Dechiphering charging profile conundrum.

[PhilandMena]

I would welcome members unbiased views (Thats Lenny out ) on why Leoch appear to be providing conflicting charging information on their pure Lead carbon deep cycle AGM batteries. I have recently purchased two of them ( LDC12-105-G27-DT).
They, (Leoch) inform me I should charge at 14.4 - 14.7V and float at 13.8V Yet there data sheet (attached) shows charging voltages of 14.4, 14.82, 15.48 & 13.8 V.
Can anyone explain this ?
Thanks in advance.

 

[autorouter]

The manual shows an ideal charging profile, with several set fixed current values, waiting for the voltage to rise to a particular value before switching the current to a different value and repeating the process.

The first stage is a low current of 5.4A (0.05 x 108). It applies that current until the voltage rises to 12V (0.2V/cell). Then it switches to the next stage.

The second stage is a high current of 16.2A to 19.4A (0.15 x108 to 0.18 x 108). This is applied until the voltage reaches 14.4V (2.4V/cell). Then it switches to the next stage.

The third stage is a lower current of 10.8A to 13A until the voltage reaches 14.82V. Then it switches to the next stage.

The fourth stage is an even lower current of 5.4A. The voltage will drop slightly when this lower current is applied, and it waits for the voltage to rise again to 14.82V. When it reaches 14.82V it is held fixed at 14.82V, and the current is allowed to fall. When it drops to 1.08A, it switches to the next stage.

The fifth stage is a very low current of 1.08A until the voltage rises to 15.48V. Then it decides that the battery is fully charged, so it switches to the final float stage of 13.8V.

Very likely your charger can't output this ideal charging profile, so Leoch suggest a good approximation that will be almost as good. If your charger is like most 3-stage chargers, then set the absorption voltage to between 14.4V and 14.7V, and the float voltage to 13.8V.

The charger output current will very likely not be adjustable, most chargers just blast out the max current until the battery hits the absorption voltage.

 

[PhilandMena]

The manual shows an ideal charging profile, with several set fixed current values, waiting for the voltage to rise to a particular value before switching the current to a different value and repeating the process.

The first stage is a low current of 5.4A (0.05 x 108). It applies that current until the voltage rises to 12V (0.2V/cell). Then it switches to the next stage.

The second stage is a high current of 16.2A to 19.4A (0.15 x108 to 0.18 x 108). This is applied until the voltage reaches 14.4V (2.4V/cell). Then it switches to the next stage.

The third stage is a lower current of 10.8A to 13A until the voltage reaches 14.82V. Then it switches to the next stage.

The fourth stage is an even lower current of 5.4A. The voltage will drop slightly when this lower current is applied, and it waits for the voltage to rise again to 14.82V. When it reaches 14.82V it is held fixed at 14.82V, and the current is allowed to fall. When it drops to 1.08A, it switches to the next stage.

The fifth stage is a very low current of 1.08A until the voltage rises to 15.48V. Then it decides that the battery is fully charged, so it switches to the final float stage of 13.8V.

Very likely your charger can't output this ideal charging profile, so Leoch suggest a good approximation that will be almost as good. If your charger is like most 3-stage chargers, then set the absorption voltage to between 14.4V and 14.7V, and the float voltage to 13.8V.

The charger output current will very likely not be adjustable, most chargers just blast out the max current until the battery hits the absorption voltage.

Thank you for your reply. What you say makes sense to me as it it agrees with the charging profile for this battery. For what its worth I have always considered your input on charging issues to be informative and more accurate than some of the posts I read.
I raised this question as the information I received from so called battery experts was IMO a little misleading in as much as one said its for a 5 stage charger but has not replied to my queery why a 5 stage charger is allowed to charge at a much hifger voltage than a 3 stage charger. Thanks again for your input.