Backyard Aquaponics
A place to discuss aquaponics

Thanks F&F, what about whether a deep cycle battery is necessary or if a car battery is OK? I could get a new one for probably $60.

BTW, I'm planning on driving less than 100 watts with the battery and charger. Probably just a small pump around 40 watts?

You are probably going to want a deep cycle. The chemistry of the cell is such that repeated use and charge is efficient, where a non-deep cycle is not. A car battery would probably work a few times, but then become less and less charged, so you'll get less and less back up time out of it.

Here again a car battery $60 will do the job you want but a $120 deep cycle battery will be twice as good
Shore a car battery will be ok
i say horses for corses here during recent stormes ,fires ,ect power was out for days
dont say it wont happen here it probley will

I was planning on running this pump through the battery on all the time, not just as a backup. Does that affect what type as well? The plan was that this pump would be hooked up to the charger->battery->inverter running always, do I need to get some kind of switch just for when the power goes out or is this always-running through the battery thing OK to do? I guess I should do a search of the forum, huh?

If you use a car battery then you will kill the battery if you let the voltage get to low. A deep cycle battery will keeps its ability to hold a charge if you run it down. Either way, be sure you have a smart charger so you dont fry your battery too.

Kthx, not sure if my charger is smart. Is it that it varies the current lowering over time that makes ti smart, or some kind of monitoring built into it?

Simple 2 stage recognises when the battery is full and then puts a float charge on it (just to hold it at full).

Thanks Sleepe!

I just read a bit about batteries and it sounds like a float charge will be what is going down most of the time.

http://www.windsun.com/Batteries/Battery_FAQ.htm

Hey I just read that RVs use deep cycle batteries. We have our travel trailer that has been parked in our yard since we moved in 2003 (I call it my albatross because it is a 15 year loan and we aren't likely to use it anytime soon/ever again). I bet the battery on that is deep cycle. Maybe the electronics for it are detachable as well? When the trailer is unplugged only the interior lights work from what I remember. The power management for the battery on that is probably exactly what I'm looking for.

As you have now learned. A car battery could serve as a backup in a pinch for a short period of time but would probably be trash after only one or two hard uses. A deep cycle battery is designed to survive deep discharges much better. Then the more you spend, the more amp hours you get out of it. My battery I got should keep my air pump running for 20 hours and only be discharged half way. You want to make sure you get an appropriate charger for whatever type of battery you choose since they are often not interchangeable.

From my understanding of things, running the inverter and pump from the battery all the time while the battery is on the charger might not be so good but I don't really know how to go about designing a set up that can do quite what you want. I know there are ways, I would just have to do a bunch of research to figure out how to do it myself.

Just a thought on that TCL,
a car is constantly using and charging the battery.
Only, it is a generator ( alternator ) does the job.
That is why I like the idea of converting one to wind power.
But for me too many trees (large) keep the strong wind to high up
for a ground fitted unit.

In one sense it is risky to have the backup only running when the power goes out, because you wouldn't know if it didn't work unless you tested regularly or when the power went out. On the other hand running everything all the time might be more risky as you have four components that could wear out at any time from use (charger, battery, inverter, pump), sort of like a self-imposed power outage with no backup.

Don't they make small petrol generators that can come on in a power outage. Just seems like stuffing around with a battery that may fail anyway. With a gen all you have to do is cycle the fuel every now and then.

or convert a jerry can and have more than 24 hrs run time (depending on size of the genny)