Very Inexpensive Battery Maintenance Charger

pnichols, you have proven yourself to have never been in the least sarcastic with your questions never mind have been insulting. It is a pleasure to answer your questions...

Evaporation loss in a flooded battery is addressed by surface area of the electrolyte being minimized first by the small area of the filler hole then secondly by the miniscule area of the filler cap breather.

We all know the warmer water or water solution gets the higher the evaporation loss. But few RV batteries are exposed to 50C temperatures for prolonged periods of time. Therefore in a sense of priority evaporative loss is considered minor in the scheme of things.

Electrolytic water loss due to evolvement of hydrogen and oxygen is a horse of a different color. Even the larger of the two, oxygen, migrates through the cell cap with the greatest of ease. It is order of magnitudes smaller than water vapor. And along with hydrogen atoms it is accumulated under pressure which water vapor does not have by itself.

Chemical action and reaction increases with temperature. What may be a minor event at say 10C may become uncontrollable at say 50C

Plastic is a less than ideal conductor of heat. Heat radiation is such a concern of some auto manufacturers that they install a plastic shell over an underhood battery at an attempt to mitigate radiation effects.

Using a sensitive IR instrument with temperature resolution to one-tenth degree is yet another tool an individual can use to find and diagnose battery problems. When I am trouble-shooting a large off grid system or cruising sailboat battery bank issue it is the first instrument I use. Temperature variation is an alarm to delve deeper into the cell to find out what's up. The bank of course should be biased with a high amount of regulated charging amperage for this to be valid.

RV'ers who live in environments of extreme summer-winter temperature variation need to adjust bulk charging and float voltage limits appropriate for their ambient temperature. I manually adjust for 5C variations. Each 5C lost or gained warrants temperature compensation.

I do it manually, some thermistor systems do it automatically, the best kind of course measures interior battery temperature (or tries to).

The used WFCO I have, has a "working" voltage setpoint of 13.75. When temperatures climb above 30C, the output voltage is going to get routed through a 300 amp rated Schottky rectifier. This will render output voltage .4 volt less or a finish voltage of 13.35 If temperature climbs above 40C I'll move (it would be an all-time record). After have used the unit for almost a month, the factory 13.2 volts float event seems to be unobtainable. I attribute this to unavoidable frequent shore power glitches.

With a VRB example an AGM, an amp hour (better yet a kWh) meter is invaluable. In float mode the amount of energy gained in an indispensable tool for determining whether a voltage set point is valid. I do not have one here and I grumble about it. A kWh meter is high on the list of "must get".

Let's keep the personal attacks out of this discussion.......any further flaming in this thread will result in immediate closure without further discussion.....

Thought I would add a bit to some of this which I believe is pertinent.

I monitor battery temperature with a probe on the battery post when on the road/boondocking/camping.

I have had FWC's for years and for the past 5+ lifeline AGM's.

My 9 year old converter is a 9260 Progressive Dynamics with the remote to select the mode to charge when needed.

Prior to Solar and a good controller that has temp compensation I always did the following if my batteries needed charging:

If my battery post temperature was 90deg+ I would switch my converter out of boost mode 14.4 and drop it to Absorb 13.6... Did this for both my FWC's and Lifelines.
According to all the tech documents for batteries I always felt that I was not stressing my batteries. And likewise, when my batteries were cold 60deg or less and the PD would not go into boost mode 14.4 I would use the remote to switch to boost.


During storage I let my PD do the work.... Both my FWC's and Lifeline

13.2 float and the 14.4 every 23hrs for 15 min....

My lifelines are now 5+ years old... I test them for capacity quite often... They still have the original capacity.... Resting voltage v/s ah removed... (all one can do with AGM's)
Periodic load checking 20/c discharge to 60% SOC (40%)

When off grid my solar takes care of my batteries now...

I sometimes see 14.9vdc when the batteries are cold and charging....
And barely 14 when hot. Temp compensated...

