An Proto-Teach Éireannach

[Scruff]

Spoiler Alert.



More about this later....

[DamonHD]

Let me tell you all about the benefits of LFP 1°C out today...you know what that means? It means I've about €15k of useless hardware in my workshop totalling 5.2kVA and 3.5kWh.

You know what they need? More weight, expense and complexity! Solar freakin' battery heaters bro! 

I'll get on with testing the useful ones will I?

How did the smartest battery charger in the world do?

Interestingly my LFP AC-coupled Enphase battery (model B270-1200-LN-I-EU00-RV0), outside, seems to be claiming a working ambient temperature range of -20C to 45C.  I haven't seen it shut down yet in the most extreme temperatures that we get here in sunny London 'burbs since it went in, from a little below zero to over 30C where it lives.

Rgds

Damon

[Scruff]

Hi Damon, yes I've wondered about this. I know Telsa Poowerwalls have 300W internal heaters that use utility power with solar priority to maintain an operating temp >20°C. They will only install them in uninhabited spaces or outdoors so in atmospheric conditions.

The cheaper stuff like Pylontech I reckon relies on operating temperatures and coincidental lower PV input in inclement temperatures. With LFP I can force the internal temps up with C1.5 discharge (pretty effin' inefficient to keep the tank 50% full so I can throw away 50% in order to replenish 100%).

Charging it cold is harmful, the higher rates of charge you use the more harmful it is, so at 5°C you might be taking 5 cycles off it's lifetime or 50 depending on how fast you push the power.
It may have throttling but I think most have threshold cutouts instead.

At the end of the day it'll take 10 years to prove you didn't get 2k cycles to whatever they said DOD and the test gear to prove it. If they're still in business in a decade.

Remember a warranty isn't an assurance of quality, it's a coefficient built into the price of the original purchase spread out over the number of units the probability of a successful claim is made.
A lottov people; don't push their hardware/ don't measure their hardware / resell it for something better / lose the receipt / break it / void the warranty / don't know how to prove it's outtov spec / install them indoors etc etc...

There's a sliding rule in product design of does the risk of failure warrant the cost of preventative measures.
In domestic the answer is often no, in industrial the answer is often they're not going to fall for BS and they might press charges.

[Scruff]

The last of my mains charger host has swung the bat.



I have very little confidence Studer are any better and I'm not bothered investigating when I can use MS instead.






Don't pay much heed to the readouts. It's a factory refurb that had a super spoofer Capxon electrolytic cap failure replaced by a Nichicon. The service centre soldered the shunt while they were in there and the meters are inaccurate. I have it dialled up to 15.1V to compensate for the 0.4v drift.

No temperature compensation. This is called a programmable unit. I have 4 options to change the current, abs voltage and float voltage. I call that selectable. I don't know what the Pro is alluding to in the title, I asked Sterling and they say it's because it sounds cool.



A rather disappointing 1.235 SG
80% SOC

Sure I ought to compensate for temperature with specific gravity reading but they are relative results ±
2°C

In the interest of keeping my battery in good shape, I let the SunSaver finish the job for Sterling.




What are the morals of the story?

€700 of mains chargers does not get you past 90% SOC.
Mains chargers are compromised.
Mains chargers do not charge batteries.
Battery sellers and battery charger manufacturers are liars.
Always validate your hardware before integration.

Lead is operationally high 90s% efficient.
This charge lead once a week mandate?
Was that written by the same persons who use and advocate those chargers?

I find charging it once a month to be ample!

[Scruff]

What does this mean comparing technology?



I can get 2k cycles from lead to 80% DOD
Another incriminating graph that seems to not exist is LifePO₄ cyclelife at 10°C. It's never 25°C in Ireland, my vehicular fleet are all lubricated with 10w-40. So the jury is out on what they will do but let's be generous and say for argument's sake 2k cycles.



This is art, or biased representation:



Let's compare top-shelf LiFePO₄ to D-Grade Lead.


