First Top Charge

Double check the readings and take another SG sample on Battery #1. Either that, or it's been taking the brunt of the charge with the way you have the batteries wired, or which terminals you attached the Mega Watt S35-12 to. Ask folks for proper method of connecting to which terminals, the Mega Watt S35-12... there is a proper way to do it, in the event battery #1 is indeed showing 1.300 for the SG on all three cells.

Also, check the water level on battery 1 compared to the other 3... Is it the same, or a bit lower? If you are in AZ, very, very hot down there. Ask MexicoWanderer about heats effect on electrolyte, and how to get your electrolyte to Tropical Blend or Summer Blend... you might need to run them a bit higher on distilled water to drop the SG a bit, deliberately.

I just completed the "dip" and here are the results: Using hand held meter.
Batteries 1/2 and 3/4 are series pairs. Then paralleled. With the Positive out being on 1 and the negative out on 4.
Bank voltage=12.85v

B1 6.45v
SG
1=1.30
2=1.30
3=1.30

B2 6.39v
SG
4=1.295
5=1.290
6=1.290

B3 6.42
SG
7=1.285
8=1.290
9=1.290

B4 6.42v
SG
10=1.285
11=1.285
12=1.285

Based on the differences in SG between the batteries should I take additional steps with individual batteries? What can the difference in battery voltages be attributed to, position in the charge line?

The shunt is connected to the Mega Watt with two #12 solid copper. And from the shunt with two #12 solid copper spliced to 4ga on to the battery. The #12's are all ~2.5".
I will begin keeping track of SG and voltages in a log. I appreciate all the great inputs and the time taken to explain how things should look! Any additional thoughts?

You may indeed have started off with utterly fresh desulfated batteries. If specific gravity in all cells is 1.280 or whatever the batteries come with, then top charging the first time will freshen the lead sponge on the plate surface and do little else.

The more time a battery is correctly floated the fewer top charges it's going to need. Top charging is like taking mega-vitamins, you don't want to O.D. just because the bottle is sitting in the medicine chest. Or do equalizations which would be like taking prophylactic doses of an antibiotic.

Use a hydrometer correctly! It is a valuable instrument!. Keep a chart. Dip all twelve cells! Note the date. Do it again in a month. If all cells remain at 1.280 you needn't do a thing. If the battery is on float and specific gravity in all cells, falls from say 1.280 to 1.275 while being floated, the batteries are most probably slowly stratifying the acid. Do a top charge to mix the acid and freshen the plates. Again, this is with the batteries being floated.

If one or more cells drops in gravity faster than the others, I nick-named them "weak-sisters". Use a marker pen and note on the lid next to the cap 1, 2, etc. so you can remember which cells to dip first. If they start out weaker they will stay weaker for the entire life of the battery. They are the "go-to" cells when dipping. If the cells check good, forget the rest. A full dip should only need to be done every third month.

In the specific case of using the Mega on 4 golf-car batteries, time needed to do a top charge is going to vary throughout the life cycle of the batteries and how deeply cycled they get. Heavily cycled batteries will start to have unequal cell gravities a lot sooner and a lot more pronounced than lightly cycled batteries. Really heavy cycling may incur need for top charging every 7-10 days.

It is impossible for plates to sulfate without acid specific gravity not dropping. Sulfuric acid is the component that makes sulfation. So if specific gravity is full density in all cells, two things are evident a) No residual sulfation has formed on any of of the plates and b) the acid has not stratified.

After a month or two of occasional cycling your cells will take on personalities. You are looking for the the "Weak Sister" cell. It will be your go-to-first cell throughout the life of the battery bank. My bank of 24 cells has several weak sisters after 22 years. I always pick on the weakest. When it has lost .005 points the other 23 cells get zapped with a top charge as well. I had to hire Robles and his damned backhoe to move the weak sister cell closest to the door of the battery shed. The Freas is hanging just above it. You should do the same - make the weak sister cell battery the easiest to get to.

Using Trends & Tendencies, I know how long to set the timer for according to how much gravity the weak sister cell has lost. A loss of X amount of density means a setting of X minutes on the timer. When I hear the generator cough I know the cycle is complete, and I also use a pocket timer that screams at me.

