Solar off while charging with alt. ?

[Sikafishn]

Will be putting finishing touches on alternator to house battery charging system. Do I shut off solar panels while charging off vehicle alternator?

 

[highdesertranger]

short answer, no. they play will together. highdesertranger

 

[abnorm]

NO...………...charge the house with any and all available source(s)

 

[Sikafishn]

Thanks guys

 

[deadwood]

I use solar with a voltage sensing relay. HDR is right. They play well together and I usually just leave them both to do their thing. The VSR puts in a lot of amp's in a short time and the solar does it's thing to get the batteries topped up to 100%. The only thing I don't like about the relay is that it goes both ways. So when I'm parked all day and the solar is going it will open the relay and send amps back to the starting battery.

This isn't always a bad thing. If my van is parked for a while then I don't have to worry about the battery ever draining. My only real concern is that my solar puts out a higher voltage to charge my house battery then what the starting battery is normally going to get. So over time it could shorten the life of the starting battery. I have a cut off switch between the two so i can easily separate them if I want to. But to be honest unless the van is going to be parked for a while I don't even bother.

Once summer comes back and I have a lot more sun I'll probably let the solar do all the charging and then connect to the VSR if I find I am getting lower on amps than I want to be. But overall this system has worked out very well so far and for the most part I just leave it alone and let them work together and do their thing.

 

[frater secessus]

My only real concern is that my solar puts out a higher voltage to charge my house battery then what the starting battery is normally going to get. So over time it could shorten the life of the starting battery.

I put a $10 High Voltage disconnect on my relay that breaks the connection at a given setpoint.  Right now I have it set at a high Float-style voltage, 13.8v. 

My starter battery is waterable but the caps are under the floorboard in an annoying position.  I'd prefer they don't outgas...

More rambling on the topic in this blog post.

Others have addressed OP's question:

Do I shut off solar panels while charging off vehicle alternator?

but here is a bit more in this rvwiki article.

 

[paulrh]

Will be putting finishing touches on alternator to house battery charging system. Do I shut off solar panels while charging off vehicle alternator?

Taken from the Balmar FAQ:  

[font=Arial, Helvetica, sans-serif]Can I run my alternator, solar panels and/or wind generator at the same time and charge that much faster?[/font]

[font=Arial, Helvetica, sans-serif]The problem with multiple charging sources is that they tend to fool one another.  Say your solar panel (or wind generator) is charging the battery at 14 volts and pushing in 10 amps.  You start the engine/alternator up and it sees not the true State of Charge of the battery but 14 volts from the solar panel.  The alternator thinks the battery is fully charged and puts out the minimum current (only a few amps).  The result is the alternator is not doing anything and the solar is putting in only 10 amps.  This condition isn’t damaging to the charging assets, but it is inefficient charging.[/font]

[font=Arial, Helvetica, sans-serif]The above makes sense especially when it is coming from a reputable firm like Balmar.  If this is a valid point Balmar are making is there a device with two inputs, one output, that upon sensing a voltage from the alternator it closes the other, less powerful source off?  [/font]

 

[B and C]

My batteries charge from the alternator, solar and shore/generator. I don't stress over this. I let the one win that wants too. I never disconnect anything. They do play well together. My batteries are always getting charged from one of the sources.

If you want to micromanage your system, go for it.

 

[paulrh]

My batteries charge from the alternator, solar and shore/generator. I don't stress over this. I let the one win that wants too. I never disconnect anything. They do play well together. My batteries are always getting charged from one of the sources.

If you want to micromanage your system, go for it.

When it comes to potentially destroying 1000's dollars of kit prematurely I would like to know the science behind things rather than just leaving it to chance. Maybe that is just my engineering background that makes we want to understand why things happen.
Balmar, with their R&D budget, have intimated that multiple sources are in conflict. This has peaked my interest in the subject.

 

[B and C]

They are in conflict. No argument there. The one that wins is still charging the system and the others are idling. Is there harm in that?

 

[paulrh]

They are in conflict. No argument there. The one that wins is still charging the system and the others are idling. Is there harm in that?

Yes, there is a very real chance of harm if anything I have read is to be believed. The harm is the higher voltage but lower current source wins leading to an undercharged battery bank as there are not enough sunlight hours in the day to restore the battery to full charge (a real scenario for the higher latitudes or anyone experiencing inclement weather). Given an either/or situation I want to charge my batteries from the source that can supply the most current.

 

[B and C]

I haven't run into that problem. Mine get full nearly every day (depends on conditions). All of these variables are mitigated to an extent by how they are setup. Early in the morning, my solar starts kicking in around sunup. Later when I fire up the generator for coffee and breakfast, the charge rate goes way up (amps into the battery). After I shut the generator off, the solar kicks back in and works for the long tail charge to get that 100% charge back. I have done nothing to manage my system but use what I need when I need it. Same on driving days. If I had a larger solar array and bigger battery bank, I would run stuff off the solar and not need the generator for the high amp loads. I only have room for two hundred watts on the roof and carry an additional two hundred watts in portable panels that I deploy when in the shade or conditions warrant it.

