The fan slows down...

[PhotoPete]

Cooking dinner the other night with that kitchen hood fan running. I noticed that every time I turned on a 12 volt light in the camper the fan speed was affected. I've seen it before over the years, but never really bothered with it.Is there anything I can do to the power system to make it so that does not happen? Like can I upgrade to a different converter or some such thing? For what it's worth I was connected to shore power at the time, still am as a matter of fact. I must have too much time on my hands!Just curious if there is a solution or not.Photopete

Ps. I just discovered that not all lights affect it. Must be a light that's on the same circuit. So how do I make more circuits within a fixed panel?

 

[JohnDar]

Strange. I just tried running my stove fan and then turning on the kitchen, living room, and side counter lights. No change in fan speed. To add it to a new circuit, you would first have to isolate it from the one it's on and then run wire for it over to the fuse panel and hook up to an empty fuse holder.

 

[irvin56]

mine has always done it. I just fiquered that was the way it is. It seems like it is running off the 12 volt side and not enough battery power??

 

[pegmikef]

To add it to a new circuit, you would first have to isolate it from the one it's on and then run wire for it over to the fuse panel and hook up to an empty fuse holder.

Yeah, I just added a 12 volt outlet. I found that there was a blank circuit on the fuse panel and used it. I almost missed it, but I noticed that there was one more fuse than labels. They had fused the unused circuit too and somewhere on another thread I read that several different rigs have one or more blank circuits.

 

[RuralPastor]

Cooking dinner the other night with that kitchen hood fan running. I noticed that every time I turned on a 12 volt light in the camper the fan speed was affected. I've seen it before over the years, but never really bothered with it.Is there anything I can do to the power system to make it so that does not happen? Like can I upgrade to a different converter or some such thing? For what it's worth I was connected to shore power at the time, still am as a matter of fact. I must have too much time on my hands!Just curious if there is a solution or not.Photopete

Ps. I just discovered that not all lights affect it. Must be a light that's on the same circuit. So how do I make more circuits within a fixed panel?

Pete, if you really want to know the answer, keep reading...
Technically, your fan slowed down because your voltage dropped. This could occur for several different reasons:
1. Wire size is not sufficient to carry amperage to both fan and light, thereby dropping voltage (I doubt this is the cause).
2. Battery is weak and not able to support additional load without dropping voltage (could be).
3. Converter is "free running" during light loads (12.8--13.7 volt), and then the additional light brings the battery voltage back to 12 VDC +/- because the converter cannot handle the amperage of both (not necessarily a bad thing, unless you're continually running electric stuff). This actually would mean that your fan is running too fast (when the light is off) and then runs normally (when the light is on). OK, now that I've totally confused the situation...here's something you could do:

Turn everything off and measure the voltage at either your battery or your fuse panel (should be 12.8--13-7 VDC)
Turn the fan on (and nothing else)and measure the voltage at the fuse panel with a volt meter. (will probably drop to 12 and then rise a bit: this is a key test)
Turn the light on (with the fan running) and measure the voltage with your meter (I'm guessing the voltage will drop and hold around 11.8-12.1)

If you do this, record the readings and post them here. It would give me a clearer idea of the problem. If not...just enjoy the sound of a quiet fan!

Mark

 

[JohnDar]

Just a bit of additional information. The only time I see any change in my 12V lighting is when the converter goes into BOOST mode. Then the lights brighten a tad. When it's done, they return to the original brightness. It normally does that if we have several 12V lights on. Most times, we use a small 120V table lamp at night instead of the 12V's, just for the ambience. I have the Charge Wizard pendant indicator on mine and can tell at a glance that it's gone to BOOST mode. First time it did that was a WTF moment until I looked it up.

 

[PhotoPete]

Mark, I ran the test, got 13.7 all three times. Shore power is plugged in. What am I doing wrong?

 

[RuralPastor]

Pete, sorry for the delay, I just checked back this morning. Hmmm (scratching my head)....I'm leaning towards a weak battery. Let me ask another question: When the light is turned on and the fan slows down, does the fan pick up it's speed after a moment, or does it continue to run slow? Here's why I ask: It would be considered normal to have the fan decrease speed for a second, and then pick up again when the light is turned on. One other thing you could try: turn on all your 12 volt appliances (as much as possible), stay plugged in to your shore power, and check voltage. If the battery is bad, I'd be looking for a steady decrease in voltage on the volt ohm meter.

Here's what could be wrong:
1. Battery is weak, and not able to pick up intensity of loads.
2. Bad/weak connection anywhere on that circuit (check connection at fan/switch/lights, etc.)

It still puzzles me that you're getting 13.7 when the fan is running with the light (provided it's still running slow then). However, this does tell me that your converter/charging circuit is putting out the voltage to charge your battery. Stay with me on this, I believe we can work through it. You got me curious now!

Good luck Pete.

 

[BorgX]

I just did some learning this weekend which I bet is the cause...

Just above the range hood there are 3 wires that are joined together. Main feed, the vent hood, and then the main wire goes on to feed the over sink light and the main cabin lights as well as outside light. Way too much on one circuit! Shocking actually... I would expect that the fan slows down when you turn the MAIN cabin lights on (at least that is the case on my 21FBS). The fan is the first thing on the circuit. I would suspect running a single wire off of another circuit directly to the fan would correct the issue...