Heater spikes the elect

[TRACKUM]

I turned on the heat today and it seems to create some kind of a spike evey once in a while. In this case I use the word 'spike' to mean the electricity seems to go off and on again. This happens intermittently.

I warms the motorhome just fine. Any ideas what I might check?

[Rif]

Heat pump? Gas furnace? Stand alone electric heater? 120V power or 12V power?

[Jack Mayer]

It is likely your converter cutting in and out as the furnace depletes the battery bank. If it is a 3 stage converter then it is likely sending 14.4 - 14.6 volts out, and you will see the lights brighten in that case. Not all converters operate in this fashion, but that is likely what it is.

[Kirk W]

If we assume it is the typical RV furnace, I'd then agree with Jack but if this is a 120V-ac heater then it is probably a very different matter. We need to know some specifics to address this. Are you connected to shore power? What type heater?

[oldjohnt]

Based on my experience, IF its a 12 VDC powered forced air unit,,,,,,,,,,,,,, and if your Conveter/Charger is a multi stage (voltage changes subject to battery state),,,,,,,,,,,,, and ESPECIALLY if your battery bank amp hour storage capacity is minimal (IE not much energy storage capacity, maybe only a single battery),,,,,,,,,,I AGREE WITH JACK it may be Converter/Charger voltage change/switching you're experiencing.

 

I might also suspect a poor, loose, resistive, or carboned connection somewhere in the supply voltage circuit that feeds the furnace,,,,,,,,,,,,,or a faulty carboned resistive switching relay in the furnace control system,,,,,,,,,,,,,,,

 

Is what you call a "spike" a seemingly voltage increase or decrease (lights may dim or get brighter, what I'm thinking above), OR is it more a brownout like lights flicker or seem to go off momentarily??? Do you know if this happens only when the furnaces fan starts up (a relatively brief high current experience) ?? Or is it just at random times when the fan is already running????

 

Converter/Charger or bad/resistive connection in supply circuit, or minimal battery energy capacity sure comes to mind.

 

John T

[oldjohnt]

Bill B, For sure if its say a 1500 Watt 120 VAC resistive heater, they certainly draw a fair amount of current in which case a loose or burned resistive connection (panel or receptacle or a wire nut or other splice or simply wiring terminals) can cause flickering or brief brownouts AND I CONSIDER THAT MORE DANGEROUS then if its a 12 Volt unit. A Thermal Magnetic Breaker likely wont trip in such a situation (no long term high draw or a short term surge) where perhaps an Arc Fault protector might.

 

John T

[Ray,IN]

Dennis and Carol, unless you provide answers to Rif's questions your original question cannot be answered accurately; and you have some of the best electricial help already waiting.

[TRACKUM]

This is a Suburban Gas Furnace. It is the original equipment for my

1999 Winnebago Ultimate Freedom. Let me tell the background that might shed some light on this situation.

In August my electrical problem first showed its hand when the power started going off and on again intermittently. And at that time I discovered some bad batteries so I replaced all 5 of my coach batteries with 12 volt deep cycle for a hundred bucks each. This did reduce the problem from daily power problems to occasional power problems. In September I posted this forum to see if I could get some ideas to solve my occasional power problems. Based on the advise I received I started checking connections and found a couple of places where I tightened screws and the like. This reduced my problem from occasional to rare. Things have been moving along nicely with very rare instances of the power going off and coming back on. Then the temperature dropped and I turned on the heat. After an hour the lights went dim for a moment. The power never shut off like before just seemed to stress the system, enough that the fridge shut off a few times. I'm thinking the fridge shuts down as a safety feature. We have been using the heat now for a month and every time I use it after an hour or so this power problems starts up again. Once they start the problem keeps happening over and over again every twenty minutes or so. Therefore, I shut it off for a few hours and the cycle begins again.

[Kirk W]

Can we assume that you are connected to shore power when this is happening? Have you monitored the voltage to anything inside or at the batteries themselves? My first suspicion at this point would be the batteries, if you are on shore power. If you are, try lifting one cable from the batteries to remove them from the circuit. While there, examine them closely to see if electrolyte levels are proper, any signs of corrosion on the connections, electrolyte on the battery tops, and any distortion of the battery cases.

