Author Topic: Battery technology changing fast, what type to choose for a new system?  (Read 1384 times)

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giduddy

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All concerned;

   I have plans of setting up a grid interactive system next spring with enough battery storage to be 100% off-grid capable @ 48vDC.  I am going hybrid with solar and wind, 5kw solar and i have a 110v Jacobs ready to fly, about 2.5-3kw.  I live remotely enough that the power from the utility is ok at best.  But to help recoup a bit of investment faster, i would like to dump and excess onto the grid.

I notice that the current battery market changing rapidly and wondering what type of battery bank would people use these days?  lithium, nickel-iron, leaf car batteries, wait for Tesla to come out with the latest chemistry in battery technology, or just stick with tried and true lead acid, or slightly used industrial battery?  I like the appeal of the nickel iron, but not the price tag.  I do work for a company that imports things from China once and while, and I could have the opportunity to buy them right from the manufacture and skip the middle man, but that would also mean that i would be on my own as far as warranty and whatnot.

just wondering what other peoples thoughts are. and if i should wait a year or two, which i really do not want to, or just go for it with what is available today.

Thanks in advance

Dustin
« Last Edit: June 26, 2017, 08:47:03 PM by giduddy »

Bruce S

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I have to say right up front that I live in the city so power is merely a switch flip away.
However, I have dabbled in more than a few different battery chemistries.
I honestly still like the robustness of LA batteries, they get a bad rap because of the lead, but these things are 98% recyclable. AND the lead is 100% recyclable.
I currently have a smallish setup using NiCads as well and they love being used.
I'm also dabbling in Li but these need TLC and I'm not currently that interested in babying these things  (OperaHouse does wonders with them) .

Hope this helps

Bruce S
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george65

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There will always be something new and better on the horizon and if you wait for it now, by the time it arrives there will be something else coming and you'll end up waiting forever and never get a thing done.

having looked at this myself, for me where I am my choice would be to go with refurb Forklift battery packs.
I can buy them near me and get a 24V, 30Kwh pack with auto watering system which is guaranteed for 2 years with a reasonable service contract that extends that to 5 years for $2500.

That to me is the best value I can find. The company offer the things for residential off grid use and talking to them they are happier with that to warrant than in mobile/ forklift applications.  30KWh would be a decent size pack and although I would personally go more for solar, I'd also have a diesel Veg fueled generator for topups and supply in the inevitable 2 straight weeks of bad weather we seem to get here.

There -may- well be something better on the horizon and if it does miracle that it turns out to be better and cheaper, by the time I need to replace the Lead cells the tech will be established and the price fallen over it's initial "new fad" level.  If there is nothing better value, then I'd go for the lead until there was.... I wasn't here any longer to worry which is the more likely situation.

I would not be worried about the tech so much but the best value. there will be a number of parameters you have to take into account but I would be after the bang for the buck on it's merits rather than worrying about what the tech was.

Just my 4c.

madlabs

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Part of the answer to that question is your intended usage profile.

I live off grid. I have 9 years into 16 cheap golf cart batteries. I think I'll get a few more yet. These aren't Trojan T105's, they are Sam's club bargain brand.  I have gotten this service life out of them because I charge them every day. If the sun doesn't do it the generator does. With 4.3kW of panels in a sunny location I have run the generator for 126 hours in the last 2 1/2 years. Not bad.

The classic off grid paradigm around here was get a big enough battery bank that you can go three days without sun before needing to fire up a generator. To do that you need some really quality batteries like Surettes. Depth of discharge and time spent discharged are the biggest factors in battery life. In my case, I keep the discharges as shallow as I can and then charge it up first thing in the AM. Along with keeping the water level up and occasional equalizing I have gotten a long time out of a cheap set.

All that said, as I am rolling up on needing to replace my batteries I am taking a look at nickle iron. I'll wait until the bank is really failing and decide then.  But if I was buying them right now I'd buy another set of the same.

george65

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 I have gotten this service life out of them because I charge them every day. If the sun doesn't do it the generator does. With 4.3kW of panels in a sunny location I have run the generator for 126 hours in the last 2 1/2 years. Not bad.

I believe this is a key factor in battery life, any battery life.

With the low cost of decent output used panels now, I would be over sizing any array I had the space to do it.  This would allow for cloudy days where you get some input but a diminished one. By over sizing the array you allow for and get a better return on the less than perfect days which are the ones you really need to account for.  On the sunny days you have power to Burn and if your bank has charged up by 10 am, you have shortened the discharged time and done the batteries a favor.

Here used panels can be had for $50 for a 250W panel and cheaper in some parts. I bought a dozen 250's about a month ago for $40 ea.
I'm going to start with 10Kw on the new place back feeding and see what bills I end up with.  I can get 7.5 Kw on the outdoor entertaining area roof, another 7.5Kw on the garage roof, both facing the correct direction and then probably 20Kw+ on the house in an east/west direction.

Seems to me when off grid especially, the more panels you have, the better off you are!  Generation with panels seem cheap now, storage with batteries is expensive and I don't see it really coming down despite the predictions.