Explain shore power vs battery

bearcat77 · 03-27-2017, 01:36 PM

So here's the short version of my current situation: We thought we were plugged in at home, but maybe not due to a 30 amp adapter that didn't want to sit right in my weatherproof outlet cover. So possibly haven't charged the battery since December. The battery has been inside all winter, but we'd hook it up occasionally to show off the new trailer to friends and family. So possibly we've completely drained the battery, because today, the slideout went out, but only came back in a couple feet then stopped.

I addressed the weatherproof cover issue, so hopefully now I have a good connection. Tested the outlet and trailer power cord and both show hot. After a few hours of charging, I've only gotten the slide in a few more feet though.

So my questions are:
When hooked to shorepower, do you still need a full battery to run everything? I thought shore power would bypass battery, but maybe not.

Does it take forever to charge these batteries? Again I thought I would immediately be able to run the slide with shore power, but here I am a few hours later, getting just a trickle of power.

Does this mean my battery is done? I know I can run it up somewhere and get tested, just wondering if I should consider this battery "trustworthy" still. It's brand new otherwise.

I guess I should add the trailer is plugged into a regular household outlet with the use of that 30 amp converter.

Thanks for the help.

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sennister · 03-27-2017, 01:50 PM

Shore power will trickle charge the battery. It isn't like it is applying a big battery charger on boost. If fully depleted it might take a day or two to charge it back up.

Even if you are plugged in, keep in mind that the 12V is what powers the slide not 110V so you are dependent on the battery.

Happy battery, happy camper.

bansai · 03-27-2017, 01:53 PM

Do you have a voltage meter?

When on shore power, as long as you don't have a blown fuse somewhere, you should see at least 13 volts on your battery. Anything lower and you may have a blown fuse.

You can pick up a cheap one for less than 20 bucks. I think it's a totally required item for your camper's tool kit. If your battery is not getting charging current while plugged in, you can use that same meter to troubleshoot where the issue is.

I use a 'regular' household outlet all the time to plug in my camper, shouldn't have any problems there unless you are trying to run all of your 120 volt stuff off of that circuit.

When you are plugged in, *everything* should work, even if your battery is at a fairly low state of charge. I think you really need to put a voltage meter on your battery so you know whats going on with it while plugged in, and when it isn't.

Guessing you have a blown fuse somewhere that is preventing you from discharging from your battery. This is a pretty common issue.

Edit - after re-reading your post a second time, the fact that your slide out worked at all is a good sign, but the fact that it isn't working at all now, is a bad one. You should never let your battery get below 12 volts. Impossible to know how bad it was damaged if you dropped it much below that point. It can realistically take a couple of days to recharge it with the converter. During the off season, consider investing in a battery tender trickle charger and keep it on your battery over the winter. These things are too expensive to not maintain.

bearcat77 · 03-27-2017, 02:07 PM

Is there a fuse before the battery somewhere that I should hunt for? I think fuses after the battery are ok, because we were in there all day Saturday playing with everything and testing everything. And the slide went out fine today, although it sounded a little weak, and then coming back, it tries, but it acts like you would expect a near dead battery operated device to act.

I did buy a voltmeter, expecting to need it someday. Didn't expect it this soon though. I'll dig that out and start reading the manual.

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oldmanAZ · 03-27-2017, 02:08 PM

Buy something like this...
Robot Check

to plug into your trailer's 12v power port/cigarette lighter port. It will show your 12v system voltage. It should show ~13.6v to 13.9v when charging.

My trailer's converter doesn't supply really good current flow when charging. If yours is like mine, it may take a day or more to fully recharge your battery.

If your battery was completely discharged, it may be damaged and have to be replaced.

dalebra · 03-27-2017, 02:10 PM

You don't need a battery even hooked up to run the slides in and out. You have something else going on. Maybe a faulty "Power Center" the box that has the fuses for 12V circuits and circuit breakers for 120Vac circuits. The power center converts 120vac to the 12vdc bus which runs your slides and lights. Turn some lights on in the inside and then try and move a slide..... Do the lights dim to almost nothing? If so you have a power issue. If the lights don't dim then you have a slide issue.

Danno · 03-27-2017, 02:13 PM

Quote:

Originally Posted by sennister

Shore power will trickle charge the battery. It isn't like it is applying a big battery charger on boost. If fully depleted it might take a day or two to charge it back up.

Even if you are plugged in, keep in mind that the 12V is what powers the slide not 110V so you are dependent on the battery.

Happy battery, happy camper.

If I can just correct you on this;

When you are plugged into shore power, the built-in inverter will power all 12 volt accessories regardless if you have a battery hooked up or not. The slide is in fact 12 volts, but it will always be the inverter supplying 12V power to it if it is plugged into a 120 volt outlet.
If you never dry camp, then technically the only reason to have a battery is to apply the electric brakes should the trailer ever accidently become detached from the tow vehicle.

dalebra · 03-27-2017, 02:24 PM

Danno is absolutely correct.
When plugged in, no battery required!

Isaacs · 03-27-2017, 02:28 PM

Is it possible that the converter can't supply enough power to both charge a dead battery and run the slide at the same time?

bansai · 03-27-2017, 02:29 PM

Quote:

Originally Posted by dalebra

Danno is absolutely correct.
When plugged in, no battery required!

Yep, X2 on that.

What is weird is how he said the slide was working, sort of... and then isn't. Sounds like the camper didn't know it was plugged in, and was trying to pull current from the depleted battery. 90% sure he has a blown fuse / tripped breaker. The locations of these things are all so heavily dependent on the particular unit I'm at a loss on where to suggest he looks first. I'd start in the power panel where everything should be readily testable with a meter. Make sure the GFCI outlet isn't tripped (although I'm not certain if that would explain this behaviour). It sounds like the camper doesn't know it is plugged in, when it is, so that's a pretty good clue. If the battery isn't getting charging current when plugged in, that's another one. Blown fuse somewhere on the 120 side is preventing the converter from seeing his shore power.