 

Lights dimming and the refrigerator shutting down likely mean very low voltage in the 12V-dc system.

[oscarvan]

 

Lights dimming and the refrigerator shutting down likely mean very low voltage in the 12V-dc system.

 

Definitely. Get a multi meter and start monitoring the voltage. Easy way is to get a 12v plug to go in the 12v outlet. Attache a foot or so of wire to the plug (with DIFFERENT LENGTHS for the + and -) and attach the volt meter. This way you don't have to live in the battery compartment.

 

You say you have fresh batteries. One other possibility not mentioned yet is that your converter may be failing.

 

Assuming you are connected to shore power which I don't think you've confirmed yet.

[skp51443]

A decent $25 multimeter is the place to start, most big box hardware stores have decent ones if you want it right away, Amazon or the like have more selection if you are willing to wait. Look for one that does at least 10 amps, 20 is better and shows 1/100 (0.00) volts as you'll find that helpful over time.

 

Check your voltages with the converter charging and with the converter unplugged to see if the converter is working. Charging you should see something in the 13.2 to 13.8 range, more with a smart charger. When not charging it should drop some, how much depends on your loads and battery state.

 

Then lift the ground wire off the bank and check the battery voltage after 10-20 minutes to see the state of charge. It should be 12.6 or above, 12.6 is fully charged but you might see it a bit higher if the converter was charging at a high rate, give it some more time to settle or put on a small (1 amp) load for 10 minutes and see if it drops back to 12.6 or so.

[TRACKUM]

You guys are the best!

I got a multi meter and It was reading 12.5 volts everywhere. I turned on the furnace and it dropped to 11.5 to 11.9, which I thought would be ok since it draws so much power. Things ran that way just fine for a couple of hours.

Then I realized that most of my problems were happening after dark when the Solar panel wasn't charging the batteries. So tonight when I got home from a party I plugged in the multi-meter and it showed 11 volts. I turned on the furnace and it went down to 8.8 volts and all hell broke loose, lights on and off and all of that sort of thing. I shut everything down for about 10 minutes and the meter was back up to 12 volts.

 

My thinking is that the converter is the source of my trouble. Now I have the "Heat Interface" system with the Freedom Combi...Inverter/charger. Should I replace the whole system for 1200 to 1500 bucks or just have a new converter added to what I have?

[Bill Joyce]

Dennis and Carol: I think you need to isolate your problem and see if it is repairable first. First, make sure the Freedom charger is actually turned on, it can get turned off and it is easy to not notice it is off. Check all your wiring and make sure something is not loose or corroded. Also check the charge settings, sometimes they get put to strange values on a reset and do not match your batteries, or the charger got turned way down and not put back up. Freedom's are repairable. if you do want to replace it, I would go with a pure sine wave replacement, you can get a Magnum MS2012 for $1,217.69 from http://www.imarineusa.com/magnumenergyms20122000watt12v100atruesinewaveinvertercharger-1.aspx.

[Kirk W]

Bill is right that you need to find what the problem is before you start to replace parts. Isolate the batteries to be sure that they are not the problem first as they are a more common failure than the converter.

[Wrknrvr]

First simple thing you can do after resetting the system as needed as Bill Joyce and others said is to hook a battery charger to the system. That will tell if all other things are correct. And your system will function as needed. Then you will need to remove the charger and try to reset the inverter.

If you call the manufacturer they should help you with that. Or if you need to take it somewhere that can do that if do not feel comfortable doing it yourself.

Most of the time a hard reset will fix your problem. but not always. Last summer I reset one of those several times. It might work correctly for one day or two weeks. But finally had to replace the unit.

 

 

Vern

[Wrknrvr]

Something else that needs to be done is to charge the battery's to 12.0 volts or there about. As most inverter/charger will not function if the battery's are below a certain level of charge.

Hopefully this will get you going again.

 

 

vern

[Guest ticat900]

I turned on the heat today and it seems to create some kind of a spike evey once in a while. In this case I use the word 'spike' to mean the electricity seems to go off and on again. This happens intermittently.

I warms the motorhome just fine. Any ideas what I might check?

might be cheaper just to repair your existing inverter/converter

[Wrknrvr]

This site will help with doing a hard reset of the inverter/charger.

