how to properly hook up power in pop-up camper battery

pods8

Explorer
Is using the car charging method while driving home enough to maintain the health of an AGM?

Would depend on how well its charging, how long you are driving verse how depleted it was and then how long you'll be sitting (batteries self discharge as well). However shore power chargers aren't very costly so in my mind its just a good idea to have one and easy to plug it in after a trip for a day to make sure everything is 100% topped off, also plug in periodically if sitting for a long time, and also I like to plug in while prepping the camper for a trip so the lights/fridge/etc. that might be running aren't depleting things. You don't need a high amp charger/convertor when time is on your side (ie plugged in at home verse trying to dump in a bunch of amps while a generator is running). I've just got a basic 6amp stage charge hooked up to my 210amp battery bank on my current camper to plug in at home, may take a little bit longer than bigger chargers but regardless its full the next day...
 

dags

Adventurer
I will be storing the camper at a public storage unit, no choice as the camper won't fit in the garage.

I'm thinking each time i drive back will be a minimum of 1.5 hrs driving and then leave the camper for 2 weeks with no charging.
 

dwh

Tail-End Charlie
Depending on how far down the battery is, 1.5 hours almost certainly won't be enough to get it fully charged.
 

pods8

Explorer
I will be storing the camper at a public storage unit, no choice as the camper won't fit in the garage.

I'm thinking each time i drive back will be a minimum of 1.5 hrs driving and then leave the camper for 2 weeks with no charging.

Outdoors? If so a small solar panel might be wise.
 

dags

Adventurer
I had a feeling i was heading towards solar


Solar is darn confusing - anyone have a kit recommendation, if i'm going to do it i might as well get an 80w unit
 

Pest

Adventurer
I had a feeling i was heading towards solar


Solar is darn confusing - anyone have a kit recommendation, if i'm going to do it i might as well get an 80w unit


We got our pieces from amsolar.com. Not the cheapest prices, but idiot proof instructions for installing everything, and the components are excellent quality. No problems at all with our 150 watt panel and maximum power point tracking charge controller.
 

pods8

Explorer
There were some really low priced panels on solarblvd for a number of months, nothing at the moment. Can check back in from time to time, they had panels in the 60-130watt range for $1.35+ a watt which is rather low.
 

dags

Adventurer
Maybe i should start a thread on solar, but one thing i don't understand is can you have the solar attached plus have shore power and the hookup to the car alternator power?
 

Pest

Adventurer
Maybe i should start a thread on solar, but one thing i don't understand is can you have the solar attached plus have shore power and the hookup to the car alternator power?

Yes, as long as the solar charge controller is either 1) turned off when connected to shore power or 2) has a "shore power" charge mode, like ours, which just decreases the peak output voltage of the unit to be at or below the shore power charge controller. Otherwise the solar charge controller can raise the charging voltage higher than the shore power charge controller and potentially back feed the shore power charge controller.

Having the solar on while the vehicle is running creates no problems if connected via the trailer plug, it will prevent back feed.
 

dwh

Tail-End Charlie
Yes, as long as the solar charge controller is either 1) turned off when connected to shore power or 2) has a "shore power" charge mode, like ours, which just decreases the peak output voltage of the unit to be at or below the shore power charge controller. Otherwise the solar charge controller can raise the charging voltage higher than the shore power charge controller and potentially back feed the shore power charge controller.

Having the solar on while the vehicle is running creates no problems if connected via the trailer plug, it will prevent back feed.

Wait...what?

I'm sorry, but this makes no sense to me.

What solar charge controller do you have? I've don't think I've ever heard of one that has a "shore power charge mode".


One of the purposes of a solar charge controller, is to PREVENT backfeed from the battery to the solar panel when the sun is down (otherwise, the solar panel becomes a heating element and consumes the stored power from the battery).
In other words, no worries about "backfeed" IN to the solar charge controller from the battery side.
The solar charge controller doesn't accept a backfeed.

As for a solar charge controller feeding power into the 12v bus at a higher voltage than the mains powered battery charger and overpowering (backfeeding) the mains powered battery charger - where is the power going to backfeed TO?
The electrical grid? That won't happen.

So what if the solar charge controller raises the voltage on the 12v bus? It won't matter. What if the battery was at 14.4v and the solar charge controller is disconnected and then you hook up a mains powered charger to the battery? Wouldn't the BATTERY backfeed the mains charger - even without the solar charge controller connected?

No, because the mains powered charger doesn't accept a backfeed. If the voltage on the 12v side is higher than what the mains powered charger can overcome, then it won't be pushing any power into the 12v bus, but it won't be accepting a backfeed and converting it into 120v either.


A device designed to hook up to a battery and charge it, isn't going to allow itself to be overpowered from the battery side. At least, it shouldn't. Not by any voltage in the normal "12v nominal" range anyway.


And a trailer plug has got nothing to do with anything, except for hopefully being controlled by a relay so it's disconnected when the key is off, so the engine battery doesn't get drained along with the aux battery.
 

SChandler

Adventurer
There were some really low priced panels on solarblvd for a number of months, nothing at the moment. Can check back in from time to time, they had panels in the 60-130watt range for $1.35+ a watt which is rather low.

