deep cycle lead or lifepo, what do i ned for a 16kwh system -20

[Solardaveo]

i have decided on getting 16-20kwh solar in the other sections and was directed here to talk about batteries,
im not fond of lifepo due to the harvesting tech and damage they caused to get it, but also which i know low with lifepo but fire risk and explosions etc makes me want to get deep cycle batteries , which i know have to be double that of lifepo ,

i want to know a little more aboiut them also what size i should get and what type what to look out for etc, there is a ddue on ebay selling batteries deep cycle
and then if you use lifepo ive seen peeps runing ev to houses ? can we not have or use thses too ? like emergencys go fill up at tesco lol ev bat

so for my 16kwh system i could upgrade to 20kwh later what batteries would i need? my daily useage is 12-15 kwh,

i got a quote on 24kwh which was well over powered i could run half so gone for half plus a bit
''For 24Kwp panels, 70º inclined, oriented to South, assuming 93% efficiency

Jan 603kwh
Feb 1137kwh
Mar 1729 kwh
Apr 2332 kwh
May 2441 kwh
Jun 2146 kwh
Jul 2190 kwh
Aug 2046 kwh
Sep 1711 kwh
Oct 1312 kwh
Nov 897 kwh
Dec 564 kwh

December is again the lowest production month, with 564 kwh, or 18,2 kwh a day on average.
May the highest production month, with 2441 kwh, or 81,3 kwh a day on average.''

 

[12VoltInstalls]

fire risk and explosions etc makes me want to get deep cycle batteries

I’m not sure that is accurate at all

 

[Hedges]

How often do you expect to cycle the batteries? How deep?
Lithium has about 5x the cycle life of lead-acid. Which only matters if deeply cycled often enough.

A batterie sized for "3 days autonomy", enough to run the house without sun for 3 days, most nights would only cycle 15% then recharge. Under those conditions, forklift FLA batteries can last 20 years. They require maintenance.

I use AGM for grid-backup, expect to reach 10 year float life before using up 65 cycles to 70% DoD.

If sized to cycle 80% every night, LiFePO4 is probably the better deal for you. It's primary issues are that it can't tolerate charging below freezing, and current output is limited by BMS (so size for your surge needs.)

 

[Solardaveo]

How often do you expect to cycle the batteries? How deep?
Lithium has about 5x the cycle life of lead-acid. Which only matters if deeply cycled often enough.

A batteries sized for "3 days autonomy", enough to run the house without sun for 3 days, most nights would only cycle 15% then recharge. Under those conditions, forklift FLA batteries can last 20 years. They require maintenance.

I use AGM for grid-backup, expect to reach 10 year float life before using up 65 cycles to 70% DoD.

If sized to cycle 80% every night, LiFePO4 is probably the better deal for you. It's primary issues are that it can't tolerate charging below freezing, and current output is limited by BMS (so size for your surge needs.)

hmm im gonna do some reading as i dont understand this cycles thing, my usage is 15kwh a day, as i run my workshope i have some decent loads, i do work during day time though and sleep at night so usage is low at night just netflix and fridge hehe ,
my plan was to get 16kw roughly 30 550w panels, as that calculated to cover my needs, now ive no clue how that would workout into cycles?

''A batteries sized for "3 days autonomy", enough to run the house without sun for 3 days, most nights would only cycle 15% then recharge. Under those conditions, forklift FLA batteries can last 20 years. They require maintenance.''
is this saying like if i use 15kwh a day thats 45kwh in 3days so a 45kwh battery would have a full cycle? and a 90kwh battery only discharging to 50% (ive seen somewhere saying don't let them drop below 50%?) then charging would be like you say here with nighttime use being low and daytime charging again, that they prob discharge 15% at night before recharging and using main pull in day hours ?

@

12VoltInstalls​

the LiFePO4 technology is still listed as dangerous under category CLASS 9 (Miscellaneous).
The low energy density ensures that it is very rare for lead-acid batteries to catch fire! For connoisseurs of the industry, it is not uncommon that lithium is highly dangerous, but it seems politically desired that these issues are not made known overheating problems with lithium batteries.
The most common causes for premature failure of LiFePO4 cells are overcharging and over-discharging. Even a single occurrence can cause permanent damage to the cell, and such misuse voids the warranty


so not only is the political gain saying its safe and pushing data which without years of testing they cant garentee yet like that of history on lead but if it overcharges or empties then its fucked first time ? that doesnt seem good given the cost of the batteries it kinda scares me, i kinda wana buy em and forget buying them for 10 if not 20 years like he said on the deep lead fork lol.
the ligame seems a gamble really, somany people posting about them failing, my lifepo battery is broken on my drone from plugging it in to progam on the pc and leaving it while i ate, now the battery is swollen, and wont work so i had to order new, now if that happened to a ~£~8000 battery set i would be gutted lol and probly jump into my terminal box lol

 

[Hedges]

Using power straight from the PV panels to loads doesn't cycle battery. Discharging battery to supply a load, then recharging, is cycling.

