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Hi Amy,

Thanks for your detailed response which was very helpful for my understanding.

I did find some interesting additional information on the internet, - so it must be true... ;-) but I'm an engineer and it sounds sufficiently credible that you might be interested. (Item in "quotes" below.)

In conclusion, I plan to use available #10 marine grade cable professionally fitted with MC4 plugs at each end, cut than in two as per your suggestion and then connect it to the SMK panels via an altE SMK to MC4 Array Adapter Set. Hopefully the standard SMK leads on the panels will be long enough to allow the serial connection between two panels.

Quote:
"Cross-mating any connector, regardless of the brands involved, is not a UL approved connection. It does not matter that both connectors may have independent UL approvals, as they were tested to their own, specific individual tolerances and specifications.
I have seen numerous connections failing due to cross mating issues. The issue is that the metallurgical chemistry of the contacts are going to be different unless they are from the same manufacturer. Over time, the difference in chemical composition causes oxidation and other issues that can lead to temperature rise and other problems.
Another issue is that, companies don't generally release tolerances for their products. This results in possible gaps in the contacts when cross mating, which leads to arcing, and ultimately connector failure."

If exposed connections are your biggest concern, a simple application of some petroleum jelly may help the cause or some of the dip they use for hand tool handles or perhaps some wax.

Lion, excellent questions, which unfortunately don't have a black and white answer, nor a short answer.

None of the wires altE offers are tinned. Likewise, the cables coming off your solar panels also are not tinned. This is an age old dilemma for boaters, tinned wire is definitely best for boats, but no one I know of makes tinned wire with the solar connectors, and to correctly make them yourself requires a very expensive tool.

Most boaters we deal with in your situation buy the SMK pre-crimped wire like this, http://www.altestore.com/store/Cables-Wiring/Wiring-For-Solar-Panels/100-SMK-Connector-Cable-10-AWG/p10449/ twice as long as you need to go for your first connection and cut it in 2, one piece for plus and one for minus. For example, if you are using a combiner box, you would use this wire to the combiner box, and then provide your own tinned wire for the rest of the system.The advantage of using professionally crimped connectors vs tinned wire you crimp yourself is worth using a length of non-tinned wire for the outside connection that will be most exposed to the elements.

Unless you have other components that I don't know about that are MC4, I don't see any reason to convert over to MC4, just keep with SMK. Or are you wiring them in parallel with an MC4 coupler like this, http://www.altestore.com/store/Cables-Wiring/Wiring-For-Solar-Panels/MC2MC4-Branch-Coupler-1-Male-to-2-Female-Ends/p7163/? If so, the answer to whether MC4 and SMK are compatible is also a little controversial. Yes they will work together, but some are concerned about long term connectivity, will they eventually not make a solid connection. I've got a foot in both camps for that one. Again, most people just connect them together with no problem. If you are concerned about it, you can use an adapter set like this, http://www.altestore.com/store/Cables-Wiring/Wiring-For-Solar-Panels/SMK-to-MC4-Array-Adapter-Set-MF-Pair/p10616/ .

Sorry, as I said, no short clear answer available. You can give us a call and we can discuss pros and cons with you to help you decide.

Amy
Solar Queen (and boater)
altE Store

Hello,
I'm finalizing the configuration of a new system (my first) and have a few questions regarding the connectors and their respective wires.

4 x 260w panels will be wired into two parallel strings each attached to its own MPPT controller in a marine environment, so I need marine grade tinned wire.

Are any of the altE wires  marine grade?

I am able to source marine grade but need to know the specs for the fittings. (I understand MC4 require specific external diameter).

The panels come with SMK fittings.
is there any practical benefit to converting from SMK to MC4?

Many thanks for any advice.
Lion

Well, simply 7 amps x 12 volts =84 Watts, so any panel above this should work.

The reason I was specifying that size pump is that's what I've always used at this cabin (and I have an extra one of that capacity), but now I'm building an elevated holding tank at a different location on the property and this holding tank will just serve a sleeping cabin with limited water needs.  The sleeping cabin is about  70 feet from the water level and will be about 20 feet above the water level.  I don't want to have a float switch involved because that will require an electrical line from the holding tank to the pump (i.e., 70+ feet).  The pump has to be very close to the water level because that's how these style of pumps operate best.  They can't "pull" water  very high, but can "push" water a long ways and up quite high (my current pump that supplies water to the cabin is about 1 foot from the water; the cabin is about 60 feet from the water and about 20 feet above the water level).  So for the pump serving the new holding tank, I just want a small panel wired directly to the pump.  Don't want a battery involved because batteries require maintenance.

I'm installing an 8000 w array on my barn Pretty ideal case facing south with no shading. I'm debating Sunny Boy vs Solar Edge. I like Solar Edge system over Sunny Boy for 2 reasons: 1. Failsafe to 1 volt per panel output
2. Monitoring of each panel output.
However the cost for Solar Edge is about 50% more and SMA is the industry leader with good track record.
I'd like feedback on your opinions and/or experiences with either or both inverter systems. Thanks.

Thanks, makes sense now!

Robert, no. If an appliance is say 48 Watts, if you use 12 volts then it draws 4 amps, if you use 48 volts then it draws 1 amp. Watts=Volts x Amps. So run time would be the same. Operating voltage is usually what drives your setup for both the appliance and the inverter.
The only benefit of using a higher voltage is smaller current so smaller gauge wire, as you mention, which tends to be cheaper and easier to work with.

Hello,

I have 4 150 amp hour batteries. When wired in parallel, this would give me 600 amp hours at 12 volts.

If I wire it in series, I would get 48v at 150 amp hours.

The question I have is when wiring in series, with the reduction of amp hours, do you actually loose run time? If so, other than cable size, why would you?

Thanks,

Rob