Electrical help please

[twindman]

Sort of long story. I have 2 6V batteries about 5 years old. They were about a quart low but still above the plates. Added water. Plugged in to house. House read around 110 volts. Converter was drawing about 6 amp. When I turned on the water heater, the surge protecter said low voltage - 100 V. I check outlets and it was in fact 100 v. Oh, the heater draws 7 amp. I was hooked up with my 25 foot 50A cord to a 25 ft 30A cord to a 100 ft 15A extension cord.
So 1) why the drop in voltage. Too long a run of cords?
2) It also took the converter 8-10 hours before it stopped running. I do have the extra thing on the converter to do a trickle charge. Are my batteries going bad?
Thanks for answers.

[BB_TX]

Hard to say how much total amps you were pulling. But that 100', probably 14 ga, extension cord plus the multiple connections was dropping the voltage. At 110 volts at the house you were a little low to begin with.

[1retired06]

Might be a good idea to have the batteries checked, since you have hit the the five year mark.

[RichR]

Its called voltage drop-wire size on the 100ft cord is not designed to carry that voltage.

[NCFischers]

I agree with both posts.

[H. John Kohl]

NCFischers is my go to man for electrical problems.

[Art-n-Marge]

I have made long runs of the sewer line (as long as the slope continues downward, and I have had long runs of water hose longer than 100 ft, but I would never run electrical cords on the rig more than 30 to 50 feet because as the cord distance gets longer the worse the power gets that can actually cause some damage to some things. 150' on high amperage needs (like a trailer) is not a good idea and one must really know wire gauge and distance ramifications for electrical wiring, and it's more than an "if-the-cord-connects" mentality. You also need to know the big picture of what you're doing. Since I'm NOT that type of guy, I try and keep electrical wiring very simply in distance.

NCFishers, like many others is very good source of this type of advice and knowledge. I used to think H. John Kohl was as well, but he's just let out his secret. H. John is still someone I'd listen to.

1retired06 does have good advice about having the batteries checked. You don't say what the voltage of the batteries was reading (isolate the batteries to get the proper reading). If the battery water level ever gets that low and over 5 years, just refilling the water might not fix things completely. It's a good idea to have the batteries checked to find out their condition going forward. This can be done at some autoparts stores for free or for a small fee.

[mhs4771]

Yep, not good for anything with the voltage that low. Under normal voltage the water heater should be drawing 12 to 14 amps.
Too much cord plus small guage equals low voltage/current.

[Art]

According to voltage drop charts, a 15 amp cord will loss 7.6% or 9.1 volts over 100 feet. I agree that 100+ feet is a long distance for small gauge wires with substantial amp draws. Use larger gauge wires if you cannot shorten the distance.

[DQDick]

I would also expect to have to replace your batteries. 5 years is about the limit of reliable battery life.

[Tom S.]

"I was hooked up with my 25 foot 50A cord to a 25 ft 30A cord to a 100 ft 15A extension cord."

You probably could have used that 100 foot cord to de-ice some airplane wings. Way too small to be trying to charge batteries with, run the converter, and other small items in the unit.

[Carl n Susan]

As others have written, that 100' 15 Amp cord is too puny for a heavy current draw and is the cause of your low voltage.

You likely have the IOTA DLS55 converter in your 2006 rig. I think it was closer to 2008 before Montana upgraded to a "smart" converter. The IOTA is a good converter but only a single stage one. It can easily be upgraded to a muli-stage "smart" converter with the addition of an IQ4 module for around $25 http://www.iotaengineering.com/iq.htm

It probably is worth testing the cells of the battery to ensure they haven't been harmed, but good GC 6V batteries will last a long time if not abused.

[paulinbaja]

Your problem is the total length of wire. But the main issue is the #14 cord. The voltage drop in a length of wire is reflected in the total length of the wire and the current carrying capacity of the wire. 14 gage is usually rated at 20 amp, the NEC usually requires 14 gage wire be protected by a 15 amp circuit breaker. The long runs of the greater size wire most likely would handle the 15 amps you were attempting as #8 and #10 have less voltage drop per foot at 15 amps than does #14.

After you calculate the requirement in AMPS select wire based on de-rating the current capacity 20% for each 50 feet of length. Starting with #14 @ 15 amps, #12 @ 20 amps, #10 @ 30 amps and #8 @ 50 amps. As the lengths get longer allow an additional "de-rating" to be on the safe side. Each coupling also has a small effect on the total voltage drop.

Example, you need to have 20 amps and the run (length of wire)is 110 feet. Starting with #10 cord (30 amp) you de-rate it 20% for the first fifty feet 30 amps X 80% = 24 amps, now you de-rate this again by 20% for the second fifty feet, 24 amps X 80% = 19.2 amps. So you see, in this case you would need the whole run at #8 wire.