If PV production exceeds loads, your battery just sits at "float", doesn't supply any current except maybe a couple seconds motor starting surge.

If you have a 2kW coffee maker and a 1 kW PV array, obviously the battery will be drawn down while making coffee.

At night, all your power comes from battery. That is likely the main source of cycling.
Night time kWh / battery kWh capacity = DoD.
That may be all the cycling you get, assuming sun each day. Cloudy days, you will probably cycle deeper.

Batteries are spec'd with a number of cycles vs. depth of discharge (lead-acid) or number of 80% or so cycles (lithium.) So you can estimate years lifespan.

The old advice is that you will kill your first battery, so get a cheap starter set. That may be even more true with lithium. Certainly for DIY using individual cells, hopefully not for packaged batteries with built-in protection.

I would expect reputable brand batteries to be more reliable. But some big names (LG) have had multiple recalls. I would look for something with a track record.

 

[12VoltInstalls]

30 550w panels, as that calculated to cover my needs, now ive no clue how that would workout into cycles

Was there another thing you neglected? 15kWh is going to make like 75kWh on a better sun day…

my lifepo battery is broken on my drone from plugging it in to progam on the pc and leaving it while i ate

that’s a different kind of lithium battery I’m fairly certain

not only is the political gain saying its safe and pushing data which without years of testing they cant garentee yet like that of history on lead but if it overcharges or empties then its fucked first time

there’s fire safety training videos showing various things from shooting LiFePO4 to drilling through them, etc.
I’m not defending the political winds at all, but I also believe them to be reasonably safe with proper fuses and installation.
I’ve never caught mine warmer than ambient and once I saw ~165A of charging into my ~5kWh of cheapo LiFePo4 with the generator doing 60A and the SCC’s doing the rest.
I believe them to be safe.

some big names (LG) have had multiple recalls. I would look for something with a track record.

Even if they’re cheapo Chins and BtrPower LOL?

 

[Solardaveo]

Fair play , the 75kwh per day is only summer though eh and can’t store that for winter with batteries only storing a few days apparently , so yeah I’d use my 15kwh. And the rest spare be welding grinding or somthing els to waste power exess like a hot tub heard heating water is a loss you can do for exess , I don’t want anything on grid so can’t sell back to the grid ofc I’d just have to power shit n charge batteries do the workload in the sun times lol but on the flip if I don’t have 15kw solar then in winter I’m doomed

Could always disconnect a few in summer eh ? Lol
This is how we will be set up

 

[12VoltInstalls]

on the flip if I don’t have 15kw solar then in winter I’m doomed

I get that.
I’m completely offgrid, but small overhead to support. This is the first winter operating LiFePO4 and the ability to sustain partly charged versus the lead deep cycle batteries of the prior years has been surprisingly good as long as I don’t run sanders and saws. I’ve had to supplement with grid in years past but I don’t have that available on this property I bought. (I could get connected but the powerco wanted $3500 to connect me and I’m unwilling to give them that much to bill me monthly for power I probably won’t even use)

Due to ‘factors unmentioned’ and being busy I’m still eaking along active with just four 315W panels and four 100W panels because stuff is halfway installed. Another 1100W sitting here unconnected, plus I could connect another six 100W panels freestanding if I wanted. My friend had pneumonia a month, I had an timeout with covid a week, and other stuff like a foot of snow so I haven’t had help to pull the remaining solar cables through the underground conduit. But I digress.

So my wintertime daily kWh need is at a bare minimum ~1200Wh (basically never but has happened) but realistically I need 2kWh+ and I’ve been doing that 12 days out of 13-14 believe it or not! A lot of ~500Wh days of production, but then we’ll get some sun and extend a few more days. I have 5kWh of LiFePO4 storage.
The recent snow has ‘given’ me ~50W of charging early and late where I’d typically not get anything mostly due to reflectivity but also higher VOC

My point is you are going to be fine unless you’re in Washington State or Northeast Kingdom of Vermont (over 80% cloudy skies the last three months iirc)

Because I’m curious I need to look into a Cerbo or something and see what’s really going on with 12V loads, 120V (basically fridge and coffeemaker), and solar production over 3-4 SCC’s

This is how we will be set up

is that you? Or an example?

