Charge controller question

[Cameodon]

My 5th wheel is solar prepped, which means it has 2 SAE connectors wired directly to the batteries (2- 85 AH deep cycle 750 amp batteries, wet) . Connector on roof has SAE 8 gauge wire approx 20 ft from batteries, Connector on side of RV SAE, 10 gauge about 3 ft from batteries. both wired directly to batteries, of coarse no charge controller. 1200 watt inverter/charger. Fridge runs on 12v/110v. looking at

Renogy Advanced Rover Li 40 Amp 12V/24V DC Input MPPT has one - one + input plug. How do i connect both SAE connectors to controller? Wire them to a common lug and from there to controller? Thanks.​

 

[Mark_K5LXP]

"SAE" is not the correct vernacular, perhaps you mean MC4? That would be a "standard" solar connector. Not knowing exactly what connector might be there could imply there's a connector per conductor or a connector per pair of conductors, so identifying what connectors you have would make things a little easier to understand.

Mark B.
Albuquerque, NM

 

[Gary RV_Wizard]

There are some "SAE approved" 12v connectors commonly used in the vehicle industry, but not sure that any of them are standardized for solar panels or used by any of the solar equipment manufacturers.

 

[jkane]

I am going to guess that we are talking about a ZAMP Solarport plug, which is indeed an SAE connector, just wired reversed polarity (from what most people would consider normal).

 

[Cameodon]

I am going to guess that we are talking about a ZAMP Solarport plug, which is indeed an SAE connector, just wired reversed polarity (from what most people would consider normal).

 

[Cameodon]

That is correct!! It DOES have SAE connectors. You do NOT have to use ZAMP, you can buy SAE connectors with reverse polarity. The question was can the TWO SAE connectors on rv be attached together to the charge controller.

 

[jkane]

Sorry Cameodon, I should have fully answered your question.

You can use the existing ZAMP connectors ... however I would do the following.

On the roof, I would cut the connector off, they are high resistance and not really "standard". I would then terminate the existing wire in your rooftop junction box, pulling wires from your on-the-roof panels to that location and completing the connections in that junction box.

I would leave the ZAMP plug on the side of the RV alone, just create a cable for whatever portable panels you might use to the ZAMP plug, being mindful of the polarity.

As to connecting the "free end" of these cables to a solar charge controller, it is pretty easy. The cables from the roof will go to the PV+ and PV- of your charge controller (after you have connected the B+ / B- to your battery). What about the side of your RV cable? Slightly more complicated. You should not connect dissimilar panels in parallel to the input of your SCC. The weakest panel will drag down the other panel(s). What you can do is either have a portable panel with a built-in charge controller (many of the suitcase solar panels include that charge controller) or place a smaller charge controller alongside your main one, with the PV+/PV- to the ZAMP connector and the B+/B- to the battery (yes, in parallel with your Renogy charge controller). They will, for the most part, cooperatively charge the batteries as long as both controllers are set to the correct battery chemistry.

Hope this helps.

 

[Cameodon]

Thanks, I appreciate your help. I’m sure you are correct so please don’t misunderstand anything I say. Of coarse the dealer says I MUST use all camo equipment, I expected I help from a dealer anyhow. I say that because after 7 units I gave been treated likeI owned the joint when buying and they want nothing to do with me if I have a problem!! LOL.
I have looked at wiring diagrams from ZAMP and they don’t really show using both connector locations as I recall. I assumed the larger wire to roof was compensation for the greater distance?? I now have 1-100 watt monicrystaline (sp) panels on roof a house thinking maybe I’ll add 2 more identical one portable to chase the sun maybe later. But you don’t recommend that?? Thanks again!!

 

[jkane]

ZAMP is expensive ...

The 10 gauge cable (to the wall of you RV) is good for ~ 30A, depending on your panels that can support anything from a 12V 240W to more. The 8 gauge cable has lower loses for the same distance, but is good for ~ 40A, again at least 480W of 12V panels. (see Cerrowire Resources - Ampacity Charts for reference).

What you really have to know are the specific types of panels that you have (voltage and current), what your charge controller(s) support, and battery bank. With that you can get a recommendation for how to set up your panels for the maximum benefit. Look for series and parallel solar panel setup.

From what you have provided (I am guessing here), you have:

1) A 12V battery bank consisting of 2 85Ah batteries in parallel. This gives you 85Ah of usuable power since they are lead acid and you can only use 50% of the storage capacity before you begin to seriously impact the batteries' capacity and longevity. This is not going to be a large enough for real usage.

2) You have a 1200W inverter. That needs 100A to run it, so you could run the inverter at say 1000W (small microwave) for about an hour before your batteries are dead.

3) You have a 120VAC / 12VDC fridge. I think they draw about 40Ah / day (not always running). So you can run your fridge on battery for 2 days, if you don't use your lights

4) Your solar charge controller will charge your batteries at a rate of up to 40A. A 12V battery bank could therefore handle about 550W of solar input (before you waste power). IF you batteries can handle 40A of charging current, you have to look that up. Now it would not be "bad" to have 600W of solar feeding this charge controller since you would not be getting 100% of the rating of the solar panels in the real world.

So ... lots of stuff to talk about. You have to first decide what you want to do, what your goals are. Then people can talk with you about how to get there.

You could also just wire up the solar charge controller, throw on the panel that you already have, and see where that gets you. What have you got to lose?

Cheers

 

[Cameodon]

Pretty much what i was thinking. With no solar on fully charged batteries the fridge ran 22 hrs...with pretty much nothing in it, I know it should do a little better than that when full. We plan on a trip where we will boondock in Maine mid-late April to maybe early-mid june. VERY rare for it to get above 70-75 that time of yr. With lows mid 50-mid 60 at night very likely. We will have our 3500 inverter gen which will run 1 ac and everything else. 1 A/C if any is definitely all we need. AT this point I want to be able to leave4-8 hrs during the day with fridge running and maybe run tv a couple hrs in the eve.
Hoping at best to start gen in morning, make coffee,top off batteries as at worse they should be half full or close. Worse case maybe run gen an hr in the eve before bed. Like I said I have 200 watts on roof now, plan on another 200, maybe on ground, maybe on roof. Plus probably another 1 or 2 like batteries. I almost KNOW the fridge will run all day and knight plus 2-3 hrs tv on 4 batteries. Oh well, at least it makes sense to me but we already know I don't know a lot about solar!!!

 

[jkane]

That is a plan. Remember to cool the fridge down on A/C at the house before you take off, and load only cold food into it. That will extend your battery the most. Having the generator will help, a lot, since you won't have to stress about the battery. Top up some in the morning when you need the 120VAC, then in the afternoon if you need the A/C. Your solar should coast through the day. As those Lead Acid batteries start to get full, it gets harder for them to take more charge, so you might not hit 100% before nighttime ...

Have fun!

 

[Cameodon]

Thanks for the help…we seem to think alike! As far as the 10 gauge wire/outlet very easily to 8 gauge. At this time there’s only 1 outlet in trailer wired to the solar so fridge and tv will be only thing we’ll use solar for.we have battery fans we can charge with genie the morning/evening. To simply have the fridge and maybe tv some on solar is all I’m looking for right now