Solar Panel Mod Controller

So basically you turned the solar array I to a trickle charger for the 12v? Is there a bms installed as well to not overcharge?

SM-N986U1 ?

 

Into*

SM-N986U1 ?

 

That's cool. The module has a power draw for memory then?

SM-N986U1 ?

 

I've been watching this for quite sometime. Finally decided to reply. How beneficial is this and would there be other options like adding a "power station" to trickle charge?

SM-N986U1 ?

 

This is also a top solar charge controller. I installed it in my prius. He has already integrated the Bluetooth interface.

Victron Energy SmartSolar MPPT 75V 10 amp

 

Pictures

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sweet choice, I wanted the 100/10A but went with EVEVER 30A. The solar charger powers a lifepo4 battery which then powers a subwooofer amp.

 

Here in Germany I had paid 100€.
I don't know how much the device costs in the U.S.

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So I bought a cheapo adjustable buck converter (well, actually, to get to $25 for free shipping I bought a couple of them plus a bag of Schottky diodes). Maybe I'll use the other converter for something someday.

I didn't bother with the units with fancy displays, since it'll be tucked away next to the battery. This one has a bicolor LED with an adjustment for when it changes color.

There are pads on the board for adding a Schottky diode to the output, which I did (and cut the trace that shorts around it) so the battery won't push current back through the module after sundown.

This module has both constant-voltage and constant-current features. In theory, I could adjust the current to a lower limit, and share the power more generously with the ventilation feature. However, as seems to be pretty much universal with these things, the CC feature senses the current on the low side. The shunt resistor on the board is in the return from "OUT −". There's no way that will ever work in a Prius where the battery and solar panel both have the low side grounded to the body: the current won't be passing through the shunt.

I spent a little time trying to shop around for similar modules where the current shunt is on the high side, but usually that's a detail that isn't advertised, sellers may not know, and ultimately I gave up trying to find one. I'll just use this one, and its adjustable CC feature will be moot. It's rated 5 amps and it's never going to get more than that from the 60 watt solar panel anyway, and the XL4005 IC still has some protection features built in. Also, because I'll be setting the module no higher than around 13.5 ahead of the Schottky diode, it should be no more than 13.1 reaching the battery and drop further at higher currents, which will also tend to keep current limited.

Here's the module tucked into a clear plastic tube some windshield wipers came in (I've been recently getting some mileage out of that stuff). Just a little protection from random objects contacting it, but open at the ends so, mounted vertically, some convective cooling might happen.



I did take a small sample of this wiper-package plastic and hold a match to it; it just kind of drooped and wrapped around the match.

This all has to start with the first significant revamp of the power-distribution thingy:



I generally like DIN-rail construction, but using separate rail terminal modules for low-side returns just takes up too much space and too much assembly (there are specialized modules with a bunch of terminals bussed together, but that's more money). All I really want is something like a regular bus bar from a household panel. Maybe I can just attach that to the edge of the DIN rail:



I've never had a good photo on here showing the VCM-06 low-voltage disconnect where it lives on the underside of the rail, so there's that, too. Attaching that ground bar with 10 mm M4 standoffs leaves room still for things to clip on to the rail (except right where the two standoffs are). For some larger things than I'm using, longer standoffs would work. I tapped the rail with M4 threads and just screwed the standoffs right in. The fit is about perfect.

Because the rail isn't very thick, I tried something new (to me) for tapping the threads in it. Instead of drilling to the recommended size (3.3 mm) to start an M4 tap, I used a drill about half that size, then air-hammered a pointed punch into the holes until they were 3.3 mm. That made them volcano-shaped and deeper, so tapping them made more turns of thread.

I don't really like chomping into OEM harness wires, so I made the connection up at the top of the left C pillar. The connection to the solar panel noise filter is just above that corner of the headlining. The terminal on the harness is a 4.8 mm flat-blade female, 82998-12380, as shown in the wiring diagram. The mating 4.8 mm male blade is not shown on that page (as far as the diagram's concerned, the harness just plugs into the noise filter), but can be found by poking around the wiring diagram for other places the -12380 terminal is used in a harness-to-harness junction. The mating terminal is 82998-12370. So I just made a little Y connector:



The poor-man's "connector housing" over the male blade is just some PE tubing I had around, cut to a length that will cover that terminal and the mating original harness connector when that is inserted. The real plastic housing from the original harness terminal will be removed and used on the female terminal here, to plug in to the panel noise filter.

It helped to use a not-very-hot heat gun and square off the open end of the PE tubing a little. A blob of PlastiDip secures the other end to the wire.

Here with the plastic connector shell filched from the original terminal (also shows the slight squaring-off of the PE tube end a little better):



and all joined up over the headlining:



I love it when a plan comes together. Charging at 71 mA in the waning flat rays of evening. (Went up to nearly 100 mA when I lowered the hatch, got it out of the way of the rays.)

 

Happily charging at around 1.4 A on a clear, midday, 40° N latitude, roughly equinoctial day, at 13.16 V (limited to my CV setting on the buck converter, low enough to be a safe float voltage and to avoid waking up the VCM-06).

Open the doors and the dome lights come on and the output hits about 2.6 A, at about 12.9 V, now limited by what the panel is producing.

At 2.6 A (about half of the buck converter's rated output), the warmest thing is the Schottky diode I added, at about 54 ℃. Should check again on a hot summer day and higher output, but the derating curve for that diode doesn't show any issue at 5 A until well above 150 ℃ case temperature, so I don't anticipate a problem.

 

Interesting device. What is the orange doohickey sticking up above the battery cover?

I am a little leery of the unfused direct connections to the battery posts.

 

This is the connection for my Ctek charger.

In the meantime, I have replaced the connection with this one:



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This is the Ctek charger.

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