But I do NOT top charge batteries that exhibit full specific gravity. That is a waste of time and energy, and yes it is harmful to perfectly innocent plates. The mild 15 volt setting means 15 volts would have to be applied for a long period of time to genuinely hurt a good battery, so an hour or two extra time per top charge is not destructive but I try and tweak the timer even more accurately.

The amount of time expended writing this took up more time than dipping the weak sister cell, starting the generator and twisting the intermatic knob and repeating ten times. Top charging becomes intuitive. My bank needs it every 13 - 16 days, because like me, it is old and infirm. When it was new, when dinosaurs roamed the earth, I could go a month to a month and a half between top charges.

Again, the idea of top charging is to dramatically reduce the need for full-on battery equalization which requires ten times of not more the amount of attention and energy that top charges require. Like the difference in expending energy to fetch the evening newspaper versus dropping and doing a hundred pushups.

And to repeat this point again, doing blind, automatic top charges is not intelligent. It is the specific gravity in the weak sister cell that calls the shots. When the shots become predictable elapsed time wise, graduate to the timer and verify once or twice, but you need dip ONLY the weak sister cell.

POOR QUALITY and FAILING batteries are difficult to maintain specific gravity at 100% despite attempts to charge them the normal way. This is the classic sign of a Mickey-Mouse grade new battery or a good battery that has grown gray whiskers. I'll make a statement to illustrate. Take a Rolls battery and compare it to an off brand warehouse big box battery the same BCI grade. The Rolls battery will require 1/5th the number of top charges the first year of operation of heavy cycling. Hell, the Rolls may require 1/10th or less. The differential is discouraging to those in the know. Lesser batteries are like spoiled brats, they need to be lorded over and slapped around and frankly I have neither the time nor the interest to waste. The philosophy and illogical thinking of "Gee I buy tires for ten dollars each and get a whole 5,000 miles on them, and I only need to air them up twice a week" escapes me.

Battery maintenance should be a piece-of-cake, occupying maybe <1% of the time in a camper's routine day. It takes me less than a hour a week to manage a ten ton battery bank and I would scowl if it took more...

morning, sjturbo,

Did you verify those V readings with a handheld multi-meter? And how is the shunt connected? Is there a 4ga wire from neg batt post to one post on the shunt, and another 4 ga wire from other shunt post to charger?

thanks

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It appears you have the mega watt s-350-12? I'm assuming you bought it just for top charging and EQ'ing?

It appears it is not performing at it's best, on that big bank. Try splitting the bank next top charge, and compare results. I'd certainly be interested to see how much of a difference it would make, amp wise.

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As for EQ'ing: At those low currents, you should isolate the 6's, and EQ them individually. The mega watt drops to about 9.5v, and that could be bucked (stepped down) to 8v using an inexpensive "constant voltage/constant current dc-dc buck converter". You could then zero in on the 12a @ 8v required to EQ a single 235Ah 6v battery. I use a separate cv/cc power supply I bought just for this, called a gophert cps-1620 ($110 incl shipping). It goes from 0-16v and 0-20a. Very handy, but a buck converter would work well with that mega watt. Either of these would do:

http://www.amazon.com/GEREE-Converter-Constant-Voltage-Current/dp/B00OV2AQDY/ref=sr_1_48?ie=UTF8&qid=1415720444&sr=8-48&keywords=constant+current+buck+12a

http://www.amazon.com/Beautyforall-DC-DC-Converter-Step-down-Module/dp/B00L1AT9DC/ref=sr_1_67?ie=UTF8&qid=1415720917&sr=8-67&keywords=constant+current+buck+12a

Just something to consider.

