what the heck???

[rbryan4]

Originally Posted by Brian B-P

As long as the Escape's battery disconnect switch is on, there is a path from the solar panel through the solar charge controller to the distribution panel and the various DC loads. Since the fan etc. work, that switch must be on (or the solar output is wired to the load side of the switch, rather than the battery side).

The battery has been removed; I didn't see any comment on the switch position.

Ok that makes sense. I'd assume the battery isolator switch was left on.

[Jim Bennett]

Originally Posted by goalie39

If there are any capacitors in the system, they can hold charge for quite awhile -- so best to assume there is always some potential for a shock.

I have never heard of capacitors in solar panels before. What is the purpose of them?

[Viajante]

Originally Posted by Brian B-P

As long as the Escape's battery disconnect switch is on, there is a path from the solar panel through the solar charge controller to the distribution panel and the various DC loads. Since the fan etc. work, that switch must be on (or the solar output is wired to the load side of the switch, rather than the battery side).

The battery has been removed; I didn't see any comment on the switch position.

There is a path if the solar cables are still connected to the battery cable lugs after the battery is removed. I don't know if ETI makes the cable connection permanent. Otherwise separate the cables.

[J Mac]

Originally Posted by Brian B-P

As long as the Escape's battery disconnect switch is on, there is a path from the solar panel through the solar charge controller to the distribution panel and the various DC loads. Since the fan etc. work, that switch must be on (or the solar output is wired to the load side of the switch, rather than the battery side).

The battery has been removed; I didn't see any comment on the switch position.

When Escape installed the second battery, under the bed in the cabin, they installed a battery disconnect switch for that battery only (I believe), (with the thought being that it was such a PITA to disconnect otherwise). The battery on the bumper was easily accessible so it didn't need one. I removed the under the bed battery due to the PITA factor so I am assuming that the disconnect switch is not in use. Am I wrong? Later today I'll drive out to the storage facility to double check.

[ReagentGrade]

Originally Posted by J Mac

I just parked my rig at a storage facility. I removed the single, 12 volt battery on my my Escape 17, so I could keep it on a 'trickle charge' at home, because I won't be using my trailer for an unknown period of time. When I gave the interior a "one last look over before I lock the door" I noticed that the solar panel's read out, on the wall above the sink, read that a charge was present. The roof top panel was receiving full sun and there was 3+ amps coming in. I turned on the fan and it worked, led lights worked too. BUT there was no battery on board!!!

What the heck

J Mac, what kind of solar charger controller do you have?


Jim B has an MPPT solar charge controller. From what little I know of these, it may be able to provide relatively clean/continuous 12v.

Would a PWM charger controller do the same, especially with no battery? Doesn't a PWM clip the power coming in if it exceeds 14v or so and interrupt the power as the battery reaches a full charge? Clipping might not be a problem, but if it interrupts the power, that might be a real problem.

I'm not an expert on this stuff, do I have this all wrong?

Rich

[J Mac]

Originally Posted by ReagentGrade

J Mac, what kind of solar charger controller do you have?


Jim B has an MPPT solar charge controller. From what little I know of these, it may be able to provide relatively clean/continuous 12v.

Would a PWM charger controller do the same, especially with no battery? Doesn't a PWM clip the power coming in if it exceeds 14v or so and interrupt the power as the battery reaches a full charge? Clipping might not be a problem, but if it interrupts the power, that might be a real problem.

I'm not an expert on this stuff, do I have this all wrong?

Rich

Hi Rich, I have the Go Power, Escape installed, panel and charger/controller.
I just returned fro the storage facility and the Go Power panel on the wall is blank so I believe all is well.

[J Mac]

Okay. I don't have a battery cut off switch so...When re-installing the battery, the procedure should be:
1) Cover the solar panel completely, then...
2) Should I attach the positive terminal to the battery first or the negative terminal to the battery first.

[War Eagle]

Originally Posted by J Mac

Okay. I don't have a battery cut off switch so...When re-installing the battery, the procedure should be:
1) Cover the solar panel completely, then...
2) Should I attach the positive terminal to the battery first or the negative terminal to the battery first.

