What is your solar controller telling you?

[booster]

As would be expected, since we put the solar on and improved our shore charging, we have been in quite a few discussions about charging, batteries, solar etc with friends, acquaintances, folks we meet in campgrounds, etc. One thing that seems to come up pretty regularly is from folks that have the basic 100-300 watt RV solar systems on their rigs. They state that their solar system is "inconsistent" or "not giving full output" all the time. They understand about sunny/shade, sun angle and all that stuff pretty well, but can't understand why one day their solar controller says the got 75AH and on a similar next day it was only 40AH, or less.

Very valid question, I think, and good they are watching what is going on. The solar controller is saying how much power it generated, and it doesn't care where it goes or what it is used for. It will also generate only as much as is needed at any given time. Under good sun conditions it might do 15 amps maximum, but if you only have a place for 2 amps to go, that is what you will get out of the solar. If you are out hiking all day, and have just stopped driving with full/near full batteries, your solar is not going to have a very big AH output that day, as your aren't using any power to speak of, and the batteries are full from the drive. If you watched DVDs all night, ran the furnace, maybe the microwave, etc and are charging up all you stuff the next day, you will have a high AH day.

Output of the solar will begin to drop shortly after it goes into absorption mode, so that is when you are starting to fall of getting maximum out of the solar for the day. It is also a good time to plug in anything that you need to charge up like your laptop or such, if you haven't already, as you are not shorting you main battery charging by doing it (at least not much), as they are at absorption voltage and getting all that they can take. Keep adding stuff that uses power to the system, and there will no effect on your battery charging unless the voltage drops below absorption voltage. Things like our laptop seem to like the higher absorption voltage and charges faster. We ran into folks that would always shut everything off during the day, and run their other stuff at night so the solar would fill the batteries better, which is true while in bulk, but by 1:00pm they may be in absorption mode so the batteries will not be affected by other stuff as long as the voltage holds. Those folks were using battery at night to cover what they could get during the day as extra solar capacity.

We have been testing in the driveway, trying to find the best cutoff amperage for our solar, with the odd multibank we have, and I can say with certainly it is very hard to get batteries totally full on solar, unless you have a very big solar system, or very low drawdown. This makes sense because our shore charger can be in absorption for 6+ hours before it hits ending amps on our batteries. Many days you might not get to absorption voltage before mid afternoon, even in good conditions, so you won't get full that day. On days we get full, we actually see much less AH on the controller than on days we don't, because of the amps tapering as the batteries fill.

For getting batteries totally full all the time, the solar is at a big disadvantage compared to the shore charger that has all night to do the final/slow absorption finishing, so the solar will also be a bit harder on the batteries because of it. With wet cells, it just would mean you equalize with solar on a day you are full from, or during, driving to condition them. Maybe once a week. AGMs would not be able to be helped concerning the shorter charge by equalizing, but you would want to plug in or drive enough for a full fill regularly to minimize the affects. Lithium batteries won't care if the get full, so solar is great for them. You can run in the middle of the state of charge without issue, and all the solar you can put out will be put into the batteries because they are not nearing full and tapering, if you can afford them.

[Davydd]

I'm totally confused by all this. Maybe it won't come clear until I have solar and batteries in hand to monitor.

One curious question I have is does solar only work and contribute while parked or is it working while driving down the road? Or does it make any difference if the engine alternator is doing the charging? Is it working in concert to charge faster or is it an either or situation? I guess the same question with an Onan generator, but that I plan to eliminate.

[booster]

Originally Posted by Davydd

I'm totally confused by all this. Maybe it won't come clear until I have solar and batteries in hand to monitor.

One curious question I have is does solar only work and contribute while parked or is it working while driving down the road? Or does it make any difference if the engine alternator is doing the charging? Is it working in concert to charge faster or is it an either or situation? I guess the same question with an Onan generator, but that I plan to eliminate.

I guess the easiest way to put it is that any and all of the charging methods "work" whenever they are on and connected. That doesn't mean that they are contributing the same as if they were the only thing running. Mostly it has to do with the voltage that whichever charging is running at. If you have solar running at 14.5v, generator running the shore charger at 14.4v, and the alternator running at 14.2 v, they all will contribute. The voltage the batteries see will be the highest of them, or 14.5, assuming all of the methods are producing enough amps to hold that voltage. The solar might not be able to hold the 14.5v by itself, but with the others contributing up to 14.2/14.4v, that can allow the solar to hold the higher voltage because it has to contribute less amps. Solar setups are typically on all the time, but put themselves to sleep at night.

