Forum Discussion

MEXICOWANDERER's avatar
MEXICOWANDERER
Explorer
Aug 21, 2014

CHARGING TERMS Bulk/Absorbsion/Float

Lots of confusion about these three terms. Let's simplify things a little.

We have a TWO STAGE CHARGER. The main charger and a float. Not a three stage, that's a bunch of marketing hooey.

The MAIN charger has a VOLTAGE LIMITED point. The voltage rises to this limit point in volts then stays there for god only knows how long before voltage is changed to a much lower maintenance value for maintaining the battery in hibernation.

Let's keep temperature compensation back behind the barricades on this one. This is a simple accurate explanation.

You connect the charger to the battery and turn it on.

As long as the battery is charging and the voltage is rising, slow or fast HAS NOT REACHED THAT AMBIGUOUS pre-determined and preset voltage set point IT IS CALLED BULK CHARGING.

The voltage keeps rising and bingo, it reaches the voltage set point whatever the hell the nut farm slide rule boys at the manufacturer has determined to be the maximum voltage charge point.

WE NOW CALL THE CHARGING PROCESS "ABSORBSION" and forget about the word BULK.

The voltage limit has been reached. How LONG the voltage stays steady and the battery is allowed to charge is anyone's guess - Groucho, Harpo, and Zeppo now have control of the charging process. WHEN, HOW LONG? I ask. How long does the battery stay at "absorbsion" voltage limit before dropping down into float?

The absorbsion VOLTAGE LIMIT (setting) and time spent at this voltage limit...

SHOULD HAVE THE ABILITY TO BE ADJUSTED BY A USER

But they don't have that ability. I would like to see one that does...

This is like a car that automatically goes 37 miles an hour. In bumper to bumper rush hour or across the wilds of West Texas.

But knowing what your SMART CHARGER

CANNOT POSSIBLY DO

Should be job one. Learn about the mess that is under your counter and the gyro gearloose smart chargers that are purported to be "better".

INTELLIGENT battery charging DEMANDS adjustable voltage set points and ADJUSTABLE time spent at absorbsion.

Good luck trying to find these features.

Press a button, take a pill, Don't Worry be Happy!
  • NinerBikes's avatar
    NinerBikes
    Explorer
    Aug 23, 2014
    MEXICOWANDERER wrote:
    No paisley shirts and fluorescent ties allowed in the lab.

    My company challenged Technobabble for our clients. One of whom as an example, paid four thousand dollars, and furnished quite a bit of gift material to establish if yes or no an OEM's claim of "Miracle Selenium Plate Alloy" affected either the 5 hour or 20 hour amperage rate. We were given 12 batteries. Six with the selenium and 6 without. A total of (16) 80% DOD exercises were performed. I merely handed the customer the results of the exercise. The sixteen L-16's went to a good cause.

    US Borax (named because they were so rude on site) challenged a vendor that their 8D battery was "junk". Do something or we're going to find another vendor.

    I found out on site their Terex Titans with massive lighting systems were DOD'ing batteries anywhere from 50 to 95 percent due to inadequate drive pulley ratios on 24 volt alternators rendering 11 mps charge rate at engine idle. The machines spent 70% of their shift idling. I recommended they switch to the Leece-Neville 3825JA alternator, a bolt-on swap. it would have increased idle amperage to around 55 (as seen on my test bench).

    A sneering foul-mouthed maintenance supervisor started spouting garbage. I turned to the vendor and said "Every second you spend with this outfit is a waste of money" We departed. Such situations were an important percentage of my income. Time spent: a little over five hours. Gross income three thousand dollars.


    Gee, I wonder if you were a little East of Edwards Air Force Base for that one? Seems like portal to portal charges were due. Mining folks, where time is money, are a surly lot. So are General Contractors.
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Aug 23, 2014
    Voltage limit (regulated) power for charging

    When this voltage is reached (pretty simple to determine). A timer starts.

    After the timer gets bored, the charger switches to a lower voltage maintenance level called float.

    Now give the above to the paisley shirt and fluorescent tie crowd and they will amplify it to 2,000 words and sixty seven empty promises.
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Aug 23, 2014
    No paisley shirts and fluorescent ties allowed in the lab.

    My company challenged Technobabble for our clients. One of whom as an example, paid four thousand dollars, and furnished quite a bit of gift material to establish if yes or no an OEM's claim of "Miracle Selenium Plate Alloy" affected either the 5 hour or 20 hour amperage rate. We were given 12 batteries. Six with the selenium and 6 without. A total of (16) 80% DOD exercises were performed. I merely handed the customer the results of the exercise. The sixteen L-16's went to a good cause.

