My Interstate Lithium Battery Adventures

[InterBlog]

We're jettisoning our on-board generator anyway. We're not yet clear on the actual order of operations, air suspension vs. generator removal and now potentially toss diesel heater installation into the mix. But I'm anxious to get rid of that ball and chain of a generator. In 2.5 years, I've used it to make exactly one dozen pieces of toast. Which we don't even need anymore because our inverter now supplies the same functionality. The plan is to have one or two portable Hondas on hand just in case we need it/them for hurricane evac.

[lewster]

Originally Posted by InterBlog

We're jettisoning our on-board generator anyway. We're not yet clear on the actual order of operations, air suspension vs. generator removal and now potentially toss diesel heater installation into the mix. But I'm anxious to get rid of that ball and chain of a generator. In 2.5 years, I've used it to make exactly one dozen pieces of toast. Which we don't even need anymore because our inverter now supplies the same functionality. The plan is to have one or two portable Hondas on hand just in case we need it/them for hurricane evac.

Add the Easy Start to your A/C and a 2000 watt inverter/charger and you will only need a single Honda 2000!

[InterBlog]

This thread could use a status update, a more technical one than I am capable of providing, but let me just add a few cents worth and maybe LB_3 will chime in.

I'm writing this from the local Cabela's parking lot (they are friendly to travelers and RVers, including people cranking gensets) as I'm testing our Interstate's electrical system holistically. It's so hot outside right now that I can't really rest my bare foot on the metal floor flange that accepts the computer table leg - it's heating up from below to an uncomfortable level, the heat is that severe. The van is absolutely getting pounded with incident solar energy in this concrete crucible adjacent to the Gulf Freeway. It's bearable in here with the a/c running on genset, but it's not what I'd call frosty.

I'm duplicating conditions as they will soon manifest on the road to Nova Scotia. I'm a morning person, and I anticipate rising every day at dawn, driving about 5 hours, stopping for lunch, napping, and then continuing the drive. Napping means I have to be able to run a/c off-grid, so that's part of what I'm testing now.

We did get the EasyStart that Lewster recommended in the comment above (it's also discussed in part on another thread), and it does work. We actually have four-way charging now - not LB_3's original design, but <insert story here> about how the alternator charging wasn't working as expected, and so we needed a fall-back on the solar, especially given that we upgraded to a 12 volt Vitrifrigo refrigerator. Those batteries are now a habit that's got to be fed.

In two sessions of system testing yesterday and today, I managed to make the following mistakes:

(1) I "babied" the a/c boot-up sequence like I do in my home office in order not to trip circuit breakers (babied = bringing loads online gradually because I have a huge amount of crap running in my office and normal household circuits don't like it). By that I mean that I intentionally turned on the a/c fan before the a/c compressor. This resulted in the inverter faulting out and the whole thing shutting down. Unbeknownst to me, the system LB_3 built would have gone through a second power-up sequence and eventually turned on the a/c without my intervention, but one sees a flashing fault light and one naturally assumes it's game over at that point. Home-made systems do not operate as consumer goods - they don't necessarily use the same logic, is the take-away. The other take-away is that the EasyStart must be allowed to do the job for which it was designed. Just crank that sucker up all at once (the a/c) and the EasyStart will do the rest. Don't try to baby it - things will just get out of whack.

(2) On my second Cabela's parking lot test, I became startled by the fact that the three simultaneous inputs (alternator, solar, and genset) had driven up the lithium input to about 100 amps. I didn't know if that was safe, so I rushed to shut down the chassis engine to unload one source. Normally there would not be three simultaneous battery inputs, but it's so effing hot out here that I could not bear to shut down the engine before the coach a/c was up and running.

During this somewhat frightening distraction, I pushed the inverter button at the wrong time, did not successfully disengage the inverter, and ended up running the a/c off the lithium batteries (which it will do) even though the generator was also running (under no load). Classic failure pathway - distraction leads to improper actuation. I wanted to try taking a nap and I didn't notice the failure until the lithium bank had gotten sucked down by about 15%. (Sigh.) The take-away from that trial is that, even with good design, this stuff is never idiot-proof.

