Community Forums

jayman_1975 · 06-25-2016, 10:10 AM

I bought my TT last Aug and had a solar system put in by my dealer at the time of purchase. The TT comes built "solar ready" with a zamp solar, roof 3 panel connection box as well as wires run into the coach for a converter and then down to the battery.

For some strange reason my dealer opted not to use any of this pre existing wiring and did their own install with new wires. This is how they did it.
They put the panel half way from the front to back and off to one side in order to run the wires down the fridge vent. Then above the cupboards to the end panel which is right beside the main door. This is also where the awning buttons and slide buttons and battery and tanks monitoring gauge is installed. This is where they installed the Samlex controller. Very ideal spot to be honest as it's easy to see and in a central location.
Sadly, from this location it's close to impossible to run wires directly to the battery so instead, they ran them back (in the opposite direction of the batteries) into the main power/converter center and into the fuse panel. From there the factory 12v power wire coming from the battery is used to carry the power to the battery. This is a 6guage wire but they don't even run a seperate ground run all the way, it's just a foot long ground to the frame connected at the batteries.
I questioned my dealer about this and they told me that they do it this so the TT can in essence, use the power directly off the panel as its producing it and being sent to the battery. I was fine with this until I did some testing and realized how much power loss I have. When the controller reads for example 14v during the bulk charging stage, I'm only reading 13.4 at the batteries. Not sure how much of a real world loss this equates to but I imagine that it will be limiting the ability to charge at full potential during poorer sunlight. I did bump the controller up to bulk charge until 15v so as to get at least 14.4 actual to the batteries.

What do you guys think? To fix this I would have to run wires from the panel from its current position all the way along the roof to the factory installed 3 port zamp connection box. Or move the panel up to the front but then I have holes where it is screwed down now. Then move the controller to where the wires run into the coach (which is under a panel in the storage above the head of the bed) which means the location of the controller is not ideal. This however, would allow for a direct connection from there to the batteries which I imagine would eliminate the voltage loss that I have now.

You think it's worth the hassle or just leave it as is? I'm wondering if the voltage loss im experiencing now could be due to natural current draw in the TT as its drawing from the line before it reaches the battery which is why I'm seeing the discrepancy from the controller to the battery. Maybe I'm over thinking this all.

mel s · 06-25-2016, 10:25 AM

Quote:

Originally Posted by jayman_1975

I bought my TT last Aug and had a solar system put in by my dealer at the time of purchase. The TT comes built "solar ready" with a zamp solar, roof 3 panel connection box as well as wires run into the coach for a converter and then down to the battery.

For some strange reason my dealer opted not to use any of this pre existing wiring and did their own install with new wires.

You think it's worth the hassle or just leave it as is?
Maybe I'm over thinking this all.

jayman
How many hours/days/weeks have actually used the solar?
Is it preforming to your satisfaction?

I wouldn't be concerned, (or make any changes), unless and until the dealer's install proves unsatisfactory.

Mel
'96 Safari

jayman_1975 · 06-25-2016, 10:42 AM

Good advice. Actually I haven't used it much yet, but I am trying to run my Coleman 12v cooler as a way to keep beers/pops cold instead of having to pack piles of ice into coolers and then run into town when it's all melted and drinks end up warm. My volt meter says the cooler is drawing about 3.5a so in 24hrs it will use a decent amount of power. Just want to make sure I'm getting the most out of my set up. And if I need to add another panel, does it pay to wire it in to the controller as it is now.

baphenatem · 06-25-2016, 07:47 PM

Alas, long wiring runs between the charge controller and the batteries usually results in undercharged batteries. The only exceptions to this are if the wiring is intentionally oversized to significantly reduce voltage drop between the controller and the batteries, or if the charge controller also has voltage "sense" wires to tell it what the voltage really is at the battery terminals. The best location for the charge controller, electrically speaking, is as near to the batteries as possible.

Running the bulk charging voltage up to 15 volts may help to compensate for the undersized/too long wiring but you will want to monitor the system for excessive water loss in the batteries. The higher voltage may cause excess gassing during the bulk and absorption charging phases under certain conditions. In any case it will be difficult to determine the total state of charge since the system was not installed with a charging monitor.

jayman_1975 · 06-26-2016, 09:22 AM

From what I have read, batteries need to be charged up to 14.6v (some even recommend 14.8v) in order to get completely charged up. Due to the voltage drop in my system, I never see at the battery the voltage reading on the controller. I watched it yesterday as it neared the end of bulk charging. The controller read 15.0v and held it there for the time determined by Samlex. The highest voltage I saw at the batteries with a volt meter was 14.6. Please correct me if I'm wrong but it would seem that this "work around" is getting the batteries where they need to be without going to high? I do realize that I am still losing current in peak charging time due to this voltage loss so I will never be able to get full potential of the panel but I also am realizing that for my usages this probably isn't the end of the world.

mel s · 06-26-2016, 10:37 AM

Quote:

Originally Posted by jayman_1975

From what I have read, batteries need to be charged up to 14.6v (some even recommend 14.8v) in order to get completely charged up. Due to the voltage drop in my system, I never see at the battery the voltage reading on the controller. I watched it yesterday as it neared the end of bulk charging. The controller read 15.0v and held it there for the time determined by Samlex. The highest voltage I saw at the batteries with a volt meter was 14.6. Please correct me if I'm wrong but it would seem that this "work around" is getting the batteries where they need to be without going to high? I do realize that I am still losing current in peak charging time due to this voltage loss so I will never be able to get full potential of the panel but I also am realizing that for my usages this probably isn't the end of the world.

jayman_1975
IMO what is most important is whether or not your equipment satisfactorily preforms the particular task you want and need it to accomplish.
Mel
'96 Safari

baphenatem · 06-26-2016, 10:52 AM

A peak voltage of 14.6 is pretty good, as long as it is not for a prolonged period. 14.4 is essentially the magic number, where gassing starts at about 80 degrees F. This voltage value has a negative temperature coefficient, thus decreasing with increased temperatures. Ideally, you'd have a temperature sensor on the battery to compensate for this, but as you mentioned good enough is most of the time good enough.

pman1088 · 06-27-2016, 08:45 PM

Voltage for charging is largely dependent on the specs for your specific battery. 14.4 is a general/generic for flooded cells. For example a Trojan T-105 bulk charge is recommend by Trojan for 14.8, float at 13.5 and equalizes at 16.2 Temperatures, Age and SoC all come into play.

jayman_1975 · 06-27-2016, 10:18 PM

I don't have a temp sensor on my batteries. So you're saying that 14.4 peak is too high when it's hot? In not sure what I can do about that. How does a temp sensor work into the equation. Does it hook into the controller?

pman1088 · 06-27-2016, 10:35 PM

The temp sensor would be placed at your battery, but is hooked/wired into your solar charge controller.

drdarrin · 07-05-2016, 04:27 PM

Quote:

Originally Posted by pman1088

The temp sensor would be placed at your battery, but is hooked/wired into your solar charge controller.

If your controller is designed to utilize one. Not all of them are.

If it's not, then you are correct. You've already done all you can do without running a bigger wire to the batteries. That might be worth doing if you want to maximize your system.