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Battery charger question Answered


I have just bought a charger for my motorcycle.

it was advertised as having a trickle charge function; which I believe is good for battery longevity ( and I only use the bike once or twice a week).

However, it does not have a trickle charge function but it does have a pulse function ( which it recommends for motorcycle batteries as the normal ampage output is too high for small batteries).

Thiis is meant to be gentle and does not create the bubbles caused by electrolysis, but is it worse or better for the battery than a trickle charger ?



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1 year ago

Trickle charge is pulsing at the end of the charging cycle...
See, normally, one first charges with constant current till the charging volate is reached. Then the charger switches over to constant voltage.
If the current is dropping below a certain threshold with constant voltage, the battery is considered charged. As a lead-acidbatterery has a self-discharge, the trickle-charge is simply the charge loaded into the battery equal to the charge lost due to self-discharge. This is selfregulating for lead acid if you leave the battery in constant voltage.

But: A constant discharge can lead to the buildup of gases in a battery (Oxygen and hydrogen). Often, pulse-charging (Sometimes even discharging a little bit (like half a second) and then charging) helps to counter this effect as far as i know...
So yes: A pulse-charge is propably better than a constant CC/CV (+TC) but not 100% sure. Othery may chime in with more info on this...


Reply 1 year ago

Hi Orngrimm,

Great! thanks for the info. : )


1 year ago

It depends on how the manufacturer definse "pulsed".
In the most basic form the charger will really just turn on an off at an interval not long enough to cause serious bubbling.
If implemented as "trickle" it will reduce the amps once the battery gets full.
And once full the charger will only send short bursts of low current to keep the battery full.
I have a cheap one from Aldi with a LCD display.
With the batttery a bit drained it starts on full (for motorcycle use) power.
Once the last two bars are left for the charge the current is reduced to about half, or in my case about 1.5A.
It reduces again to about 500mA when the last bar turns on.
And whenever the thing says the battery is full a LED changes color and then blinks every few seconds.
My multimeter registers that something goes into the battery during this blink but is unable to get the reading before it is gone

Jack A Lopez
Jack A Lopez

1 year ago

Is it a contradiction for this thing you call, "charge function," to be both "trickle charge function" and "pulse charge function" at the same time?

I mean, I think the word "trickle" simply means "small current", and if you want to quantify how small it is, this done by dividing the battery's nominal capacity, in ampere*hours, by some quantity of time, in hours.

Also there is a funny kind of jargon for this, brought to you by the letter "C." The jargon looks like: C/3, C/10, C/100, and similar.

For example, if you have a battery with capacity of 10 A*h, dividing that number by 10 hours, gives the C/10 rate, which is (10 A*h)/(10 h) = 1.0 A. The C/100 rate for the same battery would be 0.1 A = 100 mA.

I think C/100, or less, is small enough to be called "trickle." Although, honestly I am not sure where the line gets drawn.

In advertising copy, the meaning of words can be exaggerated, or diminished, almost without restraint, to the point where we don't know what they're selling.

Also, for lead acid batteries, there is a charge method called "float" (also "float charge", "float charging") which is essentially charging with constant voltage. For lead-acid batteries, this kind of charging kind of naturally leads to diminished, almost zero, current at the end of the event. Like, suppose the battery and charger have the same voltage, and are connected by wires having resistance R. The current (Vcharger - Vbattery)/R = 0 when Vcharger = Vbattery.

But getting back to my original question, about a charge rate, an electric current, being both "trickle" and "pulsed" at the same time, what is the meaning of "pulse?"

A current that is pulsed is one that is not constant, with respect to time, but do we care about that?

I mean, the reason it might not matter, is because charge is the time integral of current, and that might be the quantity that is important, to the task of "charging" the battery.

In other words, if current is defined in a time averaged sense (with the averaging period small compared to the charging time; e.g pulses with periods measured in seconds or less, compared to charging time in hours, or longer) then the current can be both "trickle" and "pulsed" at the same time.

By the way, you are asking about a starting battery for a motorcycle, probably lead-acid chemistry? Am I right? I mean this is not a battery for an electric motorcycle. If it were, I would expect it to be "big" rather than "small." and I would almost kind of expect it to be a better (more energy dense) chemistry, like Li-ion, or something, if it were a battery for doing the work of pushing the motorcycle down the road.