It sounds like you have it figured out for your circumstances and are willing to micromanage. Good luck.

 

[highdesertranger]

I also charge off of all three, solar, alternator, and shore when available(rarely). I don't have a problem and I never disconnect anything. IMO you are reading to much into that quote from Balmar. highdesertrager

 

[paulrh]

Quite possibly reading too much in to the Balmar quote.
What device do you use between the batteries or alternator/house batteries to control the charge voltage?

 

[B and C]

The charge rate (alternator output) is controlled by the alternator or your ECM (engine control module) depending on vehicle. No magic there either. My vehicle does have a battery isolator (three diodes) to prevent one battery from draining the other battery. A continuous duty solenoid will work just as well and maybe better as the isolator drops a small percentage of voltage.

 

[highdesertranger]

I use a solenoid between the alternator and house battery. I have a GM 10SI alternator output is regulated at 14.2v then 13.8v. it's 63amps. I have a 12SI that is 94amps waiting to go in. highdesertranger

 

[Seminole Wind]

balmar's info is not based on their RnD, it is based on their desire for more sales. SIMPLE

it does not matter how many charge inputs you have going to the batteries. if any particular charge source sees a battery voltage at or above that sources set point. then it will reduce charge. but that really does not mean anything. the set point is basically the absorption voltage and if the other charge sources are putting out enough current to keep the voltage at the absorb set point. well then they are already providing as much as the batteries will take.

there is not such difference as high volt source vs high amp source. if the source does not have enough current, the voltage will not climb.

the only issue you may run into is setting priority of charge sources. for example, today it was pretty cloudy in the pacific north west. solar alone was not going to cut it by my standards. so i fired up the generator. for the first couple hours as the voltage climbed both solar and generator based charger were putting out full potential. then when the batteries hit the absorption threshold and the batteries could no longer accept the full output from both sources the output of one or both needs to taper off. in my case i want the solar to always put out max or at least take the lead with the generator backing down first to unload the generator to reduce fuel consumption (inverter generator with ECO mode) all i have to do is make sure the absorption set point for the soar is a tenth or so of a volt higher than the set point og the generator based charger. easy to do for me as my charge controller set point is adjustable down to the hundredth of a vlt and the charger set point is adjustable down to the tenth of a volt.

works good for me,i can see on my gauges, when the charger hit its' set point it starts to tapper off while the solar chuggs away. if it gets cloudy and the set point starts to drop since the solar cant keep up then the charge ramps back up.

later in the day when the output of the charge has fallen way off i just shut it down to save fuel while the solar finishes.

 

[XERTYX]

I've never used multiple charging sources before so bear with me. The only thing necessary to charge via solar and the alternator is to install a voltage sensing relay between the starting battery and the house battery? The regulator remains connected to the house battery and if full it simply doesnt charge the house battery due to it sensing the voltage and not overcharge the battery. At the same time the alternator and VSR work in unison not to overcharge the house battery. Also if parked and the house battery is full excess solar energy is transferred into the starting battery unless you use a manual disconnect? That sounds like a win win to me as I'd like to also use the vehicle system for things like electric cookers and radio equipment while driving and if I over did it and discharged my starting battery I could replenish it from the house battery. Forgive my ignorance if I completely missed a crucial point here.

 

[bullfrog]

I'm sorta old school, we used to mount units designed to produce 110 AC or 220 AC directly on the motor to power welders, power tools and etc. Most found it wasn't as efficient to run a several hundred cubic inch motor to do this and went to the independent units you often see mounted on flatbed trucks. Even most trucking companies frowned on drivers using inverters There are many efficient small inverter generators on the market today. I guess if you are on the road more than 4 hours a day and are willing to spend a little more on maintenance it would work, I do that myself with the new 18 volt vehicle chargers for power tools. But remember you can only completely discharge a battery a limited number of times as most people with new solar systems find out, and using a vehicle while driving and a small generator on cloudy days to keep enough batteries from discharging to far is probably best untill better batteries and the controlers to charge them correctly get cheaper.

 

[maki2]

You have indeed missed a cruicial point. You would never want to have the electrical appliances powered by the battery that starts your vehicle. It is not designed for that. You need a deep cycle house battery for those items. Deep cycle batteries are made with much heavier plates, so it is a matter of how a battery is constructed that makes it be suited for specific use. It is not about how it is getting charged.

Start expanding you knowledge with a simple explanation about the difference in battery types and why you use which one for powering appliances and which one for starting the engine from this link to wikipedia article explaining the . https://en.wikipedia.org/wiki/Deep-cycle_battery