Do I need to "top off" the battery if it is fully charged?

2oldman,
That price was 21+ years ago. Paralleled 2-volt cells per case. 12 of them. Or 3300 amp hours @ 24 volts. .330" positive plates. Surrette batteries made in Canada. I had a 35' shipping container transported drom the Port Of Oakland to Lazaro Cardenas, Michoacan. It was stuffed to the gills including the Kubota generator, chargers, tools and a few tons of electrical gear. The shine from the stack of 500 peso notes just inside the doors hanging in a transparent documents bag made the Aduanero the port Customs inspector go blind for an hour or so. I should not have sold that container shell. Srupid move. The trucker and monster tow truck company begged me to purchase it. Hector with his Cat backhoe unloaded the container and set the batteries. I built the shed around the batteries but the only level spot is 100 meters from the house and Quicksilver. The door to the shed plus frame is marine surplus US Navy K-monel off a WWII minesweeper. The inside of the shed is clad in 11-gauge 304 perforated matting. This was all done with material shipped before I got sick. Glad it was in Mexico when the IRS asked me to declare my net wortlessness. The locals are terrified of the shed. One of my toys is a Leyden Jar. Plus I have a 129 db keypad entry with IR detector and an inside pressure pad

I sorta wish I had a 4K PSW inverter instead of the Trace 4024. The Gould 400 amp charger plus the 120 amp Trace and the 385-amp 50-DN connected to the Lombardini adds up to 1000 + amps at 28 volts. Quicksilver has a 400-amp Niehoff alternator. Sounds mighty impressive until a person realizes diesel costs 3.50 gallon. The Kubota/Kato drinks like a fresh off the wagon man from Ulster.

And there you have it. A Nerd's Nirvana...

MEXICOWANDERER wrote:

For benefit of some I can repeat TWICE PER YEAR on an otherwise floated battery, and as often as once every two weeks on an off grid battery that is cycled daily and manages to have a cell that slumps specific gravity despite trying your best to arrive at full charge daily.

I regret if I have missed this in the past. Specifics seems helpful but I do get trends & tendencies. Thanks.

profdant139 wrote:
OK! Some very interesting feelings about batteries are being shared here, and sharing is good. ;)

I think if I had 23 grand at stake, I would be very passionate. I have two ordinary Napa marine group 31s that cost a total of less than $300, and my last set of two lasted for five years with heavy camping use. They lived in my garage on the BatteryMinder when not on the trailer. So I have a lot less at stake, and I probably won't be buying a lot of extra equipment (ammeter, commercial-grade hydrometer, and manual charger). I have one of those squeeze-bulb hydrometers -- it accurately predicted that one of the cells in one of my former batteries was about to go bad, which it soon did. Good enough for an amateur setup.

However, I am very interested in re-wiring my panels with ten gauge wire, not only from the controller to the batteries but from the panel to the controller. I could then install a quick-disconnect between the panels and the controller, so that I could run my cable directly to my batteries and "boil" them. That project does not seem too daunting, even for someone with limited technical skills.

The hard part will be to figure out how much "boiling" is enough, and when to do it. There has to be a "cookbook" out there for non-experts -- if your battery has a rated capacity of X amp/hours, then you should boil it at Y volts for Z hours. I know that is not the expert way of doing things -- but there is a time and a place for lowest-common-denominator checklists and procedures.

There is Mexicowanderer's formula. Barring that, you babysit them while trying to apply a CONSTANT c/20 charge rate in amps, at fixed amps, until V rises at battery terminals up to 16.0V or until your Specific gravity ceases to continue climbing for the weak sister cell, the one cell per battery pack that is always a laggard and running low first in specific gravity. Whichever occurs first while babysitting, SG stops rising, or battery reachs 16.0V, then stop, shut down, and wait 48 hours, then measure open circuit voltage across the terminals. I seem to recall in my batteries, that 12.73V was a good number at 75F temp. Higher the battery temp, higher the voltage. Also measure SG across all battery cells, see if they are all at the same level in terms of battery acid density, did you get all the sulfur off the cells and back in battery acid solution?

OK! Some very interesting feelings about batteries are being shared here, and sharing is good. ;)

I think if I had 23 grand at stake, I would be very passionate. I have two ordinary Napa marine group 31s that cost a total of less than $300, and my last set of two lasted for five years with heavy camping use. They lived in my garage on the BatteryMinder when not on the trailer. So I have a lot less at stake, and I probably won't be buying a lot of extra equipment (ammeter, commercial-grade hydrometer, and manual charger). I have one of those squeeze-bulb hydrometers -- it accurately predicted that one of the cells in one of my former batteries was about to go bad, which it soon did. Good enough for an amateur setup.

However, I am very interested in re-wiring my panels with ten gauge wire, not only from the controller to the batteries but from the panel to the controller. I could then install a quick-disconnect between the panels and the controller, so that I could run my cable directly to my batteries and "boil" them. That project does not seem too daunting, even for someone with limited technical skills.

