wouldn't it be a boring world if we all had the same opinions though or only one choice of a battery charger????? I say to each their own, its their RV, their money and their choice. I like my Xantrex and Progressive Dynamics, others like their Magnum on and on and on among so many different brands and choices out there.

 

Best wishes God Bless all

 

John T

[Rif]

Well John, I agree that we are going to bore people if we continue this discussion about how a quality 3 stage charger functions much longer. Still, I think it’s important that folks be given accurate information about how things work so they can troubleshoot problems accurately. You presented your BOTTOM LINE, and now I will present mine. Beyond that, we can just agree to disagree.

 

Here’s the statement you made that I disagree with:

 

“THATS WHY all the so called "Smart" 3 or 4 Stage Chargers start out at an initial BULK CHARGE voltage of 14+ BEFORE they slow down to the ABSORPTION CHARGE in the 13.6 + or - volt range. The Initial higher voltage BULK CHARGE first brings the battery up to a certain state of charge before it backs off to the lower ABSORPTION and FLOAT charging voltages. A Smart Charger does NOT sit there INDEFINITELY on and on and on (subject to load and battery and and charge state) at 14+ volts once a certain state of charge is achieved. They utilize 3 or 4 stages.”

 

1) My disagreement is with your assertion that the voltage drops down to 13.6 during the absorb stage in a 3 stage charger. (Sometimes the words “Saturation” or “Acceptance” are used in place of “Absorb”) In spite of your assertions to the contrary, none of the sources you cited in your response support that statement. The first two sources agree that 3 stage chargers have Bulk, Absorb, and Float stages, but neither of them say that the voltage is reduced to 13.6 (or anything other number) during the Absorb stage. They both say that the current is reduced and the voltage is held steady. And, neither of those sources are battery or charger manufacturers, although you implied that they were.

 

2) Let me point out again, the third citation does not support your statement either. The PD with Charge Wizzard is not a 3 stage charger. I cannot find anywhere in their literature where they claim that it is. They call it a 3 MODE charger. This is not just a matter of semantics. It functions in 3 different modes. It does not function like a true 3 stage charger does. They never use the words BULK, ABSORB, or FLOAT, or do they themselves call it a 3 stage charger.

 

3) I have no idea why you quoted from Trojan’s website. Nothing contradicts anything I have said.

 

4) I have already quoted from Magnum (one of the most respected 4 stage charger manufacturers) twice, so I will not do it again. Instead, this time I will quote from Xantrex, another highly respected manufacturer of 4 stage chargers, and the company that made of your chargers. If you can find any manufacturer of quality 3 or 4 stage chargers whose charging profile drops the voltage during the Absorb stage, please point me to it.

 

The Inside Scoop on Battery Chargers

 

“Why is my battery not charging?” is a common question that plagues many. Unfortunately, there is no clear cut, one-stop shop on answers as the reason varies widely. Many folks simply don’t understand how batteries work, not to mention the broader scope of battery technology, chargers and electricity.

 

So … how exactly does a charger work?

There are many different types of chargers with different technologies, algorithms, sizes and options, but the bottom line is that a charger works because its voltage is higher than the battery voltage which causes current to flow to the battery. In most simplistic terms, the voltage differential causes current to flow from the source (charger) to the load (battery). However, I’m the first to admit that the devil is in the details. For instance, while a lead-acid 12-volt battery needs exposure to at least 14 volts in order to fully charge, if the voltage is higher it will cause it to gas out, drying the cells which will, eventually, cause damage.

 

What is multi-stage charging?

