Popping my top

[boywonder]

The side door storage is similar to the door galley construction......cherry, biscuits face frame, Antique flat Zar polyurethane (sprayed the final coat on this one), friction hinges from Mcmaster and baltic birch covered in Nautilex Decko dot vinyl and fuzzy trunk lining......


I'm typically not into having the fasteners showing right on the front, but in this case there was no other way......

[86Scotty]

Thanks


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[boywonder]

So I added another 200W of solar to the roof......

I've been using a single 120W Kyocera panel and Samlex controller for a while and when spending more than 2 days boondocking the batteries cannot keep up with running the electric water heater during the day.

When I say "not keep up" this means that my house batteries are are down to 70% state-of charge (SOC) or less. So by day three if I haven't driven the van I usually don't turn on the water heater.

I added a pair of Renogy Eclipse 100W panels to the system. Since my controller is a simple PWM controller, all three panels are wired in parallel. These panels are monocrystalline and are roughly 20"x40"...they were the smallest/highest energy 12V panels that I could find.

Doing some research on the inter-web thingy I found that mixing panels is typically not a good idea for the following reasons:

If the panels are wired in series, the panel(s) with the lowest current rating (Imp) will determine the current for the array.

For parallel wiring, it works the other way, the panel(s) with the lowest voltage rating (Vmp) will determine the voltage for the array.

The old Kyocera panel has a Vmp of 16.9V and the new panels have a Vmp of 17.7V so I'm taking a hit of .8 volts by mixing these panels.

The new setup works great..technically I have somewhere between 300-320W on the roof and in direct sunlight I'm seeing 225-230W when the batteries are low and the controller is in absorb charge mode.

With the single Kyocera panel I was seeing about 80W or so max, so the new setup has almost tripled my solar power.

I previously had 16 AWG wire running from the panel to the controller; this has been upgraded to 10 AWG with the new setup and was a PITA to pull the new wires.

Since the old wire was a rubber jacketed power tool 2 conductor cable and the new wiring is two individual 10 AWG wires I also had to fabricate another bulkhead connector that allowed dual strain reliefs (I need my head examined!!-another PITA). The two rubber-plugged connectors on the outboard side of the bulkhead are for my roof lights; I store them inside.







I used some 6063 aluminum channel to mount the new panels to the four existing 1/4-20 bolts that attached the front crossbar block to the penthouse roof.

[boywonder]

...a couple of additional thoughts....

The SMB front hole pattern where I mounted the panels was not even remotely symmetrical.....tolerance roughly +/- 1/2 inch or so....

I have a manual top, so I'm now at 4 links shorter on the chains (3 links would probably be OK and I have about 5" of spacers on the helper springs. The helper springs are slightly preloaded even when the top is raised.

Additional helper spring preload would be even better.....perhaps I'll attempt some longer spacers. I'm a little concerned about the weld strength of the tabs that react the helper spring load on the plates above them.

[rallypanam]

Nice... I have 3-100W (similar/same panels as your new ones).. and love it. Even in partial shade I get enough juice to bump my batteries enough to last essentially indefinitely.. although I don't have hot water heater.

More the better I think!

[boywonder]

Originally Posted by rallypanam

Nice... I have 3-100W (similar/same panels as your new ones).. and love it. Even in partial shade I get enough juice to bump my batteries enough to last essentially indefinitely.. although I don't have hot water heater.

More the better I think!

If I don't use the water heater the panels will top off the batteries indefinitely without much of a problem as long as the sun is shining. On the partial shade thing, that's one upside of parallel panel wiring; of course the downside is fatter wires to the controller.

Perhaps I should post this in the electrical section, but when I'm running the engine my battery monitor shows about 20-25 amps going into the house batteries when they are at a low state of charge.

I just checked this camping over the weekend.......I expected more...

Assuming my stock alternator is 125A that's 100A going elsewhere, or not being needed depending on the various loads like firing spark plugs, charge starting battery, running the headlights all the time (I have a 2008), powering the radio, various control modules, etc.

BTW I'm revving the motor when checking the charging current...just seems like more should be going into the house batts.

When I drove back 4.5 hours from Kennedy Meadows to OC on Monday, my house battery SOC went from 66% to 86% between solar and the alternator....not as much as I would have expected.

[rallypanam]

Originally Posted by boywonder

When I drove back 4.5 hours from Kennedy Meadows to OC on Monday, my house battery SOC went from 66% to 86% between solar and the alternator....not as much as I would have expected.

I'm no expert, but that seems low.. but I guess it depends on how big your house batteries are. My 4D would easily be at 100% from 66% after a 4.5 hour drive with sun - at least according to the Xantrex Linklite.

[86Scotty]

Very cool Boywonder, and rather interesting on the charge problem. I'll be curious to see what you figure out on that.

[boywonder]

Originally Posted by rallypanam

I'm no expert, but that seems low.. but I guess it depends on how big your house batteries are. My 4D would easily be at 100% from 66% after a 4.5 hour drive with sun - at least according to the Xantrex Linklite.

I have a pair of the lucent/alcatels 2 x175AH = 350AH

[ShuttlePilot]

Congrats on solving your solar issues. The one biggest problem under performing solar has is under sized wire/big voltage loss. And they are everywhere. Just a thought on your alternator issue is check your grounding all over the van before you wright off your alternator. Even if a new alternator is in order. Disclaimer - I have an opinion on chassis grounds. Chassis grounds are the dirtiest form of under sized wire. It's easy to have a ground strap not get put back after a repair or in many cases rely on a chassis ground to convey large amperage. For Example, in my case SMB installed a nice heavy positive cable to join the van system to the house system but no cable on the negative(chassis ground). It's an easy test since you have a house battery monitor, just clamp a heavy jumper cable on the alternator case and one to the ground buss of the house battery. The increase in amps is the loss through the ground path. If no change then your ok at your current rate of charge. A friend of mine encountered this after installing a very large capacity alternator in an RV and there was not much increase in charge rate. After running a large ground cable between the two, mostly eliminating the chassis ground, he sees a huge increase in amps.

Just a thought since your improving the performance of your electrical system.

-Eric