 

[Solardaveo]

I get that.
I’m completely offgrid, but small overhead to support. This is the first winter operating LiFePO4 and the ability to sustain partly charged versus the lead deep cycle batteries of the prior years has been surprisingly good as long as I don’t run sanders and saws. I’ve had to supplement with grid in years past but I don’t have that available on this property I bought. (I could get connected but the powerco wanted $3500 to connect me and I’m unwilling to give them that much to bill me monthly for power I probably won’t even use)

Due to ‘factors unmentioned’ and being busy I’m still eaking along active with just four 315W panels and four 100W panels because stuff is halfway installed. Another 1100W sitting here unconnected, plus I could connect another six 100W panels freestanding if I wanted. My friend had pneumonia a month, I had an timeout with covid a week, and other stuff like a foot of snow so I haven’t had help to pull the remaining solar cables through the underground conduit. But I digress.

So my wintertime daily kWh need is at a bare minimum ~1200Wh (basically never but has happened) but realistically I need 2kWh+ and I’ve been doing that 12 days out of 13-14 believe it or not! A lot of ~500Wh days of production, but then we’ll get some sun and extend a few more days. I have 5kWh of LiFePO4 storage.
The recent snow has ‘given’ me ~50W of charging early and late where I’d typically not get anything mostly due to reflectivity but also higher VOC

My point is you are going to be fine unless you’re in Washington State or Northeast Kingdom of Vermont (over 80% cloudy skies the last three months iirc)

Because I’m curious I need to look into a Cerbo or something and see what’s really going on with 12V loads, 120V (basically fridge and coffeemaker), and solar production over 3-4 SCC’s

is that you? Or an example?

bloody wish it was me lol , nah this is how i plan to setup. as instead of begin fixed on a roof, i am more free to move them, as i need
made me sad now , his setup is amazing, wouldn't need advice if that was me lol, yeah he runs a 10kwh in a cold climate which has less if not the same sun, we get to -5 briefly -10 , hes at -21 eeek, running heaters off as much as poss everywhere lol, and a bloody incinerator toilet that draws 90kwh, dang, i wana power me lights n a few bits n bobs use logs for most cooking etc

same the cost to hookup you got cheap compared to our quote, lol they wanted £4k to hookup, but want me to lay 150 meters of cable on my side to meet their closest point, and we contemplated it until we found we would be responsible for the work on our land digging etc, after that price pfft,
so generator if needed eh lol,
damn shame ya not over here, id drive up give ya a hand just for the experience, and chat , sounds like me, 1 man band and u will get there but u get there when u get there lol or if you NEED to do it then till then struggle, hell i ws too cold to stand up yesterday 3ft to the hammer so i used a rock, it worked lol if i got up i was afraid id go after the coffee roasting smells drifting out

how do you survive on 2kwh? are you man in a hut ? and just a few light bulbs, i dont think that would power my drill lol, curios too, hehe what do you use? are you cutting back on everything and freezing up hibernating ? i only ask as when i mension we use 15kwh a day people are liek how so little, are you sure thats correct , and all that lol, seems i assumed we used alot of power until people started saying we use 33kwh aday !! bloody what is that powering a pc cyber cafe ? lol

my load would be, as example.

24hrs fridge and freezer, 250watt each (that would be your 2kwh gone right ?)
evening tv and xbox, with the kids, around 150 watt
led lights, internet, music, 100 watts,

my workshop is open and running 7-7 most every day days this is me and my sons , welding making tables lathe work, animals and school etc,
so after hours my workshop load of around 12kwh aday would be running still for a few hours after sun down, but then im off to sit watch tv so it gets shut down til the next day so really i dont see me doing much deep cycling like they would on the video, using everything, exept the dark hours in winter from 3 its black, and i work another 4hrs or so drawing off batteries, not all night long

my demand is quite low, as we heat with logs, we cook with logs, so theres no cooker cost or heating, just what we use, which isnt really much , kettles on the log, lights and tv,
ive learnt that any washing and charging needs to be done midday, and we even use a twin tub which is only 200watts and 15 min cycles, unlike a modern washing machine 2hr run and over 1000wats

 

[12VoltInstalls]

how do you survive on 2kwh? are you man in a hut ? and just a few light bulbs, i dont think that would power my drill lol, curios too, hehe what do you use? are you cutting back on everything and freezing up hibernating

I don’t freeze. I have renaud’s syndrome to begin with and don’t do the cold weather well my whole life. I don’t run at 98.6 more like 97.5 and my body knows it…

To answer your questions… no, not a hut.
I fought back against doing the same thing over and over with the same results. Made major sacrifices and modified a 25’ Dutch Craft travel trailer for year-round use a few years back. Successfully I might add.