In the above example, the 14-volt threshold is not only critical, but also potentially dangerous. So, the term multi-stage charging means that the voltage differential changes throughout the charging cycle. We’ll use the typical 12-volt liquid lead acid battery as an example. The first charge stage would be the BULK stage which gets as much current into the battery as fast as possible without damage. The charger will attempt to discharge 14.4 volts at its maximum current in order to achieve the charge. Anything higher can cause heat build-up; lower will slow the charge rate. With this in mind, once the voltage differential equalizes (battery voltage meets the charger voltage, approximately 85% charged), we enter the absorption stage. In the absorption stage, the charger maintains the 14.4 volts, but the current will slowly drop as the battery increases in resistance (caused by an increase in charge level). Absorption stage will top off the battery state of charge. Once the battery is “full”, the charger will drop its voltage to 13.4 and transition to the float stage. The float voltage level is high enough to keep the battery “full”, even if DC loads are turned on, but low enough to prevent persistent gassing of the battery which can cause long term damage.

 

Source: http://www.xantrex.com/documents/tech-doctor/universal/tech7-universal_v2.pdf

 

That’s about as clear and easy to understand as it gets. The voltage does not drop during the Absorb Stage. This is my last word on the subject unless someone has a question for me.

 

I realize that this post is getting too long, but there is another point I wanted to mention and comment on. It has nothing to do with our previous discussion. That is the appropriate voltage for the Bulk/Absorb and Float stages. We’ve been tossing around 14+, 14.4 and 14.8, as well as 13.2, 13.4 and 13.6. As Jack has eloquently and succinctly stated, 14.8 is now the commonly accepted optimum voltage for the Bulk/Absorb stage when charging flooded lead acid batteries. The commonly accepted voltage for Float is between 13.2 and 13.4.

 

The reason you see many charger manufacturers still offering only 14.4 for the Bulk/Absorb stages is that 14.4 used to be the generally accepted voltage. One big reason why is that 14.8 could be too high a voltage unless temperature compensation is used, and many chargers still don’t have that capability. On a very hot day, charging at 14.8 could damage the battery. 14.4 would be safe at any normal temperature. Here is a good, athough technical, explanation from Battery University:

 

High-temperature Charge

Heat is the worst enemy of most batteries, including lead acid. Adding temperature compensation on a lead acid charger to adjust for temperature variations prolongs battery life by up to 15 percent. The recommended compensation is 3mV per cell per degree Celsius applied on a negative coefficient, meaning that the voltage threshold drops as the temperature increases. For example, if the continued float voltage were set to 2.30V/cell at 25°C (77°F), the recommended setting would be 2.27V/cell at 35°C (95°F) and 2.33V/cell at 15°C (59°F). This represents a 30mV correction per cell per 10°C (18°F). Table 2 indicates the optimal peak voltage at various temperatures when charging lead acid batteries. The table also includes the recommended float voltage while in standby mode.

 

http://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures

[Yarome]

You two DO realize that you are saying the EXACT same thing.. right? In the absorption phase the voltage stays constant while the current is reduced. How do you adjust the absorption current within the charging profile in most 3 and 4 stage "smart chargers"? You adjust the 'voltage' setting in the chargers program.

 

When talking 3 stage charging within a user friendly interface, it simplifies things to be talking bulk 'voltage' - absorption 'voltage' - float 'voltage' as opposed to bulk 'voltage' - absorption 'current' - float 'voltage' & 'current'. The magic happens within the programming... not necessarily what you see in the chargers UI. I've never seen a 'current' setting when trying to adjust absorption rates on any newer charger/controller I've ever worked with. That's exactly what you're doing.. adjusting the rate of current.. but what weekend RV'r would know that? Or really care for that matter.

[Ray,IN]

I'm learning, thank guys. Today the battery charger readout was 13.6V, charge rate 0A. This garage sale is whupping my butt, will not be able to phone Xantrex until Tuesday. Stan thank you for the explanation,it will help when I finally get to phone Xantrex.

[Rif]

You two DO realize that you are saying the EXACT same thing.. right? In the absorption phase the voltage stays constant while the current is reduced.

 

 

We are not saying the same thing. John's post that started this discussion said that in the absorption phase, the voltage is reduced. You and I agree that the voltage is not reduced, but the current is.

