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creeky
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# Posted: 4 Aug 2016 05:41pm
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A lot of folks are asking about how to use lithium for a battery.
This is the simple version. I like lifepo4.
Step 1:
Buy 4 lifepo4 batteries. Probably off ebay.
These are CALB batteries. they're of good reputation. In the US now.
Remember when sizing the batteries. Lithium can be up to 60% smaller than sizing with lead. Or 1/2 the size. This is because lithium can be safely kept at a lower state of charge and discharged deeper into the battery.
By ex.: I'm charging my lithium pack to 80% of full. And discharging to 30%. Okay, it's summer. So I've not got as far as 50% dod. But you get the idea. With my lead acid I charged to 100% and discharged to 80%.
Both my lithium and my lead acid were/are around 12kw. With the lead acid I could use 2.5 for longest life. With lithium I can use 8 for longest life. You can see the advantage of the one over the other.
Step 2:
Hook the 4 batteries up in series. That's positive to negative etc all the way along. Tada. You now have a 12.8v battery. Use 8 batteries for 24v. Or 16 for 48v.
Lifepo4 come in different sizes. Depending on price and availability I would probably go for 400 amp cells for a 400 amp battery (at 12v). Rather than 4 parallel 100 amp cells for a 400 amp battery. But that's for lifepo4. It's just easier. To wire. To maintain.
Step 3:
Hook up your solar controller.
Watch your charge specifications. You may wish to charge with a programmable solar charger. Or an adjustable voltage standard charger. Remember lithium can also handle higher amperage when charging. Huzzah! That means if you're running a genny the genny doesn't run as long. If lead acid wanted to charge at 10% of total ampacity, lithium is happiest at 50%. Of course with both battery systems you can go higher (or lower). But ... lifespan.
There are a number of solar controllers that have lithium chemistry settings built in. I like the new mppt prostar from morningstar. but that's because my ts-mppt-60s were programmable. so after 5 plus years on lead acid I was able to reprogram, flash the eeprom, and voila! a lithium battery charge profile.
Step 4:
Hook up your inverter.
You may wish to find an inverter that has a slightly lower or higher cut off point for low/high voltage protection. Depends on your lithium chemistry. With lifepo4 you're pretty good with SLA settings. But you might want to get fussy. Pay attention to what your "brand" mfcter says. (of course)
One great advantage to lithium is you can discharge deeper. 80% is okay. But like any battery. Lifespan!
The reason I like lifepo4 is that its the safest. Works the easiest with current (ha ha) charger/inverters. Can pretty much use the same charge program points as SLA.
Plus. You can add parallel strings no problem. This is really nice. And you can add that next parallel string later on down the road. Which is even nicer.
Step 5:
Give creeky a hug! I like hugs. Don't worry. i'm best at the manly hug. You know. Back slapping and all that.
Cause we're celebrating. You're system is up and running.
Now if all this sounds as easy or easier than lead acid. It is. Now monthly you'll check your cell voltages to make sure they're staying in balance. And that'll sure beat watering.
And when you go away. Just use some of the battery capacity up and then leave it sit. No worries. No need to trickle charge or any of that nonsense.
Have fun.
(you can play with BMS and all kinds of neat web reporting and stuff. If you're a gadget type.)
Hope this helps.
and if you want more of a challenge. google "diy tesla battery power wall." to see how folks have made their own tesla power walls. warning: you need to be able to solder.
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FishHog
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# Posted: 5 Aug 2016 09:36am
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great info creeky. thanks for sharing.
My only fear is cold weather, as I leave mine long term through the winter months. But hopefully by the time I need to replace my FLA, that issue will be resolved.
FishHog
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MtnDon
Member
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# Posted: 5 Aug 2016 09:52am
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What issue do you mean? Charging when below 32 F? If there is no use and therefore no charging they can sit for months frozen, IIRC.
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sparky30_06
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# Posted: 5 Aug 2016 10:20am
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One word of caution. We do a lot of UPS hook up in the field and have some unfortunate outcomes. Everyone is in the false state of mind that it's only 12 volts or 24VDC or 36VDC or 48VDC. DC voltage is very dangerous and the amount of amperage these batteries are capable of producing is greater than the main breaker on most people circuit breaker box in their house. I'm not writing this to scare people away but please be mindful of what you are doing. I have had battery terminals vaporize in front of my eyes. I have seen wrenches get arced in half. I have seen heavy gauge wire become toaster elements. I have seen the arc flash burns this can leave on a person and the property damaged that results also. Please be careful guys.
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FishHog
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# Posted: 5 Aug 2016 10:43am
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Quoting: MtnDon What issue do you mean? Charging when below 32 F? If there is no use and therefore no charging they can sit for months frozen, IIRC.
