Epic solar boat adventurer - Stress testing my old battery

I've had this big old deep cycle battery for years, and I don't know enough about it so I thought I'd learn some stuff.

It's a conventional, unsealed, 100ah lead acid, deep cycle thing.

At least I think it's 100ah. That's the kind of thing you'd think someone would emboss onto the side rather than adding it as a stamp. That and the voltage.

At least they went to the trouble of embossing the + and - marks.

So with this kind of battery, it seems they don't mind being run down as much as, say... a car battery might. Car batteries hate it when they are run down, and it shortens their lives in a big way.

A deep cycle battery (also called a flooded battery apparently) is a bit more forgiving, but they still see damage with every bit of use. The lower you allow the voltage to get before recharging, the less charge cycles you get from them before they need replacing. 

As I understand it, 11.8v is considered "empty", but that's at rest 6 hours after you stop using it.

I need to know what "empty" is when I'm cruising along drawing 20 amps or 35 amps (that being the amount of juice the motor pulls from the battery at speeds 4 and 5 of 5.

So my education for today turned into more questions than answers. It looks like it's business as usual.



120 Things in 20 years thinks the Internet might not know something I need to know.

Aquaponics - Inverter based electrical backup system

We get a lot of blackouts.

Fish hate blackouts.

I'm going to blackout proof my planned, larger, aquaponics system by building an electrical backup. I also need to build my planned, larger, aquaponics system.

Here's what I've done so far...

Attractive isn't it.

I happen to own a one hundred amp hour deep cycle battery. That's it in the bottom right corner of the picture.

I also own a multi-meter, a battery charger, a powerhead, and a bucket of water. 

As of today I also, also own a 200 watt inverter. It's a device that turns 12 volt battery power, into mains power. I had to buy it. A small inverter doesn't cost much and you can pick one up online, or in camping sections of department stores.

A power head is essentially a fish tank stirrer. It aids in supplying the water with oxygen, and will also create a bit of a whirlpool to concentrate fish waste solids into the center of the planned, larger, fish tank. This will allow the solids to be extracted from the fish tank, and moved to the planned grow bed where they belong. 

The powerhead is a critical component, because I'll be relying on it to supply oxygen to my fish in case of a power outage or pump failure. That's the powerhead in the blue bucket. It's basically just a small motor with a propeller on it. According to the box it came in, it moves 5000 litres of water per hour. The best part is, it moves all that water with only a 12 watt motor. My pump also moves about 5000 litres of water, but it has a 150 watt motor. 

The pump's main purpose in life is to supply the grow bed with nutrient rich water, but the bacteria will be fine for a couple of days if it fails. A system full of fish on the other hand, will start to suffer within an hour or so if the water isn't moved around.

I'll run the pump on a timer, so that it runs for around 10 minutes of every hour. I'll run the power head all the time.

The plan is to run the powerhead from the large battery, via the inverter, and to run a battery charger to keep the battery topped up at all times. Based on the tests I'm currently running, and on my rough calculations, in the event of a blackout, I estimate the battery should last approximately forever. 

So far I've been running the powerhead for 4 hours using the battery alone (ie without the charger), and the batteries capacity has actually increased. Which is odd. I'm guessing it has something to do with the day warming up, which might be changing the battery's abilities. 

This electricity stuff is really the kind of thing I should know something about. Perhaps I'll look into it.