Charge battery from 12 volt power receptacle to charge controller to charge battery

[SoulRaven]

I received my 100 watt panel today. Since I am going to be keeping my solar charging portable (I don't want to install the panels permanent on my tow vehicle or trailer) I am working on a few ideas on different setups to charge my batteries while driving. One idea I had was to use the  12 volt receptacle in my Ford Escape in the rear cargo area connected to the "solar in" connection on the charge controller, then connect the "battery" connection to the deep cycle battery I am charging. I will be using some sort of quick connect and disconnect connectors. Maybe sae or even male and female 12 volt power connectors ( otherwise known as cigarette plugs).
This way, when I am driving my battery will be charging, then if I am going to stay somewhere a few days or more, I can put out the panel and quick disconnect the ciggy plug and connect the solar panel. I don't see any problem with this because the charge controller doesn't care where the power comes from, it will charge the battery the same.
Am I overlooking something here? It seems like a pretty simple solution to charging the battery while driving without having the solar panel mounted permanently. I don't want to permanently install the panel on my tow vehicle or my small Runaway trailer because of aesthetic and other reasons such as, I would have to be parked in the sun to have the panels work. I want to be in the shade and still have my batteries charged. So my panels will have to be portable so they can be placed out in the sun while the vehicle and trailer are in the shade. Makes sense to me.

 

[rvpopeye]

I guess that set-up would work it would be a quicky method to get you up and running.
The rear cig plug will probably have too small gauge of wiring to get the most out of your alternator to the rear battery though. Plan on upgrading your set-up in the near future.
AND remember that the panel will be live unless it is covered (or dark outside)!

 

[VanLifeCrisis]

i dunno about that one, id definitely wait for the pros opinions here. i know the controller has limits on what its fed, not sure if thats a factor.

 

[SoulRaven]

i dunno about that one, id definitely wait for the pros opinions here.  i know the controller has limits on what its fed, not sure if thats a factor.

The paper work that came with the controller states 42 max input voltage. No problem there.

 

[SternWake]

Your charge controller cannot just be fed from the vehicle, for many reasons.

If you are driving and want to get some extra charge into the trailer battery, run a separate cable ( fused) to the trailer battery.

Your assumptions in this matter are dangerous, and wrong.

http://www.amazon.com/Keeper-KTA141...sim_263_1?ie=UTF8&refRID=147ND97WNXYBJX94R5M6

 

[SoulRaven]

I guess that set-up would work it would be a quicky method to get you up and running.
The rear cig plug will probably have too small gauge of wiring to get the most out of your alternator to the rear battery though. Plan on upgrading your set-up in the near future.
AND remember that the panel will be live unless it is covered (or dark outside)!

I looked at the wires and they look to be at least 14 gauge. The cig plug is fused at 20 amps. So I would think that maybe you are right that the plug would not deliver as much as the panel. But, there is a fuse box back there and I could maybe run wires from a heavy wire there. I think that there may be a 40 amp fused wire for a 7 pin charge wire for a trailer there. I am going to have to do some research.

 

[highdesertranger]

why do you want to run it though the charge controller? wire it straight to your alt with a disconnect or a isolation solenoid. highdesertranger

 

[SoulRaven]

Your charge controller cannot just be fed from the vehicle, for many reasons.

If you are driving and want to get some extra charge into the trailer battery, run a separate cable ( fused) to the trailer battery.

Your assumptions in this matter are dangerous, and wrong.

http://www.amazon.com/Keeper-KTA141...sim_263_1?ie=UTF8&refRID=147ND97WNXYBJX94R5M6

Ok, you have given me the short answer. But I am a little more inquisitive about things, so could you give me a few of the many reasons? I am new to the solar side of life and am trying to learn about it.

 

[SoulRaven]

I charge my house battery plugged into my front ciggy plug while driving with no controller at all other than the typical engine charging system. No solar panels, and no dead batteries or ill effects in over a year of using this method.

 

[SoulRaven]

I charge my house battery plugged into my front ciggy plug while driving with no controller at all other than the typical engine charging system.  No solar panels, and no dead batteries or ill effects in over a year of using this method.

That is very interesting. I was afraid that if I did that there would be too many amps pulling at the battery to try to charge itself through the ciggy plug wiring. My thought was that the charge controller would keep the current at a level that the lighter could handle. I really don't want to go through running a heavy cable from my battery into the cargo area to charge the 100 watt agm battery that will be running the 12 volt fridge when I am sitting still for a few days. I may give the ciggy plug a try. How do you have that connected? With a male plug end to the  power outlet to some sort of clips at the batteries?

 

[SoulRaven]

Your charge controller cannot just be fed from the vehicle, for many reasons.

If you are driving and want to get some extra charge into the trailer battery, run a separate cable ( fused) to the trailer battery.

Your assumptions in this matter are dangerous, and wrong.

http://www.amazon.com/Keeper-KTA141...sim_263_1?ie=UTF8&refRID=147ND97WNXYBJX94R5M6

I am glad that I haven't tried to connect the controller to the 12 volt from the ciggy plug yet. Especially since you said it is  dangerous. What would happen? That is why I am checking out things first so I don't make a bad mistake and cause damage. I am trying to research this on line and am not coming up with much. I am going to assume that is because it is just not done this way. But I can't for the life of me see any problem with doing it. Can you expand on what you are referring to about being dangerous? All information will be appreciated. Like I said I am new to some areas of the solar and the charge controllers are what I am in the dark about right now, but I am in the process of learning about them. Thanks 

 

[GotSmart]

I charge my house battery plugged into my front ciggy plug while driving with no controller at all other than the typical engine charging system.  No solar panels, and no dead batteries or ill effects in over a year of using this method.