But that's why I'm sitting in this scorching parking lot, right? To discover and work out any kinks ahead of real-time operation.

Anyway, I'll close with a pretty picture of the spare fuses I mounted this morning. I did a light Rustoleum coat on a piece of scrap steel bar, 3M'd it to the back closet wall above the main switches, and then stuck my magnetic fuse holder on it. All nice and organized. Given that I went to all this trouble for the sake of the fuses, Murphy's Law says that we'll never blow another one again in our lives.

[Troutboy]

I do enjoy all your input and takes and lessons learned. However, the one question I often wonder is.....

With your hatred of that Houston heat, why stay there. Relocate to a more friendly and tolerable environment....[emoji16]

We have room in Colorado.....

[73shark]

Originally Posted by Troutboy

I do enjoy all your input and takes and lessons learned. However, the one question I often wonder is.....

With your hatred of that Houston heat, why stay there. Relocate to a more friendly and tolerable environment....[emoji16]

We have room in Colorado.....

Probably because LB_3 works at the Space Center.

[LB_3]

IB can humble the best of engineers. I was pretty pleased with how the system was running. Then I hand the van over to her and immediately get a stream of texts about how everything is broken. I had performed a system test with dozens of generator and A/C starts as well as as probably another dozen transitions between various power sources without any trouble other than a single gfci trip.

The story of the gfci trip is very frustrating in that it's intermittent and so far proven difficult to isolate. After finding a technical bulletin, it appears that when not using shore power, the inverter will shunt the input neutral to ground and it sometimes doesn't detect the shore power and unground the neutral wire fast enough. Not having any downstream loads on may alleviate this issue but it's proven intermittent and so far pretty rare only occurring once during about a dozen system activations. Adding another automatic transfer switch would solve the issue but I don't really have time for one and it would add another 30 seconds to the already slow system activation.

IB would be a good software bug tester because she is always doing things in ways engineers never envisioned. I can't count the number of times she has had a Dell service rep reinstall a corrupted operating system or come to the house to install new motherboards.

It's not really her fault that we engineers can get so deep into the technical details of a system that it never occurs to us to that someone might try to do things in a different sequence. I find this quite frustrating at work when engineers build us a treadmill with no power-switch. Seriously?!?! NASA has the only treadmill in the universe with no power switch. They never envisioned the need for the astronauts to turn off the treadmill? I guess they assumed it would rarely fail and that one of us on ground could power it down using the upstream circuit breakers when we needed to do maintenance. We do however have a radiation detector with a power switch, however if the crew uses it the device will brick itself if the ground hasn't first powered down the primary sensor. Ugh, the only thing I hate more than dumb engineers is when it's my turn to be the dumb engineer.

Having built the system, and knowing how the Easy-Start takes over the a/c start up, it never occurred to me that one would do anything other than just turn the A/C to on. But trying to baby the system by turning on just the fan first circumvents the Easy-Start and results in the generator voltage sagging below the inverter's cutoff limit and the system resetting.

Lesson Learned #1: Just turn the a/c on and don't try to baby it.

While much of the system is automated, not all of it is. It's an either or proposition with the inverter and alternate power sources which leads us to IBs second issue. If the inverter is inverting it will keep inverting. It has an internal 30A transfer switch but it won't interrupt existing power so if you want to use shore or generator power you must first turn off the inverter.

Lesson Learned #2: Turn off the inverter before starting the generator or plugging into shore power.

As for IB's distressing sight of pumping 100 Amps into the battery, it's expected and safe. I didn't necessarily plan to charge from the generator and alternator at the same time but I did size the wiring and heat sink to handle the BMS's rated capacity of 100 charging Amps. The BMS will shut off the charging if it exceeds 120 Amps or if the BMS gets too hot but I put a sizable heatsink on the back of the BMS and it's mounted to an aluminum panel so it should be fine.

