Solar??

[Scootr74]

Ok, if I have wired my car's charging system to the camper battery and the is a solar panel already wired to the camper battery - do I need to turn off the solar panel when the truck is charging the camper battery?

Both charging systems are "switched" so either can be turned on/off to charge the camper battery.

Thanks in advance!

 

[Stan@FourWheel]

good question

I never really thought about that

I'm not to big into the solar system thing, but that said, I would not be afraid to hook up solar in my house or camper as long as I had the basic instructions handy

in the new FWC's we have both systems hooked up to the aux. camper battery at the same time, BUT we have a controller hooked up to the solar panel, so that might keep things in check ?

In a standard camper, the trucks charging system is wiring to the battery separator / isolator to keep the aux. camper battery and the truck battery separate. It opens when the truck starts to allow the alternator to recharge the aux. camper battery, and it closes when the truck is not running to keep the truck battery safe and full.

When we put a solar panel on a new camper, we put the solar panel on the roof, the wires come down into the camper and we hook those to a charge controller, a basic in-line fuse, and then the wires go directly to the aux. battery.

So at that point, when you are driving down the road on a sunny day, the aux. camper battery and the trucks alternator will be recharging the aux. camper battery.

It seems to be working just fine for us. I haven't heard of any problems with the camper having problems with both systems charging at the same time. I'm guessing the charge controller will keep any power from coming from the trucks alternator away from the solar panel (avoiding possible damage to the panel) ?? Again, I don't really know all the details, but what we are doing seems to be working just fine.

Hope this helps with some sort of explanation.

here are some basic solar panel links if you want to read up ...

http://www.fourwh.com/85wattsolarpanel.pdf


http://www.fourwh.com/chargecontroller.pdf


our service manual page has more links too


http://www.fourwh.com/servicemanuals.htm



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Ok, if I have wired my car's charging system to the camper battery and the is a solar panel already wired to the camper battery - do I need to turn off the solar panel when the truck is charging the camper battery?

Both charging systems are "switched" so either can be turned on/off to charge the camper battery.

Thanks in advance!






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[lqhikers]

solar my way

as some one who keeps it basic my solar system is set up as follows,2 panels (both wired to solar controller)which is fused at controller then wired to 2nd bat. Truck bat is tied to 2nd bat with fused cut off switch.
When driving i close switch ,ties two bats together,when i set up camp i disconnect switch .From what i understand the controller has diodes that keep voltage from feeding back to panels .
I have seen people hook panels with clips to bat without controller,seems to me if you did not need a controller they would not sell them!
I also read about one weak bat taking charge causing good bat to overheat/charge which would damage it,seems reasonable.
I use 12 volt rv/marine deep charge (costco)and their is no doubt in my mind that the bat will work just fine until the warranty runs out! (just replaced 2nd bat a couple of months back dead cell 3 months after warranty ended!)
Your needs might be different but the above works for me.
Drive slow and enjoy "its the journey"
Les,Lqhikers

 

[lqhikers]

Forgot to also say that if i forget to open switch witch ties both batt. together and drive with system tied together nothing happens to system.
Les,Lqhikers

 

[Scootr74]

I wasn't too clear...

The solar panel is connected using a controller.

I'm thinking that the way I everythnig hooked up is good. I have confirmed charging with either the alternator or the solar panel to the camper battery.

Just a thought, but if I were to turn "on" the truck system without running the tricks charging system - I think I could charge the truck battery using the solar as well as the camper battery...

Just my limited knowledge of electricity, but current flows both ways - no? So if the trucksystem was switheced on but not running the loop between the truck and the camper would be open and the solar charging would then take over....

Oh, I don't have one of the super duper battery isolators, just a thermal circuit breaker and a 12V isolator (looks like a solenoid with "in", "out" and "switched on" posts.

Seems to me I'm thinking correct - as lokng as the "swithced on" post doesn't draw more than the 12-14V the solar panel is putting out it should work.

 

[lqhikers]

More solar thoughts

Scootr74,I think that when you are running your truck and the alt.is charging your system the solar controller reads that the batt. are fully charged so you would not get any charge from solar. system while driving.
When you are stopped and the two batt. are tied together you will get a charge from the solar to both batt. If your switch is engaged,from reading your last post it sounds to me like your two batt. are tied together with a solenoid that is closed when your engine is running but opens when engine is off,if so your truck batt. would not charge.
I have two solar panels and have charged both batt at he same time.(had a elect trolling motor) so would hook boat batt up when not fishing.
You cant beat solar for long term camping!
Drive slow and enjoy "its the journey"
Les,Lqhikers

 

[pvstoy]

On Stan’s link for the controller (see below):

Sounds like nothing is needed with this set up with the Schotkey Diode and Float Voltage. When you run the engine the alternator goes higher than the shut off voltage and the diode prevents power to the panel.

