Anotherpower.com Forum
Renewable Energy Questions/Discussion => Renewable Energy Q&A => Topic started by: Wolvenar on December 28, 2013, 10:51:16 am
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We will need to replace our battery bank very soon here, and such are shopping around.
I have been looking into NiFe batteries because of their super life plus extremely tolerant of abuse. My reasons for these particular attributes over efficiency and any other drawback are rather simple. Basically because of rapid onset of health issues. I am not sure how long I will be able to deal with heavy jobs, like moving batteries. I don't want to deal with a bank replacement in 4-10 years. I'm sure my wife wont be to happy about dealing with such either. I'm trying to set this up so its as fool proof as possible. I want to minimize the failure points. Of course I know there will always be light maintenance and maybe the occasional failed component replacement, but the less the better.
Any which way, Rossw brought to my attention they have a very wide voltage range over their charge cycle. Our current inverter has a range of 17 to 31 volt in its manual, however I have seen it's built in charger equalize batteries at 33.4v. I read that the NiFe batteries have a equalizing voltage of over 38v when setup for a 24v configuration.
So my questions are:
Is there any way to use this battery chemistry with this inverter.
Are there any obvious problems these batteries present?
Would Midnight Solar MPPT(s) play nice with this chemistry?
---EDIT---
From the owners manual
NiCad and NiFe Batteries
Disadvantages These types of batteries can be used but are not optimized for the DR Inverter for the following reasons:
• Alkaline batteries, such as NiCad and NiFe types, have a nominal cell voltage
of 1.2 volts per cell. Xantrex inverters and battery chargers are optimized for use with lead acid batteries having a nominal 2.0 volts per cell
(that is, 12 cells for a 24-volt
system and 24 cells for a 48-volt system).
The number of cells required in a battery bank for alkaline batteries must, therefore, be adjusted for a 24- and 48-volt system
(i.e, 20 cells for a 24-volt system and 40 cells for a 48-volt system).
• Alkaline batteries require a higher charge voltage to fully recharge, and drop
to a lower voltage
Another option for 24 volt (only) alkaline battery banks is to use only 19 cells
instead of 20. Fewer cells allow the battery charger to operate more closely to the
settings used for lead-acid batteries. However, the battery voltage will drop to as
low as 18 volts when discharging the batteries.
Consult the battery manufacturer or supplier regarding system requirements and
battery charger settings for alkaline type batteries.
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I am not sure of the listed high scale voltage of the DR as an inverter is limited to the chargers max output, or the components voltage limits. Who knows now if i would get a real and informed answer from Schneider Electric (Xantrax) if I were to call them, but I will give it a shot on a weekday.
If so, I will just have to get an answer from the guys at Midnight if the MPPT works well with the NiFe.
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Pretty sure the Midnite Classics can do that battery type.
Try asking Ryan next time you see him in IRC.
Tom
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Wolv;
Ryan says:
Yes should work just fine. We have a lot of flexibility built in so he should be able to tune the algorithm exactly to the batteries liking.
Ryan
Tom
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Great! part of the problem solved.
Thank you Tom and Ryan
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Good Day Wolvenar,
I see this was posted sometime ago but since I have recently shipped my panels to the Philippines I should be ready to order batteries soon. I am curious what you ended up deciding to purchase in the way of a battery bank. I have since decided that lithium batteries of most configurations is over_price so I am stuck with fel, agm etc etc. Any advice from your experience would be appreciated.I am working on Arduino projects to monitor each battery and input output ac and dc current voltages temperatures inverter status and charging. long road to that part but I believe if I can get the microcontroller to read and take actions like cooling, desulphate, equalization (a reason why I have separate banks of batteries). Any thoughts?
one last thing, I'm ADD like crazy some days and my health and long work hours I am seem at a loss as to post my own topic. is there a "post a topic for dummies" on this sight?
Attaching my wiring diagram, bank 1 is squirrely looking and may or may not be wired right. 3000w on front roof 3000w on rear roof nothing but sky. 2017 plan to double panels and batteries.
Thanks for your help,
Solarnewbee
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I have since decided that lithium batteries of most configurations is over_price so I am stuck with fel, agm etc etc.
It's easy to think that, if you compare say 300AH LFP with 300AH of lead-acid.
But when you do the numbers and consider that 300AH LFP is approximately the same "useful working capacity" as 1000AH of lead-acid, the equation doesn't look so bad.