All of this makes for some very odd and sometimes not too nice interactions, which I have written about other times. Having all the stuff running at the same time can make them shut off charging too early, or too late, or not even start charging in the first place (directly to float). We have on/off switches on all of the charging methods and have be experimenting on when they should be used. In general, you would rarely need more than one method running at a time based on what we have seen, and when to use them gets pretty obvious.

[gerrym51]

Booster- i thought there was a contoller available that co-ordinated all 3 charging sources-panel-alternator-shore power-althouth i think the most likely combo in alternnator/solar panel

[booster]

Originally Posted by gerrym51

Booster- i thought there was a contoller available that co-ordinated all 3 charging sources-panel-alternator-shore power-althouth i think the most likely combo in alternnator/solar panel

There very well may be some that do that, but none that I have found in the "normal" RV type parts. Outback has a lot of features, and for sure the solar and shore power share information and battery monitor. What I couldn't tell by reading the manual was how they work all the stuff together. It will be very interesting to see how Davydd's system actually integrates all the parts.

We found conflicts with the shore charger and solar, both ways and the alternator can also mess up the solar to a degree, depending on what type it is.

IMO, the biggest causes of overcharging are the alternator and the solar, either alone or together.

IMO, the biggest causes of undercharging are the shore chargers and solar, both alone and together.

Of course there are exceptions to all of this.

[stanw909]

I don't have a fancy charge controller just a $35 Chinese one but it has a protective circuit that prevents overcharging. It does not have an amp or voltage readout but the batteries seem to be doing fine after a little over a year of service. I have never used a temperature gauge on them but they only feel warm to the touch when charging. Maybe the controller cuts them off early and doesn't charge fully but it works well enough so far. I have 220 amp hrs of Optima blue tops(4) and on a sunny day the controller cuts off by 1:00 pm. Freezer runs 24 hours and some lights and fans are all we run. No inverter or microwave. No room.

[stanw909]

Forgot to mention the panel is 155 watt. I have room for one more battery of 55 amp hrs. I also didn't answer the question. My controller tells me next to nothing but it has worked so far. I might just be lucky.

[booster]

Originally Posted by stanw909

I don't have a fancy charge controller just a $35 Chinese one but it has a protective circuit that prevents overcharging. It does not have an amp or voltage readout but the batteries seem to be doing fine after a little over a year of service. I have never used a temperature gauge on them but they only feel warm to the touch when charging. Maybe the controller cuts them off early and doesn't charge fully but it works well enough so far. I have 220 amp hrs of Optima blue tops(4) and on a sunny day the controller cuts off by 1:00 pm. Freezer runs 24 hours and some lights and fans are all we run. No inverter or microwave. No room.

More important than the battery size is how much power you use overnight before charging again. At 155 watts and off by 1:00pm, you must not use a whole lot of power.

What brand and model is the charge controller, maybe we can see what it actually is doing.

[Davydd]

I haven't delved into the details all that much as I am giving Advanced RV the time I know they are going through to refine their systems. So it is kind of a wait and see. What I do know from the past is they use an Outback Inverter/charger and a Silverleaf controller that seems to be the main and only interface you use inside your B to monitor everything. They also install a second under the hood alternator pretty much as a standard now.

[gerrym51]

Roadtrek insists they have a proprietary controller-but i don't know?

[markopolo]

I think Roadtrek refers to their method of power control and/or implementation as proprietary. (not necessarily a proprietary piece of equipment) Just my interpretation though.

Originally Posted by booster

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Under good sun conditions it might do 15 amps maximum, but if you only have a place for 2 amps to go, that is what you will get out of the solar.
........................

That's a key point and very well explained / described in that sentence. It should give everyone a better understanding of what to expect with a solar charging system.