Charging lead to 100% once a week? B0110x! Maybe with chargers like I've shown you. Charge to SG 1.28 once a month!
This can be automated...ie...maintenance free.

Therefore the other 27 days a month you can cycle lead between 20% & 80% with a coloumbic efficiency of unity. Comparable to Li-ion.

C-rates. At 4>10 times the cost lead can deliver higher instantaneous power on a € to € comparison on the simple basis that 100Ah of LFP C1 costs the same as 1000Ah Lead C10.
Lead in this instance has 10 times the range and the peukert derating ought to be negligible.

Most people compare li-ion reliability to lead liability. Glossing over that li-ion has a BMS built into the price and lead doesn't because it's intrinsically safer.

If we give lead an LVD, HVD monthly EQ BMS it will exceed Li-ion reliability through simplicity and a far more useful temperature operating range.

Can we save weight with li-ion? Sure.
Do we safe space with li-ion? Arguable...additional high current chargers with big heat sinks, disconnect contactors, balancers, thermal management hardware, fuses for balance leads (you know who you are), third party regulators for system integration. In my experience I have not saved any space. I believe it's possible when the Li-ion battery approaches >5kWh usable.
Can I use 100% of a LiFePO₄ cell, as people claim? In most cases no. The usable capacity is 90% of the actual and the device has been derated and rescaled.
In certain circumstances, you could but it'd not be advisable.

My conclusions so far on the matter.
LiFePO₄ is 50% lighter, more fashionable and more expensive.
The proclaimed benefits over lead are because people are using lead wrong (not entirely their fault) and li-ion is electronically protected to prevent this.
Wouldn't electronic protection for lead be a fraction of li-ion cost?
Who makes lead chargers that charge lead batteries?
Why do people not check that their charger actually charges their battery before making recomendations? Isn't that obvious?

Why does lead die prematurely?
Because people don't charge them right!
How do we charge them right?
Capable products are rare. I know of one genuine manufacturer.
Ought I spend 4>10x more on an alternative battery chemistry because I can't source a high-fidelity lead charging device?
Subjective!

[Scruff]

Interestingly my LFP AC-coupled Enphase battery (model B270-1200-LN-I-EU00-RV0), outside, seems to be claiming a working ambient temperature range of -20C to 45C. 

Slow day at the office...I had a look at the manual for this.

Wow!
It's an alternating current battery!
Capable of 7300 cycles!
& your warranty may be affected if you do not maintain an internet connection, of your AC battery.
I see they are using the internet connection for "measuring battery health" (sounds like meter tuning to me)

I see they quote the cell RTE but not the device RTE?!

Ok I can't be reading any more about AC batteries, I can't respect a manufacturer who either can't use the correct terminology or is breaking the laws of physics.

In answer to the question Damon (couldn't find the reference)

The inverter probably operates at -20°C but the charger won't cut-in until above 0°C. Cut-out is not as good as foldback. Neither are as good as not having to....well, that is to say, without running negative input for a solar freakin' battery heater bro.

It'd be better to keep it indoors.

[bigrockcandymountain]

https://images.app.goo.gl/HY2Ddt2DJizo7TDk8

I was looking at your chart awhile back and noticed the deep cycle lead acid cycle life is way more of a curve than i thought it should be.  I have only ever really looked at the chart for these surrette rolls s550 and it is almost linear.

With a linear curve, assuming price per kwh of battery is the same, there is no benefit to upsizing a battery.  You can kill it in 1000 cycles, or spend twice as much and have it last twice as long. 

I am on year 5 with my battery and we cycle it every day.  It gets charged to 60v every day and absorb is 3 hours.  It uses some water at this setting.  I equalize a few times a year and clean and add water 3 times a year.  Time will tell if this is a good way to care for lead.

Your thoughts on lithium are pretty interesting.  I don't have a whole lot to add, so i thought i would post and let you know i am following this thread closely. 

[Scruff]

Would you believe that I don't think I'm a cynic Big Rock. Experience tells me to test everything nonetheless because delivering 100% duty capable systems is my thing and it's not something I'll let a marketing department take advantage of my reputation over.

