Good Day,

I am having trouble to compute the charging time of my battery with this kind of set-up:

(2) 300W 36V PV Panel (1) 500W 24V Wind Turbine (1) Hybrid Charge Controller (6) 12V 200Ah Batteries @ 24V Configuration

The batteries are connected to series-parallel connection that will give 24V 600Ah output. enter image description here

How long is the charging time of my battery?

Thanks in advance! :)

  • \$\begingroup\$ Your death battery kill good batterry. :) Separate every battery charge channel for fast charge. You kill good battery if other be corrupted on same group. \$\endgroup\$
    – dsgdfg
    Apr 11, 2016 at 8:48

2 Answers 2



Your battery has (seen from the outside) a capacity of 600Ah.

In an ideal world: If you would start with a empty battery and could charge it with 600A it would be full in an hour.

In a real world: Each battery loses some energy while charging. This can be between 10% to 40%. Our empty battery would be full after 1.4 hours.

You can charge in the best case with 800W (300W PV and 500W Wind).

800W / 24V = 33A

600Ah*1.4 / 33A = 25H

This is a simplified version of the reality. Your wind and solar will probably never reach the 800W.

  • \$\begingroup\$ My Battery is Deep-Cycle Battery so how can I calculate the charge current in amps. \$\endgroup\$ Apr 12, 2016 at 1:34
  • \$\begingroup\$ Deep-Cycle only means, that it does not get damaged if you discharge until a certain low level. It does not tell you anything about the current \$\endgroup\$
    – Botnic
    Apr 12, 2016 at 7:17

Botnic gives a good simple answer. Here is the additional information that makes the answer 'complicated'

I assume that you are using lead acid battery, but the same applies for lithium ion. They use a constant current-constant voltage charge scheme which means that it's not a simple calaculation.

So a 600Ah battery charged at 600 amps will take longer than one hour to charge. Lead acid are even more complex because as they get fuller, they get less efficient so that for every amp you put into the battery, only 60% or less actually goes to the charge, the rest is wasted.

For a lithium ion battery you take the expected time to charge multiply by 1.4. So a 600Ah battery charged at 600amps, would take 600/600 × 1.4 to charge. The 1.4 is for the constant voltage stage of charging, which is different than the 1.4 that is used in the first answer, which was for ineficciencies. A lead acid battery is similar, but takes a little longer because of the inefficiency as it fills up.

So with this info, aply to your numbers.

  • \$\begingroup\$ My Battery is Deep-Cycle Battery so how can I calculate the charge current in amps. \$\endgroup\$ Apr 12, 2016 at 1:33
  • \$\begingroup\$ @ynanperillo - Whats important is that its lead acid battery, not deep cycle, but more than that, your charge controller will determine the charge current. But based on your solar panel and wind turbine we can estimate charge current. Solar panel: 300watts/36volt = 8.33 amps. Wind turbine:500watts/24volts = 20.833 amps. If both the solar panel and wind turbine are 'running' at the same time, then 29.16 amps total charge current maximum. \$\endgroup\$
    – Filek
    Apr 13, 2016 at 5:11
  • \$\begingroup\$ The above calculations are simplified, you are running a 36volt solar panel at 24 volts for the 24 volt battery bank, so it will likely run at lower than 8.33 amps. The only way to know would be to get the I-V curve from the manufacturer, but at least you have an approximation. And obviously during the night, only the wind turbine would be running so charge current would be 20.8 amps max. \$\endgroup\$
    – Filek
    Apr 13, 2016 at 5:13

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