My Interstate Lithium Battery Adventures

[InterBlog]

And on THAT note...

Here's my next blog installment. I'd appreciate constructive criticism. Or, I should say "we" would appreciate constructive criticism, because this was a collaborative effort, partly in the form of: I wrote it, then LB_3 went techno-wild editing what I wrote, then I reeled him back in, then rinse, then repeat.


Seriously, I'd like to hear from NON-engineering folks on the comprehensibility of it. We don't need to write for the benefit of the engineers - they already know this stuff. I'm trying to get it down to simple explanations without shedding too much necessary elaboration.

LITHIUM BATTERY UPGRADE, PART 2: AC SYSTEM

[amirm]

Great write-up as usual. Questions from engineering type though :

You don't have any input circuit breakers for either the inverter or charger. Did you make a conscious call to not put them in there (Xantrex install manual mandates it as I think the charger).

Also, when your AC charge is running, it would suck tons of current which means that there may not be sufficient current to run either the Microwave or AC under generator or shore power. What do you do in that circumstance?

In my case I have dual AC panels: one for what is not on the Inverter and what is. On the former I have the inverter itself, the charger and hot water heater. They are the proper Blue Seas breakers meaning they can be used as switches. As such, I turn them off if they interfere with usage of A/C or microwave.

[LB_3]

Originally Posted by amirm

Great write-up as usual. Questions from engineering type though :

You don't have any input circuit breakers for either the inverter or charger. Did you make a conscious call to not put them in there (Xantrex install manual mandates it as I think the charger).

Also, when your AC charge is running, it would suck tons of current which means that there may not be sufficient current to run either the Microwave or AC under generator or shore power. What do you do in that circumstance?

In my case I have dual AC panels: one for what is not on the Inverter and what is. On the former I have the inverter itself, the charger and hot water heater. They are the proper Blue Seas breakers meaning they can be used as switches. As such, I turn them off if they interfere with usage of A/C or microwave.

Thanks for the feedback.

The generator has a breaker in it and I’m counting on the shore power having a beaker as well. In some camp grounds that may not always be true so I may need to rethink that. But we are rarely in campgrounds and when we are we almost never plug in. In fact, the last time we plugged in to shore power was in October of 2016. The surge suppressor will also cut the power if the voltage sags so there is some marginal protection in campgrounds that are not up to code.

The A/C is pretty small at 11,000 BTUs so it only draws about 13 or 14 amps. The charger draws a max of just over 9 when the battery is depleted so there is still enough margin available for the A/C. The priority switch cuts off the A/C when the microwave is in use so we don't have to worry about doubling up on those loads.

We have a switch on the DC output of the charger if we need to shed the charger's load to make room for the A/C start-up surge and the charger has a plugged cord allowing us to completely remove it from the system if needed. We've considered putting the charger on a switch but we didn't think it was necessary.

In general, there are limitations on our system that will need to be actively managed as with any 30A RV but I don't believe we have a terribly unsafe system.

As for the general comments about large 12v inverters, I agree. I really don't like seeing 100+ Amps being drawn by the inverter but I do take some comfort in knowing I used 4/0 cables and 600A buss bars. Now let's hope nothing rattles loose. :-)

[InterBlog]

FWIW, I've never seen a campground pedestal that doesn't have a breaker.

Of course, I've seen relatively few campgrounds. The last one was, as LB_3 said, in October of 2016, which was actually BEFORE the lithium batteries were installed. I was in west Texas in a sand-dune-amplified heat wave and I had to run A/C for a few hours until the sun went down and it cooled off... Monahans Sandhills State Park, great place, one of the most unique landforms in Texas, but sort of like one of those DIY tin foil sun ovens when it is hot outside.

My original goal had been to sustain the ensuing track record of 0% hookups and almost 0% generator use, so incoming AC issues were not at the top of my priority list to examine more closely.

Goal HAD been. Aaaand then along came this new-fangled roof air conditioner now being sold by ARV that one might actually be able to sleep underneath without going stark raving mad. Which, if true and attainable, would open up a whole new range of camping experiences. If we do move to have that unit installed, we will revisit the AC system design.

Meanwhile, I'm glad we didn't drop the shore power connection option entirely, because we did think about doing that.

[LB_3]

The lithium charger was a late addition. I assumed between the sun and alternator we wouldn’t need to charge from the generator or shore power but once we installed the 12v refrigerator our system demands went up considerably and the charger is a nice backup option though we have yet to actually use it.

[InterBlog]

Originally Posted by wachuko

Rather than creating a thread for this... thought it would fit the theme of this thread. Hope that is okay with InterBlog.

Interesting read on getting rid of generator and going a 420 Amp Hour battery from Lithionics. Article is from 2016 so maybe it was already discussed...

https://www.thefitrv.com/rv-tips/our...-and-inverter/

This was one of the first accounts of its kind. At the time when James started investigating the lithium option, IRRC he concluded that there was not much chance of him DIYing the system that he wanted, because one or more of the main vendors was not selling direct-to-consumer because of the risks involved. I think I saw him say that in one of his videos.