Indeed, the lead-acid "curve" ought to be linear. It's odd. If you pick two points they're directly proportional. eg. 80% DOD = 2 x 40% DOD.

Li-ion is definitely curvey. 20% lower discharge envelope = 50% more longevity etc..

Er on the side of overcharge (not to be confused with overvoltage) with lead. If you look at the efficiency graph I posted it's hard to be wrong that way. Tail current is more telling as a threshold than a timer. I never (have to) EQ my crowns but they're dialled up pretty high (14.8v + temp comp) in normal operation.
I find that batteries that are used every day and have adequate input to see a full charge every so often tend to last as well as those that are rigorously maintained.

[DamonHD]

Ok I can't be reading any more about AC batteries, I can't respect a manufacturer who either can't use the correct terminology or is breaking the laws of physics.

In answer to the question Damon (couldn't find the reference)

The inverter probably operates at -20°C but the charger won't cut-in until above 0°C. Cut-out is not as good as foldback. Neither are as good as not having to....well, that is to say, without running negative input for a solar freakin' battery heater bro.

It'd be better to keep it indoors.

Enphase's engineering seems good.  Mangling the name into something cringeworthy is the marketing dept's job.

The insurers would prefer it inside, but it and my off-grid LA gel are ouside partly because the house is small, and partly to minimise any fire risk (filling the stairwell with burning battery/wiring seems unwise.

Rgds

Damon

[Scruff]

Enphase's engineering seems good.

Seems to be. From what I've heard they've the industy's highest efficiency on some of their hardware.

Mangling the name into something cringeworthy is the marketing dept's job.

They're all at it. Dumbing it down for us simpletons to understand. 
Next they'll be putting polarity indicators on interfacing MC4s....oh wait...
The difference between a grid tied device manual and an off-grid device manual is like Seasame Street is to CNN.

The insurers would prefer it inside,

It'd work better and for longer.

partly to minimise any ...risk

I tell ya now breathing hydrogen for half a decade never did me an ounce a'harm!

[Mary B]

No way would I have a lithium battery inside, way to big of a fire risk and my insurance agent said the same. If I had an attached garage and a Tesla my insurance rates wold double unless I added a fire suppression system in the garage that can handle burning lithium batteries. He asked about the solar, told him sealed lead acid that is vented outside via a positive pressure system on the battery box. He had no issue with them living under my workbench in my office where they stay warmish(floor is cold in here... no basement or crawl space and no floor insulation). I was surprised he knew the technology and terms!

[Bruce S]

After seeing the hazmat training the FireFighters had to go thru for the Homes and Elec/Hybrid vehicles here in StL; I'm with Mary B on this one.

I now use older marine deep cycle batteries couldn't beat the price.
like BRCM, I set them to charge, check the water and get them into absorb once in a while.
Easy for me since my system in nano-sized compared to most others here.

However, I do still mess around with small LI batteries. They are fun projects for our LED light strings.

Scruff, I too am following this thread pretty closely.

Cheers
Bruce S

[Scruff]

Ironically I saw an interview with Battleborn's CEO who said they set the low temp cutout at -3°C because most people using them never met me are charging @ <C10 and they "like putting then inside".  How's that for failsafe!?

Thanks for the support...ie. following...I knew I came to the right place. It sure beats responses like "Li-ion is viable because national grids have started integrating them after they were donated to them as a PR stunt from the manufacturers. V2G is the future of RE and I'm €10k in the red on my solar+1kWh battery install!"

Thread's gonna change gear soon. I must introduce yee to the soon to be grid-tied 3 phase truck.
Bleedin' cold out, so I'm wrapping everything else up before I start & the postal service is a bit broken.....Xmas, Covid, Brexit, icy roads and the Irish only use Summer tyres..

Last time I did a (van) conversion, it ate a Toyota Corolla inside a fortnight after I transmuted it into wood, screws and sundries. This one's gonna be something else.