I’m thinking more and more to do a retrofit with a panel or two and a controller. One could re-wire with a switch to charge any battery from the panels while camping.

My Blue Tops are pushing 11 years old and have served me well, but I worry that they are on the way out. (picture: camper battery on left, truck battery on right)

Maybe time to re-do the system???

INSTALLATION MANUAL
VERSION v2.2 10/07
MODEL BZ 240 PWM CHARGE CONTROLLER

********************

DESCRIPTION: The BZ 240 PWM charge controller is a high efficiency, 12 volt only, shunt type charge controller capable of charge currents of 14 amps. Features include a low loss Schotkey diode to prevent night time battery discharge, three LED battery gage, easily adjusted float voltage, MOV lightning
protection, battery voltage temperature compensation, easy installation, powder coated finish and five year limited warranty. The BZ 240 may be flush or surface mounted. Made in USA

***************
OPERATION: Operation of the BZ 240 is fully automatic. When the battery voltage is lower than the float voltage, full solar charge current is applied to the battery. When the battery voltage equals the float voltage the BZ 240’s PWM circuitry activates and maintains the float voltage. During PWM operation
battery charge current will diminish. DURING OPERATION THE BZ 240 MAY FEEL WARM.
Three LED’s indicated relative battery charge. The Green LED indicates full battery charge, yellow LED indicates about 2/3 charge and the red LED indicates about 1/3 charge remaining. When the red LED lights reduce power usage or stop using power until the batteries are recharged. When no LED’s are lit the battery is fully discharged. To avoid damaging the battery, do not discharge the battery completely.

THE BZ 240 FLOAT VOLTAGE IS CALIBRATED TO 14.1 VOLTS.
NO ADJUSTMENT IS NEEDED WHEN USING WET LEAD ACID BATTERIES.
FLOAT VOLTAGE CALIBRATION:
Battery float voltage is the voltage that the BZ 240 allows the
battery to charge up to and not exceed. Battery float voltage is pre-calibrated to 14. 1 volts. In most installations the float voltage needs no adjustment. Check battery manufactures recommendations for proper charge voltage.
Do not attempt to adjust the float voltage on cloudy or overcast days. To properly adjust the battery float voltage a Digital Volt Meter is required. Disconnect the battery from the BZ 240. Locate the float voltage
adjustment control, see wiring diagram. Connect the Digital Volt Meter to the BATT+ and BATT - terminals of the BZ 240. Adjust the float voltage control, turning the float voltage control clock wise to increases the float voltage and counter clockwise to lower the float voltage, until the required float voltage
is displayed on the Digital Volt Meter. Disconnect the Digital Volt Meter from the BZ 240 and reconnect the battery. Observe proper polarity when connecting the battery to the BZ 240.

 

[Jack]

As pointed out by others the charge controller is the key item. It isolates the solar panel when the alternator is providing more power (voltage) and connects it to the battery when the alternator is off or sourcing a lower voltage. Any of the better (read MPPT or Maximum Power Point Tracking) charge controllers should work fine as long as the their amp rating is equal to or better than the maximum that can be sourced by the PV panel. Be sure to include the fuses on both legs as shown in pvstoy's post. Size them for the max rating of your charge controller. If your charge controller max current is 10A, then choose 10A fuses, but be sure that the PC panel sources less than 10A. If not, get a higher capacity charge controller and bigger fuses.

PV panels are rated for a nominal 12V, but actually produce a voltage that can vary from 18V to 0V, depending on the sunlight. It is the task of the MPPT charge controller to optimize power by outputting a voltage of about 14V and as much current as can be obtained for the given sunlight. Because of the optimization, you can generally get more power from a smaller PV panel when you have less than optimal sunlight (which is most of the time). About 14V is the optimal charging voltage of your battery and virtually all 12V appliances are quite happy with 14V. As an aside, your house voltage can be as low as 110V or as high as 125V, depending on you power company, how far you are from the transformer and how much current you are drawing - but your appliances don't care.

The FWC charge controller is a PWM - a pulse width modulated charge controller (which is not a bad choice), but the MPPT controllers can provide up to 30% more power at less than optimal sunlight. PWM controllers just keep the voltage at about 14V. What this means is that the FWC 80W PV panel looks like a 50W panel in the afternoon while an 80W panel with an MPPT controller looks like a 70W PV panel. Given the cost difference of about $25 between the two types of controllers (at 10A to 15A), and about $80 between a 65W and an 85W Kyocera panel (which I believe FWC supplies - a good choice), the MPPT type charge controller is clearly the way to go. (Are you listening, Stan.)

FWIW, Moringstar makes a series of low cost, low amperage MPPT controllers. These can be ganged together if you add a second PV panel.