The hard part will be to figure out how much "boiling" is enough, and when to do it. There has to be a "cookbook" out there for non-experts -- if your battery has a rated capacity of X amp/hours, then you should boil it at Y volts for Z hours. I know that is not the expert way of doing things -- but there is a time and a place for lowest-common-denominator checklists and procedures.

MEXICOWANDERER wrote:
Maybe it's because I have twenty-three grand worth of batteries at risk

Wow.. how many and what kind?

Maybe it's because I have twenty-three grand worth of batteries at risk that I am so sensitive about this. What some folks consider "chump-change" means eating tortillas and salt for a month or having a normal diet.

The formula DEMANDS 5% of ampere hour amperage and it demands starting with a full as possible battery and it demands that charging cease when voltage rises to 15.0 volts. For benefit of some I can repeat TWICE PER YEAR on an otherwise floated battery, and as often as once every two weeks on an off grid battery that is cycled daily and manages to have a cell that slumps specific gravity despite trying your best to arrive at full charge daily.

I would be happy as heck if a battery came along and had fewer demands than a Hungarian Movie Actress. I would MUCH prefer to spend my time elsewhere. But the way things stand now if I ignore the few minutes a week needed to keep the monsters happy I end up having to scramble for money to cover the cost of premature battery death. It's a free-world. Do as you wish. I do not criticize people who destroy their batteries by neglect and remain silent about it.

MEXICOWANDERER wrote:
I love it when folks change the words around, fabricate their own perception of a thread subject line then pontificate. TOP CHARGING IS A STRICT FORMULA. A FORMULA INCLUDES TIME, frequency of appropriate application, and possible permutations of inappropriate application.

Checking tire pressure for instance does not mean a person should do it every hour nor does it mean every five years. Reading an excerpt of a long thread dealing with technical issues and arriving at a conclusion and a public denouncement of the excerpt claiming personal certification of experience is a perfect example of how information gets twisted. Distorted. And such a jump to conclusions does not reflect kindly upon the poster. 'Nuff Said.

Mex, he bought my portable folding solar panel kit off of me. I know what it does and does not do after the charge controller. It will give 14.4V at the charge controller terminals, but when run through 5 meters of chinesium 16 gauge wire with a few connections and then clamping on the battery, there will be about 14.0 to 14.1V provided at the battery terminal, if you chase the sun and aim the panel at the sun several times per day.

Is it good for while camping to fill up the battery in use? Yes. Is it good as configured to top charge or equalize charge most group 24 or 27 DC batteries? No, it is not. I know, I tried and tried and tried, on a group 24, and it was far from enough for the 150 Amp Hour T-1275 I picked up to replace my group 24. The unit he bought is an introduction to solar panel battery charging, it works for camping, but something else would be better for top charging to 15.0V, and an occasional equalize charging when the specific gravity between cells is out of normal range of 10 pts variance, or the battery appears to have lost capacity and plates are sulphated.


If profdan would like to learn, I suggest he read the full drama session thread called "My screwy 31" by landyacht318 for an education on batteries, how to charge them and how not to charge them. It's a long read but very educational.

Some of us learn by reading, some of us learn by doing, and the school of hard knocks. Some want simplicity in battery charging, others prefer doing it manually, doing it right, and doing it by the book.

The geekiest or nerdiest or purists among us go our own way, and set up to recharge, top charge, and equalize charge manually. The rest of us fall short of maximizing our battery's potential, in terms of life span, or do trade offs of convenience for lost battery life. The spectrum runs the whole gamut.

I love it when folks change the words around, fabricate their own perception of a thread subject line then pontificate. TOP CHARGING IS A STRICT FORMULA. A FORMULA INCLUDES TIME, frequency of appropriate application, and possible permutations of inappropriate application.

Checking tire pressure for instance does not mean a person should do it every hour nor does it mean every five years. Reading an excerpt of a long thread dealing with technical issues and arriving at a conclusion and a public denouncement of the excerpt claiming personal certification of experience is a perfect example of how information gets twisted. Distorted. And such a jump to conclusions does not reflect kindly upon the poster. 'Nuff Said.

profdant139 wrote:
2oldman, yes I am connecting the panel to the battery.

And Mexicowanderer, how does one create a charge greater than 14 volts? That's all the panel will produce. And the three stage converter in the trailer maxes out at about 13.5.

Suggest you look at the back side, where the stickers are. Each panel in that portable folding solar kit is capable of producing 17.0 or 17.2V. The charge controller should produce 14.4V, IF you forgo the stock wiring and run a fat 10 gauge set of wires the 15 feet from solar panel to battery terminals. Add more distance between the panels, or thinner wire, or both, and you lose voltage at the battery terminals, it's the nature of DC or direct current electricity.

It sounds like your panels are exceeding your camping requirements and that is a good thing.

Your posts kinda suggest that your solar isn't able to exceed 14.0V. If so you might want to consider a charger that will and they are easily available. They are available online, auto stores, etc.

You should get a lot of useful life by continuing to use the maintainer even though it may not be perfect for the battery. One of my cars is on a maintainer 6 months of every year and the battery is doing great after many years. Of course the alternator will kick up the voltage for the other 6 months.