Which solar charge controller do you use?

[peppster66]

Hi, I am in the planning stages of adding a solar set up to my 97 Roadtrek, hopefully this spring, I will be adding 2 x 100w renogy mono solar panels, but I am not sure on the controller, there are 20amp,30amp,( and even 40amp for a lot more money). I have been studying the topic, there are so many different brands, types, and models, not sure which one to go with, and it seems very important that I do not over charge my house battery system. are there controllers that have it built in to the system as to not over charge and hurt my electrical system, or will I need to add an on/off switch into the system? They offer 10AWG wiring, and 12AWG wiring, is one preferred over the other? And one last question, is it possible to run a line from the charge controller to the main battery in the engine compartment , to keep it topped up when were boondocking for long periods of time, it seems like a good idea, I just don't know if its a smart thing to do,or will I be causing more problems than solutions,,,, thanks,,,,,,

[InterBlog]

If you are in the mood to tackle a TLDR, my husband has this thread on Air Forums that describes our process. A few of the thread participants are actually electrical engineers, and some of their insights are valuable. Plus, Lew Farber weighs in - he's perhaps the best-known high-end professional solar upfitter who works extensively within the constraints of limited Class B footprints.

However, we switched to lithium, and so it may not be a direct comparison to your situation (it sounds like you might be retaining conventional battery(ies)). The solar charge controller we chose was the ElectroDacus, launched on Kickstarter by a brilliant independent EE in Canada. The upside is that it's a remarkable product; the downside is that we don't know that it has ever been tested in a Class B operating capacity. We decided to roll the dice and take a chance on it in part because, right now, there are not many choices on the market if a DIY lithium conversion is involved. Some of the players will not sell to the public because of the potential consequences (chiefly fire) of screwing up a lithium conversion.

[booster]

For a "normal" type class b system of 100-300 watts on lead acid batteries, the two most popular controllers seem to be the Blue Sky Solar Boost models with the Pro Remote, and the Trimetric battery monitor with the added on solar controller from them (Bogart).

Both are programmable to get optimum settings and they run off of shunt for charge accuracy. We have our 300 watts on a Blue Sky 2512.

The Blue Sky is an MPPT controller and the Bogart is a PWM controller, so that may be a secondary consideration.

I have heard very few complaints on either of them.

I would stay away from any controller that does charging based on time only, with no shunt and amps charge control, as they can, and have, chronically overcharge already full batteries and damage them.

I am sure there are some other models out there that would also be good, but I have no history with them.

For wiring, bigger is always better for solar as voltage drop is not your friend.

[mojoman]

I run a Midnite MPPT controller "the Kid" , its programable for lithium. I have 4 100 watt panels which is about the max for this controller.

[JohnnyFry]

Do not even consider using 12AWG wire, is is too small and the voltage drop will kill most of the benefit. 10AWG is minimum, many recommend using 8 AWG, especially if the run is more than a few feet.
MPPT controllers are the most sophisticated, but are more expensive. Do not skimp on yhe controller or wire size. Considering the work involved, you want it right the first time.

John

[Michael4104]

The solar charge controller we chose was the ElectroDacus, launched on Kickstarter

I went to his kichstarter page, but can't see a way to order one of his controllers or even how to pledge for one.

[BBQ]

.

If you have room on the roof for more panels,
you will most likely add more panels in the future,
even if you don't think you will ever need them.

The simple fact is, the panel price will continue to drop,
at one point in the future,
because the additional panel cost is so cheap
it will be a no-brainer to add more panels.
So be prepared for it now,
both in wiring, and in the controller.

[peppster66]

Thanks for all your replies, as always , you guys are a great support, one quick last question for you, what gage of wire is best to use from the solar controller to the battery, I think it will be about a 6 foot run in length, thanks again,,,,

[BBQ]

Originally Posted by peppster66

Thanks for all your replies, as always , you guys are a great support, one quick last question for you, what gage of wire is best to use from the solar controller to the battery, I think it will be about a 6 foot run in length, thanks again,,,,

There a website with a table of wire length vs wire gauge vs voltage.
I don't have the link on hand, but I am sure it is easy to locate by google.

[InterBlog]

Originally Posted by Michael4104

I went to his kichstarter page, but can't see a way to order one of his controllers or even how to pledge for one.

I believe the owner, whose name is Dacian Todea, creates them in batches. I say this because I'm remembering my husband mentioning to me that he had also committed to purchasing his next gen unit which might be out this summer. Dacian is extremely responsive to emails. electrodacus -at- gmail should elicit a prompt response to your questions if you email him.

[Buford Wilson]

The Tracer-3215RN controller came with my 2016 ZION SRT. One AGM battery, no voltstart The 3215RN works good with the 200 watt panels on top.

I never had a problem with it in the year since I had the RV. I didn't have to touch it. It's installed in a small cupboard to the left of the refrigerator, at the top. Hard to see anything in there. So I got a got a MeTer MT-5 remote display for it. $12 on eBay and it connects to the controller with ethernet cable.