Then, factor in LFPs advantages: higher cycle efficiency, "no maintenance", no gas/venting considerations, about 1/5 the volume, about 1/10 the weight, far "stiffer" in use... I am definately happy I went LFP. My only complaint is that I didn't take the plunge earlier, or buy more. A single 300AH LFP bank is out-performing my old 1000AH AGM bank by every metric I have.
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Rossw
What price range are the lfp's going for here? Where did you buy yours maybe I can afford factory direct Shanghai.
Thanks
Solarnewbee
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At the time, I paid about $0.9 USD per amp-hour of cell. (so, nominally 3.2V) - ie, around $270 per 3.2V/300AH prismatic LFP cell.
If you do the maths, that's a little over $4000 USD for a bank that performs similarly to a 1000AH/48V.
Put another way, to be competetive - your AGM cells would have to be $90 or less per 2V/500AH cell.
Last time I priced them, they were more like $400 USD each (which is why I only had second-hand ones).
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I agree with ross, buying lead acid of any type makes you think you have a lot of battery because of size and weight. When it comes to performance, LFP just plain works, no disapointments there. Its like having a perfect battery, similar to the gas tank in your car.
Cheers LH
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Thanks Guys
I have a best price China Alibaba.com is $162-185usd per 200ah battery and door to door shipping to Philippines $825usd so my 12 lot would be $173.5 average X 12 = $2082usd + $825 = $2907usd shipped. Whereas how many Lfp batts do I need. More math so 3,2v 300ah X 4 in series = 12.8v @ 1200ah/4=300ah?? Rossw Help! I am so used to 12v batts with 6 cells add up parallel halve in series. If I can find Lfp batts at affordable ie under $4000usd with shipping that will give me the ah I want. Typhoon and rainy season is my only concern so I want a few days of reserve. Oztules said grab all the panels you can and batteries to meet your nights and crappy periods and all the rest is just noise.
Rossw if I use 8 3.2v 300ah lfp in series to get my 24v (25.6 nominal) to the inverter(setting my PJ to 26v?) what's the ah for just that set? I would still like 2 batt banks for maintenance and reserve purposes. If I could get 10 years out the batteries thru constant upkeep and attention thru monitoring that would work for my measly veteran pay I may be living off of in the Philippines if desert storm doesn't catch up to me haha.
edit: removed image
Guys maybe in 10 years some older lithium tech will still be in production and lead acid will be a thing of the past. Maybe.
Thanks for y'alls help
Best regards,
SN
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Whereas how many Lfp batts do I need. More math so 3,2v 300ah X 4 in series = 12.8v @ 1200ah/4=300ah?? Rossw Help! I am so used to 12v batts with 6 cells add up parallel halve in series.
LFP is nominally 3.2V/cell, so 4 in series is a "12-v equivalent". 8 in series for 24V, and 16 in series for 48V.
Being SLIGHTLY higher in voltage reduces the current slightly - eg, in my old AGM days, 24 series cells gave me almost exactly 48V, so a 1KW load took 23.2 amps from my batteries (including losses).
With my LFP, sitting at 52V, that drops to 21.3 amps. It may not SOUND like much, but it's a 10% drop in current - which is immediately a 10% increase in amp-hours capacity if you stop and think about it!
Running series/parallel with LFP is exactly the same as with lead-acid, except the higher cell voltage means you only need 2/3 the number of cells to get the desired voltage.
Rossw if I use 8 3.2v 300ah lfp in series to get my 24v (25.6 nominal) to the inverter(setting my PJ to 26v?) what's the ah for just that set?
8 x 300AH cells in series is still only 300AH
I would still like 2 batt banks for maintenance and reserve purposes.
Yes, that's still a nice idea. For my money though, I'd rather have two banks run permanently in parallel, but wired such that I could (if I needed to) isolate one bank. Two banks in parallel makes it easier to charge them, and reduces the depth of discharge on each, giving you better battery life.
If I could get 10 years out the batteries thru constant upkeep and attention thru monitoring that would work
10 years from AGM is probably a big ask IMO, unless you really mollycoddle them. It's not impossible, but it's a big ask.
The LFP are pretty much guaranteed to still hold 80% capacity (or better) after 7 years of discharging to 85% DoD (ie, only 15% left in them) EVERY SINGLE DAY. Your typical AGM probably won't last 6 months under those circumstances.