I will try to answer all questions.
Stopped charge at ~8:30 last night. Total charge time ~11hrs.
Voltage at stop time ~14.8v (dropped off quickly to 13.5v).
Voltage measured this morning 07:00 (10.5hrs after charge stopped) 12.88v at batteries with only Victron monitor connected at bank shunt.
Cables are all marine grade 4ga. Exception is 3" doubled #12 solid from Mega Watt shunt.
Length Batt-Batt ~8", Batt-Shunt ~16", MW-Batt Bank ~ 12"
MW-Regarding the unlimited amperage @ 15v, The ah rating for the four batteries in series parallel is 470ah Each battery is 235ah. If I understood correctly the charge amperage should then be ~23a. When I first started the charge amperage at MW was set at 15v @ 33a quickly dropping to 5.4. Within an hour the amperage was a 3.3a. Amperage leveled out at ~2.4a. When I increased the voltage to 15.3 during the last two hours of charging the amperage rose to 4.5a.
Did this rate of charge pose a risk of damage to the plates?
I will check SG on all cells and report back! Thanks again for all the support!

To the OP, did it take 10 hrs for the batts to get to 15V?

A fast dip should be done and all cells should be a max gravity. This is the problem with unlimited amperage at 15 volts being applied. The battery really cannot utilize the extra wattage correctly. At 5% of amp hour rating the energy GENTLY reverts light coatings of H2SO4 and drives them back into solution.

This system needs a 12 volt 100 watt (NAPA) electric light bulb wired in series with the Mega's positive lead (for simplicity). This will slow down the charge rate so that all that energy isn't destructive to perfectly innocent plates. Chronic overcharging wants to extract antimony out of the positive plate and deliver it to the negative plate. Both plates suffer.

When voltage rises to 15.0 cease.

This should be a flip a switch, note the clock, watch voltage rise steadily until it hits 15.0. note the clock, then connect a TIMER to the AC powering the charger. The next top charge, twist the timer and walk off. For example two hours and 10 minutes the first time should be dialed in the second time. This is good enough for top charging and does not make a person a slave to the batteries. "Twist! Yawn! Time for a stroll" Equalizations are the same, note the time spent the 1st time, and set the wind up timer. A couple of tweaks with hydrometer verification and you'll be mighty close just by using the timer. Let the spring wound timer do the legwork, go do something important like nothing-at-all if you want. Watching a battery do it's thing ranks right up there with watching paint dry. But setting a timer by hand is the key. I use a six hour Intermatic. They are bulletproof, and cannot be fooled by outages, or sloppy timing mechanisms.

I am pretty sure, with the bubbling you are seeing, at 15.0V, that's about perfect. Bumping it to 15.3 and seeing slightly more bubbling and more amps, is spot on. I'd give it 15 minutes at 15.3V, shut it off for the night, and disconnect the terminals from MegaWatt to the battery for overnight and then in the morning, lets see if you are showing 12.73 to 12.77V still at the terminals.

So, you have these four batts in series/parallel, correct?

What gauge and length of cables did you use to wire 1) batt to batt, 2) batt to shunt, and 3) mega watt to bank ?

Thanks.

For comparison, I had a 16" length of 4ga, with cheapo ends, from neg batt post to shunt. I changed it to 2" of 2ga with heavy duty ends. The V drop went from .03 to .01, just thru that one wire. I have since wired everything with 2ga and heavy duty ends.

When you take your battery readings; with the pos probe in the usual spot; move the neg probe around to various posts:

1) to the 2nd shunt post (from battery) to determine V loss thru neg charger-to-shunt wire, then

2) to the 1st shunt post (from battery) to determine V loss thru the shunt itself, (compared to #1 reading), and

3)to the neg batt post, to determine V loss thru the batt-to-shunt wire (compared to #2 reading).

As for the .03v difference between charger and batts, if that has remained steady for any real length of time, that is as good as you're going to get at this time.

And make sure you use the same meter for each reading, not the handheld for some, and the installed one for others, as there could be a discrepancy. For example, my power supply, motomaster hand held, and uni-t clamp meter all show different V readings on the same circuit, so i only "trust" the motomaster to establish "true" readings.

Thanks for the questions. The 13.2 voltage was taken when I disconnected the converter. The battery bank had been in float mode (PD9270) for about 24hrs. I measured at the battery bank just now. The reading at the Mega Watt was set at 15.0v the battery bank measured 14.97. I assume this is a 30millivolt difference due to cable voltage drop. I have the volt/amp meter wired across a shunt on the negative side of the MW. Is that why I am not seeing the voltage change you indicate?