I have many friends that have had the same continuing results with Lifelines.... One had 7 + years on his lifelines....

Jim

Mex,

Is it possible that two kinds of "bubbling" are being talked about here?

Is it possible that outgassing due to a chemical reaction in the electrolyte from too-high a voltage being externally applied at the time will manifest itself as "bubbles". If so, might this be possible at temperatures way different from those normally associated with "boiling off" water vapor? And further, might the charging voltage being compensated for temperature (as recommended by battery OEMs) be referring to the controlling of this chemical outgassing ... as oppposed to controlling just water loss through high temperatures?

P.S. Not being sarcastic here .... just scratching my head on what the heart of this dicussion might really be about.

By the way, I still hold with: The temperature that us battery users are supposed to be worrying about with regards to what voltages we apply to a battery is the one easy for us to control ... the air temperature around the battery. The battery manufacturer's design, of course, controls the degree of transfer of this outside temperature into the interior of the battery.

Pnichols said:

"But didn't you say you were floating them (assuming day after day?) at 13.75V? If that kind of float voltage ruins wet cell batteries over time (as all in the forums say, due to their converter experiences), why wouldn't it ruin an AGM battery where the manufacturer specifically states to use 13.2V for float? It makes me think that Lifeline has something unbeknown to us in their AGM construction or chemistry that is different enough for them to recommend a float voltage lower than what most other AGM manufacturers specify."

Allow me to offer a possible different reason for Lifeline recommending a 13.2v float charge:

As a battery manufacturer, the last thing Lifeline needs is thousands of their batteries being returned for refund. Now, when this does occur, and it does all too often, one must ask them-self, was it poor engineering on Lifelines part, or a complete and utter lack of understanding, resulting in poor to no attention to maintenance, on the part of the consumer?

After reading dozens of on-line testimonials by folks who, as a last resort, went out and bought a proper charger and/or maintainer, it is very obvious to me it is the consumer's bad, not the manufacturer's. But even then, what is still lacking is their understanding of how, or why, that charger or maintainer "saved" their batteries. And in my not so humble opinion, that is what these relevant forum threads should be about.

As for Lifeline's 13.2v recommendation, may I submit that perhaps they are simply trying to "save" their own asses. For surely they must be aware of the lack of effort on the average consumer's part to educate themselves, and are therefore forced to publish extremely conservative recommendations. In essence, their recommendations are likely geared toward 'worse case scenarios', and it is becoming blatantly obvious to me that consumer ignorance is probably the worse case scenario a battery will ever encounter.

jrnymn7,

Yes of course the temperature of electrolyte is important. But if every post and every response was forced to include an encyclopedic definition of temperature compensation it would be cumbersome. The back and forth conversations on this forum had discussed temperature compensation both with chargers and hydrometer use to the point where I feel comfortable skipping disclaimers and caveats. With flooded batteries you may have noted that innumerable times I have recommended examining cell electrolyte by eye, cell by cell to see if the cell is bubbling, and if so, establish the degree of bubbling. A cell at 40C may bubble vigorously at 14.4 volts where is would not at 20C charging rate. Those bubbles by the way are hydrogen and oxygen the components of H2O.

One cell or almost all, when some cells bubble vigorously while others do not is a dead giveaway that further examination is called for. It is entirely possible for a cell to bubble and have low specific gravity.

Mex said;

"Well an IR thermocouple could not define one-tenth of one degree difference between ambient temperature and both copper battery posts, so I'm not going to worry myself sick over the issue. This isn't like dealing with nitroglycerine where one small boo-boo makes for a spectacular result.

