My Interstate Lithium Battery Adventures

[LB_3]

The smallest alternator Mercedes installed in the T1Ns were 90A alternators so I started there.

[amirm]

Originally Posted by FlyFishinRVr

@amirm, in the Bosch data that you found, was there anything that indicated how long that unit can deliver that amperage? For example, at 1500 RPM can it deliver 171A indefinitely, assuming the temp never exceeds 171*F? Is there another chart that shows how temperature effects the output given that they list temperature as a factor in the table you linked? I ask because I'm assuming the longer the unit runs, the hotter it gets, but where's the temp limit and how does it behave at that limit (does it step down significantly, or just shut off)?

I can't find any MTBF data in my few minute search.

In practice I don't think it is a huge problem. Most of the time you are not recharging a dead battery and even if you were, in 2-3 hours it would be topped off and the rest of the time there would be no draw. So the percentage of time it runs hot due to high current would be pretty low relative to all the driving one would do.

Also, all current AGM based Airstreams are pulling over 100 amps in my testing anyway. If there were issues here we would know about it.

This assumes of course that the retrofit to lithium limits the current to the same value which mine does (using Sterling Battery to Battery charger).

[FlyFishinRVr]

Originally Posted by amirm

I can't find any MTBF data in my few minute search.

In practice I don't think it is a huge problem. Most of the time you are not recharging a dead battery and even if you were, in 2-3 hours it would be topped off and the rest of the time there would be no draw. So the percentage of time it runs hot due to high current would be pretty low relative to all the driving one would do.

Also, all current AGM based Airstreams are pulling over 100 amps in my testing anyway. If there were issues here we would know about it.

This assumes of course that the retrofit to lithium limits the current to the same value which mine does (using Sterling Battery to Battery charger).

Thanks.

I guess it also assumes a similar amount of battery storage as yours. If you doubled the storage capacity and kept the same current limit, it would take 2x as long to fill it up.

But you make a good point, and given the pace at which you can fill the lithium cells, if you limited the draw to 50-60A(ish), you could push 4-500A into a battery bank in a typical 8hr drive. That should be enough to fill a 800Ah pool that's been fairly heavily used, shouldn't over-tax the big 220A alternator, and should leave plenty for the chassis.

[InterBlog]

New electrical control center panel, aluminum to replace the previous black plastic prototype. LB_3 designed it with those handles which one uses to yank it off its neodymium mounting magnets for access to the guts behind it. It sure looks spiffy!

We got the repaired solar charge controller back from Dacian a few days ago and the 12 volt side is now back up and running. Next steps will be to get the inverter online and also the new alternator's connection.

[FlyFishinRVr]

Originally Posted by InterBlog

New electrical control center panel, aluminum to replace the previous black plastic prototype. LB_3 designed it with those handles which one uses to yank it off its neodymium mounting magnets for access to the guts behind it. It sure looks spiffy!

Spiffy indeed!

Nice work you guys. Looking forward to the write-up of the finished project and how it all performs (assuming it's not like one of my projects, which means it's never truly "finished" as I'm always tinkering with it, LOL).

[Troutboy]

Very cool and looks awesome. I see 1/8 inch aluminum sheet for my power distribution panel, but cut it myself. Two large squares. Good to know about this company and the work they do.

If you were to do this again, would you have the black plastic template made? Was that step necessary?

[InterBlog]

Originally Posted by FlyFishinRVr

Spiffy indeed!

Nice work you guys. Looking forward to the write-up of the finished project and how it all performs (assuming it's not like one of my projects, which means it's never truly "finished" as I'm always tinkering with it, LOL).

Ohhhh, it'll be finished, one way or another, come hell or high water. In my case, I have professional ambitions for which our Interstate is essential, so it simply has to get finished and get working. Following some of Amirm's observations, LB_3 and I have even talked about perhaps weaving in redundant solar charge controllers (plural) for even greater reliability, but we've held off on those types of ideas until we see how this present configuration performs.

[LB_3]

Given that the plastic panel was only $40, I would do it again. When the manufacturers didn't give cut-out dimensions I used a micrometer or calipers to measure the actual parts. My measurements were good and everything fit nicely on the laser cut panel. But water jetting is a different animal and most of my holes were a few thousandths too small. The problem there is that the water jet kerf is a variable width depending on the cutting speed so I should have included that in my tolerance stack.

Beyond that I still screwed up a few items on the first panel. The opening in the cabinet was a trapezoid hole and I never would have gotten the gapping even on the first try using a tape measure.

There was also some scope creep between panels. The new one has illuminated rotary switches on the top which required cutouts for the BlueSea switch to move down for clearance of the illumination modules. I also wanted a way to turn the illumination off at night without turning off any loads so I added a small push button for that.

I initially wanted a hinged design but there was too much stuff in the way like the smoke detector and thermostat to allow the panel to open up, down, or to the left. Opening to the right would have been far less than 90 degrees due to the same obstructions which would have been difficult to wire up. That lead me to the pull handles and magnets holding it closed. It works well and is clever enough but it makes it impossible to organize the wiring. To work on the panel I needed enough slack to let the panel hang down a bit but with over 40 wires interning that small area, it becomes an unmitigated visual disaster. I could barely get all the cables pushed back enough to get the panel in place.