3 hours 19 minutes is what that system got them in terms of A/C operation off batteries, that being with 420AH of batteries. Compared with our 2 hours +/- of operation, with 300AH of batteries. That capacity is useful in certain specific scenarios, but obviously it doesn't achieve as much as many folks would hope to see. Off-grid is still going to involve some sweating.

[youngpeck]

Originally Posted by LB_3

. . . but once we installed the 12v refrigerator our system demands went up considerably and the charger is a nice backup option though we have yet to actually use it.

LB, I hope this is not too far off-topic but could you elaborate on this? We have a newly-installed Isotherm 12-v fridge (w/ all-LED lighting, 300 amp-hour Lifeline battery system, 400 watts solar, 2200-watt Samlex converter/charger) and will be starting to use solar-only extensively this spring. We anticipate our usage of electricity to be minimal. I'm curious as to when and how much you anticipate needing to use your charger option with your 12-volt fridge.

[Lotus54]

Nice overview.
I’m used to reading tech manuals for various electronics and they rarely give any sort of overview at all. Maybe a block diagram if you are lucky (some companies are better than others). It makes it easier to get a basic idea of what is trying to be accomplished and what various components do in the system with a base description as you have given.

Maybe for some that don’t realize, block diagrams don’t generally even show everything - just major components. So things like circuit breakers are usually not even shown.

When I was designing radio systems (or even subsystems such as changing to VoIP console systems) I would make such block diagrams and even descriptions for the users. It helped me think of various scenarios of how the system would be used and cover everything, plus of course allowing the users to successfully utilize the system in day-to-day operation.

Great job.
Mark

BTW, I had access to Visio and while there were things I didn’t like about it, I found it very useful for making schematics and block diagrams. I use it at home for making schematics still- like when I did the mod allowing the espar heater to run with the engine off and utilizing the house battery.

[InterBlog]

Originally Posted by youngpeck

LB, I hope this is not too far off-topic but could you elaborate on this? We have a newly-installed Isotherm 12-v fridge (w/ all-LED lighting, 300 amp-hour Lifeline battery system, 400 watts solar, 2200-watt Samlex converter/charger) and will be starting to use solar-only extensively this spring. We anticipate our usage of electricity to be minimal. I'm curious as to when and how much you anticipate needing to use your charger option with your 12-volt fridge.

You can estimate how much your fridge will consume based on the published specs for the fridge.

For instance, in our case, our Vitrifrigo fridge IRRC needs 45W to run (per the manufacturer). Let's conservatively assume its compressor runs 12 hours per day. 45*12 = 540/13.4 = 40AH gobbled by the fridge on a daily basis, if it indeed runs half the time, which I expect it to do in warm weather. (13.4 is the lithium battery voltage).

We have 300AH of lithium so we have 240AH available (lithium batteries can be safely drawn down to 20%). Your analogous calculation would be based on having 150AH available (draw your Lifelines down to 50% without damage before needing recharge). So you can do an analogous consumption calc in your case.

It is more difficult to calculate the specifics of solar recharge because there are so many variables (latitude, time of year, weather, degree of shade, panel efficiency, etc.). You may have to experiment to get a feel for what your system can accomplish.

I can say that I've been pleasantly surprised at how our panels can keep up with the demands of the fridge, when we are not moving for several days. Even at 45 degrees N in late August in a partially-shaded area, 300W of solar did a good job of keeping up, even as the panels remained flat on our roof (not optimized).

Pretty pic below to illustrate - I had this parking pad cut out specifically for boondocking, but those surrounding trees are still danged high. You can tell that our panels will be shaded for much of the day, even when the sun is out (which is a minority of the time, in that part of Nova Scotia which is coastal and often socked in with clouds and fog).

That being said, planning electrical capacity had to be like planning for a 24-hour, 25-year rain event. We have to look at realistic worst case. In the event of a long run of bad weather, we might need to either run the engine or plug in to recharge, so we better have those options available.

[InterBlog]

Today in the category of "first world problems", I created this image melange to respond to the most common question we get regarding our lithium system:

Did we really need to size the system to run the microwave?!

Yes, because the amount of (1) time (2) energy (3) propane (4) fresh water and (5) gray water tank space that we save by popping food into the microwave and thus avoiding dish-dirtying is significant (remember, all this is taking place off-grid so there’s no use of supplemental facilities).

Doing dishes properly in a van is a female dog. Seriously, I have no idea how Interstate owners with smaller counter spaces even manage it. I defined 5 steps here but really there are 6. We typically first store dirty dishes in the wash pan under our couch (yuck!) until we have accumulated a large enough batch to make firing the hot water heater worthwhile. Give me an Amy’s organic burrito on a paper plate out of the microwave any day of the week. It’s either one of those two options, or eat more junk food, which I am not prepared to do.

