Charging a Battery Bank

landyacht318 wrote:
well, 12 pages in to this thread.....

Thngs can always be taken to extremes in the search for Ideal.

Ideal could very well not be worth the effort, or expenditure.

I think there is a big hangup on which product best fits the bill, and in general, a bunch of conflicting yet strong opinions.

Just the point I've been making throughout the entire discussion .... :R

The OP by his own description is not a hard core, full time dry camper but rather just someone who mostly camps on electric sites but on occasion would like to dry camp for a few days at a time. He's already purchased a 3000 watt Champ inverter genset, was talking about buying FOUR 6 volt GC-2s, yet only has a garden variety WFCO 8955 (which HE claims is faulty) with which to charge these batteries. Sorry, but throwing everything in one's wallet just to solve a problem for a few days of camping just makes no sense to me at all, particularly when he still has no idea what his average daily power requirements may be. :R A couple of GC-2s to replace a single 12 volt? ... sure, not unreasonable, but he still has to have an effective way to charge those GC-2s. In this case the OP has expressed interest in Duracell AGM GC-2s which are in fact moderately priced East Penn Deka batteries ... right on the battery itself East Penn provides labeling which insists that temp compensating charging is REQUIRED for these batteries. Further, that same warning is detailed more than once in their own AGM battery technical manual ... yet pundits continue to argue it just isn't necessary? :h

Sure, I understand how those much more fully educated about and interested in battery technology may insist that manually adjustable chargers are the ultimate in battery maintenance BUT do you really expect the average RV owner to have the same level of interest in battery maintenance?! The reality is, most of us don't, we just want to go camping, so in fact your quoted statement above is closer to reality than one might think. ;)

In this particular case the OP has the option of choosing readily available GC-2 East Penn Dekas wearing the Duracell label that would certainly represent a good start for the task he has in mind, plus a Parllax ParaMode charger that offers the correct charging profile for this battery and does offer temp compensated charging as REQUIRED by East Penn, so although neither may be "the best of the best" both are IMO certainly a reasonable solution for an average RV owner who just wants to do a few days of dry camping from time to time. If he later decides after being out a few times with this combination that he needs even more reserve he still has the choice to then add a couple more of the same batteries, perhaps add a solar system to augment his charging capability. This graduated approach for the average user to me makes a lot more sense than simply throwing one's wallet at a perceived problem without a clear understanding of all of the intricate issues involved in building an effective battery / charging system.

While I too appreciate the commentary offered by those much better versed in this subject sometimes "ultimate", although desirable in it's own right, just isn't necessary. ;)

https://www.youtube.com/watch?v=GC1jIKpC7Zw&list=UUoPqTkOluQsuu3RpGnxVwFw&index=17

The above video nicely shows the realtionship between volts and amps on a charging battery.

My Meanwell power supply has only a voltage dial, but can deliver 40 amps until the chosen voltage is reached, at the DC output terminals, then amps taper.

The MAstech power supplies can control volts and amps independently as the video shows.

A converter controls the voltage only. It outputs whatever amperage required, upto its maximum, to reach/maintain the voltage preprogrammed as 'best; for your battery. Once that voltage is reached, on the DC output terminals, then it it is in constant voltage mode/Absorption and the amperage required to maintain tha tvoltage will decline as the battery charges more and more.

When these amps taper to a certain level, then the battery can be considered full charged.

Flooded batteries can be verified with a hydrometer. AGM batteries require this amperage required to maintain absorption voltage as a full charge determinant.

So it all comes down to fully charging a battery
Fully chargng a battery requires time at absorption voltage.

Absorption voltage changes with battery temperature.
Absorption voltage duration varies with the amperage at whcih absorption voltage was attained, and the health of the battery, and of course its state of charge when absorption voltage was reached at the amperage it was accepting from the charging source.

These factors eliminate a one size fits all charger as being perfect for any battery in any given usage at any state of battery health in any temperature.

Really there is so much room for error regarding achieving ideal, it is rather impressive lead acid batteries can last as long as they do.

Which shows this level of obsession is not required.

But one should know what 'Ideal' is, even if they cannot be bothered to aquire the tools and perform the tests, to achieve it.

Lot to be said for just getting product X and replacing batteries when they simply need it

A lot of you folks in this thread over the years have probably sunk a good chunk of money (and time) into determinig just the right equipment for correct care of your expensive RV batteries. If you would have know about a piece of gear like this early-on, your total $$ outlay may have been less ;) : http://www.mastechpowersupplies.com/switch-mode-power-supply-hy3050e.html

well, 12 pages in to this thread.....

