Battery charging - what do bulk absorption and float mean?

As batteries are charged they go through 3 different states - bulk absorption and float. Here's what is happening at each of these stages and a quick overview of the changing behaviour of the DL-300 charge controller through each of these stages.

1. Bulktroubleshooting
In the first stage of the process current is sent from the wind turbine to the batteries at the maximum safe rate they will accept until voltage is brought up to nearly 80-90 percent full charge level - see table below. During bulkcharge the LED lights on the DL-300 charge controller supplied with the LE-300 and LE-v150 wind turbines blink green there is a long delay and they blink green again.

2. Absorption
In the second stage voltage peaks and stabilizes and current begins to taper off as internal resistance rises. The LED lights at this stage blink green but there is now only a short delay before another green blink.

3. Float
At this point the charge on the batteries is maintained at an optimal level also known as trickle charged. The voltage is reduced to lower levels in order to reduce gassing and prolong battery life. The DL-300 features Pulse Width Modulation (PWM) and sends small short charging cycles or 'pulses' when it senses small drops in voltage. At this point the LED lights are a solid green - no blinking.

As the batteries become fully charged and are no longer able to accept any further electrical energy the battery voltage will rise. When the voltage reaches the regulation level (varies with battery type see below) and starts to dump power the controller's lights are a solid red. This energy is dissipated as heat into the surrounding environment. More or less power is diverted to the dump load according to how much is being supplied to the battery from the turbine.

12V Setpoints
Mode Flooded Sealed
Bulk 14.6 14.3
Float 13.4 13.4

24V Setpoints
Mode Flooded Sealed
Bulk 29.2 28.6
Float 26.8 26.8

Tell us about your project

Our Off-grid experts will come back with recommendations

Please leave your details and our experienced team will be in touch soon to assist you.
Please complete all required fields.
x
Can we help?
Leading Edge
Off-Grid Power Requirements
Please complete this form with your specific requirements and we would be happy to put together a bespoke off-grid power system. We will recommend a solution using our own British made wind turbines, best-in-class solar panels and deep-cycle batteries.

Contact Information

Once we have assessed your requirements, our experts will call you to discuss the equipment you'll need to achieve your goals.

What Is The Application?

Please tell us as much as you can about your use case. We understand that you may not be able to answer all questions. We will call you to discuss your requirements in any case.

Device Name
Voltage
Power Draw (W)
Peak Power Draw on Startup (W)
Standby Power (W)
Hours Active Per Day (W)
Days Per Week In Use (W)

Voltage Preference

Do you have a preference for the system voltage?

Outputs Required

Do you have a preference for the systems output?

Site Location

Please tell us a little bit about the site location

Other Details

No. of days autonomy required

Is there anything else we should know?

Leading Edge
Sign Up To Receive Our Newsletter

Stay up to date with Leading Edge innovations and offers by joining our mailing list. Occassionally we send informative newsletters, offers and promotions that we think you'll find useful or interesting.

Your Details

Please provide your contact details so that you can receive our newsletter. We will send this occassionally with information about our latest innovations and offers.