M116A3 Build

[featherliteCT1]

You have a great looking electrical system.

Have you tried putting a high amp load on your system to test if any of the terminals get hot?

I recently plugged into my 1000 watt inverter a small Mr Coffee coffee maker that draws approximately 800 watts. In about three minutes the terminal at the positive post of my battery got too hot to touch, even though the terminal was terminating a 2AWG copper wire with a copper lug. No other terminals or breaker connections got too warm. I cleaned the lug with scotch bright pad and tested the terminal again. The second time the terminal just got a bit warm to the touch; however, none of the other terminals got warm. I have not yet coated the terminals with oxy guard because i am still fiddling with the system and did not want to get that black grease every where.

[lfhoward]

Hi Featherlite,

That’s a good question. I had a 300-ish watt draw during my bench testing and everything stayed cool then. I couldn’t go much higher because the small inverter I was using couldn’t handle it (not the one in the camper). Today I got to 8-10 amps draw in testing (about 100-130 watts) in the trailer. That was the fantastic fan on high plus the Propex heater, the inside lights, and the 18 volt battery charger for the drill. I didn’t think to touch the battery terminals— I’ll definitely check this out. Everything had to be disassembled and reassembled in place, so all the connections are potentially different than on the bench.

[tony.latham]

I can’t wait to get out camping next!

I'll bet!

Nice clean install (as anyone would have expected that's been following your thread.)

And I'm happy to see that Propex controller too. I used my little heater on a solo trip yesterday morning. The evening before, I was desperate to find a bit of shade...





Tony

[bdosborn]

It all came out great, you'll get years of reliable service out of that setup.
Bruce

[lfhoward]

Thank you Tony & Bruce! I am much happier with the electrical system now after the redesign.

One of the interesting things I noticed now that I have Victron controllers & battery monitor is how little power I get from solar when parked under trees. Even with both panels deployed, it was only like an amp or less. Being able to see the power generated and the amp draw of my electrical devices is really neat. Before I was just guessing. Now I have quantitative data!

[lfhoward]

I got to visit the trailer today where I park it and bring some random things up there that it needs. I brought a 15 amp fuse for the shore power fuse box, some MC4 cables for the portable solar panel, the instructions for the battery heater thermostat, and some blocks of wood to keep stuff from shifting in the side compartment and touching the solar charge controllers. Mostly I used the trailer as my “office” and got a bunch of work done in the afternoon. I had the back door open and the fantastic fan running to create a breeze. The view out the back door is some trees and a stream.

[lfhoward]

I picked up a second Renogy Eclipse 100 watt solar suitcase for my camping rig. Here are the stats of the panel:



I did this for a couple of reasons. First, running a single 100 watt panel would likely not get the solar input 5 volts above battery voltage, which is the minimum for the Victron 75/15 to start charging. The Vmp of 17.6 of one panel would mean the battery would have to be discharged to 12.6 volts before the charger would kick in (likely with lead acid batteries but not my new LiFePO4 battery). With two panels in series, the Vmp would be 35.2 volts, which is perfect. Second, putting two panels in series allows more charging power without increasing the amps and without needing thicker wires. The 200 watts of auxiliary panels should be a nice complement to the 210 watt Hightec Solar panel on the roof (back ordered; still running my tired 140 watt panel). I’m looking forward to trying out the solar power system on my next camping trip.

[featherliteCT1]

I continue to learn from your solar setup postings.

If you connect the two portable panels and the one roof mounted panel to your MPPT controller at the same time, in full sun, do you need to worry about exceeding the MPPT controller's 15 amp output rating?

[lfhoward]

I continue to learn from your solar setup postings.

If you connect the two portable panels and the one roof mounted panel to your MPPT controller at the same time, in full sun, do you need to worry about exceeding the MPPT controller's 15 amp output rating?

Thanks!

Normally that would be true with a single charge controller but I am running two:


Each one has a 15 amp max, and each can theoretically do 200/210 watts of solar in full sun. The 30 amp charge with both combined is a 0.2C charge rate, which my 156 Ah battery can handle.

[lfhoward]

My 210 watt roof panel from Continuous Resources just arrived. That’s a couple of weeks earlier than expected! Nice!

[tony.latham]

...would likely not get the solar input 5 volts above battery voltage, which is the minimum for the Victron 75/15 to start charging.

Is this just a Victron controller issue? Or perhaps an MPPT? I'm using a Renogy PWM...



Tony

[lfhoward]

...would likely not get the solar input 5 volts above battery voltage, which is the minimum for the Victron 75/15 to start charging.

Is this just a Victron controller issue? Or perhaps an MPPT? I'm using a Renogy PWM...



Tony

I’m pretty sure it’s just a Victron charge controller thing. I have a lithium compatible Renogy PWM that was attached to my first solar suitcase and it didn’t specify a 5 volt threshold to start charging. I haven’t tried charging my new LiFePO4 battery with that controller because I installed the Victrons. I suspect Victron programmed in that minimum because MPPT needs enough of a differential in voltage to be able to charge efficiently, but that is just a guess.

[tony.latham]

but that is just a guess.

But an educated one.

Thanks,

Tony

[John61CT]

Yes, Victron very purposefully prevents the charging circuitry of the SC from powering up until significant energy levels are being produced.

Like all quality MPPT, they are designed to work with quality higher voltage panels

not the low voltage consumer grade ones sold through big box retail or over the internet.

[featherliteCT1]

john61CT,

Do you consider Renogy 100 watt mono panels to be of decent quality? I am thinking they are good quality.