 

 

http://www.wholesalesolar.com/inverter-repair.html

 

When doing this the batteries need to be charged to about 11.5 or more before you try and operate the system after the reset. If the batteries are low enough the inverter will sense it and not operate. Also when you connect the positive battery lead there is normally a spark. Not excessive but it will make you think.

Some inverters will reset with being disconnected for 15 minutes or so but sometimes it takes 24 hours to do a reset.

Some time ago I had a inverter from about 1990 that was gray in color. Could not find who made it and the hard reset would not work. The next day I remove the negative lead and did a reset and the ---- thing worked.

 

 

Vern

[oscarvan]

Bill is right that you need to find what the problem is before you start to replace parts. Isolate the batteries to be sure that they are not the problem first as they are a more common failure than the converter.

 

He did state he replaced the batteries, which would point at a charging issue. And, i believe that even with bad batteries that won't HOLD a charge, with a properly functioning converter the voltage should be in the ballpark.

[shaman52]

Does the inverter have 120v AC feeding it? Should have 2#10 gauge going into it from a 30 amp breaker located in your load center.

 

Here is a link to PDF drawings of 12V and 120V wiring diagrams for your coach. http://www.winnebagoind.com/diagram/Wiring.htm

 

By the way you picked a very nice Winnebago.

 

Good Luck!

[Kirk W]

 

And, i believe that even with bad batteries that won't HOLD a charge, with a properly functioning converter the voltage should be in the ballpark.

 

That just depends upon what the battery problem is. A shorted cell can drag down the supply, as can several other battery problems. Even new batteries can be bad or they can also be boiled dry and have little or no electrolyte. It isn't usually a good plan to assume something is good, particularly if you are trouble shooting long distance.

 

[TRACKUM]

^{I shut off the outside 50 amp power source. I turned off all the 12v loads I could find. and my multi meter read 12.7 volts. When I turned on a light it dropped to 11.9}

^{Is this telling me that the batteries had a good charge on them?}

[TRACKUM]

A decent $25 multimeter is the place to start, most big box hardware stores have decent ones if you want it right away, Amazon or the like have more selection if you are willing to wait. Look for one that does at least 10 amps, 20 is better and shows 1/100 (0.00) volts as you'll find that helpful over time.

 

Check your voltages with the converter charging and with the converter unplugged to see if the converter is working. Charging you should see something in the 13.2 to 13.8 range, more with a smart charger. When not charging it should drop some, how much depends on your loads and battery state.

 

Then lift the ground wire off the bank and check the battery voltage after 10-20 minutes to see the state of charge. It should be 12.6 or above, 12.6 is fully charged but you might see it a bit higher if the converter was charging at a high rate, give it some more time to settle or put on a small (1 amp) load for 10 minutes and see if it drops back to 12.6 or so.

So if it is 12.6 after all that what does this mean to me?

[Kirk W]

^{I shut off the outside 50 amp power source. I turned off all the 12v loads I could find. and my multi meter read 12.7 volts. When I turned on a light it dropped to 11.9}

^{Is this telling me that the batteries had a good charge on them?}

If all that you turned on was one light and your battery fell by 0.8V that seems excessive to me but it depends upon how many amps you were drawing just how far is normal. A furnace requires at least 10.5V for the blower to turn fast enough for the sail switch to close and allow it to supply heat. Most refrigerators will drop out at about the same voltage. If you turn that light off and wait a few minutes, does the voltage return to 12.7V or very nearly so? If so that is a good sign but a larger load is really a better test. If you can leave the battery isolated for 24 hours and check the voltage again, that too will tell us a lot more. You should be able to lift the negative battery lead to isolate it and turn shore power back on to get 12V power from your converter and that will give you the chance to see what the battery does overnight as well as testing the reliability of your converter.

[skp51443]

If the batteries are staying at 12.6 that means they are charged. You shouldn't see a big drop like you are to 11.9 with only a single light, maybe an amp, pulling them down. I'd begin to suspect a bad connection at some spot.

 

Check the batteries on the posts and see if you see that big a drop there. If you don't see it there just start following the wires looking for where the drop appears. I'd start by checking the ground line as it is usually less effort than the hot side.