The trick to long life with lead-acid is to not discharge them too deeply, too often. The downside to that is with a bank big enough to only take them down 20-30% DoD (maximum), is a very big, expensive and heavy bank, that will also take a lot of power to charge properly - which means lots of PV (or generator), big wiring, beefy charge controllers etc.
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Your awesome Ross thanks.
One other thing is will my moot controlled work well together in parallel?
10 years time span I was thinking about lfp's not lead acid. Just got a quote from China factory $176 to $205 per lfp cell depending on pieces needed. 16 cells for 2-24v banks. Prefer 32 but money will determine.
I repaired an HVAC unit for a guy Saturday out on Johns Island SC and he has 34 panels on the roof and no storage but only pays max $79 a month to the light company down from $350 and up in summer. 3800 sqft house, real nice electric bill.
Thanks again!
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I repaired an HVAC unit for a guy Saturday out on Johns Island SC and he has 34 panels on the roof and no storage but only pays max $79 a month to the light company down from $350 and up in summer. 3800 sqft house, real nice electric bill.
Everywhere seems to be different, and each contract seems to vary.
Within 3 miles of me, I have people who are getting:
* paid 66c/kWh fed into the grid
* paid 40c/kWh fed into the grid
* paid 6c/kWh fed into the grid
* paid nothing for power fed into the grid but "use their own power first"
And then, various combinations of the above!
If you are getting paid "net metering" it probably makes little difference how you do it.
If you are getting paid for production at one rate, and paid for consumption at another (like many here are) then it changes HUGELY. If you get paid more per kWh you pump into the network (like, 66c/kWh) and only pay 30c/kWh for power you use, then you are FAR better off to export all your power, put off the washing, dishwasher, electric water heating etc, until night time and sell your "expensive" power, then buy it back when it's "cheap".
If you get paid less for your exported power than your consumed power, you're better off using as much of your power as you can - but NOT just putting everything on at once! Especially if you're on time-of-day metering. Ideally, you would use up to but absolutely no more than you produce at any given time (so peak loads around solar noon when you have most power to spare) but spread your loads out over as much of the production time as possible.
It all changes, depending on your arrangements with the electric company.
In some places, and in some cases, you could make a decent amount of money simply using a charger and charging batteries overnight on cheap power, then exporting it again during the next day when they pay you more for it!
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This is where the island has an advantage.
They claim it costs them over a dollar/kwh... small system ( 300 odd services over 1500sqkm, with too many staff, running diesel generators.
The gov subsidises this so it costs us only 28c/kwh
Because of the massive wholesale cost, they have seen their way clear to give one for one.. at all times..
So feed in is 28c and draw at any time is 28c.... this won't change in future I suspect... unlike the mainland where wholesale is very cheap.
..........ozutles
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28 for 28 thats how it should be down here on the small island, it would not cost any body anything you can use the old meter's that are in place., but there greed wont let that happen.They would not have a power crisis now if they were not greedy but they have had it so good for so long they refuse to see the elephant in the room. It will be there total demise.As more and more people realize how easy it is to produce power. It is sooo easy and cheap now thanks to china.( you don't need any gvment subsidy ) and we have the perfect system with only the hydro. If only we had a decent forward thinking poly.like electric Eric.
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They've put in gas turbine gennys in South Carolina run on compressed natural gas for use during peak use times but they sure don't pass that on to the customer they still charge peak time adjust and raise the per kWh after so many kWh. The customer I mentioned before when I went back with the CORRECT motor cap, said his bill was over $500 May to September and as low as $175 the rest of the year, so $79 average is great relief. If he had a lithium battery rack or batteries at all, he would easily go off grid with just those 34 panels.
He said tho that something about the grid tie wasn't to his advantage but I forgot what that was.
Adios Muchachitos!
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old thread but why start a new one when subject is correct.
:)
Acquired a forklift batt thats been sitting for a year. 48v 510AH Looks to be in great shape though charge level was at 11.7v per 12v section. Sg wouldnt even float bulb. Recently got 48v pj inverter working with a grid tie. 12kwh have now been pumped into it. SG is rising at 12.25 now (12.85) is full. Today while i was at work my sweetie went in garage and freaked out, she said "its boiling" and it smells like acid! Charge rate couldnt have been more than 38A as the solar its connected to rarely generates over 2kw. This battery is probably capable of a 70A charge rate. No bad cells all normal.
Do i need to install a vented hood over this battery? How do you guys put these in your basements and survive? I know some of you have rolls surrette and trojan etc they must gas too.. do i need to just put the monster in an outshed and let it get cold??
