Generator or Inverter for residential use?

RonSwanson

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Depends on how it's used but in many/most cases adding PV means always using the battery as the power source so if you have a PV system that can charge the pack at least once a day you're going to get a charge cycle each day if you drain the battery.... but it all depends, either way, it's lifetime will definitely be way shorter VS only using the battery during outages.
Perhaps this is that case with a Growatt system. My understanding is that this is not so with a Vitcron system.
 

thechamp

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Perhaps this is that case with a Growatt system. My understanding is that this is not so with a Vitcron system.
I doubt it's the case, those things are intelligent and you can choose how you want the system to operate.
 

cfvh600

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Depends on how it's used but in many/most cases adding PV means always using the battery as the power source so if you have a PV system that can charge the pack at least once a day you're going to get a charge cycle each day if you drain the battery.... but it all depends, either way, it's lifetime will definitely be way shorter VS only using the battery during outages.
If you don't plan on using the battery every day, don't keep it at 100% SOC.

Apparently it causes damage.
 

RaptorSA

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looks like 25-75% DOD is the best use case.
Personally I always find the discussion around lithium do's and don'ts to be a complete waste of time in the real-world, best left to academia and massive industrial implementations where dealing with fleets of thousands of batteries, slight optimizations could result in some practical benefit or savings.

The time you waste in researching and implementing these "best practises" is more valuable than whatever puny difference it makes. Not to mention that the bigger the battery the smaller the effect, so in a system like this and the way in which I'll be using it I'd probably have to triple or quadruple the lifetime I have left on this planet to be able to see any benefit.

Like I said, if I assume the rated cycles of 6000 is BS, which it probably is, and it's more like 4000 to get to 80% usable capacity, that gives me 100 years to get to 20% degradation if I cycle it 40 times per year.

The quality of circuitry components on this thing would be the real thing to worry about since that will be the thing that takes it down eventually and there's nothing I can do about that.
 

wingnut771

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Personally I always find the discussion around lithium do's and don'ts to be a complete waste of time in the real-world, best left to academia and massive industrial implementations where dealing with fleets of thousands of batteries, slight optimizations could result in some practical benefit or savings.

The time you waste in researching and implementing these "best practises" is more valuable than whatever puny difference it makes. Not to mention that the bigger the battery the smaller the effect, so in a system like this and the way in which I'll be using it I'd probably have to triple or quadruple the lifetime I have left on this planet to be able to see any benefit.

Like I said, if I assume the rated cycles of 6000 is BS, which it probably is, and it's more like 4000 to get to 80% usable capacity, that gives me 100 years to get to 20% degradation if I cycle it 40 times per year.

The quality of circuitry components on this thing would be the real thing to worry about since that will be the thing that takes it down eventually and there's nothing I can do about that.
true true, would only apply for offgrid daily use, not for occasional emergency use. although, after reading that doc, it says storing battery at high energy degrades it without cycling, so even if you don't use it for a year you would have lost capacity storing at 100%. maybe keep it at 75 for storage and when loadshedding hits move back to 100?
 

RaptorSA

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true true, would only apply for offgrid daily use, not for occasional emergency use. although, after reading that doc, it says storing battery at high energy degrades it without cycling, so even if you don't use it for a year you would have lost capacity storing at 100%. maybe keep it at 75 for storage and when loadshedding hits move back to 100?
So even before reading the article, I was planning to keep it at a lower percentage stored anyway.
More like 85-90% though... I don't want to be caught off guard.

P.S. The reason I know some of this stuff is because I deal with Lithium Polymers used in my remote controlled cars a lot, and one does not simply f**k with a LiPo battery (which reminds me I need to find an old military ammo case to store mine, I'm playing with fire keeping them stored in a closet).

When those things eventually die due to internal crystallization they go out in spectacular fashion... I've yet to have one do it though. It's pretty amazing to realize how much energy is in one of those things when you watch the videos of them catching fire. The thought of a 4.8kWh pack on my wall catching fire is the stuff of nightmares, but apparently stability and safety is one of the main reasons Lithium Iron Phosphate is the way to go... should I be wrong though, the plan is to grab the cat, run outside, take fetal position and watch the world burn.

I keep my old LiPos around so I can take potshots at it with a .22 when I visit the farm again one day... :cool:
 
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wingnut771

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So even before reading the article, I was planning to keep it at a lower percentage stored anyway.
More like 85-90% though... I don't want to be caught off guard.