That alone cut back my monthly expenses by over $1000 a month. (Lotsa in between I’m leaving out)
I bought a small piece of property in April 2023. Moved the camper here, off grid. There’s power lines overhead of my southerly property line ~12 feet horizontal from my solar panels, two poles on my property. $3500 was way too much imho.

What do I use…
2-cup coffeemaker 2-3 times per day, 60W small household refrigerator, 12V LED lights, 12V waterpump; laptop, phone charger, cordless tool chargers, sanders, pestOffense, etc. Plus it’s just me.
I run 90mW and 200mW 12V lights mostly.
Furnace is LP ~120 gallons last winter iirc and like 2A draw. I have a 52” tv on the wall but I never use it.

 

[Solardaveo]

I don’t freeze. I have renaud’s syndrome to begin with and don’t do the cold weather well my whole life. I don’t run at 98.6 more like 97.5 and my body knows it…

To answer your questions… no, not a hit.
I fought back against doing the same thing over and over with the same results. Made major sacrifices and modified a 25’ Dutch Craft travel trailer for year-round use a few years back. Successfully I might add.

That alone cut back my monthly expenses by over $1000 a month. (Lotsa in between I’m leaving out)
I bought a small piece of property in April 2023. Moved the camper here, off grid. There’s power lines overhead of my southerly property line ~12 feet horizontal from my solar panels, two poles on my property. $3500 was way too much imho.

What do I use…
2-cup coffeemaker 2-3 times per day, 60W small household refrigerator, 12V LED lights, 12V waterpump; laptop, phone charger, cordless tool chargers, sanders, pestOffense, etc. Plus it’s just me.
I run 90mW and 200mW 12V lights mostly.
Furnace is LP ~120 gallons last winter iirc and like 2A draw. I have a 52” tv on the wall but I never use it.

haha i like it, if i didnt have 6 kids thats what id do too, furnace log brick powered i guess eh ? keep warm from fire there's no better way . have you seen the gasifiers? you can generate from them too,and keepo warm, real easily

lights is my next look at, as the shop bought are 14wats each and light the room, whereas i have some strip lightsi am tinkering with that are 13watts but run them soft on the drivers and you can run them at 2watts, there 2 ft, and my god they light the room way better,
otherwise solar lights seem to last while im awake lol, just simple amazon jobs,

kids bump up the bill lol, n my 15 yr old lad, he is welding a suit of Armour an offroad buggy and forging knives which has blowers on it lol,

just the workshop lol just it pulls 12kwh a day while i am in there i dont mind flipping a jenny on when i need to , but i can see me running the banks low lol, when im working i work and everything is electric,
my lads looking into bio diesel and generators, he also looking at compressing gas recently, which shocked me how easy it was to do, hes on his next now, making gas to prove he can bottle it from waste, it seems like it will work but we will see hope it does cause hes a good trouble fixer,


kids wouldnt turn off the tv lol we just got a 50 , u the guy with the big screen but watch on the laptop eh , nice do you work the land then ?

im gona look to get 8kwh pannels as i go in summer, and max out batteries , then get another 8 kwh ,
just gota figure out now how the batteries work, what to get etc
going to see if there is any full planners i can enter my stats into to see howmuch cycles i do etc

 

[12VoltInstalls]

have you seen the gasifiers?

Ya. Ish.
I’ve been a fan of the tulikivi burners for a long time. No it’s a ‘brand’ but it originated hundreds of years ago as a means of more heat, less wood: central masonry burner with a hot AM fire reradiates all day long.

if i didnt have 6 kids thats what id do

Mine became legal adults like ten years back Lol

otherwise solar lights seem to last while im awake lol, just simple amazon jobs,

i still run “32W” fluorescent twin T8’s in the shop but I suppose I shouldn’t be. Going to get some LED shop lights if I can get a ‘instant rebate’ on them.
But either way I would say it’s accurate to describe all my lights as solar lights…

we just got a 50 , u the guy with the big screen but watch on the laptop eh , nice do you work the land then ?

I bought the 50” 2018-ish on a christmas sale. At that time I was renting a 48x48 building for a shop and mounted it high on a dark wall about 10’ up for ‘company’ while working- antenna tv so mostly old westerns or fox sports or whatever, or youtube auto channels, welding, woodworking stuff.
Now it’s in the RV on a custom side-hinged wall mount I welded. If you swing it open it reveals several SCC’s, inverter, DIN rail breakers, etc. I use it for a computer monitor if I use it at all.

do you work the land then

I’m not much of a farmer. But I do plan to terrace a steep section and grow produce to sell. The property is small so I won’t be planting 50 apple trees but rather will have a few hundred quarts of blueberry production along with perhaps some sugar pumpkins, various plants like basil- basically good yielding things for a small space