[Yarome]

 

We are not saying the same thing. John's post that started this discussion said that in the absorption phase, the voltage is reduced. You and I agree that the voltage is not reduced, but the current is.

 

Yes and no. You're right that the current is reduced... he's right that in order to reduce the current, you have to reduce the voltage value in the chargers user interface. Technically, John's not reducing the voltage, but that is how the chargers program interprets how much to reduce the current.

 

If YOU want to manually enter a custom current rate for your absorption phase, you would have to use your chargers user menu, go to the absorption setting and reduce... (wait for it).. the 'voltage' value.

 

Does that make the water muddy enough? It just depends on which side of the coin you're looking at. It's much more complex just changing a single value.. even in your bulk charge you might have it set to 14.8, but if you have a temp sensor connected, it might actually be running at 17v.. or.. 12v.. with varying current rates. Same difference... just trying to keep it simple for the end user and letting the magic happen behind the scenes. Like WINDOWS!!

[skp51443]

If the charger puts out a constant voltage and the battery's internal voltage rises due to the state of charge the current flow will drop as there is less voltage difference to drive the charging chemical reaction.

 

Measuring just the battery or charger voltage is not a simple thing since they are tied together, all you can see is the voltage of the system as a whole.

[Rif]

Absolutely Stan. Thanks for pointing that out.

 

Yes Yarome, you're really muddying the waters now.

 

At no time in this discussion did anyone say anything about reducing the voltage value in the in the chargers user interface, or adjusting any other configuration settings. The issue is also not about how the charger goes about adjusting voltage or current internally. The issue is strictly about what happens to the voltage (as measured at the battery or output of the charger) when a charger transitions from the bulk stage to the absorb stage during a charging cycle. As you and I agree, the voltage is held constant, and the current is reduced. The voltage (as measured at the battery or the output of the charger) is not reduced during the Absorb stage.

[Yarome]

At no time in this discussion did anyone say anything about reducing the voltage value in the in the chargers user interface, or adjusting any other configuration settings. The issue is also not about how the charger goes about adjusting voltage or current internally.

 

Rif, therein lies the rub. I could certainly be wrong, but my impression was that the OP was asking for help to understand and adjust the voltage settings during the various charging phases. That was 'exactly' what they were talking about all the way through post #18 or so, from my read on it... and some here and there since. Until, that is, the discussion was brought up arguing the distinction between charger voltage settings vs current when in absorption mode.

 

It's good information.. and interesting as all get out.. to know what's going on behind the scenes, but it's not really germane to the OP in deciding what charge rates he should use for his battery bank.

 

I could have misunderstood so I'll step out of it.

[oldjohnt]

WOOOOOOOOOOO HOOOOOOOOOOOOOO this has been respectful, fun, friendly and informative in my opinion for us sparkies SORRY WERE BORING THE OTHERS LOL

 

We may have to all agree to disagree but its all with due respect I say we can ALL STILL BE CORRECT. Its depends on which manufacturers information you want to cite. The good Rif man cited info for how Magnum charges,,,,,,,,,I cited equally good info about how Progressive Dynamic charges. I agree he is correct concerning Magnum and I cited equally valid info about how PD charges (its the stages and voltage levels from their literature NOT mine). I MAINTAIN WE ARE BOTH RIGHT (with respect to which charger) AND NEITHER IS INCORRECT. Magnum may use one algorithm and voltage for different stages of charging while PD may use another. I cited basically what PD uses, while Rif cited basically how Magnum does it.