I'll post more on the wiring later but I had a bit of a scare when I initially plugged in the volt meters and exposed as sneak circuit. The 4 wire volt meters were intended to measure the voltage loss to and from the inverter since a loose connection on a circuit running at up to 250 Amps could generate a lot of heat. This sneak circuit powered up the fantastic fan for a milisecond before it blew the 1A fuse on my measurement input wires. Given the 22 awg wires in this circuit, I'm glad I had those tiny fuses in place.

This occured at 3AM so I figured it was time to take a break and assess wether fatigue was a contributing factor. I measured the resistance between the +/- on and across the power and measurement wires on a spare voltmeter display at just under 10M Ohms so the circuit isolation appeared good. I'm really not sure how putting 12v to both the + and - input lines caused the power to work it's way over to the power side of the meter (perhaps the 12vs on the negative input wire was more than it could handle. I'm no longer going to try to directly measure the delta between the battery + and the inverter + and battery - and battery -. Instead I'll measure between the battery +/- and the inverter +/-. And instead of looking for non-zero voltage readings I'll need to look for a divergence between the two displayed voltages.

The 200A alternator is in as well so no worries about melting down the alternator.

[InterBlog]

Today is my first full-scale mobile office test day for the system, and I've been sitting here in our driveway with the inverter running (you can see its little orange indicator light in the lower right hand corner of the control center that is mounted in the upper cabinet) for about the past two hours, waiting for something to fault, fluctuate, or catch fire.


None of those events have transpired. The computer system is drawing about 2.5 amps only (per the inverter), because its internal battery is already topped off. Earlier this morning, the solar was inputting about 11 amps prior to the lithium batteries reaching 100% and idling (that's one benefit to living in Houston - some of the best solar potential in the entire country). Everything that is currently running in the rig (including propane solenoid and TV used as second monitor and which is being powered by the 12 volt side) amounts to about a 5 amp total draw right now. As the day goes forward I'll begin to add loads such as microwave, Fantastic, etc., just to see what happens.

I'm a happy camper, literally and figuratively, but there's a certain pinch-myself component to it. It took so much work and effort to get this far that I can scarcely believe that this moment has arrived. And with all the challenges we had, there's also an awareness that it might temporarily come to a screeching halt until we troubleshoot yet another unforeseen new predicament.

[amirm]

Congratulations. I am sure it is an exciting moment! I almost had the same thing 'till I found two problems I had to resolve. But then it stayed rock solid to my amazement!

[InterBlog]

Oh, we already know that it will take some additional tweaks and adjustments before it is optimized. I'll let LB_3 cover those. He's already talked with Lewster about part of it.

I had to interrupt my work day to take my Spring-Break-home-from-university daughter to some regular appointments, and my computer failed proper shut-down before I left the van (always been common which this machine, don't know why, but it's unrelated to the van's power system). So I've inadvertently set up a dead computer battery recharge experiment. Right now it's sucking about 11 amps total but PV1 (the solar) is still supplying 14 amps to the system.

[LB_3]

Originally Posted by amirm

Wonder if the standard 220 amp Bosch alternator can be used with T1N? I was looking for aftermarket alternators until I found its specs:



As you see, it has an excellent design in how it produces all of its power at very low RPMs. Even hot it is able to put out in excess of 100 amps.

Oh, I just remembered that this is a smart alternator controlled by the engine ECU so likely can't be put in older vehicles.

I ended up installing the 200AH Bosch alternator, AL0817N. I felt it was a good compromise between performance and price compared to the aftermarket.

There are some decent write ups and YouTube videos so I didn't bother with any of my own detailed write up:

The tool call outs here saved me half a dozen trips back to the tool chest:
https://sprinter-source.com/forum/sh...ad.php?t=18432

And the video of the belt tensioner here might have saved me an hour because I started the replacement after dark and it truely was a blind access: https://youtu.be/UiANNFNsiMI

[Lotus54]

You do know about these, yes?
http://accessories.us.dell.com/sna/p...03730682485791

If you are not running any AC it would be more efficient. ( although I'm sure you thought of that)

Looks good.
(If you don't had an SSD in it already, it is better on power and very noticably faster)

Mark

[InterBlog]

Yes, we parsed those products, and aftermarket products, with and without Dell support tech assistance.

The problem was that my computer is too large and no adapter has been manufactured for it. Most of the Dell "notebooks" are adaptable, but not the full-sized "mobile workstations". Dell and others assume that nobody in their right mind would board an airplane with anything this large, so they don't bother to produce a piece that will do that job.

For as long as I can run the inverter during the day and there's some degree of charge going back in via the solar, it's really no fault no foul, and I don't even have to think about using it.