[cruising7388]

Originally Posted by Buford Wilson

The Tracer-3215RN controller came with my 2016 ZION SRT. One AGM battery, no voltstart The 3215RN works good with the 200 watt panels on top.

I never had a problem with it in the year since I had the RV. I didn't have to touch it. It's installed in a small cupboard to the left of the refrigerator, at the top. Hard to see anything in there. So I got a got a MeTer MT-5 remote display for it. $12 on eBay and it connects to the controller with ethernet cable.

As far as I know, Roadtrek uses this same solar controller on every solar equipped coach but they don't provide any operating manual for this controller. I had to surf the internet to find one.

It's interesting. Some builders prominently display their solar controllers. Roadtrek on the other hand sticks it in the back of a cabinet making it hard to read and certainly not easy to configure. On first impression, that seems counterproductive but on second thought, there may be more method to doing this than meets the eye. Could be they they stash the controller out of sight to discourage tinkering with the solar charging parameters by folks that don't appreciate the potential for battery damage and even failure caused by an improperly entered charging program.

[booster]

I am not familiar with that model of controller, but can say that if it is does not run off of a shunt, it can't do a a good job of taking care of the batteries, regardless of how they program it. Because of coach loads, etc, there is no way that the unit will know if the batteries are full or not, so it will guess, or run off straight timers, to determine the charging stages, neither of which are very accurate.

Roadtrek doesn't seem to like to use mainstream components anymore, with private label or unknown brands. I can't say if it is to save money or give better products, but sure does make it hard for customers to know what is going on.

[MsNomer]

I have Bogart's Trimetric solar charger and meter. It appears to be rock solid and Ralph at Bogart is a real treasure. He answered the phone promptly every time I called and patiently led me through setting up the charge parameters for my particular batteries.

[cruising7388]

Originally Posted by booster

I am not familiar with that model of controller, but can say that if it is does not run off of a shunt, it can't do a a good job of taking care of the batteries, regardless of how they program it. Because of coach loads, etc, there is no way that the unit will know if the batteries are full or not, so it will guess, or run off straight timers, to determine the charging stages, neither of which are very accurate.

Roadtrek doesn't seem to like to use mainstream components anymore, with private label or unknown brands. I can't say if it is to save money or give better products, but sure does make it hard for customers to know what is going on.

Roadtrek maintains that their multiple charging sources, i.e. alternator, shore power and solar are integrated to ensure compatability with each other and are designed for correct charging programs for the batteries employed. How they presumably accomplish that has never been explained. What's disconcerting is that the manual for the controller they use permits the selection of various lead acid battery types but there is no choice for lithiums that requires a different charging format than lead acid batteries require.

Their lithium batteries and inverter are proprietary but I think that's not a cost saving measure and more likely a requirement for product modificaton of these components to meet their particular specs. In a way, it accrues to the benefit of the owner. For OEM branded components, the OEM warranty has to expire before the Roadtrek warranty takes effect. For proprietary components, the Roadtrek warranty applies from the get-go.

[booster]

Until Roadtrek decides to put a proper battery monitor in place, none of us or any of their customers will have any idea how well they take care of the various battery types. That is likely why there is no monitor, as they don't want anyone to know how well, or poorly, they do it.

They also leave their customers not having any way to know how much power they have left in their system, which can be very frustrating when you run out unexpectedly.

[cruising7388]

Originally Posted by booster

They also leave their customers not having any way to know how much power they have left in their system, which can be very frustrating when you run out unexpectedly.

Well, at least their control panel panel is finally equipped with a 4 digit voltmeter measuring 10 millivolt increments which you can interpolate to provide a rough estimate of battery state.

[gerrym51]

I have this same one in mine and never touch it. i have the zion with agm and 200 watts solar. as long as the green lights are on on it-the second one blinking green when battery full-i',m happy

[cruising7388]

Originally Posted by gerrym51

I have this same one in mine and never touch it. i have the zion with agm and 200 watts solar. as long as the green lights are on on it-the second one blinking green when battery full-i',m happy

Roadtrek probably programmed your controller during the build to match your AGM batteries which is fine. What's not clear is whether the controller can cope with the recommended liithium charging protocol which is to dispense with maintenance charging and shut off if it senses a fully charged battery. I couldn't find any battery choice in the manual that will implement this protocol.

[booster]

The AGM program is actually as important as the lithium with shutoff, and if there is no way for the controller to measure current to the batteries, it has no accurate way to determine when the batteries are full.

Just because a controller or converter has an AGM setting, that does not mean it knows how to charge your battery bank properly. It most likely runs on timers, so it will be correct at specific bank sizes and state of charges. About all the will be correct are the voltages.

We have a very nice, and not cheap, Magnum inverter/charger and if we run it on the preprogrammed AGM setting, and not off of the shunt options, it would do a horrible job on our battery bank of AGMs. A setting like that can't work on everything as it is not a one size fits all type application.