I'll post a schematic this evening.

[amirm]

Originally Posted by LB_3

As for IB's distressing sight of pumping 100 Amps into the battery, it's expected and safe. I didn't necessarily plan to charge from the generator and alternator at the same time but I did size the wiring and heat sink to handle the BMS's rated capacity of 100 charging Amps. The BMS will shut off the charging if it exceeds 120 Amps or if the BMS gets too hot but I put a sizable heatsink on the back of the BMS and it's mounted to an aluminum panel so it should be fine.

I'll post a schematic this evening.

Good stories you all.

On above, I actually pumped in excess of 120 amps into the battery bank when I had your BMS and nothing faulted or shut off. I am suspicious of it actually performing that function (reported the same to Dacian).

The battery bank was cool as a cucumber though. You can easily pump 3C into them and that means 300 amps.

[LB_3]

Charging/Inverting System:


DC Schematic:

The 12v-12v converter may not be wired like in this schematic. I think it actually feeds switch 3 that has the Apple TV and audio amplifier but my memory is a bit fuzzy at the moment and the wiring behind the panel is a disgrace so I avoid looking in there as much as possible.

AC System:

[LB_3]

Originally Posted by amirm

Good stories you all.

On above, I actually pumped in excess of 120 amps into the battery bank when I had your BMS and nothing faulted or shut off. I am suspicious of it actually performing that function (reported the same to Dacian).

The battery bank was cool as a cucumber though. You can easily pump 3C into them and that means 300 amps.

Luckily, we can't put much more than about 100A into the battery since the Sterling charger really only puts out a max of 45A due to a nearly 3% voltage drop from the alternator and more constantly 38A-41A. The Lithium charger puts out about 55A under ideal conditions but more commonly about 49A. And the solar maxes out around 15A-20A but is generally in the 13A range in full sun.

3C on a 300Ah battery is 900A. I don't think the suspension could support all the copper.

[LB_3]

Oops, the battery relay was in the wrong place. Hopefully an admin will allow me to edit my earlier post and delete this one.

[InterBlog]

I got a good chuckle out of those responses. The human brain does not run on engineering theory - it runs on a wealth of unconsciously-internalized schemata, and it's very hard to override those imprints. It takes conscious effort, and when the inside of the Interstate is 100 degrees or higher, overriding the imprints is a challenge. Of course I know intellectually how the EasyStart is supposed to work, but when I'm effing miserable, I default to the normally-applicable schema, which says to power up gradually. It's an involuntary substitution of an existing precedent. Which of course will lead to failure in that context.


Thus we move out of the realm of mechanical and electrical engineering and into the realm of human factors engineering. Those are profoundly different things.

LB_3 gave an example of the space station treadmill. Here's another example. I once served as an assistant operator on a groundwater treatment system installed on a Superfund environmental remediation site. Ergonomically-speaking, water treatment systems have the characteristic of needing to be viewed as fully analogous to living things. You do X, the treatment system responds by doing Y, just as an animal would. In fact, domestic systems are explicitly regarded as living things because they literally are - it's the microbiological organisms that conduct the treatment, and those organisms must be kept happy - ecstatic, in fact - or nothing good will come out at the other end of the process.

Well, with domestic wastewater treatment, we've collectively had the time (over 100 years) to work out the kinks and make the engineering fit the unconscious expectations of human brain. Superfund wastewater treatment systems, not so much. There are far fewer of them, fewer opportunities to incorporate lessons learned in design iteration. At the site where I worked, the lead operator and I spent 90% of our time circumventing the mechanical and hydraulic engineering in order to make the system fit the human brain, and 10% of our time actually operating the system. Because if it didn't behave in a way that was systematically consistent with brain expectations, then we couldn't anticipate its needs, and therefore it would fail.

Human factors. Don't underestimate 'em. Huge airplanes sometimes crash entirely because of human factors issues.

[Troutboy]

Haha. Now your in my world interblog. Environmental engineer w/WW and certified operated for industrial facilities. Seen at least 30 of the groundwater sites and operated a few. I get it 100% now.

