Creating power for your home, off grid.
Emphasis on nuts-n-bolts, hands-on projects.
I see on The Solar System page you are using a 12v NiCad system. I have 10 - 1.2 volt Nickel Iron batteries to make a 12 volt battery bank at 600 amps. These are new ChangHong batteries. My question is what can I run on them now at 12 V and will an Outback inverter work? I see you are using a Trace with your NiCads.
We got these NiFe batteries to experiment with. They seemed like something we total solar amateurs would have a hard time killing. We want to see if we can run efficient AC appliances from them using only 12v. These batteries are kind of pricy so we want to see if they are something we can handle before considering buying more to increase their voltage or amp hours.
So my questions are:
Is it possible to wire for both 12v and 24 at the same time, so if we decide to expand from 12 v to 24 v, we don't have to re-wire?
All our wiring runs will be short.
We won't need more than 2000 W from an inverter.
We have 12 - 210W panels. I can use as many as needed for this experiment.
Thanks very much for your very informative site. I look forward to any feedback pro or con on this issue.
Yes, I still think that alkaline battery chemistry is superior to lead-acid. I do in fact have some Ni-Fe cells, as set of 10 that I picked up at the local metal recyclers back in 1982. I went in to cruise some old car parts that they had and found that there were about a half a dozen pallets of 80 ampere-hour Exide Nickle-Iron batteries that Oregon State University had gotten rid of. At the time, I knew nothing about them, and since I was half living on the street in my Housetruck, I didn't want a big load of mystery cells.
The 10 that I did take held a charge, so well in fact that ten years after tossing them into a corner under my house, they still had enough charge to create some sparks when shorted.
I look back now and could kick myself several times over for not picking up the whole batch. The guy running the sale was a friend and he was in a jamb because they had allowed these batteries to be "recycled' without knowing what they were, thinking that they were lead-acid. I probably could have had the whole lot of them, probably 1,000 cells total free for the hauling. Oh well, that opportunity will never come again.
I do use an old Trace 812 inverter on my Ni-Cd batteries. The charge controller is a Trace C12, set for Ni-Cd voltages. I do experience inverter shutdowns from over voltage when the batteries reach the end of their absorption stage and before they begin to float. The inverter stops "searching" and goes to deep sleep. If I need it during this time, I simply turn on a few incandescent lights for a few seconds to make the battery voltage drop a bit and the inverter resets itself and comes back to life. I don't know what an Outback is going to do under similar circumstances. Perhaps it is more tolerant of higher charge voltages?
As for 12/24, it's never advisable to tap off a battery pack for dual voltages, it causes imbalances that can lead to severe under/over charging of the halves of the battery, although Ni-Fe might be more tolerant of this abuse. Generally, a balancing DC-to-DC supply like a "Vanner Voltmaster" is used to keep the halves of the pack balanced under load and charge. Another possibility is to get a 24 volt-to-12 volt DC-to-DC converter and just step the higher voltage down to the lower.
I've gathered some resources about Ni-Cd and Ni-Fe batteries, as well as some forum posts about my Alcad Ni-Cd battery set:
The first time I used my Alcad UHP65 batteries was as engine starting batteries on my bus:
Here's a post about the second set of Alcads that I got for free:
A page with some Home Power articles in PDF format:
More questions? Ask away.
(how embarrassing, I just noticed that my solar page is still showing a Trojan T105 lead-acid battery instead of a Ni-Cd cell. Got to fix that!)
I think we need to get 10 more for a 24 volt system and that would solve future issues. The new NiFe batteries will be taller then the ones we bought last year. They are taller to accommodate more electrolyte so they don't have to be watered as often as the previous ones.
We bought the the initial ones to experiment with as a back up emergency system to power a small DC freezer, DC washing machine, a light or two and a couple of fans. That's all we found we really needed or wanted when we lost power for 3 weeks a couple of years ago.
Now we are wanting to go AC and integrate the system more into daily use.
Thanks for the NiCad links. I have an online and hardcopy subscription to HomePower magazine. Issues 12 and 13 don't appear to be online but I bet they're on the DVD.
Great site. I will post more as we go. We are slow, which is another reason NiFes are a good choice for us; they can sit empty indefinitely until we find the time to mess with them.
If you get time for some of this.....
1. Could you post some pictures of the types of batteries you find to be salvageable? I would save them at the junk yard when the come in, if I knew what I was looking for.
I have never seen the Fe-Ni batteries nor Ni-Cads.
2. I was reading the solar system page. I have a very deep interest in the flat plate water heater pictured there. Perhaps you could post a picture or link for the pump? Also the source for those plates. As always, alternative energy (for me) boils down to a question similar to this...what do you want to do, build a chainsaw or cut wood? I choose a brand new Husqvarna, and never looked back. Its seems that alternative energy is the same way for me. I'd rather scrap a bunch of dreams, to get the money to buy one working flat plate collector, then spend endless hours fiddling, trying to build something that will only work marginally.
3. The Outback inverter description, you mean simultaneously? I just want to make sure yours doesn't have mystery feature. Which would be good, just mysterious.
If you follow the links to the forum posts about the Alcad batteries, there are some photos. My Ni-Fe batteries are old, they are encased in stainless steel. These are also known as "Edison" batteries, and were used extensively in railroad signalling and sometimes in telephone switching systems. The very old Edison cells were in a rectangular glass jar with a white ceramic lid.
The flat plate collectors I have are also old, probably from the 1980's, they are "Colt" brand. I don't imagine that there is much difference in panel construction these days unless you go for evacuated tube designs.
The pump I use is a small AC induction motor with a magnetically-coupled centrifugal pump body that came out of an old heat-pump water heater. It doesn't have to make much in the way of pressure, and the flow doesn't have to be spectacular, either. Any regular boiler circulating pump will work fine, if that's what you have. I have built DC powered pumps, and used positive displacement pumps, but the one I have now has worked best of all (if I keep snakes and slugs out of the cooling fan fins, that is).
Yes, "simultaneously", thanks for catching the typo. I took a few minutes to update the page with some corrected photos and added a small blurb about the hydro plant that I now use to generate power. New content on the site, not sure I can handle all the modernity.
Please, Tell me there is better equipment available today without all the hassles of past equipment issues. Also the weight of the old stuff as well. The RR equipment was actually very simple back then and worked MOST of the time.
James in da GRAYDAWG
I THEN GOT OLD AND RETIRED
I LOST MY SEATS AND GOT A NEW GIG
I AM NOW A HAULIN SOME OLD DAWGS &
I BECAME THE GRAYDAWG
Users browsing this forum: No registered users and 1 guest