The accumulator is constructed of pure lead plates, right? The mats have 1.300 specific gravity electrolyte soaked into them, right? The construction and chemistry is the same as any other AGM, do you disagree? If the plates were alloyed with something weird like palladium or bismuth, I would be very cautious about deviating from OEM specifications. But they aren't. It waddles, quacks and has feathers, so it is indeed an AGM battery and it can well tolerate 13.75 volts float up to around 30-32C. These critters live day in and day out in RV's and emergency vehicles, where charging system voltage ranges from 13.8 - 14.4 "

Pnichols said;

"But didn't you say you were floating them (assuming day after day?) at 13.75V? If that kind of float voltage ruins wet cell batteries over time (as all in the forums say, due to their converter experiences), why wouldn't it ruin an AGM battery where the manufacturer specifically states to use 13.2V for float? It makes me think that Lifeline has something unbeknown to us in their AGM construction or chemistry that is different enough for them to recommend a float voltage lower than what most other AGM manufacturers specify.

That's what concerns me about what you are doing.

By the way, I think those temperatures in the temperature versus float voltage charts refer to the most logical thing - ambient air temperatures that the battery is sitting in."

...And there it is! It's all about temperature. Not outside ambient temperature necessarily, but cell temperature. If for example, it is a nice sunny 85*F day, but the battery compartment is say 110*F, then the batteries can only be brought up say another 5*F before they will start to gas. How much voltage does one think it would take to raise the battery's internal temperature by a measly 5 degrees F ??? And left unattended to for extended periods of time, how long does one think it would take for that battery to lose enough water to expose the plates?

Moreover, during normal daily cycling, higher temperatures greatly reduce battery longevity. For example, daily cycling a battery stored in a 110*F cabinet could very well doom that battery to a 2-3 year lifespan.

Now for some real world, logical analysis, as opposed to an emotional frenzied reaction; usually symptomatic of ignorance:

I was experiencing very excessive gassing with my 4 gc-2 batteries. So I thought it was from the higher voltages (14.8-15.2v) I was using. And, in a way, it was. But I now know it was a result of lack of ventilation and temperature compensation. You see, I have been charging at the same voltages for weeks now, but at lower ambient temperatures, and with the batteries completely open to lots of fresh air. The result? My batteries are no longer gassing excessively. In fact, after doing several 15.2 volt top charges, and a 16v EQ'ing, there was very little, if any water loss.

Now imagine if I was long-term floating those batteries under the same conditions, i.e; with insufficient ventilation and/or temperature compensation. Do you think maybe, just maybe, the lack of ventilation and higher resulting temperatures could eventually cause my batteries to lose water? After all, it does not require voltages in excess of 14v to cause gassing, necessarily. It is the resulting cell temperatures, at or above their inherent gassing temperatures, that causes water loss.

I leave this with you for your sound consideration.

Traction Batteries = Locomotive batteries.


3B1-C batteries. 2,680 amp hours. 2-volt cells. Absorbed glass mat 60.5" height. New wave submarine batteries.

pnichols wrote:


I have a question ... does anyone know more about "traction" batteries? It seems that they may be superior for use in RVs than just plain deep cycle batteries - if they could be found in sizes that will fit into most RVs.

That's what my L16's are. They're typically pretty tall (and heavy) and unsuitable in most RV's. Some of the new DP's have them in either flooded or AGM.

My 2-volt Rolls wet cells have .330" positive plates. So thick, ampacity is inhibited, that's why I settled for two jars per case - 767 pounds times 12, plus a 155 pound 1/8" steel case. It took a Dina 10-wheeler to move them from the port, and a Cat backhoe to set them.

That's why I did not seek the ultimate in thick plates for my AGM usage. This battery has to be loaded into the car, and unloaded and carried to a hotel room. To me. an AGM that has plates the thickness of an average golf car battery is a good compromise. I don't need a 130 lb traction battery that has the same amp hour capacity. Other folks might. This battery is going to outlive me. It's a funny thing when a person gets old and "Lifetime Guarantee" causes uncontrolled giggles. "Retains 80% amperage after 25-years" is another pointless objective. So when I chose the Lifeline I balanced four or five factors into the equation and arrived at compromises that I feel best suited my needs. I can take this unit down to 10% of capacity rarely and not have a fatal reaction. I would hate to try and do that with an AGM Johnson Controls, Deka, or Optima battery.