I guess I could unhook them and leave them sit dormant. Hopefully a weekend winter trip would work without charging at all. Might work. Kind of nice now to just show up use the system and walk away like I do now.
But yes, charging when cold is my concern. May look at relocating to the inside where they will warm up when I'm there, if charging is needed. I'm a few years away from replacing my FLA's anyway, so don't need an immediate answer, and am enjoying following this technology.
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creeky
Member
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# Posted: 5 Aug 2016 12:31pm - Edited by: creeky
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Quoting: Sparky Please be careful guys
I second that emotion. Gloves. Glasses. Easy and careful motion. Lead acid or lithium or whatever.
Fishhog. That's another lithium advantage. you can keep them in the conditioned space as they don't off gas. So head out in the winter. Start the fire. Warm up the cabin. Shovel the snow off your solar panels. You're set.
I'm looking forward to this winter. Just to see what happens. Last year I heated my lead acid twice. To keep them at 10C. Remember lead acid derates rapidly when cold. But they also kick a lot of heat with the poor efficiency.
This winter I have/am building a bigger, more heavily insulated box (R39!). i have the inverter inside the box. so the inverter heat will contribute to warming the interior of the box. And I will install heating pads. Fingers crossed.
I monitor temp through the morningstar controllers remote temp fittings. Currently (sorry, love that joke) sitting at 26C.
Also. I found a study on dendrite formation (the stuff that kills lithium). It looks like 5C is a better cut off. Now the study didn't refer specifically to the 2nd gen GM Volt battery chemistry I have. Which apparently was changed for better low/high temp management. But ... 5C is my low temp minimum. Unless I travel all winter. Hmmmm.
And hot temp wize that goes for lithium as well as lead. Lead ages at double the rate at 35C. Lithium ages only a bit faster until you hit 35C. Then the aging rate begins to climb.
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MtnDon
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# Posted: 5 Aug 2016 01:38pm - Edited by: MtnDon
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Safety: batteries and wrenches... I have a set of wrenches dedicated to my battery bank. Dedicated in tbat (1) they stay in the battery compartment; actually in two slots in a wood block on the inside of the door. And, (2), the entire combination wrench is covered in two layers of 10 mil PVC tape, except for the working end. They are both 1/2", one has the box end open / uncovered and the other has the openend not covered..
F
Half inch does all fasteners that are close to the batteries, buss bars, shunts, etc. The 10 mil tape is the tape used to wrap gas pipe fittings thar are buried. HD and very sticky. My original thought was to use heat shrink tubing but I did not have enough large stuff on hand when I had the idea.
Safety: Don't forget fuses. Type T are best to prevent meltdowns. If using parallel strings one fuse per string.
Re: winter / lithium. Our cells will be relocated inside because of tbe cold charging issue.
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MtnDon
Member
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# Posted: 5 Aug 2016 01:47pm
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Re: lithium... another thing I like is their ability to sit for months with no loads, no charging. Why? Lightning!! We had another lightning event recently. Two of our 4 Midnite SPD's were knocked out. (Midnite SPD's have LED's that no longer light when the MOV's that provide the protection are worn out. They repair under warranty.)
We had an arc burnin one wire from the PV to the CCas well. But no other equipment damage possibly because during our lightning season of
July - Sept I do not leave the system PVoperational when absent. So far the FLA batteries don"t seem to mind a couple of weeks just sitting...
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NorthRick
Member
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# Posted: 5 Aug 2016 02:40pm
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Different situations for different folks.
We use our cabin on weekends. It sits unheated the rest of the time. When we leave Sunday afternoon, the batteries are partially discharged and we count on the solar system to bring them back to full charge while we are gone. Being in Alaska, this is often at temps below freezing. So, right now, lithium is not for us in that application.
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MtnDon
Member
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# Posted: 5 Aug 2016 04:23pm
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If anyone is looking, electricarpartscompany also has decent $$ on cells and their freight costs are reasonable. The cells sold on the ebay link are listed as; new, other. ??? And he/she has not yet rellied to my inquiry, whereas ECPC replied in 4 hours.
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creeky
Member
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# Posted: 5 Aug 2016 06:05pm
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For Canadians I'll add "canadian electric vehicles" (canev dot com). if you contact them they will sell you lifepo4 cells up to 400 ah. that's where I was going to get mine. before I fell into the lucky hand.
Really. If I was building my solar shed again. I would dig a hole in the ground passed the frost line. Insulate the hang out of the top and sides. And let the earth keep my batteries at 55F (12C) all year long. Hmmm.
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MtnDon
Member
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# Posted: 5 Aug 2016 06:23pm
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We have a hole, 24" diameter, 7 feet deep at our mountain property. It is lined with a playground slide tube. I made an insulated plug for the top. R15 thick. A bicycle inner tube is slotted ina groove around the circumfefence. It only has a few psi pressure, only protrudes enough to contact the wall. In the ground around the first 12" depth there is approx. R20 insulation. The top is also capped with a hinged wood lid tha thas an additional R20 of foam.