I'm floggin' off a lottov hardware now that it's the season for starting projects. I've 1m³ of underwhelming power lekytronics and extortionate "camper" hardware on the way to the eBay. If yee see anything in this thread yee fancy that's not hardwired or test gear it's probably for sale. PM for details.

[Scruff]

[Scruff]

I'm still waiting for WuPoG to be useful again...March maybe?



In the meantime, I rearranged things to give her proper low temp. foldback limiting the charger to C10 below 10°C by implementing the temp sensor to trigger the relay and the relay to actvate the remote access input limit feature, with an external input cutout at 3°C.

I don't think I'll do another li-ion build. This battery that's only useful 8 months a year is a real drawback.

I know...I know I should just do what everyone else is doing and add a solar freakin' battery heater bro...300W oughta do it! And that won't affect the stellar LiFePO₄ RTE one bit and should help extend the solar ROI by a coupla years!








In any case the reason I wanted to fire her up was to see if she can stoke a 180A inverter stick/TIG welder.



The answer's; Like a boss!.

I bodgengineered a fume extraction system together too...I got flux lung. It does work but not perfect.



The blower is 350W better than nothing but i think I'll do the big jobs outside.

Is that a world first high efficiency, low noise, minimal quiescent, indoor approved welder generator set? 

What?
Oh the Rogue? Fantastic machine! I learned to stick weld in 2 hours! ..Now that I can melt metal together there'll be no stopping me MWAHAHAHahahahaha!!

[Scruff]

My Solar Freakin' Battery Heater wasn't working today Bro. I think I'd best close the loop with a Battery Freakin' Solar Heater Bro!



I've invented another fly-lead.

This one is a preventative measure to stop that embarrassing moment when the supply trips after one changes over the supply forgetting the combi charger is plugged in and the inverter combi is now plugged into itself. 

It's the same configuration as an industrial machine switch. Self-maintained.

There's a momentary switch on the relay coil to activate the relay and the coil is also powered by one of the relay's switched outputs hence when the power is cut it doesn't automatically restart. The user has to reactivate it.





One of the main motivators was that it's my belief that good electrical design requires one point of interface. I'd like to leave the back-up online to keep the humidity at bay with the self-consumption warming the boards. Being a lead battery it's better suited to a stand-by application because I can keep it charged (floating) and use it in Winter.
Instead of leaving instructions with Mrs. Scruff for the event of a powercut in my absence that requires her to go into the workshop, identify the chargers and turn them off before switching from grid to back-up. She can now just go grid to back-up (through off) and not worry about anything else, for the meantime, I might put the solar array on the same circuit until I sort out the diversion control..or frequency shifting something something...

[Scruff]

Unscheduled power cut just hit. I hit the changeover switch. Strolled passed the two empty ridicously expensive and complex li-ion 3.5kWh combined (when full) gensets and stoked up the 20kWh lead contingent in the powerplant. That's great the heating system isn't scuppered and I'm not reduced to throwing LiFePO₄ briquettes on the fire as a heat source.

Solar Freakin' Battery Heaters Bro, almost as good as a coupla sods a turf in the Winter.

I'll put away the violin now. I think the wheels are falling off the band wagon....



Did I tell ya that we're getting FITs in Éire? Guess how I know? A solar installer cold called me trying to offload some li's to me at "cut-rate" lower than industry standard pricing.

[DamonHD]

FWIW external temperatures here were down to -2C outside and are currently just above 0C, and when the snow melts from enough of the PV on my roof, there might be some excess energy tp try to put into the Enphase battery.  Interesting to see what happens at that point.

Rgds

Damon

[Scruff]

Yes Damon can you post some data I'm curious?

I don't think there's an internal heater in that one. Quite possibly the answer is irreparable harm if the C rates are high enough in relation to temperature, where there's no proportional foldback, but it'll take years and some sophisticated test gear to prove.
Most manufacturers are pretending that >0°C = ok and <0°C = bad.
From the data I've seen, it's highly dependant on the relation of temperature to chare rate. Specifically, are the electrons travelling faster or slower than the lithium ions because any li-ions getting to the finish first are plating the anode permanently increasing internal resistance and reducing active material?

