It’s been over a week since my last journal entry. It’s time now for another one.
In brief, since my last entry, I’ve been
- promoted at work;
- started wiring electrical components together;
- started scoping out supplies to hook up my water system;
- developed pain in my left foot; and
- started looking looking into drafting a will.
On getting promoted, it’s been a fairly long labor of love. I enjoy what I do, feel proud of what I’ve accomplished, and really can’t stop talking if a conversation about machine learning engineering starts.
But it’s also been tiring. I’ll save the details, but in addition to the isolation of working alone from home, my recent work environment has been more “fast-paced” than usual (as job description euphemisms go). With the stressors of home-buying, staying in shape, and trying to stay socially connected (at all), I’ve teetered on the edge of burning out.
I’m glad I’m recognized as having contributed (and continue to contribute) at the next level. But I feel that the balancing act will continue through at least the rest of the year.
On my van’s electrical system — I’ve now received all major components, as well as all cables of appropriate gauge. I’ve tested
- that my new clamp meter can read voltages and live amperages (without physically tapping the connection!);
- that my 300W portable solar panels + PWM can charge my portable power station; and
- that my 4x100W flexible solar panels + MPPT can charge my AGM and lithium batteries.
The remaining work includes
- measuring amperage from the alternator at idle, for the 100Ah AGM battery (I already know this works, but I don’t know how fast it actually charges, even at bulk or absorption stages);
- measuring amperage from the alternator at idle, for the 200Ah LFP battery;
- crimping ferrules onto 8AWG cables for my 30A shore power charger (ideally I should do this for my MPPT solar charger too);
- charging the 100Ah AGM battery to float voltage;
- measuring the discharge rate of the 100Ah AGM battery, to determine its health;
- deciding whether I want to attempt hooking up an AGM-LFP hybrid battery bank;
- installing a shunt and battery monitor between the battery bank and chassis ground;
- cutting out 4x polycarbonate sheets to glue onto the flexible solar panels, to reduce overheating risk;
- gluing 8x 48-inch T-tracks on the roof of the van, to bolt the panel-sheets to;
- hooking up the battery to the busbars;
- hooking up and testing loads (like the DC fridge, inverters, external monitor, fans, etc.) to the busbars; and
- live-testing the system on the road.
The most immediate risks I face right now are
- The lithium battery drawing too much charge from the alternator.
This is problematic because, as opposed to lead-acid battery variants (like AGM), lithium can draw a lot of power very fast. And, while the alternator can cool itself at high RPM, there’s a distinct risk of overheating/blowing it up at idle, even with an isolator. The two main solutions here are to (1) get a more powerful alternator, or (2) use a smart DC-DC charger that can regulate current draw via a charging profile.
The first option is pretty much off the drawing board, for now. I’m just not interested in dealing with changing anything that actually has to do with driving the van, at the moment.
So if I find that the LFP battery quickly overheats the alternator, then I’ll connect a DC-DC smart charger. It’s possible that I might go ahead and install one, for improved safety (and data monitoring) regardless… it’s just more work.
- The AGM and lithium batteries not playing well with each other.
This is problematic mostly because while such a system works in theory, it’s apparently unconventional among off-gridders, and therefore adds risk. That said, I have smaller 12Ah AGM and 16Ah LFP batteries for testing. The idea is that if I’m going to mess something up, I’d rather destroy a $100 system (instead of the a $1000 system).
Some things I’ve learned
- MPPT really does work better than PWM, by a sometimes wide margin.
- Solar panels really do need direct sunlight. Daylight without direct sunlight doesn’t work.
- My version 2 absolutely needs better wiring organization. I have way too many wires now.
On the water system — the main thrill this past week has been receiving the 25-gallon freshwater tank… and finding that it fits literally perfectly under the van’s sofa. I can even recline the sofa without disturbing the tank (and its fittings)!
That said, there’s so much work left for electrical, that water has been on the back foot. That said, since last week, I have
- connected an intake tube to the tank
- connected a vent hose to the tank
I still need to
- buy red and blue 1/2″ PEX tubing;
- cut maybe 2 feet of blue tube to connect the tank to the water pump;
- cut maybe 2 feet of blue tube to connect the water pump to the water heater;
- connect the tubes with NPT-PEX fittings, and crimp as necessary;
- hook the water pump to my 12V electrical system;
- hook the 1440W/120V water heater to the inverter;
- measure the actual power draw of the water heater at different temp settings;
- buy a shower head that can connect to a 1/2″ PEX tube and has an on/off switch;
- design what the final shower curtain system might look like; and
- live-test the system on the road.
In addition to all of these, I’ve also
- Got my second COVID vaccination shot! Yippee!
- Got a new phone! I decided to sign up with Visible for their unlimited 4G/5G on Verizon’s network. Alongside getting a second phone plan, I decided to get a Pixel 4a 5G, to make use of 5G wherever that may be available. This means that I’ll have two unlimited data plans, one from T-Mobile (on my Pixel 2XL) and another from Visible.
- Got a cell signal booster. There was a mix-up with my first order, but after chatting with a store rep, I finally now have a booster in my hands. I’ve registered it with T-Mobile; I’ll do so for Verizon/Visible soon. Haven’t tested it yet, but it’s one thing I’m not so worried about (yet).
On the pain in my left foot — well, it sucks, and I hope it goes away.
And finally, on drafting a will — well, now that I own property, I’ve been told that having a will will make the lives for family much easier in the ideally unlikely event of my death. Will write about that in another post!
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