 

 

NOW YOU CAN MAKE YOUR OWN CHOICE AS TO WHICH MANUFACTURER TO BELIEVE OR USE WHICH CHARGING METHOD AND VOLTAGES ARE BEST. I own Xantrex and PD and like both of them, others may own Magnum and like them. No way Id argue for anyone to use a different brand with different voltage charge levels and charging algorithms ITS THEIR FREE CHOICE!!!!!!!!!!!! (there may also be budget constraints)

 

 

HERES WHAT PROGRESSIVE DYNAMICS SAYS,,,,,,,,,,,IT THEIR WORDS NOT MINE AND PRETTY MUCH THE VOLTAGES ANS STAGES I ORIGINALLY POSTED.

 

 

3) Progressive Dynamics Four Stage Smart Charger

 

“Our patented Charge Wizard…….constantly monitors battery voltage and battery usage then selects one of the following four operating modes to properly charge and maintain the battery.”

BOOST Mode 14.4 Volts - Rapidly brings the RV battery up to 90% of full charge.

NORMAL Mode 13.6 Volts - Safely completes the charge.

STORAGE Mode 13.2 Volts - Maintains charge with minimal gassing or water loss.

EQUALIZATION Mode 14.4 Volts - Every 21 hours for a period of 15 minutes prevents battery stratification & sulfation - the leading cause of battery failure.

 

 

Its true different manufacturers use different charging algorithms and different voltages, I correctly quoted how PD does it and Rif quoted how Magnum does it. Yall can argue which is best, Im ONLY basically arguing what I posted was one method at least one manufacturer claims and I was CORRECT in citing how they do it. Whether their voltages and method is best I WILL LET YALL ARGUE THAT ONE LOL

 

Best wishes and God Bless all here, yall are free to use what charger with what charging voltage levels and charging methods you please. Just because PD and others do it one way and Magnum or others do it different does not mean many different brands cant still properly charge even if their voltages, stages, and timing may vary. Pay your money and make your own choices DO YOUR OWN HOMEWORK AND RESEARCH AND BUY WHICHEVER WORKS FOR YOU NOTTTTTTTTTTTTTTTTT because different people here use different methods or products

 

Yo Rif, heyyyyyyyyyyyy now you're winning the battle of most words, you're more windy them me lol. God bless you for all the help you provide and I hope I have also helped others, but this is an awful deep, muddy and technical issue grrrrrrrrrrrrrrrr and we may have confused more then educated????.

 

PS this may not be the place for this bust just as I was posting this I got word a dear old farmer neighbor and friend just passed. We went to visit last night at nursing home, they told us he was just sent to hospital. We were going to hospital this AM but just got the call he passed. MORAL OF THE STORY if you have anyone near DONT PUT OFF VISITING, we were a day late...........

 

John T still counting the days before we head WEST

[Jack Mayer]

I prefer to float sealed batteries at 13.2 volts. Higher voltages seem to shorten battery life significantly. I also float the wet cells at 13.4 volts. Higher float voltages cause the batteries to need water more often. I also charge the wet cells at 14.8 volts and if the batteries are just resting at float it helps to reinitiate a charge at least once a week to stir things up.

Randy, that is exactly what I recommend as well....unless there are circumstances to vary those numbers. As John points out, there are various recommendations by equipment builders. Some of those have been the same for 20 years...with no variation for modern chargers or more current experience/information. In fact I have seen charge algorithms in some equipment that was clearly not only not optimal, but actually would shorten battery life. People will argue that "the manufacturer must know"....but in the off grid industry that has proven not to be the case many times. I don't want to debate that issue - it is simply a waste of time. But one does need to understand at least the basics of good charging algorithms to prolong battery life. However, I would say that the extra life you get from the "standard" algorithm vs. a "tuned" algorithm is probably only a year or two.

[Rif]

I do apologize to Ray for the sidetrack, but I felt it was important.

 

Back to the original issue. I think Stan gave you very good advice. To recap what he said and add my own two cents :

 

Your batteries are not sealed. They are actually Marine dual purpose batteries. In fact, the manual says

 

All Exide marine batteries, except AGM types,
have removable vent caps so that electrolyte levels can
be checked regularly. You should check the electrolyte level
every month. When storing a battery for the winter, check and
fill with distilled water as needed, recharge the battery fully,
and store in a cool place. When preparing the battery after
winter storage, recharge the battery to its full charge state.