One must remember that solar performs better in the cold than the heat. They are rated to 25°C cell temperature....there's a disparity of often nearly 50°C between panel temperature and cell temperature.
+1% performance per 2°C below 25°C.

I know the Poowerwalls will import power to run it's heater and then use solar priority to supplement it, so instead of charging or powering your loads, it becomes an atmospheric heater.


Power's still out. 2.5kWh used. ~15% powerplant depletion compared to 100% WuPog depletion is another not inconsiderable factor considering WuPog cost me 5 times more than the powerplant.

Mrs Scruff didn't realise it was a powercut. That's about as high a compliment as I could ask for.

[bigrockcandymountain]

It is -21c here this morning and thoughts of using solar to heat a lithium battery are pretty absurd to me.  I'll bring the beer onboard the band wagon. 

 I've used lead outside for years in these temps with no problem. I honestly didn't know about the temp limits on lithium until you mentioned it in your subtle way scruff.

Is that a world first high efficiency, low noise, minimal quiescent, indoor approved welder generator set? 

 
Now that's progress.  Does it put out the full 180a off the inverter? What was the inverter you were running off of?

[DamonHD]

Hi,

Here is a pretty chart:



Or I could get you the raw 5-minute data that I poll from the Enphase hub.

But in any case, though the ambient temp is still not above about 4C, the battery has gone from ~0% to ~80% SoC.

Rgds

Damon

[Scruff]

It is -21c here this morning and thoughts of using solar to heat a lithium battery are pretty absurd to me.

Yurp.
Winter is the time I need a battery the most.
It also throws into question the purported efficiency and projected payback time of the technology as a practical fallacy.
What this signifies to me is that the only really viable static applications are where they're not required to be relied upon...complete with internet connections....oh 'nuther can of worms...I'll leave that shut for now...

Sure they are better in electric drive...that's a 20% efficient system (ICE)....

 

I've used lead outside for years in these temps with no problem.

My internal (under driver seat) camper battery is frequently in the 3°C to 10°C range even with the habitation space heated.
There's no way I'm putting 20kWh inside a house, I want a plant room for that and I'm not heating it outside of self-consumption losses. The only practical way I'd put a battery inside a house is if it's too small to be much use for any extended autonomy.

...until you mentioned it in your subtle way scruff.

 

Calling BS is a vocation. I'm an anti-propaganda evangelist.
I get right tired of wading through it on every job.

Now that's progress.  Does it put out the full 180a off the inverter? What was the inverter you were running off of?

It's 180A welding current MMA. The inverter is a "48V" Studer XTM 4kVA with 10.5kVA surge (5 secs).
ESAB recommend a 6kVA genset.

I didn't see what it was pulling off the inverter because my AC output meter's cream crackered atm and I wasn't too bothered because it was working. Besides, it's quite hard to weld and read a meter on another workbench at the same time.
The furthest I pushed the welder was 85A and then I pulled it back to 60A.

I'm gonna try it on the 3.5kVA 24V sister next.

I'm cheating quite a lot....it's an inverter welder so very efficient and lower inrush. 

But in any case, though the ambient temp is still not above about 4C, the battery has gone from ~0% to ~80% SoC.

Interesting. Thanks D. The ambient temp is not as significant as the internal cell temperature which will be heated by it's electronics (inefficiency) and the cells warm themselves at about C1.5.

Conveniently that looks like 4 hours to 80% linear. C5....yes, pretty aggressive for low temp. operation, probably borderline. The studies I've seen are more EV based, you really see significant deterioration at C1 and faster even way above 0°C

[DamonHD]

Its max charge/discharge rate is C/4, ie 4h for full charge or discharge.  But in thus case there was not enough unconsumed solar for that charge rate it seems.

My *estimate* is that the battery itself consumes no more than ~10W overall.  I have seen no evidence of a heating-sized load not showing up as a charge increase.

I do have data for its entire life in full import/export/generation/charge/discharge split in 15 min and ~5 min blocks, published, if you want some light reading...

