Battery Charging Facts

There are three types of lead-acid battery that are commonly used in motorhomes, caravans, boats and other vehicles for the purpose of providing 12V power in the living area. They are wet lead-acid, AGM and gel. Each type of battery has advantages and disadvantages and each requires different charging regimes. An "intelligent" battery charger such as those from CTEK, Sterling and NDS will adjust itself as required or, in some cases, can be set at a certain voltage. The optimum voltage depends on the temperature of the battery but, as a general rule in the U.K., below are the suggested charging voltages for lead-acid batteries. The Charging output for a lead acid battery (ie Amp output) should generally be 10% - 20% of the batteries maximum capacity. For example, a 100Ah Lead acid battery would require a charger rated at between 10amp - 20amp.

 

Please Note: using an incorrect charger type for your batteries can negatively affect their performance. As such, using an incorrect charger for your type of battery may invalidate the warranty unless otherwise stated.

 

Standard wet lead-acid batteries

Bulk stage:

14.4V

Absorption stage:

14.4V

Float stage:

13.6V

Reconditioning stage:

 

AGM batteries

15.8V

 

Bulk stage:

14.7V

Absorption stage:

14.7V

Float stage:

13.6V

Reconditioning stage:

 

GEL batteries

N/A

Bulk stage:

14.4V

Absorption stage:

14.4V

Float stage:

Reconditioning stage:

13.6V

 N/A

 

Lithium batteries

Lithium batteries are starting to become accepted as having unbeatable performance when used as leisure batteries. These are capable of have a 100% charge input. For example, a 100Ah Lithium Battery is capable of taking a 100Amp charge. if this is impractical for your use, the standard 10% - 20% rule should be applied. Please find below the charging voltages for Lithium batteries.

Bulk voltage 14.2V - 14.8V

Absorption Voltage 14.2V - 14.8V

Float voltage 13.6V - 13.8V