The Basics Of Lead Acid Batteries
Invented in the 1900s, the lead acid battery is one of the oldest battery designs. But they work so well that they just keep sticking around through the years. Aptly named, it’s comprised of lead plates and a sulfuric acid solution. The negative and positive plates exchange ions and the acid carries the current created by this exchange through the battery. The chassis battery and the house batteries are made of the same components, but small variations in their designs make a huge difference in how they work.
The Chassis Battery
Inside your chassis battery you’ll find six cells, each of which produces two volts, giving you a 12-volt battery. As the ion transfer happens, the sulfate collects on the plates, and over time the transfer can no longer happen due to this build up. This is called a “dead battery.” When you send a charge into the battery, it removes that sulfate from the plates, putting it back into the water, and then restores the battery’s ability to make that transfer. If the layer of this sulfate gets too thick, or is left for too long, it won’t release even when you charge it. In your chassis battery, the plates are relatively close together and have thin electrodes. This allows it to give that strong punch of power needed to start the motorhome's engine. Because such a strong jolt of power is needed, a lot of the sulfate collects from just one use and needs to be removed quickly to avoid the hardening, which is where your alternator comes in. If you run your chassis battery until it's dead, it can really cause damage and shorten the life of your battery immensely.
The House Battery
The house battery is put together in the same way the chassis battery is but with a few minor differences. The electrodes are thicker which increases the density of the energy created, there’s more space between them, and there’s area at the bottom for the sulfate to fall instead of sticking to the plates. These changes give off a lower current that will power your TV, smoke detectors, and other items that don’t need the punch that the engine requires. It also lasts a lot longer since the build up isn’t as thick and won’t prohibit the movement of energy as much as the chassis battery can. You don’t have to charge them as often, and when they die, it’s not as crucial as when the chassis battery dies. Now, don’t get us wrong, you still need to keep this battery charged as that build up can still stick to the plates, or even become solid in the bottom of the battery and unable to redistribute, but it’s just not going to happen as fast as it does with the chassis battery.