The inside of the tube stays at the aforementioned 55 F. We do have a slight issue with the high humidity level. Canned foods left in there all year develop rust spots. However nothing ever freezes or gets too hot.
No reason a variation would not work for other uses. Maybe a hand crank lift for batteries??
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FishHog
Member
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# Posted: 5 Aug 2016 06:51pm
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Now that is a good idea guys. Food for thought
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rockies
Member
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# Posted: 5 Aug 2016 09:07pm
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You mention being able to move the batteries indoors since there is no off-gassing. Would you recommend keeping everything involved with a solar power system in a small outbuilding away from the main cabin to save interior floor space or for maintenance?
Also, I know there have been lots of companies that will design the entire solar power system for you and install it but those designs all included lead acid batteries. Are companies moving over to lithium or are they still pushing lead acid for their systems?
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MtnDon
Member
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# Posted: 5 Aug 2016 09:54pm
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Electronics, in general, have longer lifespans when extreme temperature shifts are minimized. So, CC's and inverters may be best kept in an indoor environment, IMO. However in asmall space the operation noise of cooling fans in CC and inverters may be annoying. Trade off time.
Batteries such as flooded lead acid belong outdoors without question IMO. AGM,maybe inside? Lifepo4 don't seem to have the inherent danger of FLA. Thet still have a lot of potentially dangerous energy stored within the cells, so proper safe enclosures must be used indoors.
There would be nothing wrong to my mind, of storing lifepo4 outdoors if it was not for the issue of charging when the cells are below 32 F.
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Steve_S
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# Posted: 6 Aug 2016 08:56am
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Hmmmm... Maybe Creeky or someone else knows an answer to this. As this is a topic that a lot of us are watching and I know lot's of questions are queued up.
Is there a Site, Document or something that compares systems, components, capacities, which can be used to Dollar Compare side by side.
I'll use my own system as an example.
8x 260W panels, Classic-200 controller, 3kw Inverter Charger Combo, Genny and for BATTS I have 8x Rolls S-550's rated at 428Ah/20h set into 24 Volt Bank with roughly 900Ah storage.
The usual hardware aside, as that would be the same I suppose but I dunno if another piece is needed for LiIon BMS... So what would the equivalent LiIon pack for 8x S-550's ?
I have looked and the biggest thing that trips everyone is the amount of DOD between the types and so on one side you don't need so much batt because you have bigger DOD and the muckiness really takes off from there.
Somehow I think people would be able to better grab ahold of the differences & compare "known configurations" with FLA to equivalent configs with LiIon & other types of cells. A Tangible Comparison we can all relate to...
I look at the ratings & costs and this is where things go weird... An S-550 is selling @ $378 CAD retail down the road, They also sell RELiON Batteries who lists their retail prices on their website.
This is my supplier's site for those interested (! GOOD FOLKS !): http://www.solacity.com/product-category/batteries/ who operates out of Kemptville Ontario.
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creeky
Member
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# Posted: 6 Aug 2016 09:26am
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Today I would keep my lithium batteries in conditioned space. Of course I use morningstar controllers so I don't have fan noise. smile.
And the Victron is remarkably quiet. Not as quiet as that TBS was. Sniff. I miss my TBS. But I couldn't get the 48v in Canada.
For me the issue isn't storage space. Rather distance. And cost. Because my buildings are in a tree line for shade and protection from wind -- this isn't ideal for putting up your solar panels. (ha. classic understatement).
I built a solar shed in the middle of a field to capture maximum sun. Because I was using lead acid at the time. This also allowed me to safely store the batteries away from human contact. Also, I didn't understand the temperature issue.
Today I'm running lithium batteries. And I'm running all my solar panels at 96v (11 amps) (nominalv/a).
So today. I could run high voltage panel DC the 200 feet to the heated/cooled buildings and distribute from there.
Note:
I would still have a solar shed. It worked great for getting the panels up in the air. And my novel system of using dock hangers to allow the panels to be adjusted by season has worked. 6 years with no issues or maintenance.
Plus. The building stores all my camping/fishing gear. 
Note 2: I was planning to keep my 12v system (as it was already built and paid for) with lifepo4 batteries. The advantages remain: lots of 12v equipment should I go that route; easy of finding (lower cost) equipment that supports 12v (panels, controllers, inverters).
Note 3: I have noticed, for a few years now, that there is / was tremendous resistance to lithium. When you look at the solar retail/support (websites purporting to be expert) market you see entrenched supply systems. I don't think these people want to see highly profitable tech supplanted. Obvious really.