P.S. The reason I know some of this stuff is because I deal with Lithium Polymers used in my remote controlled cars a lot, and one does not simply f**k with a LiPo battery (which reminds me I need to find an old military ammo case to store mine, I'm playing with fire keeping them stored in a closet).

When those things eventually die due to internal crystallization they go out in spectacular fashion... I've yet to have one do it though. It's pretty amazing to realize how much energy is in one of those things when you watch the videos of them catching fire. The thought of a 4.8kWh pack on my wall catching fire is the stuff of nightmares, but apparently stability and safety is one of the main reasons Lithium Iron Phosphate is the way to go... should I be wrong though, the plan is to grab the cat, run outside, take fetal position and watch the world burn.

I keep my old LiPos around so I can take potshots at it with a .22 when I visit the farm again one day... :cool:
yeah, when the crystals grow long enough from opposing plates and touch each other, it shorts out the battery then the fireworks start, maybe keep some co2 around just incase.
 

RaptorSA

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yeah, when the crystals grow long enough from opposing plates and touch each other, it shorts out the battery then the fireworks start, maybe keep some co2 around just incase.
F**k that. CO2 is for huffing.
My insurance on the place is higher than market value anyway, so scoooore!
 

davdonne

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the best way to go during load shedding is the inverter
a reasonable inverter will run a comp + screen+ printer+ internet modem etc for about
4 hrs power goes off all switchers back on.
cost approx 6000.00 batt incl
 

RaptorSA

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OK, update time:
Since 4.8kWh Lithium systems seem more common these days I thought I'd share my first "battery & inverter burn-in stability" test to see what she's capable of and so that anyone else can get an idea of what they're getting into if they buy a similar-sized lithium phosphate system.

My philosophy was simple:
Leave everything as it is during a normal Saturday afternoon, then drop the mains power and double down on usage by watching 3 hours of Youtube on the projector and doing whatever else I can do with the extra time, Desktop PC internet browsing while listening to music etc. in this case.

...then stop the test the moment I reach 50% and see how much time I managed to get.
Obviously this is an extreme case, but that's the whole point (entertaining load-shedding stranded friends or whatever in the worst case).

Why stop at 50% if the depth-of-discharge is 80% default on Lithiums?
Well I know it's not flooded batteries but in real life, if there's load-shedding or an outage I'd assume it's at about the 50% mark where I'd mentally start to get antsy and plan for the worst by lowering unnecessary consumption due to only 30% drainage remaining. I try to treat it like my bank account, assume there's less available so you don't get stranded when the worst happens.
I don't think I'll ever go down to 20% if I can help it.

I made sure I had the projector, PC etc. running already when dropping the mains to make sure failover doesn't cause any issues, I didn't notice it as expected, 10+ milliseconds is enough.

Here's a summary of the kind of devices I used and how often:

Always On:
ApplianceRated Wattage
Whirlpool Fridge 220 Litres (20+ years old)Stats not available (+-130W?)
2m Kitchen LED strip20W
4 Philips Hue (white) Kitchen LEDs - 20% Brightness5W
2m Philips Hue strip light20.5W
1 or 2 Philips Hue Living Room lights+-10W
Ezviz C3W Security Camera6W Max
Asus DSL-AC52U WiFi Router18W Max
Generic Fibre CPE Router10-20W?
2 x TP-Link Gigabit Switches3-5W Max
Xiaomi Mi Android TV Box<10W

Partially idling/standby or used once or more:
Appliance/DeviceRated Wattage
3000 Lumen Optoma HD143X DLP Projector - Max Brightness (On for 3 hours)300W (330W Max)
Sony HT-DDW1500 MU.TE.KI 6.2 Surround (on for 3 hours)80W
Desktop PC - Intel i7 3770 (2.5 Hours idle, browsing etc. for 1.5 Hours, no GPU gaming loads)Not sure (150-250W?)
PC Monitors 32" & 27" both @ 1440p (same as PC)36W + 44W
3 Office LEDs (on when using PC)20W
2 Bedroom LEDs10W
Google Home speaker (music on low for a few mins)33W Max
Boiling Kettle +-400ml water (used once)2000W
CFL Bathroom light (few Nr1's & Nr2)13-15W
Dash Charging OnePlus 5T phone from 68% to 92%20W

Usage and SOC charts:
View attachment 844971
View attachment 844967

So how long did I get?
Exactly 4 hours to get to 50%

View attachment 844973


One thing to note: Not sure how to explain this but the inverter was whisper quiet (except when the kettle was going). Felt like it was almost quieter than when it's in bypass mode or whatever. Weird.

