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oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686
Posted: 12:10pm 24 May 2016
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I don't have a sensible or definitive or technical argument..... So I will tell you my prejudices.
Despite your best attempts... something always goes wrong sometime/s.. and when it does, your likelihood of getting away with it is many times higher with FLA.
Lithium, agm etc all are superior to FLA in nearly every way.... until you do the wrong thing by them... and then all bets are off.
FLA is cheap, simple, rugged, and very forgiving... and you can add that water lost from over charge, and you can equalize those cells with ease.
All other non-aqueous technologies are more expensive, require much better operating parameters, and don't suffer idiots in charge of them... like me.
The bank can't be seen in isolation.... it is part of a system, and it is the feeble part of the system, so everything needs to be made to make them happy.
First more solar.....and then some more. You want at least 8-10kw of solar for a reasonable lifestyle where you don't think about power... your useage and want should never be predicated on what's running at the moment, or any other compromising normal off grid nonsense.
If the wife wants the washer, microwave, water pumps, toaster and jug running, then that should be fine... if you cant do that, then your system would not stand the "my wife" test..... and we go back to the grid.
As Allen states above, it is a 12" rain day, and still getting 800 watts from his 10kw bank... I would still increase his solar size. Four AC systems running is quite a load.
So if you use 15kwh/day, you need a modest 20kwh battery as far as I am concerned. It does not need to be bigger, as probably 2/3 of that 15kw is day time, and the solar will blitz that, even in three layer cloud cover.... if you spend the money there.
Your bank will be pulled down by 3-4kwh o/night.. so maybe 25% or so discharge. It will be recharged by 9-11am, the rest of the day we idle, and bring the SG up to max ready for the night....a very cloudy day, maybe by 1pm... but you get the picture.
If you have FLA and fill them up every day, keep discharge down to 25% only, you will get your 10 years out of a trojan pack, and a lot of other brands.
Currently bought 40 t105 types for $195... for other projects, and 64 250w panels for $140/piece.... only about 17000.
This will make 2 systems for about $8000-$9000 each, just add inverter ( $1000) and solar controller ($200)... we don't need mppt or any other fancy stuff, we have power to burn... don't care about temp compensation of panels.. cable loss or any other piffel they tell you, you don't want max power available, you just want to charge the bank without vaporising it.... point the panels all over the place.. even south.
Both systems will be better than most other expensive systems over here. The batts will last 4-10 years depends if they add water after the first year or 2.... but the batts will probably never go below 75% charged... generator support will be required maybe 5-10 days per year.
If they are sloppy with battery maintenance, then they may be up for new batts after 3 years... a whole $3200..... now even thats making ON grid look pretty silly really.
It comes down to simply recharging every day without fail, and keeping the water up.
If they are not using water, the bank will surely die early.
I have 14kw of solar accessible, and 10kw or more in the shed ... not used.
I fully expect 10 years from my bank.... first string was bought in 2008, still perfect as far as I can tell. ( was used in the EV for a while ).
So, they are cheap as chips, tough , forgiving, and easily available, and easy to maintain..... the others are just technically lightyears better.
............oztules
Edited by oztules 2016-05-25Village idiot...or... just another hack out of his depth
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 12:27pm 24 May 2016
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Yes don't forget the wife test, if she's not happy you have got problems, if not now it will happen at some stage.Edited by Madness 2016-05-25There are only 10 types of people in the world: those who understand binary, and those who don't.
powerednut Senior Member Joined: 09/12/2009 Location: AustraliaPosts: 221
Posted: 02:54pm 24 May 2016
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Yep, that is pretty much it. Recovering them when something went wrong.
I disagree on the size of the systems though. My folks have been running for years now on a well designed 1.5kW solar system. They do have to think about their power usage, but not as much as you expect. Their batteries (flooded lead acids) turned 13 this year and are still going strong. They are showing signs of age, but still coming along nicely.
My folks did have the advantage of building the house from the ground up around the off-grid concept. Low energy lighting (for the time), gas for cooking, low energy fridge and chest freezer.
the key is in sizing the system correctly. For their day to day usage their system is actually a bit oversized, so that ensures the batteries get charged if there is sunshine.
These days, with panels so cheap, it does make sense to go much larger than you actually need. As long as your batteries can handle the charge current.
windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331
Posted: 01:10am 14 Jun 2016
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Just a follow up on Exide batteries, where I am employed 2 days/week there is a set of Exide's that I retired after 10 years. I moved them to the second site for lighter duty, originally 48V, reconfigured at 2x24V. Gone well for 2 years then one suffered an internal explosion and bit the dust, now 1x24V..
Now these batteries are on recharge by a traction battery charger ( I can not remember the name ATM), so once charged they are on boil constantly. The moved set is still working under these conditions, and it has not hurt them one little bit.
The 48V set was replaced with more Excide batteries that have 30-40% discharge over night, coupled with a SP pro. Initially we had a recharge problem as more and more over night load (15 hours) was added. The limit was how much power I could transfer to the SP pro for recharge due to cable limitations. Upgraded cable and upped the charge rate, all is good now.
Personally I will be looking at a different brand next time. Long story short boil the sh*t out of them, watch the water but run them hard.
Allan"I like this place and willingly could waste my time in it" - (Act II, Scene IV).
oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686
Posted: 01:50am 14 Jun 2016
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I agree completely.
Not much more to add.
.........oztulesVillage idiot...or... just another hack out of his depth
windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331
Posted: 09:17pm 29 Jul 2018
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An update, at my place of employment (For 4 more working days) the main battery bank failed miserably, one cell died while many positive terminals were badly corroded. Exide came to the party and supplied a large bank of gell batteries. Replacing 4 year old Excide's.
So both banks are gell and both have SP inverters.
The original 3 phase Stanbury Scaff and Lord charger has been pressed into service to help the Selectronics SP recharge them, OK also to help balance the load on the generator.
My own batteries are hanging in, near on 7.5 years now and expecting at least 10 years from them but time will tell. From what I have now seen I judge that the manufactures have outsmarted themselves with all the rubber seals/insulation around the terminals. Accepting it is nigh on impossible to fully seal the positive terminal as batteries age it would be better to let their gas go free, as I do mine.
My accumulated system figures since May 2011 are DC in 31,909Kwh 23,659Kwh out AC load 52,635 Kwh AC in (generator) 4,983Kwh"I like this place and willingly could waste my time in it" - (Act II, Scene IV).
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 12:55am 30 Jul 2018
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Oh dear, I am not sure that sealed gell cells and a Stanbury Scarf and Lord traction charger are going to be a very happy combination. But time will tell.Cheers, Tony.
windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331
Posted: 06:58am 30 Jul 2018
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I agree but in this case the output from the traction charger is fed through the SP Pro."I like this place and willingly could waste my time in it" - (Act II, Scene IV).
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 07:18am 30 Jul 2018
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What kind of Exide batteries did you have the positive terminal problem with, obviously they are FLA but are they solar of forklift batteries?There are only 10 types of people in the world: those who understand binary, and those who don't.
windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331
Posted: 07:44am 30 Jul 2018
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Solar, I am one among many up here and I suspect in many other places "I like this place and willingly could waste my time in it" - (Act II, Scene IV).
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 08:00am 30 Jul 2018
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I am using an Exide forklift battery, I have heard reducing the amount of the acid in the extends the life greatly by minimizing positive terminal corrosion.There are only 10 types of people in the world: those who understand binary, and those who don't.
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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Yes don't forget the wife test, if she's not happy you have got problems, if not now it will happen at some stage.