Thngs can always be taken to extremes in the search for Ideal.

Ideal could very well not be worth the effort, or expenditure.

I think there is a big hangup on which product best fits the bill, and in general, a bunch of conflicting yet strong opinions.

Who would not love a fully programmable Magnum inverter/charger?

i mean my solar controller allows programmable Vabs and duration, for 230$, why should a plug in grid powered charger be 4x the price for these same features?

My point is that as a battery ages, that programming needs some massaging as absorption duration will also need to increase. erhaps the absorption voltage itself too.

How is this determined? with a hydrometer or an ammeter, when holding absorption voltage. If these tools are eventually required, then why not utilize them more often and have a manual option that is very easy to manipulate?

But what if a charging source is already in float stage, and one cannot reinitiate absorption voltage without jumping through several hoops, while jumping backwards on one foot while chanting.

"Oh please lord of absorption voltage, please hear my calls and allow my smart charging source to decide again that 14.4v or higher is what my battery desires!......, as I know it to be true"

BFL13, you know as well as I that manually changing voltage takes only a turn of the wrist and a millisecond.
How long does it take to reprogram an automatic charger? Press this button for 5 seconds, then press this button 6 times, then then button 7 times, while holding instucton manaul with DW yelling at you.

One still needs to determine how long to extend absorption voltage, or increase it, and the temperature compensation is another factor in that.

If I had to choose a 3 or 4 stage automatic charger/converter, if I could not instead choose to have a voltage dial, I would choose the charger which did not require a bunch of trickery to respond to my wishes.

Gee, solar and alternator had my still depleted batteries upto 13.1v, when I startedmy generator, yet my converter saaw 13.1, thought the batteries were already fully charged and sought only 13.2v. Now if it was seeking 14.7v 45 amps would flow, but since it wants only 13.2v, one gets to run the generator for 3 amps.

If the user realizes what has happened, how do theuy trick the charging source? Load the batteries with higher loads until voltage drops below 12.6v then restart charging sources.

Seems easier to just have a dial on the charginng source. oh batteries are 77.2F, Turn it upt 14.8v. in about 4 hours, come back and check how many amps the batteries are accepting. Agms at 0.5%? spin dial back to 13.6v. Flooded batteries at 2% of 20 hour capacity, dip hydrometer, or just assume they are full and dial back to 13.2v.

Hold absorption voltage or dial it back to float.

Tricking or overriding an automatic source requires so much more effort than twisting a voltage dial. But at least PD offers a button to press or hold, assuming the human pressing the button has a clue.

Pd 92XX might not hold steady amps on generators in bulk and not be PF corrected, but at least they allow a forced override of target voltage and will revert to automatic after 4 hours without input from the user.

I think it is a shame that powermax adjustable units do not allow 16.2v. Certainly the 19.23v I can achieve with my meanwell rsp-500-15 is overkill, but the way i see it is I could have 3 volts of drop to a battery a hundred yards away and still equalize it, or could perhaps run my laptop directly off of it.

Achieve proper temperature compensated absorption voltage at battery terminals, Hold it as long as is required. That is the lead acid battery golden zone. It all comes down to this in the end. Every lead acid battery requires this to live a respectable cycle life.

Which tools allow this?

how many of them are fully automatic?
Find the compromise.

The manual, adjustable voltage powersupply/charging source compromise, can do it all, with a little input from the human who should be there to occassionally double check the top$$ automatic options anyway.


Do not fear the adjustable voltage option. It gives enormous flexibility and the ability to actually fully charge in the minimal possible time, at just about any battery temperature, and the adjustment procedure is so darn simple and takes a fraction of the time it takes to manipulate an automatic charging source

landyacht318 wrote:
No doubt East penn's pure lead versions were also not in the price range of the Deka Intimidator either.

I think East Penn can and does make an Awesome battery, but they are a slave to market forces. The Intimidator being relabelled and sold everywhere across north America, as the most budget oriented AGM available, is likely their cash cow. "AGM" to the layperson somehow indicates super battery status, and if they see they can get one for only 50% more than a flooded battery..., done deal bragging rights warm and fuzzies all round.

The only cheaper AGM is the UPG Asian AGM's and they are not much cheaper, and these too have the poor self discharge and the 30% limitations.

The intimidator CCA specs are no better than a flooded battery of same size group, the self discharge little better, and the capacity is usually less in the same size group.

Often online somebody finds the absolute cheapest product they can find, then comes online asking if anybody else has purchased it and if it is any good, and they only want to hear one answer, and will latch onto it, and the answerer and question asker both get their warm and fuzzy serotonin release.