Clearly this is no panacea so you'd still have to be pretty much on top of your usage if you wanted to get through a full day's work and still have some energy left over at night for TV etc...

Charging:
This is the recharge time. It's on the default setting of 0.1C or 0.2C so way below what's possible. I also used my oil heater while it was dumping energy into the battery to see if the breakers could take it. No issues.

Basically, charging was at twice the rate of depletion, so took 2 hours to refill.

View attachment 845089
So the initial Aha! moment is over and the look and sound of the inverter next to my kitchen is getting to me.
It's time to cover it up... with something....

Came up with a custom build using a wall panel and door with holes in so I can close it off, it'll still have lots of airflow and will fit in with the mix of "hole" panels and solid panels in the motorized room divider next to it (currently not motorized, don't ask).

I won't lie, it's a k@kload of work getting everything aligned and perfect when you don't even have someone to hold something up for you for a sec. Not to mention not having a garage or workshop, you end up having to do weird things, like first mounting a component so you can primer paint it, then taking it off again and doing the rest etc. piece by piece (so you don't have to leave things outside in the complex garden, turns out veldfires etc. drop a crapload of soot, dust etc. in the air during winter so painting outside is a nightmare).

I know it looks terrible in the pics since I've only used pink primer on the one part and I'm still busy finalizing the door I built before painting it all white, even closed up some of the door panel holes this morning one by one and sanded it down so the white coat will look consistent and not cast uneven shadows when some of the holes are plugged with no-more-nails glue from the frame... but once this this is painted I think it'll look great next to the sliding room divider I built 2 years ago.

When all is done I'll come up with some or other way to mount LED's either as feature lights or something, not sure exactly what, have a ton of options. All I know is I've got one wireless switch left open in the kitchen so this "thing" might make a nice night-light feature.

1591628982176.png 1591628949496.png
1591628924617.png 1591629043236.png
1591629187049.png1591629072086.png1591629215461.png

I also ordered some gunmetal gray panels of this stuff today so I can lign the inside of the door panel and wall in the compartment where the inverter is for sound dampening, gotta keep enough space open for airflow of course but I think I know what I need to do to eliminate most of the sound reflective surfaces, will be really interesting to see what difference it makes.

1591629890237.png

This all will be Phase#1.
Phase#2 will happen when I redo and repaint the kitchen.
Paint the DB cable strips same colour as the wall, fill the gaps between the wall panel and paint it all the same colour so it looks like a "wall outgrowth" and blend the battery+inverter door with the room divider to give that "floating" effect.

For now, I want the ability to separate the whole system and re-adjust or replace if needed without f**ing up "permanent fixtures".

I don't know, maybe I'm just an annoying lazy bastard, but all this feels worthy of sharing since the devil's always in the details. I don't do this sh*t for a living so whatever I f**k up along the way might be worth sharing.
 
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spiff

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with reference to post #883.

is there any reason we I cannot install a timer of some sort on the eskom mains supply line to my inverter and set a time so that the 2 x 12vdc x 105amp batteries get used and not just sit on charge all the time?
 

thechamp

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with reference to post #883.

is there any reason we I cannot install a timer of some sort on the eskom mains supply line to my inverter and set a time so that the 2 x 12vdc x 105amp batteries get used and not just sit on charge all the time?
No reason, but I wouldn't be concerned about a battery that is continously being float charged, I am not convinced about that study. Our car batteries are always at full charge when they are in the car, I don't ever remember a battery dying from remaining at a full charge for longer periods.

But a timer is a good idea if you feel like running them occasionally.
 

spiff

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No reason, but I wouldn't be concerned about a battery that is continously being float charged, I am not convinced about that study. Our car batteries are always at full charge when they are in the car, I don't ever remember a battery dying from remaining at a full charge for longer periods.

But a timer is a good idea if you feel like running them occasionally.
Toying with the idea of installing a sonoff to cut eskom AC at night for an hour or two. The sonoff will give me real time feed back on how much I use to charge the batteries etc.
 

crawler

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Can someone please help me.

What is main differences between this type axpert inverter and a victron, and price difference as well?

I know the 1 difference is when demand exceeds the inverters capability, it does not just top up, but switches over to utility completely

What else is there to look out for

Attached is quote I received for info
 

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thechamp

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Can someone please help me.

What is main differences between this type axpert inverter and a victron, and price difference as well?

I know the 1 difference is when demand exceeds the inverters capability, it does not just top up, but switches over to utility completely

What else is there to look out for

Attached is quote I received for info
Which Victron are you comparing it to? The specs should indicate the difference, find the specs and post them.
 
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