But there may be other less-regenerative scenarios where, for instance, I only want to run the inverter for the 2 hours it takes to recharge the laptop, then run the laptop off its own battery until another charge is needed, thus sidestepping some of the losses that are expected if the inverter is run perpetually instead. That's part of what I'm doing this week on my "working staycation" (there's an oxymoron for you), surfing in my own driveway and seeing what some of those permutations might look like.

[Lotus54]

I'm sure you checked all into it, but which model are you using?
From the Dells we used at work (mostly Latitudes) it would work, even for the full sized dock.
(Just my curiosity, and potential future use for someone)

We get just a bit less sun here!
(And solar panels don't work very well flat here, where about 60° Angle is year round optimal)
Mark

Edit:
I looked it up, you must have a Presicion? Looks like 240 watt power supply, which is certainly large!
And I'm aware of Dells haywire power supply with the extra pin- so you can't just buy a DC-DC converter...

Good to see it working!

[InterBlog]

Originally Posted by Lotus54

...
Edit:
I looked it up, you must have a Presicion? Looks like 240 watt power supply, which is certainly large!
And I'm aware of Dells haywire power supply with the extra pin- so you can't just buy a DC-DC converter...

Yyyyup! Precision 7710.

Yyyyup! For some reason, I'm remembering 230 watts, although it might be 240. It's an "up to" number depending on its own consumption rate and state of charge, but if it starts trying to demand more than a DC source can supply, it's bad news for the supply, apparently.

Yyyyup! Also IIRC, someone put instructions on the internet about DIYing a adapter for this model, and it might even be referenced higher up in this thread (it's a long thread). It's something LB_3 has not attempted because of its overall position on our priority list (i.e., lower down).

We'd left the batteries at 94% charge last night because LB_3 warmed up his dinner in the microwave (a long-term goal of his) and because we fired up the Apple TV and watched this past Sunday's The Walking Dead in here, complete with the full OEM sound system (which I'd never heard prior to last night because in 2.5 years, we never used it - and as it turns out, it's surprisingly good stereo quality).

This morning I started off the day running the toaster, microwave (repeatedly, to re-warm my tea - heck of an energy commitment just for tea, LOL), and computer system with the inverter running all morning as I worked. Because it's mostly cloudy, it basically held its own right around 94%. But then I shut down the inverter for about 2 hours to go eat lunch and do other things, and it came right back up to 100% even with mostly clouds. Pretty cool.

[LB_3]

Originally Posted by Lotus54

I looked it up, you must have a Presicion? Looks like 240 watt power supply, which is certainly large!
And I'm aware of Dells haywire power supply with the extra pin- so you can't just buy a DC-DC converter...

Good to see it working!

I have a 300w DC-DC converter, a bag full of one-wire chips, and a breadboard on my desk but since we committed to installing an inverter, programming those chips and building the power supply haven't been a priority. And given my poor soldering skills, I'm not terribly excited about burning up a $3k laptop. My previous attempt to graft a small DC-DC converter into our old Apple TV ended up sending too much voltage down the HDMI cable and destroyed two TVs before I realized where my fault was.

I ended up sucking up my pride and paying someone to do my Apple TV conversion rather than risk another television. Now I can listen to internet radio or podcasts while I work on the van and even stream The Walking Dead over the van's media system.

[InterBlog]

Understatement of the century: Not everything goes to plan with DIY.

The loss of two televisions was frustrating, but I have to keep the perspective that our DIY would have cost us tens of thousands of dollars if we'd outsourced it, so the accidental loss of several hundred dollars is small in comparison. Regrettable, but small.

After the first two TVs went bye-bye, we chose a third that was as cheap as possible. It is a mass-market low-end from China and it might have been less than a hundred bucks, or maybe it was $99.99. The idea being, until the kinks are worked out and we stop frying TVs one after another, we'll use this thing. So now I'm running daily work trials using it as my second computer monitor, and it is a complete POS. Craaaaapp!! Worst visual quality in a display unit that I've ever seen. So I foresee a fourth TV in our future, but not until additional trials are run and I'm satisfied that it's going to live.

[FlyFishinRVr]

Originally Posted by InterBlog

After the first two TVs went bye-bye, we chose a third that was as cheap as possible. It is a mass-market low-end from China and it might have been less than a hundred bucks, or maybe it was $99.99. The idea being, until the kinks are worked out and we stop frying TVs one after another, we'll use this thing. So now I'm running daily work trials using it as my second computer monitor, and it is a complete POS. Craaaaapp!! Worst visual quality in a display unit that I've ever seen. So I foresee a fourth TV in our future, but not until additional trials are run and I'm satisfied that it's going to live.

Being an EE who has spent a fair amount of time designing video systems, I absolutely despise poor video quality. You may want to try investing in a high quality cable between your laptop and the TV if you haven't already done so (all HDMI cables are not created equal!). It may clean up the video enough to not make you sick, and once you do purchase a decent monitor, the new cable can be used with it to make the picture even better. Maybe this will help get you through your monitor-destroying beta phase......

[LB_3]

The current television has a really poor viewing angle and highly off angle viewing nearly inverts the colors.