But it remains. Lead is dead. Long live the new king. Or queen. Or social paradigm suitable to your vision of the organic structures that are life.
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rockies
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# Posted: 6 Aug 2016 07:48pm - Edited by: rockies
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The reason I ask about companies building the entire system for you is that I just downloaded the 2016 catalog from "Backwoods Solar".
http://www.backwoodssolar.com/
I find that they seem to be on the cutting edge for recommending the best products but they make no mention of lithium batteries. The latest technology they recommend are the "silicon salt" batteries.
http://www.backwoodssolar.com/silicon-salt-battery-2v-550ah
They seem to be well suited for cold mountain climates and most of Canada and the price certainly looks good. Why do you think they aren't mentioning lithium?
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MtnDon
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# Posted: 7 Aug 2016 01:23pm - Edited by: MtnDon
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I have no real idea why the long time solar / off grid sellers have nothing in lithium. I believe there is more to it than inertia, a reluctance to change. Even though lifepo4 has been shown to be the safest lithium technology,as soon as the word lithium appears alongside the word battery, I'll bet there is a whole new series of HazMat regulations that come into play. For example, but I have not had a second confirmation, l have heard that one a lithium cell has been in warehouse stock over a certain time, it does get classed as HazMat. Repeat... UNCONFIRMED... could be a hoax. But with all the other regulations around I would not be surprised.
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creeky
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# Posted: 8 Aug 2016 11:10am
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Steve. Your 24v 856ah battery pack in lead acid has 20 kw of power. Of which you have use of the top 20% for longevity. So 4 kw. Well.
Before you derate for lead acid. Call it 3.5.
A lithium pack at 50% dod. To have 3.5 kw of usable power would only need to be 7 kw in size. So at 24v that would be 300ah.
Roughly 1/3 the size.
Your battery pack cost $3,200. And you can expect, at best, 2000 cycles @ 20% dod.
A lithium pack of 9 kw is $6000 Ca* (many variables). But should last 7,000 cycles.
Costing: Ebay has a 100 ah at 3.2 for 110. That would be $2,640 US right now) to build a 24v 300 ah battery. Or roughly 4500 ca. what with shipping hassles and tax. Note: the batteries are in Georgia or Pennsylvania. So a holiday to the US might be in order. Remove the shipping variable to time and gas anyway.
Roughly broken down as:
Lead acid per cycle is 1.60.
Lithium per cycle is .85.* Or half the cost.
Its been proven again and again that lithium has the lowest cycle cost.
There are some disadvantages. Charge temp. Transportation cost/hassle.
Vs. Lower maintenance. Higher efficiency both charging and discharging. Etc etc.
As for lead acid battery options at various suppliers. Like lead acid itself. There is much resistance. But, if the borg have taught us anything. Resistance is futile. In mechanical terms, it generates, through friction, wasted heat and wear. 
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creeky
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# Posted: 8 Aug 2016 11:18am
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I just saw these. 300 ah lifepo4 on ebay at $275 in the US.
You would need 8 to build an all in series 24v lifepo4 pack. Or $2,200 US. (at 3.65v fully charged that's a 9kw pack. 50% dod would give you what. 14 years of service? More?)
Now that's a deal.
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rachelsdad
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# Posted: 13 Aug 2016 06:50am - Edited by: rachelsdad
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I would love to buy these. My needs are closer to 2-3kw.
What would my options be? I'd rather not have to buy 8 just to get to 24v
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Steve_S
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# Posted: 13 Aug 2016 08:55am
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LOL ... Mmmmm 7of9 my dream... hehehe.... OK every guy had that one but could not help that.... What'ya think of the Queen eh ? Ero-Raunchy but..... LOL
Thanks for the Response... You see, That's the kind of detail which should Config A with FLA = Config B with LiIon in Amp Hours & Volts... prices are all over and some dubious ones, so sticking with "Known Good" (no name or ?? name could be (is) risky at this fledgling stage of industry.
So sticking with ReLion Battery... They only list the one 24V / 50AH @ $1297 CAD but they list 48V/100AH @ $4897 & 48V/300AH @ $13,297
Retail from where I bought my Solar Kit (Except Inverter/Charger) are a touch more http://www.solacity.com/product-category/batteries/
BTW: That E-Bay listing like so many, do not ship to Canada.
PS: I sent a suggestion to Rob @ SolaCity to setup a chart should equivalent battery banks in his kits.... Maybe he'll take that up.
You know what the Solar Industry reminds me of.... the Personal Computer Industry in the early days where everyone was secretive and the black art of assembling PC Hardware & tweaking software was the domain of the select geeks... and guys like me who'd take the old 286/12 and push it to 24mhz overclocking and burning new BIOS to handle it... geez, flashback to assembler programming... eekkkkkk push ax....
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