Help for shorten SLA battery charging time.

[nguyennam]

battery charging time

Hi everybody,
I have an electric bike, and its SLA battery needs about 8 hours for charging from entirely discharged status to 90% charged as per instructions. And this long time is not always convenient for me, especially at the daytime when I need a rechage.
So could you let me know if I can increase charging voltage/current in order to shorten the charging time, for example, down to 3 of 4 hours. If I do that, is the battery life time affected?
Thank you very much in advance for your help.
NguyenNam

 

[dindeds]

how to recover the sla battery

It looks like yr SLA battery has develop fault in some of its internal cell. Most often this type of battery fault due to dried out electrolyte due to improper charging and discharging. (You entirely discharge the battery?)
There is no cure for this type of fault then to buy new one.

 

[IanP]

sla battery fast charging effect

SLA charging & chargers
Unlike NiCads, SLAs are not really suitable for very fast charging. Most manufacturers recommend that they should not be charged in less than 5 hours, or at a charging current level of higher than 0.4C although some SLAs are able to accept charging currents of up to 0.8C for at least the initial phase of charging, without adverse effects.

More details at:
**broken link removed**

Regards,
IanP

 

[nguyennam]

sla battery initial charging

Thank you IanP for the document.
It means that I have no choice, and have to obey the rule. Anyway, I understand more about SLA, I did think that it can be charged in the very short time just like Li-Ion or Ni-Ca/Ni-MH batteries before.

nguyennam

 

[IanP]

charging times for sla batteries

One other option that you may consider is called "pulsed charging" ..
Here are some details:

Pulsed Charger.
Uses a series transistor which can also be switched. With low battery voltages the transistor remains on and conducts the source current directly to the battery. As the battery voltage approaches the desired regulation voltage the series transistor pulses the input current to maintain the desired voltage. Because it acts as a switch mode supply for part of the cycle it dissipates less heat and because it acts as a linear supply part of the time the output filters can be smaller. Pulsing allows the battery time to stabilise (recover) with low increments of charge at progressively high charge levels during charging. During rest periods the polarisation of the cell is lowered. This process permits faster charging than possible with one prolonged high level charge which could damage the battery since it does not permit gradual stabilisation of the active chemicals during charging. Pulse chargers usually need current limiting on the input source for safety reasons, adding to the cost.

Also, see picture below ..
It may work .. who knows ..

Regards,
IanP

 

[nguyennam]

charge profile for sla

Thank you IanP for your info.
I also read somewhere (I do not remember), there are the techniques of charging batteries by non-symmetrical AC current, or charging via some stages with the first one is overcurrent, ... so the charging time should be reduced and while battery life time is prolonged. But all is reading, I have try to find out the trusted document, and the circuits as well, but for the time being I find out nothing. However, I am thinking of doing experiment on my SLA.

nguyennam