[Lazy Iguana]

A car battery and a deep cycle marine battery are similar. The big difference is in the lead. What kills a lead acid battery is sulfation, or the crystallization of lead sulphate. This happens when a lead acid battery is discharged for too long.

With an automotive battery, once the thing is allowed to discharge (dead battery) the useful life is limited. Auto batteries are not designed to discharge. They are designed to provide a lot of current (amps) for starting. Once the engine is running then the car engine takes over supplying all the power the car needs.

Deep cycle batteries take being discharged better. The plates resist the formation of lead sulphate. Deep cycle batteries tend to be larger and heavier than other types of lead acid batteries of the same amp hour rating.

A lead acid battery backup system CAN work - but you have to realize the limitations and either have a large enough battery bank for all your stuff OR carefully pick what devices you want backed up.

You also have to take into account the size of your tank. The larger the tank - the bigger the pumps - the more power is needed to make it run. You may be able to back up everything for a nano tank - lights and all. But if you are talking about a 250 gallon reef tank with multiple 300 watt HQI lights forget about backing that up with a battery system unless you have a small room or walk in closet that you can fill with batteries.

But you do not always need to back up everything. If the power outage is only a few hours then maybe all you need are a few circulation pumps. In this case a simple battery backup system would work.

But for longer outages that last a few days - you pretty much are going to need a generator.

I wish I could say that a solar system would work, but the cost is still too high. I looked into panels for my boat that would be able to put a charge on a battery, as opposed to simply maintaining a battery. In other words, I needed a panel that could supply at least 55 watts (or around 5 amp hours). This would charge a battery drained to 50% in a day or two. It would also supply enough power to run some of my boat electronics.

Even better would be a 125 watt panel. A 125 watt panel would run all my electronics.

But a 55 watt panel costs at least $500. Now add the charge controller and voltage regulator and you are up to $600 easy.

So I ended up with a $100 dual bank (5 amps charge for two batteries) smart charger that plugs into the wall.

Now what solar chargers are great for is keeping a battery at 100%. Lead acid batteries discharge over time. Every day, every hour - they are slowly discharging. Maintainers work by supplying just enough current to counter this effect. So your battery is always at 100%. You only need a little bit of power for this, even for a large battery. Maintainers sold for cars only put out 5 watts of power. These chargers require no charge controller or voltage regulator - as the power they generate is not enough to do anything unintended (larger panels CAN overcharge and cook a battery by boiling off all the acid and/or splitting the water into hydrogen and oxygen which in turn could cause an explosion).

The problem is a maintainer can not charge a battery - only keep it topped off. Think of it like trying to fill and empty aquarium using a dosing pump. How long would that take?

To have a decent amount of charging capacity, you will need at least 15 - 30 watts of solar panels and a charge controller rated at at least 7 amps. Once you get to 100 watts of solar you need a larger controller. The best price I can find for a 15 watt panel (I did not look too long) was $100 at Sportsmansguide.com

I am hoping that as time goes on, and more companies get into the solar kick, prices for panels will drop.

And if Honda or Toyota would make a car with a 55 watt panel built into the roof - auto batteries would last much longer. I am surprised that the Toyota hybrid does not already have a solar panel roof. Park that thing in the sun and catch a free charge! Sounds good to me.

I would not count on GM or Ford to do this. Dodge maybe - as the parent company was bought up by Mercedes Benz and those Germans are heavy into the solar thing.