I guess the first thing I would track down is where the 120/30amp service terminates in the converter and make sure it's live, then reset every 120 volt breaker and follow the rabbit further down the hole.

bearcat77 · 03-27-2017, 02:46 PM

Thanks to everyone for the info. Unfortunately I'm stuck at work until Wednesday, so I won't have any answers until then. Again, unless there is a fuse that controls battery charging, I don't think its that. The slide did move in small increments over the course of a couple hours, and would come to slow stop. I'm inclined to say it's looking like a power center issue. I thought we were plugged in fine, I was just grasping at straws when I said the weatherproof cover may have been causing the plug to not stay seated in the outlet. The battery really should be charged. Plus, we identified a couple other issues on Saturday. There was a fuse blown behind the radio, which I took care of, and the awning LED lights do not work, and that light switch causes all interior lights to momentarily flicker when it's flipped. All of these things worked fine during the PDI in December, and haven't been touched since. Guess we may have gotten ourselves an electrical lemon. Back to the dealer again.

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**Mustang65** · 03-27-2017, 02:55 PM

Check to see if your outlet is wired properly. also check the inside outlets
Check your battery connections at the battery... Clean... tight
Main Fuse by battery ok?

Slides should work on shore power only

For best results... when using the slides or tongue jack leave the TV hooked up and running... will save your battery

Don
My Registry

RVing with SOLAR

WyEm · 03-27-2017, 03:13 PM

Quote:

Originally Posted by Danno

If I can just correct you on this;

When you are plugged into shore power, the built-in inverter will power all 12 volt accessories regardless if you have a battery hooked up or not. The slide is in fact 12 volts, but it will always be the inverter supplying 12V power to it if it is plugged into a 120 volt outlet.
If you never dry camp, then technically the only reason to have a battery is to apply the electric brakes should the trailer ever accidently become detached from the tow vehicle.

Danno is correct in how it all works, but a "converter" converts 120v to 12v and an "inverter" converts 12v to 120v. So, your "converter" is supplying 12v to all your systems and charging the battery when you are hooked up to 120v shore power.

bearcat77 · 03-27-2017, 03:58 PM

Quick update: My awesome wife decided to play electrician and found and replaced both 40amp fuses and the slide immediately worked. So, I can definitively say the slideout works on shore power even with a dead battery. Unfortunately, the awning lights still don't work, and that switch still causes the other lights to flicker, so still gonna have to truck it up to the dealer. And then, $64,000 question, what blew the 40amp fuses? Maybe a battery cable touched metal during connect or disconnect? Maybe a power surge? We've got our surge guard on there now, so hopefully no more surges. I'll test the battery when I get a chance and see if it's salvageable.

Thanks for everyone's help.

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sennister · 03-27-2017, 08:06 PM

Quote:

Originally Posted by Danno

If I can just correct you on this;

When you are plugged into shore power, the built-in inverter will power all 12 volt accessories regardless if you have a battery hooked up or not. The slide is in fact 12 volts, but it will always be the inverter supplying 12V power to it if it is plugged into a 120 volt outlet.
If you never dry camp, then technically the only reason to have a battery is to apply the electric brakes should the trailer ever accidently become detached from the tow vehicle.

I agree with everything you mentioned but he had a battery in the loop. If the battery is severely depleted or has a bad cell, the converter will not be able to keep up with charging it along with running a high load item like a slide motor. If the battery is really dead and you can plug into shore power you are better off disconnecting the battery and then the slide will likely come in.

The problem is that the converter isn't smart enough to divert the load from charging the battery to running a slide motor. That battery if dead will act like a big sponge on the system. Which is what I was talking about. I just didn't have a lot of time to type more information.

NVGun40 · 03-28-2017, 11:37 AM

Based on what you said about the awning light switch causing all the other lights to flicker, and the issues of things not running on the "possibly" dead battery: then after reading your original post, you state that you have kept your batteries indoors and taking it out and hooked it up.

So here is something to look for which can be causing these electrical anomalies. If, when hooking up the battery one time, you accidentally started to hook it up opposite of how it should be hooked up; it is possible you blew a fuse in the converter itself. These fuse(s) in the converter are NOT located in the fuse/circuit breaker panel, but are located in the converter itself.
Usually your converter is inside behind the fuse/circuit breaker panel. You will have to remove the screws holding the panel in place in order to see the converter. There you will have to locate the fuses and check/replace them.

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bearcat77 · 03-28-2017, 12:18 PM

it is possible you blew a fuse in the converter itself. These fuse(s) in the converter are NOT located in the fuse/circuit breaker panel, but are located in the converter itself.
Usually your converter is inside behind the fuse/circuit breaker panel. You will have to remove the screws holding the panel in place in order to see the converter. There you will have to locate the fuses and check/replace them.

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That is very helpful! I will pull out the fuse panel tomorrow and see what I find. Will also get battery tested tomorrow. Thanks for the info.

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DanNJanice · 03-28-2017, 01:59 PM

It measures AC & DC apps with the clamp, no need to open the circuit. Of course it also measures all typical voltages and resistance. There are much better one available, but for occasional use these are worth their weight in gold.
Uni-T Meter

oh355mbqs · 03-28-2017, 08:20 PM

I don't have my Jayco yet, hopefully the end of this week, but I believe all campers are wired the same. You say you have taken the battery in and out several times, have you connected the wires correctly? The 12v connection colors on a camper are backwards of a car, the black is hot and the white is ground. There are a couple of fuses that blow if you hook it up wrong. Might check that.

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