The fact that the vent caps are removable may not be obvious. They may be the flat type, usually in sets of 3, that you need to use a screwdriver to pry up.

 

The batteries are 115 AH batteries, not 200. You need to use that number, so the total size of your battery bank is 345 AH This means that you should not charge at a rate greater than about 70 amps. This means you need to reduce the maximum charge rate in the charger. You said you have it set to 50%. I would set it at 70% since your charger is rated at 100 amps.

 

13.5V or 13.6V float may be a little higher than most of us would like, but many manufacturers of chargers and batteries are using those numbers now. As long as you keep the batteries filled with water, it should not be a problem, and will not harm the batteries.

 

IMO, the reason your previous batteries failed was not due to the charge profile you are using. They may have indeed been defective, or since you did not check the water levels, they ran dry and exposed the plates. I've had batteries fail prematurely as well. The inverter/charger you are using is a very good one. I would leave the settings as they are for flooded lead acid batteries, and I would continue to use the 3 stage charging.

 

Again, I apologize for the sidetrack.

[oldjohnt]

FWIW I, based on a lot of experiences, also prefer a lower float level in the 13.2 to 13.4 max range. In days past I saw batteries that were kept at a constant 13.5 to 13.6 volt range, which IF LEFT UNATTENDED AS SOME PEOLE DID, eventually caused premature total battery failure. Of course, if such was solely due to low water levels that could have been prevented.

 

HOWEVER as Rif and Jack and Staney and the others and I point out and discussed so much above, I SEE DIFFERENT MANUFACTURERS POSTING DIFFERENT PRE SET VOLTAGES BE IT IN THE FLOAT OR OTHER STAGES. So make your own choices lol I also am not debating what voltage levels and what stages and what algorithms are best among so many different charger manufacturers, like Jack noted, its simply a waste of time.

 

PS I just returned from mowing my deceased neighbors lawn, ironic how the last time another close friend died, I mowed his lawn that day. A person just feels like they have to do something to help and I knew that was an immediate need, even though I normally wouldn't mow on a Sunday. Then I got home and the wife left a message she's in town AND HER CAR WONT START, so I'm headed to town with the car tow dolly NO REST FOR THE WICKED LOL

 

Thanks to all for the help and expertise, I certainly appreciate you all and try my best to help in return.

 

John T

[lots2see]

Wow. I'll have to make a BIG pot of coffee and study this thread. Lots of good info.

 

But a couple days ago I installed a new Xantrex charge controller and simple went to the Trojan battery website and got the settings for my T125s. Bulk 14.8, Float 13.2, & Equalizer 15.5 (which is not adjustable and above my CC's ability). In 5 minutes I was done.

 

Am I missing something? It is the battery mfg that tells you exactly what voltages to use.

[Rif]

lots2see, Yes, use the battery manufacturers recommendations. No, you're not missing anything. The problem arises when chargers are not designed with adjustable voltage settings. Then you have to choose one of the profiles supplied, and usually none of them are exactly what the battery manufacturer recommends. Maybe there is one, but I've never seen a battery charger without custom settings that provided a Bulk/Absorb voltage of 14.8. Usually 14.4 is tops, so you just have to use it. It won't provide as good a charge as 14.8, but for most folks it is close enough. It's only us boondocking, solar nuts that rely on our battery banks for weeks or months on end where it might make a difference.

[oldjohnt]

Lots to see, I am NOT one to recommend something different then what a manufacturer says, I don't want anyone chasing me down lol.