Same also goes for the municipal systems (donestic) now with all the technology and automation.

Nice schematics. They make sense.

[InterBlog]

Originally Posted by Troutboy

I do enjoy all your input and takes and lessons learned. However, the one question I often wonder is.....

With your hatred of that Houston heat, why stay there. Relocate to a more friendly and tolerable environment....[emoji16]

We have room in Colorado.....

We allow ourselves the luxury of hating the heat (howling about it helps to dissipate tension) because every single place in this country has drawbacks of its own, and this just happens to be our whopper of a drawback.

If we moved somewhere else, we'd have different drawbacks - it would be a lateral move in that context. I spent my first 23 years in Nova Scotia. I did not mind the discomfort of the incessant cold, wet, and snow, but I did mind the fact that life itself must shut down for long periods of time. As one gets older and the remaining time becomes shorter, one gets less tolerant of having to wait for life's activities to proceed. My 81-year-old father is downright hilarious in this regard. In his younger years, he had the patience of a saint. But he ain't got time for that no more (literally ain't got time), and he can't sit still for a single day now (which is probably what's keeping him alive).

Both LB_3 have jobs that demand Houston - he at Johnson Space Center, and my roster of industrial clients is here. We are pretty much committed to life here (LB_3 is a native Houstonian) but it's not without burdens, as any place would be.

[InterBlog]

Originally Posted by Troutboy

Haha. Now your in my world interblog. Environmental engineer w/WW and certified operated for industrial facilities. Seen at least 30 of the groundwater sites and operated a few. I get it 100% now.

Same also goes for the municipal systems (donestic) now with all the technology and automation.

Nice schematics. They make sense.

Then you know that all that automation is no substitute for the intuition of a good operator. Automation is useful, it can help with routine daily life. But the operator needs to have his or her finger on the pulse of the system, or else there will be trouble and/or needless expenses.

[toskeysam]

LB_3... great schematics! Lewster did a complete lithium/solar/inverter upgrade for us and I have been putting together a "manual" for us. My old engineer-mind has been revising circuit diagrams.....but that doesn't help my microbiologist-cancer-researcher wife. She just doesn't speak that language and that's ok! I showed her you diagram and got a big "YES!" from her. Filing away my "diagrams" and using an approach like yours. Great job!

[LB_3]

I'm hoping to add hyperlinks to the PowerPoint with specs and product manuals. But that's down the road a bit and I wish I had a web friendly way to share that and get away from the PowerPoint documents.

[amirm]

Thanks for the diagrams LB_3. One of these days I will do mine.

Questions: did you change the charge thresholds in the BMS or are you going with the defaults Dacian put in there?

I upped mine as otherwise the charger would keep staying at full power and making noise. With higher thresholds, it shuts down on its own, fixing that problem.

[LB_3]

I'm still using the default settings. I haven't noticed a noise issue yet but I'll keep an ear out for it.

I did have an issue with the Sterling charger dropping out of its bulk charging mode. It was the result of the input voltage dropping as low as 13v while driving. Putting the charger into 'regen braking' mode, which lowered the minimum voltage to 12.2 volts, solved that little issue.

[Troutboy]

Originally Posted by InterBlog

Then you know that all that automation is no substitute for the intuition of a good operator. Automation is useful, it can help with routine daily life. But the operator needs to have his or her finger on the pulse of the system, or else there will be trouble and/or needless expenses.

Yep. And with biological systems, the most important thing to live by is "keep the bugs happy!"

[InterBlog]

Originally Posted by LB_3

I'm hoping to add hyperlinks to the PowerPoint with specs and product manuals. But that's down the road a bit and I wish I had a web friendly way to share that and get away from the PowerPoint documents.

There's a product called ThingLink which does this quite nicely but when I tried to fire it up a few months ago, the freeware portion proved to be buggy. The developers sent me a fix, but the balkiness had derailed my momentum, and I never got back to it.