It is possible to extract excellent battery longevity if one can indeed reach full recharge often. It is also possible to kill the best possible battery through chronic undercharging.

Any reports of battery longevity, good or bad, without knowing how the battery was treated, are entirely meaningless.

Its just fine till it is not.

Previous repoirts, from a battery 5 years old, well the battery with the same label could have completely different internals today.

How well with the Indimidator hold up in regular deep cycle service? compared to another AGM?

Well a few have done the tests, If one wants to subscribe to the practical sailor magazine, but the Deka Intimidator did not do well from what little I have extracted from online having not subscribed.

At barely more than half the price of a LifeLine, do people really expect budget is just as good as top quality with the price to match?

People believe what they want either way. Regardless of facts.

I'll believe the person with experience and tools and desire to understand and actually measure performance over the lifespan of a battery.

The person who claims X amount of years and 'still going strong' or 'just like new', likely has none of those attributes.

I consider an adjustable voltage charger to be part of those 'tools' as well. How many amps are flowing at X voltage, reveals a lot.

Amazing how easy it is to read a temperature and twist a dial too. Seekng an autonmatic charging source which can do it all well, is pretty much not happening until one gets into the high dollr units from magnum.

The powermax with adjustable voltage, can do it all, with only a little input from a human, and likely with much less effort than reprogramming a programmable charger.

The battery's needs as to absorption voltage and its duration will change as the battery ages. Does any charging source automatically compensate for longer absorption stages required? No, but a human who can spin a dial and watch an ammeter and a voltmeter can.

All charging sources are a compromise.

LY, you're the guy for being on top of things. The OP mentioned most RVers are not, and they seem to get by ok.

But if you are "pushing the envelope" you have to be more careful, as we know. and do some work on that.

I figure the OP is no dummy, and he is just trying to find out if he will be pushing the envelope, and if so, what to do about it.

full_mosey wrote:

BFL13 wrote:
I don't need TC for the temperatures I camp in (32-90F) It is more critical for extreme temps. I do adjust my voltages up for cold temps --one of the advantages of the adjustable charger. At 35F, I set 15.2 as equivalent to 14.8 and it does the same charging profile as at 14.8 at 77F so that works right.

Those AGM specs show a range of acceptable voltages, so if your charger is in the middle, that gives you some wiggle room too. TC is getting pretty fussy for RVing. More a thing for stick house solar IMO. YMMV

One more comment on the Paramode. I don't like that the Volts are capped at 14.4. I believe that is what you see in your(in)famous hand drawn chart, even when you dipped the sensor in ice cream. A proper TC charger would have made the adjustment above 15V. You are correct in using 15+Vabs to manually adjust for battery temperature.

RobWNY;
Here again is a situation where I rely on a solar controller with a battery temperature sensor(BTS) to finish the job. In Nov 2015 I awoke to 6F outdoors. With the TT parked in the driveway, the solar controller reached a high of 15.45Vabs. Even with the WFCO plugged in overnight, the controller goes ahead and cycles through its charge stages.

HTH;
John

A curiosity with the TempAssure is /was that it's baseline temp is/was 60F. Most specs go with 77F/25C as baseline. This might mix things up a little, no idea.

Yes the batteries go with the highest voltage charger on them, so as soon as the solar controller got over the voltage of the converter it would be doing all the work. You can leave the converter "on" but it is not adding any amps till it gets dark, then it will take over again.

OP - still with us?! :W

On volts vs amps for fast charging, I see this from my Paramode days:

The 4455 graph shown earlier was when it was at original set voltage. Later I used the internal pot to make it 14.8v (so it would match my Vector 40 amper's voltage so they then added their amps to get 100 amps.) I ran another 4455 alone test at 14.8 but don't have the graph, but here is what happened:

"Before mod, it ran at constant 60 amps for half an hour instead of an hour as here, and restored about 75AH in 100min vs 91AH here. The 80-90 part took an hour before --now it took half an hour--big effect using higher absorption voltage."

So it was still maxing at 60 amps (55 amper on fat wire) but now it stayed at constant amps longer and made for a faster recharge. Same converter size, same gen to run it.

BFL13 wrote:
I don't need TC for the temperatures I camp in (32-90F) It is more critical for extreme temps. I do adjust my voltages up for cold temps --one of the advantages of the adjustable charger. At 35F, I set 15.2 as equivalent to 14.8 and it does the same charging profile as at 14.8 at 77F so that works right.

