Solar Blvd Portable 160W Set

[MarkK]

So let's say I get a new mppt controller and locate it by the batteries. How much energy am I missing out on given my panels are tied to gether with 14 AWG wire, about 3', and then 19' of 12 AWG? As in, would you at a minimum change out the 14 wire for 12 and solder it to the terminals? I'm now recognizing even if the Controller is by the battery, I'm losing about 2 amps and while the mppt can make up some, it still feels like a bunch to be missing out on. Better yet if I re-wire then the panels in series to the controller might be the cheapest way to utilize the 12 wire.

 

[Trebor English]

Connecting the panels in series will change the 160 watts, 8 amps, 20 volts to 160 watts, 4 amps, 40 volts.  Since the current is half the voltage drop is half.  That's equivalent to doubling the wire.

Do you have an amp meter to accurately measure the current?  The figuring the current based on the voltage drop is not likely very accurate.  It is close enough to know that you don't have any really bad connections.  It is close enough to tell if the batteries taper the amount of current they take to half what it was before.

 

[Trebor English]

The Home Depot web site shows AWG #6 wire for .89 per foot.  To go 25 feet, 50 feet would be about $50.  The resistance of AWG # 6 is about a quarter of the resistance of AWG # 12.  That's doubling the wire twice.

 

[jimindenver]

#6 is to heavy and stiff for a portable especially if he went series on his panel and the controller at the batteries. I have always used 10 gauge MC4 cable to get my high voltage panels out as far as 50 ft without issue.

 

[regis101]

This is a partial copy/paste from Renogy FAQ about Series, Parallel, Series-Parallel

*  WHY SERIES?
,,,,,, more batteries. Renogy MPPT Controllers can accept 100 Volts input.

>The benefit of series is that it is easy to transfer over long distances. For example you can have 4 Renogy 100 Watt panels in series, run it 100 feet and only use a thin 14 gauge wire.<

The downside to series systems is shading problems. When panels are wired in series, they all in a sense depend on each other. If one panel is shaded it will affect the whole string. This will not happen in a parallel connection.**

I chose, as a noob, an MPPT so as to be able to wire the panels in any of the three configurations depending on ambient conditions.  Just my hang up.
AND, if I remember correctly, most if not all vendors and guru's alike state that the controller should be as close to battery bank as possible. So, I didn't and don't understand why some vendors would even try to sell controllers attached to the array knowing it was going to be in the 20'-100' range away from the battery. Anything to take yer monies? Sorry. My rant.

 

[Trebor English]

I have always used 10 gauge MC4 cable to get my high voltage panels out as far as 50 ft without issue.

 If AWG # 10 is good for 50 feet then AWG # 12 ought to not be a problem at 25 feet.

 

[MarkK]

#6 is to heavy and stiff for a portable especially if he went series on his panel and the controller at the batteries. I have always used 10 gauge MC4 cable to get my high voltage panels out as far as 50 ft without issue.

Jim,

Are you using these cable runs with mc4 connectors on the open on the ground with the potential for someone to walk on it or kick it? I like some of the prices I'm seeing, but the lack of protection such as service cord has leaves me a bit worried for durability given the use with portable panels.

 

[MarkK]

Do you have an amp meter to accurately measure the current?  The figuring the current based on the voltage drop is not likely very accurate.  It is close enough to know that you don't have any really bad connections.  It is close enough to tell if the batteries taper the amount of current they take to half what it was before.

Shouldn't I be able to use my voltmeter with amp setting without being connected to the batteries to get this read?

 

[Trebor English]

Shouldn't I be able to use my voltmeter with amp setting without being connected to the batteries to get this read?

 If you want to measure the amps the batteries are taking the batteries will have to be connected.

 

[Trebor English]

I'm losing about 2 amps and while the mppt can make up some, it still feels like a bunch to be missing out on.

Theoretically your panels can put out 8 amps and based on the voltage drop on your AWG # 12 cable you are probably getting less than that.  It is supposed to work that way.  When the batteries are getting full and the voltage at the battery rises the current gets reduced.  The longer the batteries charge at 14.3 volts the lower the current goes.   The controller lowers the current to keep the voltage constant.  The battery requires less to keep the 14.3.

 

[MarkK]

Now onto the question of re-wiring the panels at some point.

These came with 14AWG wiring to connect the panels to the cheap pwm controller. Given I will add a Victron close to the batteries, is there any value in running the little bit of extra 12AWG Where the 14AWG exists? I understand 12 has less loss than 14, but my concern is whether the 14 is already limiting the potential of the 12 wire on the longer 19' run to the SC. That and they soldered the connections at the panel terminals and I'm not enthused over re-doing that so trying to justify not doijg the swap out.