Rgds

Damon

[Scruff]

Hrmmm seems like a very conservative product. It ought to last.

I think I'm alright for the light reading.

Tesla have heaters in their poowerwalls and motor batteries, renogy have heaters in their drop-in replacements, battleborn have a cutout at -3°C and/or C1. Most EVs will have coolant/heater loops (not nissan leafs and it shows), pylontech is commando too with cutout.

V2G will be heating a lottov driveways and garages as the uptake increases thanks to the unity efficiency shytehawk proponents.

1.2kWh is mighty small for a house. I've over double that in a campervan.
I'm a double solar = 3 times better than solar + battery advocate for grid-tied. Cleaner network, faster payback, more power, energy was never an issue until we contrived to make it one.

[DamonHD]

I have ageing LA nominal 2kWh usable (400Ah, 12V) off-grid storage also.

I chose the Enphase not for total oomph but because it is nimble and can limit grid flows within the 270W max of the single battery unit to ~5W.  Our overnight load is generally max ~80W, typically half that, so the Enphase can absorb most of that eg in summer.  The nearest competitor (Sonnen) seemed to not be able to neuter flows less than ~30W from eg my discussions with its UK tech director.  And some devices on the market cannot counter flows below hundreds of watts, so useless for us to kill night-time flows, even most of our day-time flows!

In any case even that small storage increased self-consumption up from maybe 30% to over 50%:

    http://www.earth.org.uk/saving-electricity-2019.html

There is a marginal case for getting a Enphase second unit, but I think better from a carbon pov is, ASAP post-lockdown, careful diversion for DHW:

    https://www.earth.org.uk/note-on-solar-DHW-for-16WW-UniQ-and-PV-diversion.html

Rgds

Damon

[Scruff]

I've thought about making an as nimble lead-acid battery. It's equally dynamic and efficient in the 20% to 80% range..& better for AGM but not as long lived.

Then automate the system to do that lower-efficiency maintenance push to SG 1.28 once a month removing the load from the battery for two days, and who'd miss it, it's grid-tied and loads cheaper.
C5 is fine for lead.

I've looked at self-consumption and diversion.
The most economic solution for me is to donate excess power to the network.

1kWh is only worth €0.16 to import.

Hence WuPoG doesn't do much except run tests and standby to be hired.

It'll take me 8 years + to offset the cost of diversion control or else double my solar array to support it say 4 years then & 2.5kW extra of PV installed with an inverter.
That is to say for me to spec a half-price PWM diverter as opposed to a 50hz transient generating phase angle fired cheap and nasty type.
A grid-tied battery I daresay never.

Looking at the payback outside of financial terms; solar can return the embodied energy in 3 years, a li-ion battery takes the lifetime of the battery.

So coupling solar to a battery the solar now has to finance the battery, the round trip efficiency and itself. Altogether a less desirable arrangement to me than simply double the solar.

I built my solar array for €1k. It averages €1 per day 9 months a year in self-consumption.
I use it or lose it and that's the best ROI I have seen, as well as the most beneficial allocation of resources to the network and lowest impact having not thrown a battery at it.

I could get WuPoG to Net Zero Export, wouldn't cost me anything more than wear and tear...I might trial her when she stops being a special snowflake and the solar is in danger of overproducing again.
I won't use as much in lecky the rest of my life as what she's cost to build paying myself for the time.

[Scruff]

I installed an new primary alternator on Froya a week ago. Clients tried the old remove the battery with the engine running trick.

No pics but direct swap. The battery light didn't return so I must go looking for a fuse. I added an E-start facility to parallel the starter battery and house battery for redundancy off the back of the split charge system.
For anyone wondering what happens when you parallel a 160A alternator with a 60A alternator..



I load tested the pair to 170A peak with the engine at a jog.


My Solar Freakin' Battery Heater and my Battery Freakin' Solar heater are offline...still...negative feedback loop...I'm gonna try throwing bovine manure and pdfs at the problem next.




My leady powerplant is standing by to be a boss at whim..




