Charging the Leisure Battery

[Appycamper]

Hi, can anyone tell me how long on average it will take to re-charge a 110 ah battery from flat. Usually it would not have been allowed to get totally flat, however due to a now fixed fault it resembles a pancake.

 

[RogerL]

It all depends.

Obviously it depends on the charging rate of your charger, anywhere from 3-20 amps and also whether current is being drawn at the same time - so 6 hours upwards but it could be several days.

 

[Appycamper]

I won't be drawing from the battery whilst it is charging, I don't know the rate of the charger. I shall have to be patient!

Thanks for the information RogerL

 

[PeakPaul]

I just bought a new battery, and it recommends you charge it every so often with a proper battery charger, because most caravan chargers dont raise the voltage high enough and only charge the battery to 80% capacity.

 

[Dave_374330759]

Depends on the current rating of the charger and the type of charger. generally if you charge at 10% of the battery capacity it will take about 12-14 hours because the battery isn't 100% efficient so you'll need to put in 20% more than it's capacity For your 110a/h a 5 amp charger will take about 26 hours. You shouldn't try and charge at much more than 10% as you can damage the battery unless it's been specifically designed for fast charging such as a traction or fork lift truck battery.

Secondly if you've let it go flat you probably won't get it back to full capacity again - the worst thing you can do to a lead acid battery is to let it go flat. You really need a smart charger to get the voltage up to 14.4v volts to fully charge it, a caravan charger only get it up to 13.8 which will only get the battery to 80% charge and continuous charging at that level will cause the plates to suphate and slowly kill the battery.

 

[Robtel]

I've read with interest the comments about most caravan chargers only charging leisure batteries to 80% capacity. I had heard about this previously and as a result I brought my battery in from the caravan and tried to charge it to full capacity on a charger specifically for leisure batteries, not sure about the make, might be a Ctek or similar name. Anyway, charger indicated that battery was already fully charged. Do all caravan charger units only charge to 80% capacity? is there antway of telling what capacity specific caravan units charge to?

Thanks

Robert

 

[Dave_374330759]

Have a look at this it gives an idea of the vious stages that are needed to fully charge a battery

Constant Current: The first & main stage of the charging programme, or 'boost' stage, during which the current stays constant. To maintain a constant injection of current requires application of a rising voltage ('pressure') to overcome the steadily rising resistance as the battery's charge rises.

Constant Voltage: "Constant Voltage" means that the voltage at which the charger delivers current to the battery remains fixed or is limited, and the current passed into the battery varies according to the battery's internal resistance, falling progressively as the battery's resistance (to accepting further current input) rises with it's state of charge. This progressively decreasing charge current is also known as the 'logarithmic' charging characteristic.

Battery Resistance: A large battery has less resistance than a smaller similar battery if both are in the same condition or status. Think of eating: a really big man eats more & can eat faster than a small kid. A fully charged battery has higher resistance than when part-discharged just as you eat more slowly when you are full. A deep-discharged or sulphated battery has very high resistance & is therefore extremely difficult to recharge again - it is 'blocked'. Constant voltage ('logarithmic') chargers cannot recharge such batteries because their voltage 'pressure' is limited. But constant current chargers often can because the voltage they apply can temporarily be allowed to rise enough to 'unblock' the battery before again being limited to a safe maximum. Constant voltage is useful for the absorption stage & the maintenance or 'float' stage when the battery already has enough charge to start the engine.

Absorption stage: Where the Constant Current stage can be thought of as the 'boost' stage, the Constant Voltage absorption stage can be thought of as the 'fill' stage. The voltage gradually rises during the constant current stage as the battery becomes charged. When the battery is from 70% to 85% fully charged (70% for small motorcycle batteries, 85% for automobile batteries) the voltage reaches the 14.4 V level at which prolongation of the constant current stage may risk gassing the battery so the charge voltage is now limited at not higher than 14.4V.). This second stage of charging is called the "absorption stage" because it allows the battery to absorb further current according to its need before progressing to the maintenance stage (float charge mode). The absorption stage continues (at the voltage limit 14.4V) until the current absorbed by the battery has fallen to about 200mA to ensure a thorough charge replenishment. Note that automotive & truck batteries which have discharged significantly might need even a few days in the constant current & absorption stages before reaching a good state of charg.

Float charge mode: When, during the absorption stage the current absorbed by the battery has reduced to about 200 mA

the voltage limit is now automatically reduced to 13.8V for the medium to long-term maintenance of the battery, without gassing.

Standby feature: During the float mode multistage chargers continuously monitor the current drawn by the battery. This is especially important when the battery remains connected within a wiring system such as of a vehicle or in a power support system. A will then push the voltage up to 14.4 if the battery voltage drops to maintain a full cahrge

 

[RogerL]

Have a look at this it gives an idea of the vious stages that are needed to fully charge a battery

Constant Current: The first & main stage of the charging programme, or 'boost' stage, during which the current stays constant. To maintain a constant injection of current requires application of a rising voltage ('pressure') to overcome the steadily rising resistance as the battery's charge rises.

Constant Voltage: "Constant Voltage" means that the voltage at which the charger delivers current to the battery remains fixed or is limited, and the current passed into the battery varies according to the battery's internal resistance, falling progressively as the battery's resistance (to accepting further current input) rises with it's state of charge. This progressively decreasing charge current is also known as the 'logarithmic' charging characteristic.

Battery Resistance: A large battery has less resistance than a smaller similar battery if both are in the same condition or status. Think of eating: a really big man eats more & can eat faster than a small kid. A fully charged battery has higher resistance than when part-discharged just as you eat more slowly when you are full. A deep-discharged or sulphated battery has very high resistance & is therefore extremely difficult to recharge again - it is 'blocked'. Constant voltage ('logarithmic') chargers cannot recharge such batteries because their voltage 'pressure' is limited. But constant current chargers often can because the voltage they apply can temporarily be allowed to rise enough to 'unblock' the battery before again being limited to a safe maximum. Constant voltage is useful for the absorption stage & the maintenance or 'float' stage when the battery already has enough charge to start the engine.

Absorption stage: Where the Constant Current stage can be thought of as the 'boost' stage, the Constant Voltage absorption stage can be thought of as the 'fill' stage. The voltage gradually rises during the constant current stage as the battery becomes charged. When the battery is from 70% to 85% fully charged (70% for small motorcycle batteries, 85% for automobile batteries) the voltage reaches the 14.4 V level at which prolongation of the constant current stage may risk gassing the battery so the charge voltage is now limited at not higher than 14.4V.). This second stage of charging is called the "absorption stage" because it allows the battery to absorb further current according to its need before progressing to the maintenance stage (float charge mode). The absorption stage continues (at the voltage limit 14.4V) until the current absorbed by the battery has fallen to about 200mA to ensure a thorough charge replenishment. Note that automotive & truck batteries which have discharged significantly might need even a few days in the constant current & absorption stages before reaching a good state of charg.

Float charge mode: When, during the absorption stage the current absorbed by the battery has reduced to about 200 mA

the voltage limit is now automatically reduced to 13.8V for the medium to long-term maintenance of the battery, without gassing.

Standby feature: During the float mode multistage chargers continuously monitor the current drawn by the battery. This is especially important when the battery remains connected within a wiring system such as of a vehicle or in a power support system. A will then push the voltage up to 14.4 if the battery voltage drops to maintain a full cahrge

Some smart chargers, like the CTEK, also have a "de-sulphation" stage which looks after batteries better and may re-generate old ones.