FAQ for lead-acid batteries
What is charging receptivity?
It is a measure of how well the batteries receive power. Larger battery banks provides higher charging. Older batteries have poorer receptivity.
Will my batteries discharge eachother?
No, as long as you have fresh batteries. Only small currents transfers between the batteries and the effect of it requires a very long time for emptying your battery. However, if you have a defective battery it will empty the fresh batteries in the same circuit, and in the long run also damage them.
Will the consumer batteries discharge the starter battery when I start the engine?
No, the starter engine lowers the voltage more than the discharged batteries and will take all power during the start. If you have a diesel that needs spark-ignition, a small amount of power will transfer from the starter battery to the consumer bank, for a few seconds, but it will never be over 1 Ah.
How long life span does my lead-acid batteries have?
In most boats only half of the battery capacity remains after three years, so then it's time to change.
Can I increase the life span on my lead-acid batteries?
Yes. By expanding the battery bank, charging receptivity is increased and deep discharges will decrease and reduce wear on lead-acid batteries. Also the handling when not in use, affects life expectancy.
How deep can I discharge lead-acid batteries without damaging them?
To avoid drastically shortening of the life span on your lead-acid batteries, marine and leisure batteries should rarely be discharged to 50 percent. In normal use, you should ideally hold over 70-75 percent of the battery capacity. Gel and AGM batteries are more durable.
Can my lead-acid batteries be overcharged?
If charging lasts for a number of hours at 14.4V, your lead-acid batteries will be overcharged. Before, the lead-acid batteries gased a lot. Nowadays the gasification are mostly removed since most batteries are closed. Therefore, there are few boats that are going on the engine so long that the gasification becomes a problem.
How much capacity do my lead-acid batteries have?
How much electricity your lead-acid batteries really contain when they are fully charged, you can not find out by measuring the voltage. If lead-acid batteries have lost capacity, you can only find out by doing a load test.
Should I top-load the batteries?
Yes, because the battery life span will increase if they get top-loaded sometimes. A solar panel can handle the top-loading for you during the weeks, while the boat is not in use.
Can a shorepower charger top-load the batteries?
Of course, the disadvantage though, is that you have to find a jetty with electrical outlets to connect your charger to, whne you are out ona aboat trip. It is easier to top-load with a solar panel.
Can a shorpower charger provide galvanic corrosion?
Yes, if earth on land is not separated from earth in the boat.
What charger should I choose for my lead-acid batteries?
Avoid old transformer chargers. Instead, invest in a modern battery maintainer. Big chargers charge faster than small, but are more expensive. However, you often rarely need a charger that can handle more than 10 amps.