Those AGM specs show a range of acceptable voltages, so if your charger is in the middle, that gives you some wiggle room too. TC is getting pretty fussy for RVing. More a thing for stick house solar IMO. YMMV

One more comment on the Paramode. I don't like that the Volts are capped at 14.4. I believe that is what you see in your(in)famous hand drawn chart, even when you dipped the sensor in ice cream. A proper TC charger would have made the adjustment above 15V. You are correct in using 15+Vabs to manually adjust for battery temperature.

RobWNY;
Here again is a situation where I rely on a solar controller with a battery temperature sensor(BTS) to finish the job. In Nov 2015 I awoke to 6F outdoors. With the TT parked in the driveway, the solar controller reached a high of 15.45Vabs. Even with the WFCO plugged in overnight, the controller goes ahead and cycles through its charge stages.

HTH;
John

The voltage dial is also an amperage dial. If one wants to limit a 60 amp adjustable voltage charger to 40 amps with an adjustable charger, they startout with a lower voltage, and bump it upwards in steps to maintain the desired amperage. Kind of a Pain in the ass to keep bumping voltage upwards though. I prefer batteries that gobble huge amperages without issue.

I've been rather surprised at battery temperature rise during higher amp charging.

While I have an automatic charger, i can't trust it, and I spend more time trying to get it to do what I want. tricking it, restarting it, manipulating it, just to get it to do the job it claims to do automatically.

Twisting a dial is so much quicker, simpler and more effective.

For example, last week a neighbor's battery group49 Deka flooded, refused to start his engine.

After a jumpstart, when he returned I put his charger on the batteries, a 2/10 amp manual transformer based schumacher. All he had was a voltmeter. After 10 minutes voltage had barely crossed the 12.6v mark with a 12.32 starting point.

Irritated that i could not see the amperage, i go get my clampmeter. The schumacher on the 10 amp setting is outputting 4.2 amps.

The possibiity of rain was high, I did not want to get my Meanwell wet, so I got my 'Smart' Schumacher and my wattmeter.
25 amp setting skyrockets voltage well past 15, and I shut off charger.

12 amp setting, same result
2 amp setting and voltage continues to drop back to ~12.8 and hovers. making this 'smart' charger essentially useless.

Go get my Meanwell, set voltage to 14.9v(50f battery) plug it in. 9.2 amps.
not a good sign for the battery, but the ability to get it to 14.9v and hold it there without voltage rising further or an automatic charger shutting off and throwing a green light, is pretty essential.

When amps tapered to 2 amps many hours later, with 32AH counted on my wattmeter, I got hydrometer. well under 1.200 on all cells.
Bump voltage to 15.3v, amps tripled and held. Never tapered.

Not a good sign. Let it go for 3 hours, amps increased, SG remained the same.

bad sign for battery.

Disconnect battery terminal from vehicle, bump voltage to 16.2v, it requires 14amps and starts slowly rising, as is battery temperature. Specific gravity does not respond.

I declare battery as a goner. Owner shrugs and says he will just carry his jumper pack and replace it when it can not reliably start the vehicle.
3 days after this, without use, he starts diesel engine with it without issue, and even used the disgusting term 'Just fine'
Sub 1.200 specific gravity is anything but, yet it still works.

Head in the sanders would wholeheartedly agree "just fine, seeeeee?". Those holding measurement tools disagree. It is however a matter of time, or abnormally cold temperatures.

I would have saved time and determined more if I had used my Meanwell right off the bat, instead of other battery chargers.

My personal hard working AGM battery at ~450 deep cycles, still maintains impressive voltages in overnight loads, nearly as good as when new, but the amps required to reach Absorption voltage are much less now, than when new.

If I did not have an ammeter I would be blind to this. If I did not have an adjustable voltage charger I would be mostly blind to this. If I could not control the voltage which my alternator is allowed to hold, i could not see the instant absorption voltage amperage if it required more than 40 amps.

if I did not have these tools, watching voltage alone, comparing cycle number one to cycle number 450, I might even be so bold as to declare it works as good as new.

It is not. It is also taking a lot longer for amps to taper to 0.5% of capacity.

Think any auotmatic charging source would extend its egg timer allotment of absorption voltage on an aged battery?

Perhaps a few would, those inteh 500+ dollar range.

I guess my rant is do not fear the manual adjustable voltage charger. in this day and age of automatic everything, the mindset is that the only good things are automatic, but with battery charging the there are moving targets and nothing automatic can achieve ideal every time anyway.
I understand not wanting to babysit a charging source, but in my experience it requires less effort doing so, than an automatic charger which does not complete the task and sends a battery to an early grave instead while flashing that serotonin inducing green light in blissful ignorance..