When re-attaching the battery cables, attach positive first, negative last.
The old rule when working on anything with a metal frame is the negative cable is always first off, last on. As someone alluded to above, when the negative cable is attached, essentially the entire metal framework of a vehicle is connected to the negative post. If so, when then connecting the cable to the positive post, while one end of your wrench is touching the positive cable connection, if any other part of your wrench touches metal, there will be an electrical arc. If you connect the positive cable first, the vehicle frame is still isolated from the battery, so no arc. And then when you connect the negative cable, there is no need to worry what your wrench touches (negative to negative) - other than the positive post! With all that said, I wouldn't hesitate to break the rule in our 2017 21' because there is nothing but non-conductive wood, plastic, putty and fiberglass surrounding our battery. No metal to arc to or from - other than avoiding arcing between the two battery terminals. But with that said, it's still a good practice to follow the automotive rule: negative cable is first to take off and last to put back on.

[J Mac]

Originally Posted by War Eagle

Attach positive first. Negative is always first off, last on.

Thanks War Eagle!!

[Brian B-P]

Originally Posted by J Mac

When Escape installed the second battery, under the bed in the cabin, they installed a battery disconnect switch for that battery only (I believe), (with the thought being that it was such a PITA to disconnect otherwise). The battery on the bumper was easily accessible so it didn't need one. I removed the under the bed battery due to the PITA factor so I am assuming that the disconnect switch is not in use. Am I wrong? Later today I'll drive out to the storage facility to double check.

You'll see when you check, but it appears that either:

1. the solar charge controller output connects between the outside battery and distribution (fuse) box, so the solar panels can still power the trailer without a battery, or
2. the solar charge controller output connects at the location of the inside battery so solar power must go through the disconnect switch to the distribution (fuse) box, but the switch is 'on' so the solar panels can still power the trailer without a battery.

[Brian B-P]

Originally Posted by Jim Bennett

I have never heard of capacitors in solar panels before. What is the purpose of them?

The mention of capacitors was presumably in reference to capacitors in the controller, not the panels. In the controller, capacitors smooth out power delivery (in their simplest application).

As a result, although the breakers as disconnects are a great idea for safety, they still leave energy stored in the controller as a potential hazard.
Bonus points for electrical types who caught the pun.

[Brian B-P]

Originally Posted by ReagentGrade

Jim B has an MPPT solar charge controller. From what little I know of these, it may be able to provide relatively clean/continuous 12v.

Would a PWM charger controller do the same, especially with no battery? Doesn't a PWM clip the power coming in if it exceeds 14v or so and interrupt the power as the battery reaches a full charge? Clipping might not be a problem, but if it interrupts the power, that might be a real problem.

The output of PWM and MPPT controllers is similar. Both involve "chopping" the power flow rapidly. PWM is pulse width modulation, meaning that the power is turned on and off rapidly, and the flow is controlled by changing how long it stays on each time (the width of each 'on' pulse is modulated). The capacitors mentioned earlier smooth out power flow, so it isn't as bad as that chopping sounds.

An MPPT controller is a PWM controller, too, but it adds the feature of Tracking the Maximum Power Point of of the panels; it boosts or drops voltage (trading voltage against current) to get the panel to operate at its optimal voltage for the sun conditions, regardless of the battery voltage.

All controllers stop charging when the battery voltage gets high enough. A crude on-off controller (not used by Escape) just goes from fully turned on to fully turned off at a set voltage (and back on to restart charging at a much lower voltage); the ubiquitous SunForce 7 amp model clicks off at 14.2 V, and back on at 13 V. A PWM controller (offered by Escape) makes the process much more smooth, "throttling" the power to maintain target voltages though the charging cycle, and never turning completely off. An MPPT controller (not offered by Escape) manages voltage at the battery the same way as a regular PWM controller; the only difference apparent at the battery should be higher charging current during the first stage of charging.

[ReagentGrade]

Thanks Brian, this is a nice summary and fills in some gaps in my understanding.