The Souper Charger got a Meter...it does kW & kWh for grown-ups {didja hear that ApprenticeVolt?} she's done now. Dare I say I've never seen another as capable.



MorningStar tell me there's a 100A MPPT in the pipeline. 


Despite WuPoG being a special snowflake (for several months now) I'm still being nice to her.

I gave her some front panel switches. One is On - Off thuther is programmable (set to input power select 4A / 16A with low temp over-ride)



Did I make that look easy?

Ha!
I'll spare you the saga of how I go the correct switches 2 months after ordering the first batch of wrong ones.

Here's the instructions:



What the omnipotent and all-knowing Swiss omitted to mention was that the On-Off switch is latching...but open is on and closed is off.

While the programmable one "remote entry" is momentary...just to be a d8€*.
Momentary illuminated switches are so much fun to implement too..
Oh and just in case you dial that combi up to 63V on occasion the input limit of the momentary pulse is 60V okay? Great!

[Artful Bodger]

Nice solution. Mine would have needed a microcontroller.
I think they mean 60VDC or AC effective aka RMS. That's around 170V pp. Feels wrong driving 36mA into the opto with the 4k7 they've shown.
That on/off is a dry contact, with no opto, so be careful how it's wired.

[Scruff]

 
My solutions never involve a micro.

..remember that time I built an ipad with relay logic? 

There was much carefulling because I hadta hack my own RJ12, and the "straight-thru" leads and connectors I got were crossover and didn't I pledge to stop terminating expensive inverters...I think I did...sounds familiar...

And then I still got it wrong.. (using dry contacts only)
Because number 6 conductor on the RJ12 port is core one etc...

Earlier set of notes flagged that..

I was souper careful with the voltage because I'm outtov spare studer smoke.
60Vdc = 170V PP?  ....ah canya draw that for me? 

The on/off dry contact is interesting. It seems to disconnect the DC. The unit turns off - off not just resting off and the remote turns off too. Not like the front panel switch which is a soft not-really-off-off.
Handy for me because I like off-off but I wonder what switching element they're using and how it'll stand up to those caps.

I can use the remote entry to soft-off too.
And I can use the programable relay to trigger the programmable switch which makes it an incredibly powerful feature.
Sadly wasted on li-ion (she's actually got 10 programable contacts and 9 are li-ion BMS    )

The relay contacts are genstart and low temp foldback which coincidentally is the input limit so that can also be manual.
I'm looking forward to what I'll come up with for the lead version.

You can also link the remote entry across all the Xtenders on the network so one button on the master will execute the same command on all the slaves.

Amazing what engineers can do when their budget isn't assumed by the marketing department and Bluetooth features wing innit!
 

[Scruff]

Looks like I'm on thuther side of LiFePO0oo chocy teapot season now. I can use the operational temps to keep them tickity boo.

That momentary switch... ...only works for the (soft) on-off programmed function.

I quite like the circuit but as one of my sensais thought me...."kill your babies" it's back to latching for the rest of the functions to work.



New output meter installed (#5; 3 died, 1 (previous gen.) didn't match the input ergonomics)...cheap Chinese chit man! Oh well, the system still works when the meter fails because it's shunted and a genuine one would cost me equivalent to 10 chit wans.

Exceeds rated spec. ...we like that. It's rare.

Burn testing now.



This is my "dump load" it's buffering into the house.
There's 170A @24v of chargers in this photo...and I have another 60A behind the camera. 
Proportional load control in the guise of charge current throttling.



Looks like my super featured Studer 4kVA that exceeds specification is heat soaking at 2°C lower than the 2.4kVA ApprenticeVolt functionally limited to entice you to buy exclusive hardware to make it useful it replaced that only meets specification...briefly..then chits the bed...
Oh wait..nope the Apprentice volt didn't really meet spec, the charger derated at upper voltage.
The 35A charger was only pushing 28A, (it's own meter said 30A but mine said 28A).

The 50A Studer charger pushes 50A...mad!

