BATTERY TEMP FLOAT VOLTAGE CHARTS NEEDED

A person CAN NOT ARGUE WITH BATTERY WEIGHT

ONE YEAR 13.65 volts float. Nominal 30c

ZERO weight loss. Not one tenth of a gram. Floating 24/7

I did testing for a living. Save arguments for amateur hour.

Batteries do not electrolysize H2O at ambient temp. Zero differential between battery and air.

Telephone Lifeline and throw these facts at the application engineer and listen to him stutter.

VLR batteries DO NOT VENT unless they are SEVERELY overcharged or operate at a temp far far far far far far (enough fars?) Above what you will ever operate them at unless your rig has caught fire.

VENTING IS ABNORMAL. VENTING IS A SIGN OF SEVERE OVERCHARGING. THINK! WHY CAN AGM BATTERIES OPERATE LYING ON THEIR SIDE? DO YOU BELIEVE RECOMBINANT TECHNOLOGY IS A JOKE? You are manifesring hallucinations out of rationalizations about what "could happens", in your imagination. Your deductions have a tire failing because it is running down the road at 81 lbs pressure instead of the max of 80. Call the manufacturer and tell them and the're going to get all bent out of shape.

There is NOTHING WRONG with strict observance to OEM specs. But please refrain from arguing this point with an attitude biased publically that is jist plain wrong

Teo tenths of one volt float difference will have zero effect on the lifeline until the battery reaches around 45c. Enough said. Call Concorde. Tell them verbatim what I said. What I claim. I will not argue this point with an educated salesman -only a design engineer. Those folks are not dummies.

When Lifeline recently explained to me about drying out their AGM batteries prematurely, I knew that they were referring to hydrogen and oxygen slowly escaping out of the one-way valves due to float voltage being too high such that the recombination process can't absorb the hydrogen and oxygen from the float voltage electrolysis of water fast enough. Hence the hydrogen and oxygen pressure builds until some irreplacable H2O (hydrogen and oxygen) leaks out of the one-way valves.

My issue when recently shopping for new AGM RV batteries was: At what float voltage does this begin to happen for any specific brand of AGM battery?

The release pressure of their one-way valves can be adjusted by AGM battery manufacturers - based on the recombination rate of their battery design. This may be related to why manufacturers can and do specify different float voltages (at any given temperature).

PLEASE REFER TO WIKIPEDIA to the definition of RECOMBINANT BATTERY. The term has meaning, not an insignificant meaning, an overwhelming significance. It is temperature related. Look especially at the part that explains what happens to H2O electrolicized out of solution. Read, study and understand.

Re: Temperature compensation

The overwhelming reason given by auto manufacturers for alternator voltage control being removed to ECU is temperature compensation. The Cadillac Allente and Olds Toronado CS144 alternators of the 80's and 90's used the 1116412 voltage regulator with remote thermal voltage control via thermistor on the battery. Lots of acid volume reserve coupled with a tropical SG blend in the southwestern states would enhance battery life considerably. My 2-volt cells have 1.260 adjusted electrolyte.

Slightly off topic because it's at any particular fixed temperature - when using the "wrong (too high of a)" float voltage for that temperature. A Lifeline representative told me over the phone that the lifetime of their batteries would be shortened because their batteries would be dryed out prematurely if I used a float voltage over their spec over the long term. That made perfect sense to me.

The same thing goes for any AGM battery at any temperature if one uses a float voltage that's too high for that temperature - it's lifetime will be shortened due to water vapor loss ... the same thing happens to wet cell lead acid batteries on a stock converter ... their water evaporates away.

I assume that the same temperature dependence issue is also why, with a multi-stage charger, all stages should be compensated (adjusted) for the air temperature around the battery ... so as to get max battery life.

Eighty degrees F provides a poor reference point. Batteries love to be stored fully charged at 35F. I have this little tickle at the nape of my neck that is suggesting battery OEM have done little if any lifespan testing at 160F. Various manufacturers have posted data all over the map regarding high temperature lifespan. Some of it is outright absurd.