I doubt that prices will be that low again for a while: http://www.oregonlive.com/business/index.ssf/2012/05/solarworld_tariffs_china.html. Without getting into the politics of the situation, the Chinese panels won't be nearly as cheap as they were a month ago.
 

dwh

Tail-End Charlie
I doubt that prices will be that low again for a while: http://www.oregonlive.com/business/index.ssf/2012/05/solarworld_tariffs_china.html. Without getting into the politics of the situation, the Chinese panels won't be nearly as cheap as they were a month ago.

The other problem, is that the Solar Cynergy panels were made with solar cells from the German company Q-cells - which went bankrupt a few weeks ago.

http://www.businessweek.com/news/2012-04-03/q-cells-files-for-insolvency-as-solar-bankrupcties-rise


<off-topic, illegal, against the rules political rant follows - please ignore>
(Personally, I'm a big fan of trade protectionism. If we could get enough of it, we might actually be able to force the corporate gangsters to bring the jobs back to the U.S. instead of farming them all out so they can get away with paying some poor Chinese guy a dollar per hour. Then maybe the .gov wouldn't have to lie about the "Unemployment Rate" which only counts those currently receiving unemployment benefits - and ignores all those whose benefits have already run out but still don't have jobs.

Nah...they'd just find something else to lie about...)
<end off-topic, illegal, against the rules political rant (rules are meant to be broken :D )>
 

Pest

Adventurer
Wait...what?

I'm sorry, but this makes no sense to me.

What solar charge controller do you have? I've don't think I've ever heard of one that has a "shore power charge mode".

HPV-22B, bought from AM-solar.com. If you will look on the right side of the picture below, you'll see a shore power selection.

MPPT.jpg

One of the purposes of a solar charge controller, is to PREVENT backfeed from the battery to the solar panel when the sun is down (otherwise, the solar panel becomes a heating element and consumes the stored power from the battery).
In other words, no worries about "backfeed" IN to the solar charge controller from the battery side.
The solar charge controller doesn't accept a backfeed.

Right, when did I dispute this fact?

As for a solar charge controller feeding power into the 12v bus at a higher voltage than the mains powered battery charger and overpowering (backfeeding) the mains powered battery charger - where is the power going to backfeed TO?
The electrical grid? That won't happen.

Correct, it would not feed the electrical grid. I said it could POTENTIALLY backfeed the mains charger. Not meaning that power would flow anywhere, but that it could damage the mains charger. Depending on the design of the charger (ie. the circuit protection features), this could happen.

Let's say that the mains charger is a full wave rectifier. If the battery voltage is significantly raised above the output voltage of the mains charger, it could be possible that one of the rectifying diodes becomes forward biased when it would otherwise not be, thus creating a short in the rectifying circuit and causing damage.

So what if the solar charge controller raises the voltage on the 12v bus? It won't matter. What if the battery was at 14.4v and the solar charge controller is disconnected and then you hook up a mains powered charger to the battery? Wouldn't the BATTERY backfeed the mains charger - even without the solar charge controller connected?

No, because the mains powered charger doesn't accept a backfeed. If the voltage on the 12v side is higher than what the mains powered charger can overcome, then it won't be pushing any power into the 12v bus, but it won't be accepting a backfeed and converting it into 120v either.


A device designed to hook up to a battery and charge it, isn't going to allow itself to be overpowered from the battery side. At least, it shouldn't. Not by any voltage in the normal "12v nominal" range anyway.

Right, 14.4V from a battery is not quite the 17V or so that a panel or a solar charge controller could potentially output. As I stated above, if the protection circuitry is not sufficient enough in the mains charger, 17V could POTENTIALLY cause a problem.

And a trailer plug has got nothing to do with anything, except for hopefully being controlled by a relay so it's disconnected when the key is off, so the engine battery doesn't get drained along with the aux battery.

I'm not sure why you are arguing this? He had asked if having the solar on while the vehicle was running would be a problem. I had simply stated that there would not be a problem...?
 

dwh

Tail-End Charlie
HPV-22B, bought from AM-solar.com. If you will look on the right side of the picture below, you'll see a shore power selection.

View attachment 102430

Oh yea. Forgot about those. Don't think AM makes or sells those anymore. That switch to drop the float voltage from 14.4v to 13.2v isn't used on modern multi-stage chargers that drop to float automatically.



Right, 14.4V from a battery is not quite the 17V or so that a panel or a solar charge controller could potentially output. As I stated above, if the protection circuitry is not sufficient enough in the mains charger, 17V could POTENTIALLY cause a problem.

Okay, but the solar charge controller will never raise the voltage on the battery side to 17v anyway. Unless it's broken, and then all bets are off.


I'm not sure why you are arguing this? He had asked if having the solar on while the vehicle was running would be a problem. I had simply stated that there would not be a problem...?

Oh. I thought you said the trailer plug would prevent backfeed.
 

Pest

Adventurer
Okay, but the solar charge controller will never raise the voltage on the battery side to 17v anyway. Unless it's broken, and then all bets are off.

Didn't say it was likely, but you never know how things can operate when you start using cheap china electronics, solar or shore charger. :p
 

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