    US Borax (named because they were so rude on site) challenged a vendor that their 8D battery was "junk". Do something or we're going to find another vendor.

    I found out on site their Terex Titans with massive lighting systems were DOD'ing batteries anywhere from 50 to 95 percent due to inadequate drive pulley ratios on 24 volt alternators rendering 11 mps charge rate at engine idle. The machines spent 70% of their shift idling. I recommended they switch to the Leece-Neville 3825JA alternator, a bolt-on swap. it would have increased idle amperage to around 55 (as seen on my test bench).

    A sneering foul-mouthed maintenance supervisor started spouting garbage. I turned to the vendor and said "Every second you spend with this outfit is a waste of money" We departed. Such situations were an important percentage of my income. Time spent: a little over five hours. Gross income three thousand dollars.
  • chilly81's avatar
    chilly81
    Explorer
    Aug 22, 2014
    Go solar - Morningstar TS-mppt-60 has so many ways to configure it's charging parameters it will make your head spin. Yes, absorption duration is one setting.

    It is marketing terminology but there is scientific merit in providing a distinction between the 3 levels/stages/phases/settings of:
    1) as much power as can be supplied as we try, but have not yet reached a certain voltage (especially pertinent in Solar where you can't just say "Set 15v!" if you don't have enough juice to make it happen).
    2) We have reached and are maintaining a certain voltage.
    3) We drop to a lower voltage because staying at that #2 voltage forever is bad for the battery.

    There's a valid reason for the 3 'levels' (if you prefer). So of course someone has to make up fancy names for them - but that's just human nature.
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Aug 22, 2014
    My offered values are for an off-grid 5.0% antimonial battery that is being charged via a generator.

    Batteryspeak is done at a quantified temperature of 20C, not 10C or 30C. Temperature derating charts can be found all over the internet.

    If I have to insert 3 pages of definitions, quantification and caveats before every answer it's going to become too much for my fingers.
  • AH64ID's avatar
    AH64ID
    Explorer
    Aug 22, 2014
    MEXICOWANDERER wrote:
    To label something as process "normal" means there has to be something commonly found abnormal to compare it with.


    As stated the labels from PD are in quotes, not my labels. Like everything else aftermarket it's a sales thing.

    MEXICOWANDERER wrote:
    13.6 is a good, normal all-around float voltage value.

    14.8 is a good normal set point for absorbsion.

    16.0 is a good normal end point for equalization.



    You need to specify the type of battery for those voltages.

    My batteries want 14.4V ± 0.2V for Bulk/Absorption and 13.25V ±0.15V.

    Neither of those fall into your float or absorption values.

    The conditioning voltage, aka equalizing, voltage is 15.5V @ 77°F, and goes up or down depending on battery temp.
  • BFL13's avatar
    BFL13
    Explorer II
    Aug 22, 2014
    MEXICOWANDERER wrote:
    13.6 is a good, normal all-around float voltage value.

    14.8 is a good normal set point for absorbsion.

    16.0 is a good normal end point for equalization.

    The charger is doing one of three things...

    Charging

    Floating

    Unplugged


    It is not a "charger" it is a "converter" so besides "charging" it is also running "loads" even when the battery is fully charged.

    If there are no loads and the battery is fully charged the converter (if so designed) will drop to 13.2v for its "float voltage" stage. some of them have a little shot of 14.4v every so often tossed in with that third stage to prevent stratification. Some converter makers go so far as to call that a "fourth stage" and even call that little shot of 14.4, "equalization"

    That is so they can sell their "4-stage converter" which is better than the other guy's mere "3-stage converter."

    You can't fight it Mex. It is sales not engineering that runs the World. You know that! :)
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Aug 21, 2014
    13.6 is a good, normal all-around float voltage value.

    14.8 is a good normal set point for absorbsion.

    16.0 is a good normal end point for equalization.

    The charger is doing one of three things...

    Charging

    Floating

    Unplugged
  • BFL13's avatar
    BFL13
    Explorer II
    Aug 21, 2014
    It is a converter for goodness sakes. "Normal" is sitting there on shore power camping at 13.6v forever. If you want faster charging (more amps) you just hit the "Boost" Button and jack up the voltage to 14.4v. Now you get more amps (of course)

    What's so complicated? The term "Boost" in this case is perfectly normal :)

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,193 PostsLatest Activity: Jan 26, 2025