Sounds like luck to me.  I wonder how long your battery will last doing this?  Charging a house battery with a 16 gauge wire?  

I ran a 4 guage wire from the alternator to a fuse, Solenoid then the battery bank.  I have a switch off of the run system (Power only when the motor is running) to power it  Well worth the $70 extra for parts (mostly wire) to safeguard it all.  No fires or components frying because of problems. 

[font=Arial, sans-serif]NEW 12V 150A CONTINUOUS DUTY SOLENOID RELAY FOR GOLF CARTS 300A IN RUSH 1114208[/font]

 

[rvpopeye]

The charge controller would have to be rated for more amps than the alternator puts out or you probably (surely) will fry it.
The suggestions to wire to the alternator with heavy wire 8 ga or even 4 ga are a good idea for max charge capability. put a fuse , at least on the alternator end of the wire too , rated for the output of the alternator.
Another at the other end too for max safety wouldn't be a bad idea.

If you get a solenoid , and if you power the solenoid from the ignition switch instead of directly from the start battery it will prevent the start battery from discharging when the engine is off.

I have mine wired that way , with an extra switch as well so I can choose when I want to connect the house battery.

I know you like to try minimal stuff first but doing it up right the first time will make you wonder why you wanted to do it any other way ?????
That's why you are asking here on the forums , right?

 

[rvpopeye]

Almost forgot........ that extra switch and the heavy wire will give you the option of giving the start battery a little extra boost when you might need it , hey , it happens.
I used a double throw switch so I can choose which battery to power the solenoid from.......

 

[akrvbob]

A 20 amp fuse in a ciggy plug is a sure recipe for a fire.

Never do electrical half-assed on a wing and a prayer; the cost of failure is too high.

You want a 4 gauge cable from either the starting battery or alternator to the house battery. Put either a solenoid or on-off switch in between.
Bob

 

[SoulRaven]

Sounds like luck to me.  I wonder how long your battery will last doing this?  Charging a house battery with a 16 gauge wire?  

I ran a 4 guage wire from the alternator to a fuse, Solenoid then the battery bank.  I have a switch off of the run system (Power only when the motor is running) to power it  Well worth the $70 extra for parts (mostly wire) to safeguard it all.  No fires or components frying because of problems. 

[font=Arial, sans-serif]NEW 12V 150A CONTINUOUS DUTY SOLENOID RELAY FOR GOLF CARTS 300A IN RUSH 1114208[/font]

No luck needed or involved.  The jumper cable is 10 gauge not 16 gauge, and was designed to jump start a second vehicle with a dead battery via the cigarette lighter plugs.  It has a 30a fuse on each end, plus my vans cigarette lighter also has a 30 amp fuse on it from the factory, and 10 gauge wiring going to it.  The van also has a 10 gauge wire running from the alternator to the starting battery, as far as I know this is also factory.

My house battery box has female cigarette lighter outlets in it, so plugging in this jumper cable into my house battery,  is no different than plugging it into a second vehicle with a dead battery.  I might add that nothing even gets warm, let alone hot.

I'm at the end of year 6 on this battery, which was a $20 recycled battery to start with.  I have been charging it while driving only since April of 2014.  I got just over 6 years on my previous battery charging it with a 12v DC gas generator only.  So as far as I can tell, charging while driving using this method has had no adverse effects on battery life either.   And I NEVER run short on power.
105
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[GotSmart]

In my experiences, the wire under the dash to the lighter is 16 gauge.  


That method should  :huh:  result in a battery that never gets a full charge, leading to a shorter life.

 

[SoulRaven]

I still have not got the answer I was seeking. I want to know why I can't just hook up from the ciggy power plug in the vehicle to the solar power inlet of the charge controller then connect to the battery of the 100 ah deep cycle that I will be carrying in the vehicle to power the fridge when not driving. I want to charge the battery while driving. If I hook up the 12 volt ciggy power outlet via a simple male to male wire to the deep cycle I am worried about the battery pulling too much current and blowing the 20 amp factory fuse at the ciggy plug, and even possibly overcharging the battery. I was thinking that the charge controller would keep the current regulated just like it does when it is receiving it from the panel. As long as I don't put any more than 42 volts into the controller (which is it's limit), I would think that there would be no danger of harming anything. After all it is a charge controller. It is supposed to have things in it to prevent over and under charging. Those are safety features to protect it, the panel (which is the source of power), and the battery it is charging.
What am I missing here. I don't really want to try to charge the deep cycle directly from the vehicle without some sort of controller to prevent over current.

 

[mariasman]

That method should  :huh:  result in a battery that never gets a full charge, leading to a shorter life.

JMHO, but if he drives sufficiently often and for a sufficient duration, then a good alternator and using generously sized cables to the battery will ensure a regular full charge.

 

[GotSmart]

Simple answer. Because it does not work that way. You can destroy the controller which is not designed to handle that much power. (Amps not volts)

15 amp fuses is what I use in my 5 sockets. Yes I said 5. All wired and fused separately

Look to post 15 for what to use in the system to protect it