[bugsbunny]

do you ever heat water in the microwave for dishes?

[InterBlog]

No, but if I MUST wash only a small batch instead of waiting to accumulate more, I sometimes heat water on the stove instead of firing the 6 gallon heater.

[unifreck]

Interblog
We take our dishes and cookware outside and use a couple containers for washing and rinsing , using our outdoor shower for water supply. I don’t want to get in the argument of where the waste water goes after a few days of boondocking. AEW

[campyvanster]

Wow - this has been quite an adventure busting through this thread in less than 24 hours. It's one of the best discussions on Lithium installations I've read -
and I've read a ton. Many thanks to LB_3 and Interblog, and all those who have contributed here. I must admit that as I was working my way through the last several months worth of posts, I kept waiting for amirm to spill the beans on his setup. Back in August of 2017, he said:

Originally Posted by amirm

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

Any chance of that happening in the near future, amirm?

[LB_3]

Originally Posted by campyvanster

Wow - this has been quite an adventure busting through this thread in less than 24 hours. It's one of the best discussions on Lithium installations I've read -
and I've read a ton. Many thanks to LB_3 and Interblog, and all those who have contributed here. I must admit that as I was working my way through the last several months worth of posts, I kept waiting for amirm to spill the beans on his setup. Back in August of 2017, he said:



Any chance of that happening in the near future, amirm?

We’re waiting.

And thanks Vanster for reading through the entire thread. I wish the mods wouldn’t lock out the edit post function after 30 minutes because there are several posts that are just flat wrong and others that became OBE by the end of the build.

[InterBlog]

Originally Posted by unifreck

Interblog
We take our dishes and cookware outside and use a couple containers for washing and rinsing , using our outdoor shower for water supply. I don’t want to get in the argument of where the waste water goes after a few days of boondocking. AEW

I do this often when we are TRULY off-grid. And when it is not raining or 35 degrees or both. Or when there is not a horde mosquitoes or black flies that would pick a person's bones clean. Numerous very large "ifs".

This weekend did not meet those conditions. In fact LB_3 almost wanted to fuss at me for dumping the BBQ charcoal ashes at the base of a tree. They're good for soil pH. But not a place to dump wastewater of any type.

[InterBlog]

Originally Posted by campyvanster

Wow - this has been quite an adventure busting through this thread in less than 24 hours. It's one of the best discussions on Lithium installations I've read -
and I've read a ton. Many thanks to LB_3 and Interblog, and all those who have contributed here. I must admit that as I was working my way through the last several months worth of posts, I kept waiting for amirm to spill the beans on his setup. Back in August of 2017, he said:

<diagrams quote>

Any chance of that happening in the near future, amirm?

I'd like to see them, too, so I can compare and contrast. And I also have two summary blog posts still to write, on the charging / inverting system, and on our DC system, which will come with their own diagrams.

Someone tried to bait me on another social media site today, in asking what's my favorite van hack. If I'd bitten, I woulda said, "Ten thousand dollars of solar, lithium, and all kinds of associated electrical doo-dads."

[campyvanster]

Originally Posted by InterBlog

I'd like to see them, too, so I can compare and contrast. And I also have two summary blog posts still to write, on the charging / inverting system, and on our DC system, which will come with their own diagrams.



Someone tried to bait me on another social media site today, in asking what's my favorite van hack. If I'd bitten, I woulda said, "Ten thousand dollars of solar, lithium, and all kinds of associated electrical doo-dads."

Ha! I hear ya on the $$$. I’m converting a box van into a home on wheels, and lithium/solar/etc. are on the horizon. Looking forward to the blog posts. I poked around and read a few of your articles and will stay tuned for more. Enjoy your writing style and snarky sense of humor.

[LB_3]

Vanster,

I’m jealous of your clean sheet project. Shoehorning our system into existing cabinet space was a huge pain and limited our product selection and restricted how neat I could be organizing the wires.
For example:

These 3 items are relatively easy to wire up and can be done in about 5 minutes per box out in the open. But with no place to stash excess wires, I had to wire these boxes in place. That would be enough of a pain but I had the fortune of not being able to cram my head in that 10” tall cabinet to actually see what I was working on. I literally took pictures with my camera and then counted the binding posts with my fingers and after tightening the wires took another photo to verify I didn’t have stray wire strands sticking out of the binding post or wires inserted too far such that the set screws were contacting the wire’s insulation.

This took about 4 hours for just the transfer switch and no amount of before/after pics will ever convey the pain I experienced that day.

[InterBlog]

Originally Posted by campyvanster

... I’m converting a box van into a home on wheels, and lithium/solar/etc. are on the horizon. ....

Just curious... is it a Sprinter-based box van? Does it have a physical connection between the cab and the rear?

When you said that, I thought of Project Amber on Instagram - a T1N Sprinter-based ambulance conversion. He was able to cut a door between his cab and the "box". In many respects, a box van would be an easier build - lots of right angles instead of body curves.