{Edit...We're pushing 44°C with continuous operation 100% - 0% @ C0.9 & 0% to 100% at C1.4 at the end of the second round trip....I've a makeshift baffle marmaladed in & dialled up the PWM fans to see it if makes any difference, battery temp is sitting at 35°C so she's having a break while I consider putting more holes in my case.}

My House Supply ChangeOver got a neon transplant.



The green one expired.
They're supposed to work for 3 years continuous!

Over-priced, RS-brand junk....psah!
 

[Scruff]

The question arises again...Can I neutralise a cheap inverter and not blow it up?

Sparky A: blew up inverter
Sparky B: said it sounds sketchy... wouldn't recommend.
Joe Public A: blew up inverter
Joe Public B: blew up inverter
Marine fitter: Never had an issue
Myself: never had an issue, haven't tried every topology.

I decided to put my money where my mouth is. Earth leakage protection aka life harm protection is the most important and overlooked part of electrical design in off-grid.
It falls into the; if it's too complicated to understand then it's probably not relevant department..and besides the system works without it.

Accepting that adapting a critical mindset..you don't know until you know, with consideration to those who seem to know what they're doing haven't had issue and those with no relevant experience/qualifications/problem-solving skills are having issues.
This leads me to consider that people blowing up inverters are blaming the neutralising link when there's other factors at play. Much like people blame batteries for system failures and not chargers.

Here's the cheapest nastiest inverter I have at my disposal.
As she comes standard, looking like a centre tapped earth but it's just a floating reference.



Live -> Earth: 131V
Neutral -> Earth: 106V

Here we see my tester flagging "No Earth"



That means no earth reference and/or continuity.
RCDs (GFIs) are not enabled in this configuration.

So let's TN-S; tied neutral supply.
..and see if she retains her smoke...




Live -> Earth: 238V
Neutral -> Earth: 0V

If that Wago was an RCD it could now save yer life.

I don't know how people are blowing inverters I expect it's by putting unsynchronised mains on the output or perhaps the DC input.

Remember. The earth and the neutral are the same conductor.
One is allowed to conduct.
Thuther isn't.
We are all birds on the wire with regards to the potential difference.

[Scruff]

To be sure, to be sure, to be sure I just linked the PE (AC earth) to the Ground (DC negative) with the Earth tied to the neutral and smoke retained...inverter still working.

[Scruff]

WuPoG is in continuous duty thermal runaway.
I'm not addressing earlier comments about the ApprenticeVolt versus Studer because I only tested the ApprenticeVolt on a single round trip and besides I think it's good for people to see the frequency I draw the wrong conclusion because if there's any underlying message in this thread it ought to be; don't believe it unless you can prove it yourself.

I've made another fly-lead.



It's a genset simulator (automatic mains input switching). It interfaces to the genset trigger and makes it so I can run 100% - 20% - 100% continuous without giving her a break to cool off as long as I have load to give her.
It's helpful too in that li-ion is a special snowflake and doesn't like floating so it'll disconnect the mains as soon as absorption is complete.


I'm having two issues; The enclosure is heat soaking and the inverter intakes are pulling air from the exhausts.

I can solve the inverter-charger heat issues with better airflow. More powerful fans, better vent placement, baffles etc.

I've ordered 4 new fans. They spin 60% more RPM for the same noise and they're all the same so that ought to eliminate the issues I was having with the oddball fan working solo from the single PWM driver split over 4 fans.
I'm gonna invert the airflow too to reduce stifling, the draft is better that way.
After that; more holes because the ones she has were for a different inverter..knowing each one is another liability, especially those in the lid what face the sky pretty often.

The next issue is the battery is exothermic. I'm not putting thermal management in there because lead effing acid makes way more sense.
So far the cells are heating up at C2, I haven't found the point at which they stabilise yet...I'm still reducing parameters and looking at feedback but we're very close to lead acid thresholds now.

I think I'll have to derate her for continuous duty. I can charge her in an hour if you don't use it heavily for 2 hours. If it's sitting as a genset offset device it's not got the same potential I was hoping.