Comet Batteries, batteries, brisbane, battery manufactures, brisbane, Queensland, Australia

Batteries that fail prematurely in Auxiliary power applications are often too small or not recharged correctly. Better life is obtained if the battery is not discharged past 50% or less depth of Discharge. It is recommended NOT to exceed 66.6% depth of discharge. While batteries can be recovered by a long slow charge immediately, it shortens the life. The less the Depth of discharge before recharge and the slower the recharge to fully charged the longer the life.

Deep Cycle Batteries can be charged to a higher Voltage than Standard Starting batteries, 2.5V per cell is ok. This does not mean that they are not charged properly by the normal charging system at 2.3-2.4V per cell. Care does have to be taken to ensure that there is not excessive Voltage Drop to the Battery especially as they can be a long way from the Alternator etc. Also blocking diodes cause a drop of approx 0.6v. Normal starting batteries can operate at voltages as low as 2.2v per cell. These batteries are usually in vehicles which do high mileage (or float charge applications), In high temperature situations and have only small amounts of discharge. If used for Auxiliary power>2.03V per cell is needed. It is advisable to always allow 10% extra charging capacity when accessing your requirements. This is often the cause for batteries in general and Deep Cycle in particular failing prematurely.

Many Auxiliary batteries in 4x4’s are not fully recharged when used for say 4 days and deeply or over discharged then driven some 400km and assumed to be fully restored. The problem is that most systems do not read the state of charge of the Auxiliary battery and charge at a lower rate or do not have the capacity to bring a Deep cycle battery back over the knee of the discharge curve. This also has been the reason for failure of Battery Chargers to perform or even self destruct.

We had one customer destroy three 10amp chargers but only after he fully discharged the battery to get rid of the memory.

SIMPLE MAINTENANCE

After using your battery and when you put the gear away it is good insurance to check the gravity of the cells with an accurate hydrometer to ensure they are fully charged then you won’t have a problem when you next want to use it. NOW is the time to complete your maintenance record click here for a copy.

Store in a cool dry environment with no discharge occurring (if not 100% sure remove the earth terminal)

A top up charge will be required at 6-8 weeks depending on the age of the battery and the temperature.

There are Push Button activated LED Voltmeters available for less that $30 which will tell at a glance when the battery is loosing charge or there are ON Board Chargers which will automatically keep the battery and not overcharged for less than $60.

If your power usage changes so too should your charging and or storage capacity

If any of this is unclear or confusing please contact Robert McGilvery on

07 3265 2233 so I can improve this publication and its results.