 

[Scootr74]

Well, the test - is next weekend

Going to Dumont Thursday night through Sunday. I'll run the batteries the whole weekend along with the solar charger. Afterwards I plan on leaving the fridge on for at least a week - I'd like to know how long I can go comfortably without running the truck to charge the batteries.

1st time to Dumont and 1st trip with the camper. Pretty excited - just need to pick up a chair or two for the campsite and I'll be set.

 

[LAWNMOWERMAN]

I just got back from a 2 week trip to Colorado+Utah and ran my fridge on propane for the entire trip.I had to turn the burner down on cold nights to keep it from freezing the contents but other than that it worked perfect.I probably used a 1/4 tank of propane for the entire trip.

 

[pvstoy]

Going to Dumont Thursday night through Sunday. I'll run the batteries the whole weekend along with the solar charger. Afterwards I plan on leaving the fridge on for at least a week - I'd like to know how long I can go comfortably without running the truck to charge the batteries.

1st time to Dumont and 1st trip with the camper. Pretty excited - just need to pick up a chair or two for the campsite and I'll be set.

That is a huge battery drain and it won't go long. Watch the drop in the battery to not over drain it and cause damage impact for the battery life. I have not used the refg on battery for tha past two years. I use the propane all the time except when getting it going it's on 110ac.

 

[Stan@FourWheel]

Hey Scootr

I didn't see any refrigerator vents in the outside of your camper in the pictures ??

Do you have an "ice box" ??

Or maybe the older 2-way type refrigerator that only runs off of AC & DC, NO propane ?

See any labels or stickers on the front of it ?

Most of the time the refrigerators suck quite a bit of juice from the battery if they are running off of 12v power only. You might want to play around with it before the big trip and see what you find out. You probably don't want to get there and have warm food and a dead battery to start your trip off.


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Going to Dumont Thursday night through Sunday. I'll run the batteries the whole weekend along with the solar charger. Afterwards I plan on leaving the fridge on for at least a week - I'd like to know how long I can go comfortably without running the truck to charge the batteries.








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[pvstoy]

My Dometic Refrigerator 3-way (see attached) draws ~ 9.5 amps to run it on dc....that will suck you dry in a hurry.

 

[Scootr74]

Running an Engle Fridge

I only have an Engle. The P/O removed the original icebox for storage and was using a regular cooler. I was lucky enough to come into a gently used Engle MT45 for $500 so I grabbed it.

I know it will run constantly on the #2 setting for at least 3-1/2 days. The solar panel took 1-1/2 days after that to indicate a full charge was back (but I must admit I wasn't checking too regularly after I turned off the fridge so it may have been charged sooner.

 

[mtn-high]

It won't run long before draining the battery to near empty...

I found out how quickly..though we lucked out and had no lasting problems in the end.

We were on the road and everyone was hungry. Saw a biker kinda bar/brewpub and figured they'd have good food and fairly quick service so we pulled in. I'd been running the fridge on the 12 v truck system while on the road and the gauge in the FWC said it was fully charged...so I left it on 12V and we went in to eat. I mean...how much could it draw in a 1/2 hour/45 mins?

2 HOURS later..after they'd lost our order and we'd waited forever...we were back in the truck. It was starting to rain and I knew there was a Forest Service road ahead where we could find a spot so we just fired the truck up and left.

Got to the campsite...and when I opened the rear door I could hear a clicking sound. The battery meter was nearly bottomed out...even though we'd been in the truck a good 1/2 hour or more it didn't seem like we had much charge. I followed the clicking....took out a few screws here/there...and it found was a (well-buried) elec relay of some sort.

Out in the boonies...too late to do anything or figure it out...I put all the screws back in and we hoped for the best. I let the truck idle for a good hour before bed to try to charge the battery as much as possible...even so the gauge never moved.

No problems arose...fortunately....and after a 6 hour drive home the clicking had stopped and the battery was again fully charged.

Live and learn. Was a GOOD lesson w/no real damage done..but it felt like we were on the brink for a bit there...

I'll use the propane from here on out!

good luck with the experiment.

mtn

 

[pvstoy]

I only have an Engle. The P/O removed the original icebox for storage and was using a regular cooler. I was lucky enough to come into a gently used Engle MT45 for $500 so I grabbed it.

I know it will run constantly on the #2 setting for at least 3-1/2 days. The solar panel took 1-1/2 days after that to indicate a full charge was back (but I must admit I wasn't checking too regularly after I turned off the fridge so it may have been charged sooner.

Thanks....that makes a big difference over a 3-way model. It would be good to know if the pannel will keep up with the low draw on your Engle, IF you can get some full sun to top off the battery. Test it and report back, and how long a Engle can run without any charge to the battery. (of course charge and battery type the results will vary)