A flooded CYCLABLE lead acid battery should not receive voltage higher than 12.9 at temperatures of 50C 122F. No charging. None. Zero. The risk of warping pasted grids is too high. For years, Land Rover used 1.250 SG acid in their batteries bound for Africa.

Yet we read, we see, we hear of no crisis, about auto battery lifespan in the US southwest. If you believe manufacturer propaganda, that theoretical commute in Phoenix would eat a dozen alternators and six batteries a year per car. Scooze me but I detect a noxious odor emanating from lot of hyperbole. Some applications engineers and Technical Writers obviously have too much free time on their hands.

Full River lists 160° as upper operating, charging, and storage limit as well, though they do state that continuous operation at 100° will result in 25% reduction in lifespan, so I can only imaging what 160° operation would do.

Some OEMs are so careless they manufacture charts for temperature life degradation that a battery would survive a couple of weeks working in 160F temperatures. I wonder how much of this is reality and how much is scare tactics?

The banes of a manufacturer are

Warranty Returns

Justified public criticism gone viral

From Trojan Website.

Trojan FAQ




1. How does temperature affect the performance of my batteries?
At higher temperatures (above 80º F (27º C)) battery capacity generally increases, usually at the cost of battery life. Higher temperatures also increase the self-discharge characteristic. Colder temperatures (below 80º F (27º C)) will lower battery capacity and prolong battery life. Cooler temperatures will slow self-discharge. Therefore, operating batteries at temperatures at or slightly below 80º F (27º C) will optimize both performance and life.
2. How do I determine my battery capacity when it is colder/hotter?
Battery capacity is basically a linear relationship. A good rule of thumb is that for every 15º F (9º C) above 80º F (27º C), capacity is increased by 10% and for every 15º F (9º C) below 80º F (27º C), capacity is reduced by 10%.

3. How do I account for temperature when taking my gravity readings?
Temperature will affect specific gravity readings. As temperature increases, the electrolyte solution expands and as temperature decreases the electrolyte solution contracts. As a result, it is a good practice to temperature correct specific gravity readings. Here are the relationships Trojan recommends using: Every ten degrees above 80º F (27º C) add 4 points to the hydrometer reading.

Example: @ 90º F (32º C) the hydrometer reads: 1.250 the actual reading: 1.250 + .003 = 1.253.
For every ten degrees below 80º F (27º C) subtract 4 points from the hydrometer reading.
Example: @ 70º F (21º C) the hydrometer reads: 1.250 the actual reading: 1.250 – .003 = 1.247.
4. How much should I compensate the charge voltage for temperature?

Temperature will affect voltage readings. As temperature increases, voltage decreases. Conversely, as temperature decreases, voltage increases. Here are the relationships:
Trojan recommends using the following: For every 1º F below 77º F add 0.0028 volts per cell or for every 1 C below 25º C add 0.005 volts per cell to the charger voltage setting.
1: A 12 volt battery @ 70º F. The recommended charging voltage at 77º F is 14.8 volts. The adjusted charging voltage is 14.8 + (6 cells * 7 degrees below * 0.0028) = 14.92 volts.
2: A 12 volt battery @ 21º C. The recommended charging voltage at 25º C is 14.8 volts. The adjusted charging voltage is 14.8 + (6 cells * 4 degrees below * 0.005) = 14.92 volts.


For every 1º F above 77º F subtract 0.0028 volts per cell or for every 1º C above 25º C subtract 0.005 volts per cell to the charger voltage setting.

1: A 12 volt battery @ 85º F. The recommended charger voltage at 77º F is 14.8 volts. The adjusted charging voltage is 14.8 – (6 cells * 8 degrees above * 0.0028) = 14.67 volts.
2: A 12 volt battery @ 29.5º C. The recommended charger voltage at 25º C is 14.8 volts. The adjusted charging voltage is 14.8 – (6 cells * 4.5 degrees above * 0.005) = 14.67 volts.

East Penn aka Deka aka Duracell aka West Marine aka Other Brand Labels

Valve Regulated Lead Acid batteries (gel and agm)