Your thoughts greatly appreciated.
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Hey there Light,
Me being a HVAC contractor I would probably run a ceiling or floor register boot with some 6" duct and a duct fan to the outdoors, maybe on a timer so it doesn't run all the time? Use the vent boot like a hood (of course after you plasti-dipped the leading edges for insulation. Don't know where you live but some HVAC suppliers will sell ductwork supplies to non-contractors. tell what you need, they like money. ask for the biggest vent boot they have.
I finally got my LFP's and battery monitoring system. I did not plan properly for space for 32 LFP's and monitors, those things took up some room since the factory packed them in 24v packs, wide and tall. Had me super nervous with all those expose bus bars so I plasti-dipped everything with a brush.
Evening!
SN
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Doing the indoor thing with lead acid is a PITA. I toiled for what seemed an eternity trying to decide "in or out" with the truck's bank. I eventually settled on "in" for mainly a couple of reasons... 1, to keep the runs short since I was basically forced to go with 12V ("free" and "decent inverter" can carry a lot of weight, despite the density of lead lol)... and 2, in an effort to give them some level of climate control.
I succeeded in the short runs effort, but even just the hydrogen alone has proven to be an annoyance at best... the fuming during EQ and all that just kinda ices the cake when it comes to the whole "reasons not to put them inside" department.
I guess what I'm saying is... "vent them until outside runs out of air"... that and "hydrogen might be the lightest element, but it sure seems to mix rather thoroughly all the way to the floor". The stuff isn't quite as itchy to rise up above the moon and escape when it's allowed to mix with air. I'm not sure why, or how, just repeatable demonstrations from the stuff influencing my sense of "get rid of it" lol
Also, get yourself some kind of monitor system that can detect hydrogen, even if it isn't calibrated to hydrogen specifically. If you've got *any* reason whatsoever (even just "cuz I feel like it") to get a(nother) carbon monoxide detector, grab one with a PPM display and stick it somewhere in the space with the batteries. The PPM won't be correct, but can provide you with invaluable information about the relative production of hydrogen, on top of picking up on the toxic gas it's intended to.
Can probably find calibrated hydrogen meters for a reasonable cost, but if nothing strikes you for its price, a CO detector will at least let you know it's there.
Sounds like those cells are throwing flags up. Increased gassing and fuming is a fact of life as they age/succumb to abuse lol
Just my buck-tree-nine-dee-fy... YMMV
Either way, vent vent vent!
Steve
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Today she again became very unhappy with me an the battery ::) cat box ok in house but no batteries in the garage ;D. No really, I do agree it needs to be vented, just wasnt sure how to go about it. and was struggling with a xantrex 3.0 that wants to get in a mood too. It goes offline and online in a constant loop without error message. Made some headway on it today though and managed to get the 48v inverter toroid to 156°. All was working sweet ...except the venting i didnt work on. :(
I looked online to see if there is something already made to vent a forklift battery maybe didnt look in the right spot but nothing jumped out, Ive decided to extend the 4 sides up a couple inches to clear the terminals and attach a hinge lid with vent hose for easy access to fill caps. Then as someone suggested, a small fan that turns on at a preset bat voltage.
The SG of the battery is now at about 1235 so its getting close. It has taken a bit with clouds and a wounded grid tie inverter.
SN I am jealous, I have 8 (40ah) LFPs and they are fabulous. I cant imagine a huge bank of them.
I cant cmplain tho, this FLA was completely donated to me so i must give it a fair try.
Steve, I have a CO monitor, its never been plugged in (no furnace or gas in house) so i will put it over by the battery. One thing i do know, you dont wanna find out you have hydrogen after ignition. Reminds me of a funny story back in high school, my buddy didnt have a sc fair project so i suggested he do electrolysis, told him i would provide the power supply ;D I hooked up 4 diodes and (hopefully a fuse i cant remember) to a 120v plug. He submersed a couple steel plates in an acquarium with inverted funnel over each. Rubberband and sandwich baggie to collect hydrogen and oxygen. At this point he was on his own, I was on the other side of the gym during the event when he decides to prove to the audience hydrogen will burn, mercy it was deafening. No one was hurt thankfully but i had no idea it was that explosive.
Thank you fellas for the comments and ideas! :)
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Lol...HHo is some powerful gas...had my share of bubblers blowing their tops