Backyard Aquaponics
A place to discuss aquaponics

fizzyj, you had a warm weather spell in Whitehorse. It is gone now, but they used to have a 60 below pub in whitehorse. Come in on a 60 below day and they put a mug with your name on the wall. After a while there was no room left on the walls. Be happy you are a Perth laddy!

On backup batteries: Car batteries are hammered by being run flat. Deep cycle marine batteries are better. Better than marine are golf cart batteries (they are usually 6 volt, so you need two in series (hook pos on one to neg on other and use the other two terminals as your 12 volt out). The difference is mostly lead plate thickness. The marine battery here is $50 US at a discount store(only slightly more than car battery). The golf cart batteries are also $50, but you need two. My backup system is setup now (getting ready for startup in March). The two golf cart batteries provide 210 amp hours and do not mind being fully discharged to 10.5 volts. It only suffers a little if you go all the way down. If you can, you should stop at 10.5 volts to protect your motors from running at very low voltage (they can burn out). With my computer control this can be done. There are simple circuits with zener diodes that can open a relay to do this without computers.

The batteries on concrete floor discharge is probably not true. I can not think of any way this can occur. I have had many tractor batteries on a concrete floor all winter and this does not happen. Two real things to consider is that batteries do self discharge do to internal factors over time. My batteries are maintained on 'float chargers' for extended storage. The other true affect is the discharge between the terminals on a battery if the top of the battery is not clean. If there is stuff on the battery between the terminals that can conduct electricity, then your battery will go flat over time. A little baking soda will cleanup your battery, then wipe it dry.

I worked at a car company and we were concerned on modern cars about how we would wakeup the onboard computers at intervals, do a little work, and then shutdown. It is a current draw that has shortened the time before an unused car can sit without discharging the battery. We maintained that time at several months for a new battery. But old batteries would not do as well.

I think the concern with the cold concrete is due to the temperature coeficient on the batteries. All batteries slowly discharge over time as the chemical reactions slow down releasing or reabsorbing electrons. As the temperature of a battery decreases so does its storage capacity and its charging efficiency. The ideal temperature for LA batteries is 32 degrees C. Another concern is in colder climates where the concrete floor can freeze the batteries causing significant damage. Same goes if the batteries get too hot. Ever started the car in the cold of winter and it sounds like it almost didn't tick over, that is why.

My solar charge controller compensates for change in temperature. During cold nights the measured voltage of the battery bank is significantly lower. Everyone I have spoken too said to keep them up off the ground, well ventilated and in a warm (not hot) spot.

TimC, very good points. Temp is important. I have the Xantrex<sp??> C40 solar charge controller with batt temp sensor so that its charging strategy can match temp. My concrete floor is a heat storage medium which evens out temp from day/nite and therefore is seldom as cold/hot as the air. In an unheated building, is that not better? We start cars down to -40 in our cold testing of powertrain. You only get a short time to get them started before the battery quits. I thought the story for not on concrete floor was that it would lose its charge; that I do not believe is true. I live in a cold area and personal experience over 45 years of maintaining car batteries says no effect from concrete floor.

What do you think TimC?

Yep, I was lost and closed off at the 3 word mark. I just don't get it, nor do I care because it's just too hard for me. There are lots of other things I can better spend my time getting a grip on

what like a bourban mon

Doug I had always heard that as well. I think it is pure huey. I have put batteries on the floor and it does not seem to make any difference.

I think the myth of batteries going flat on concrete floors is due to the temperature of the battery when it is used. A cold, charged battery will output less power than a warm charge battery. So it could appear that a battery on a concrete floor is flat. Further a cold battery has a greater risk of being over charged using conventional chargers, beacause they dont not take into account the temperature of the cells.

In a case where the battery could be frozen as a esult of being on a concrete floor I think the the claim has some truth. By freezing the electrolyte the cell can be damaged and potentially destroy cells or shorting. Thus the battery appears flat.

There are many reasons to keep batteries off of the ground. But I don't think that they would be discharged any quicker if left on a non-freezing concrete floor.

Yes, perhaps people have experienced frozen batteries that ran down in charge due to time and uncharged electrolyte freezes. In the cold winter it is very easy to forget to charge your battery every couple of months. Then the cause could appear to be related to the concrete rather than charge running down and battery freezing.

Anyway, we may never know. But I have lots of experience with batteries not going bad left on concrete.

Will storing my battery on concrete drain the charge? No. Regarding today's batteries, this is a myth. A battery placed on concrete will not discharge any faster, but a battery will discharge over a period of time wherever it is placed. If the battery has a surface layer of acid or grime which is conductive, the battery will self-discharge more rapidly than if it were clean and dry.

O.K. will fess up Found this on another site and it looks like I'm wrong.

i think the concrete battery thing is a great example how something repeated often enough by enough people "becomes" true...........

Let us try that Steve.

Doug is always right. Doug is always right. Doug is always right. Doug is always right. Doug is always right. Doug is always right. Doug is always right. Doug is always right.

Does not work with my colleagues...and it certainly does not work with my wife. Only works for others, I guess.

Hey Doug- I'll agree that Doug is always right, but my wife doesn't agree either.

-Doug Greene

The Battery thing was actually told to me when I did my automotive apprenticeship (many moons ago) by an instructor ( who can you trust!! )

my understanding is that if you sit on the concrete floor and watch your battery discharge, you'll get haemorrhoids