 

My Xantrex as it currently sets goes to around 14.4 in the BULK charge rate which is sort of in line with what Rolls Surrete speaks of on their website if I recall correctly (seems like it was 14.2 to 14.4???) BUT NOT 14.8 as Trojan recommends and Jack mentioned a lot of users preferred, and is still DIFFERENT FROM the Three Stage 14.4 BULK , 13.6 Absorption, and 13.2 FLOAT voltages my Progressive Dynamics charger generates. Perhaps to go with what the battery maker recommends one could do like the good Rif man suggests and adjust the voltages accordingly if the charger allows for such. GOOD IDEA RIF MAN

 

My thoughts are a typical deep cycle battery only has so many rated "Life Cycles" so if we have a quality 3/4 Stage Smart Progressive Charge Solar Charge Controller and a good quality 3/4 Stage Smart Charger (Be it Xantrex or Progressive Dynamics or Magnum or whatever) and we budget and use out stored energy wisely and never let our batteries be depleted any lower then absolutely necessary (preferably no more then 30% discharge to 50% max, I don't like them 20% down lol) and as necessary we utilize the Equalization feature my PD charger has (reduces harmful effects of sulfation or stratification if I recall correctly) process, WE ARENT USING UP MANY LIFE CYCLES so we ought to get many years ( 7 to 10?????) out of our battery investment.

 

We do more dry camping then the average Joe in places like Utah or Colorado BLM or Natl Forest Camps so this has been a very interesting discussion and I appreciate all the inputs and expertise.

 

THANKS EVERYONE

 

PS Just got the wife's car home, see my new post and HELP ME please

 

HAPPY LABOR DAY TO ALL

 

John T

[Ray,IN]

http://www.exide.com/Media/files/Downloads/TransAmer/Battery%20Care%20and%20Maintenance/Battery%20Charging%20%26%20Storage%20Guidelines%20%205_9_13.pdf

States float voltage for Exide batteries is 13.5-13.8, mine are floating at 13.6. You guys have educated me about charging voltage, but said nothing about my problem, which is how to reduce my floate voltage to 13.2. I'll phone Xantrex in the morning to ask them how, but in the meantime I'm going to disconnect my automatic temperature module so it defaults to the 90*F setting. Hopefully this will cause a reduction in float voltage.

[Randyretired]

I think the lower float setting will be better for long term battery life. At 13.6 if you listen carefully you can usually hear the batteries lightly boiling. My inverter/charger is adjustable and I lowered the float voltage a little bit at a time until I couldn't hear anything. The batteries were silent at 13.3. The batteries are 6volt. Now I only need to add water every few months unless we are hitting them hard, like winter boondocking. As I posted earlier I also like to reactivate the charge cycle weekly to keep the acid stirred. Some studies suggest that batteries left at a lower float for extended times shorten battery life if the batteries are not stirred occasionally.

[oldjohnt]

Ray,

 

I will just have to venture over your way someday armed with my meters and we will "play" with your motorhomes electricals. Hopefully, Xantrex can help you with lowering your float voltage to the 13.2 to 13.2 range IF that's best for your batteries?????? (this thread talks about some that use higher). I don't see how it can hurt, that's the typical float levels I've used (doesn't seem to use much water either) which is just a bit higher then 12.6 to 12.7 volts for a full charged battery. There's been so many different charge voltages used by different manufacturers in this post I lost track lol

 

Randy "As I posted earlier I also like to reactivate the charge cycle weekly to keep the acid stirred"

 

I studied so many manufacturers different methods (charge voltages, stages, timing and switching) the past few days I forget where I read it (or dreamed it lol), but it seemed one manufacturer shut down or greatly reduced the float level charge at some point, but when the batteries reached something like 12.6 or so volts, IT KICKED INTO HIGH BULK CHARGE and started the Three Stages (Bulk, Absorption, Float) all over again which would achieve the "stir the acid" you talked about. On a similar note, I like the automatic EQUALIZE charger feature (the 4th Stage) quality Smart Chargers have also.

 

Tooooooooooo much information in this thread from tooooooooo many different manufacturers lol

 

John T