[booster]

I think Marko is right on the Roadtrek "proprietary" system as being only proprietary in how they put stock parts together. We have heard of numerous changes to the parts the use, also, like chargers and inverters. I doubt that the Roadtrek system does any of the disconnecting of systems when they would interact badly with each other, as that would require a specifically designed and built relay box or controller, which I don't think they have. We have heard of some battery issues with etreks, so the likely have had some of the issues that have been discussed on the B forum over the last couple of years.

Yep, Marko, that does sum it all up. The AH totalizers in solar controllers give very useful information, and I am very glad they are there, but that information needs also be appropriately interpreted. Too many folks seem to be into the mode of thinking the more AH they show, the better off they are. Many times with lower AH they are better off, because their batteries are full. I think some of it may be bragging rights, kind of like gas mileage, so folks don't like those low numbers

[gerrym51]

Roadtrek won't do retrofits of old roadtreksbecause they say the wiring must be able to accomadate higher voltages-i suppose that makes sense

[bikerbill]

I think Roadtrek has their E-treks pretty well organized by now. They include a 6 YEAR warranty with them which covers EVERYTHING but the chassis. So for 6 years after I receive my new RT CS Adventurous E-Trek which is being built right now on the assembly line RT will cover the AC, the M-Wave, the Fridge, the roof fan, plumbing, etc and the 8 batterie and all the associated items like the solar panel, solar controller and the 5000 watt inverter. 6 YEARS. And I know they have paid for repairs/replacements for batteries while people have been on the road and its inconvenient to get back to a dealer and wait. Monitor their Facebook page sometime. A lot to learn there.

The proprietary basically is the "design" of their system. They start with 8 6 volt AGM batteries which are charged by a 12 volt generator and then are combined to feed 24 volts to the 5000 watt inverter. Inverters basically over 4000 watts need to be fed with 24 volts. I don't think they have invented any physical parts but merely its the system design and wiring that's proprietary. But once I have mine, I'll look into it further trying to determine what is their "secret sauce?"

[markopolo]

It might be a 24v auxiliary alternator (generator) and a 24v solar setup. The large battery bank being separated into a 12v group and a 24v group.
edit: here's the post showing the 24v and 12v combined setup: http://www.classbforum.com/phpBB2/vi...php?f=9&t=3002

Getting back to the solar discussion - what booster pointed out also highlights a big difference of an RV system and a home set up where you sell power to the utility. In that type of home system a greater output is a positive selling feature where as in an RV system you only want to size the solar system to what you need.

[booster]

I seem to remember reading someplace that at least originally, the 12v side charged off the MB original alternator, and the 24v side charged off the engine generator. That may also explain why they had two Progressive Dynamics shore chargers then. Someone that was here had that setup, and Roadtrek took it back and changed it, IIRC. I think to an Iota setup.

[Davydd]

What exactly is the definition of proprietary? Once a system setup is known could it not be reproduced by anyone considering all parts are from various manufacturers available to anyone? It seems proprietary may mean withheld information as long as possible even from the owners. Bikerbill, if you discover the "secret sauce" and divulge the recipe will Roadtrek's proprietary police come after you?

I have some curiosities since I think I am getting a 2800 watt inverter/charger that would seemingly handle everything in a B from what I understand, is why a 5000 watt inverter and all the gymnastics mentioned to deal with it? Also, is an under the hood second alternator (or generator) producing direct AC current like an Onan generator?

[booster]

Proprietary is probably only as good as you can defend it, and without a patent and the resources to defend it, all you can do is hope nobody figures it out. In this case, figuring it out would be easy, I think, and we have never heard of a patent that I know of.

I think the big inverter in the Roadtreks is related to their ideas about being able to run the air condition, microwave, and everything else at the same time, (with a sprinkle of fairy dust?).

[gerrym51]

Davydd-the 5000 watt inverter does have a 8 6 volt agm battery bank-although i agree offering 5000 watt usage is just asking to waste battery power.Bling is the thing .

Jim Hammill is now offering something called the 'warp core option package' on a CS. i thought he was kidding at first but now he seems's serious. 24 hours of air condioning. I think he's delerious.

[markopolo]

Originally Posted by gerrym51

....... Jim Hammill is now offering something called the 'warp core option package' on a CS. i thought he was kidding at first but now he seems serious. 24 hours of air conditioning..................

'warp core option package' tell me more Gerry. Must be lithium..... I like the description