If you added two extra batteries in a series wiring configuration to make a 48 Volt battery pack then you would need to charge it with a 48 Volt battery charger.
However, we do not recommend increasing the battery pack to 48 Volts because that would overvolt and most likely burn out the controller and motor.
Instead of wiring the four batteries in series to make a 48 Volt battery pack we recommend to wire them in a series/parallel wiring configuration as shown below to keep the battery pack 24 Volts.
With a 24 Volt battery pack wired in a series/parallel wiring configuration the original charger may or may not have enough output Amps to charge the new battery pack. If the new 24 Volt battery pack was made from four 12V 10Ah batteries then it would be a 24 Volt 20Ah battery pack and it would require a minimum battery charger size of 24 Volt 2 Amps and a maximum battery charger size of 24 Volts 6 Amps.
Also, when making a battery pack wired in a series/parallel wiring configuration all of the batteries should be the same brand, Voltage, Ah rating, and age. If a battery pack like this was made with two old batteries and two new batteries then the Voltages of the batteries could become unequalized during usage and recharging which would cause some of the batteries to be overcharged and some of the batteries to be undercharged which would lower the lifespan of the battery pack.
To use two separate 24 Volt battery packs that are made with different brands, Ah ratings, or ages of batteries they could be made into two separate 24 Volt battery packs and there could be a switch that switches between each battery pack, kind of like a truck that has two gas tanks. In this scenario, each battery pack would need to be recharged individually and in order to recharge both of them at the same time, two battery chargers would be needed. More information regarding installing two individual battery packs with a switch can be found in this forum topic: https://support.electricscooterparts.com/support/discussions/topics/1000079858
Thank you very much for your explanation, it was very useful.
Let me further inquiry something, please. If we change this setup to 24V/20ah, the new current would not damage the motor that I have ?
Also, my current setup of 24V / 10ah is not being properly charged.
Checking the output of the charger I see only 18V (while I see on many different topics that the proper amount should vary between 27V to 28V). My charger is also with the light always green, therefore I'm assuming that I have a defective charger. The 18V should not charge the battery on a slower pace, though ?
Thanks and Regards
Increasing the Ah rating of the battery pack will not change the amount of current that the controller demands from it so it will not damage the motor or any other electronics that are connected to the battery pack.
The charger needs to output around 28-29 Volts in order to fully charge the 24 Volt battery pack. If it outputs 18 Volts that will not charge the battery pack because the battery pack is a 0% state of charge at 21 Volts.
Here is a state of charge chart for a 12 Volt AGM battery. This chart's Voltages can be doubled for a 24 Volt AGM battery pack.
Hi, thanks for the support so far.
It turns out I really had a deffective charger that was outputing only 18V. Now I switched to a new one that is outputing 30V and the battery charged a litle more (after 12 hours the battery is charged to 19,6V).
It seems to me that after 8 months without usage even the battery could not be charging properly anymore, as it's not fully charged after long time. The battery is pretty new (was used only twice), but due to the charger I was unable to charge it since then. Could this be an issue ?
Regardless of that, the eZip 500 with 19,6V is still showing the battery as "low" and don't move the wheel. The 19,6V is not enough to turn the motor ?
Again, thank you very much for your prompt response and willigness to help.
So I have seeing the "Battery Pack Wiring Guide":
And there it states that wring the batteries sequentially would add the voltage. Currently I have an eZip 500 with 24V - 10ah, I would like to put two more batteries sequentially in order to have more mileage, do I have to exchange my charger from 24V to another one from 48V if I do that ?
Can anyone tell me if it makes sense to do it ?
Thanks and Regards