Low voltage is very hard on motors and sensitive electronic equipment.

[paulinbaja]

The batteries are another story. At five years they are very near the end of their life. Have someone check the specific gravity of each cell with the batteries as fully charged as you can get them. If the number is to high, they are gone. A battery supplier will usually help with this issue. You most likely have a friend with a hydrometer and the knowledge to do the test. Always wear eye PROTECTION when working around batteries!

[Overlord]

I have used a 100 foot, #10 AWG extension cord as an infrequent solution for supplying electricity to the trailer. A 50 footer would be much better though.

100 feet of #10 AWG at 120 volt supply equates to a 7.2 volt drop(6%) down to 112.8 volts.

If you are supplied by a 30 amp circuit, you could run the microwave oven on that, but I would hesitate to run a constant demand appliance like a 1500 watt space heater(technically, at a 13.3 amp draw, you could safely use the heater, but long term with the additional demands from the converter, lights and such, the cord would probably get warmer than I would like it to). If hooked up to a 15 or 20 amp circuit, maybe not so much, just the converter, television, and a few lights would be all that I would run.

With anything smaller than #10 AWG at 100 feet long, you are just asking for trouble, if you ask me.

I would strongly advise against running a high demand electric motor, like the air conditioner on a cord that long, even #10 AWG, no matter what amperage service it is connected to, though.

[rohrmann]

We have dry camped as long as two weeks using no more than a short #14 cord from our 2000W Honda. No A/C, barely are able to use the microwave, and have the fridge and water heater on propane only. Even if we were plugged into a full 20 amp circuit and had a heavier cord feeding the rig, I would not want to risk damage to an A/C trying to run it. Even with a 30 amp circuit, you can only use one A/C, and then have to be careful to not use the microwave at the same time as the A/C. It's just not worth the risk of damage to the wiring or appliances in these rigs trying to under size the electrical.

[kdeiss]

Just bring the battery's in the house or garage put them on a charger then check with Volt meter and hydrometer I am thinking at that age they are shot!
At that length of cord and guage you are having big time voltage DROP!

[jlb27537]

quote:Originally posted by paulinbaja

Your problem is the total length of wire. But the main issue is the #14 cord. The voltage drop in a length of wire is reflected in the total length of the wire and the current carrying capacity of the wire. 14 gage is usually rated at 20 amp, the NEC usually requires 14 gage wire be protected by a 15 amp circuit breaker. The long runs of the greater size wire most likely would handle the 15 amps you were attempting as #8 and #10 have less voltage drop per foot at 15 amps than does #14.

After you calculate the requirement in AMPS select wire based on de-rating the current capacity 20% for each 50 feet of length. Starting with #14 @ 15 amps, #12 @ 20 amps, #10 @ 30 amps and #8 @ 50 amps. As the lengths get longer allow an additional "de-rating" to be on the safe side. Each coupling also has a small effect on the total voltage drop.

Example, you need to have 20 amps and the run (length of wire)is 110 feet. Starting with #10 cord (30 amp) you de-rate it 20% for the first fifty feet 30 amps X 80% = 24 amps, now you de-rate this again by 20% for the second fifty feet, 24 amps X 80% = 19.2 amps. So you see, in this case you would need the whole run at #8 wire.

Low voltage is very hard on motors and sensitive electronic equipment.

Exactly. You can charge your batteries, probably, but the water heater on electric is a no way thing. It draws around 12 amps. Plus the 110 at the house is already low.

[TAKPAK]

quote:Originally posted by twindman

Sort of long story. I have 2 6V batteries about 5 years old. They were about a quart low but still above the plates. Added water. Plugged in to house. House read around 110 volts. Converter was drawing about 6 amp. When I turned on the water heater, the surge protecter said low voltage - 100 V. I check outlets and it was in fact 100 v. Oh, the heater draws 7 amp. I was hooked up with my 25 foot 50A cord to a 25 ft 30A cord to a 100 ft 15A extension cord.
So 1) why the drop in voltage. Too long a run of cords?
2) It also took the converter 8-10 hours before it stopped running. I do have the extra thing on the converter to do a trickle charge. Are my batteries going bad?
Thanks for answers.

Twindman,all the answers here are good. Perhaps a simple analogy for electricity would be to compare it to water and a hose. At a given pressure (volts) at the start (faucet and a short hose) you have a good flow/pressure. But as you add lengths of hose, the longer it gets, the slower/less water flow/pressure you have, due to the resistance of the hose interior. Same with wire. If you enlarge the size of the hose (or wire) then you get better flow/pressure, due to less resistance. Ohms law (electrical) states that as voltage goes down, amperage (heat) goes up, and visa/versa. If your house voltage was only at 110 volts, you are already off to a bad start. Then using the #14 wire/100 foot cord, it really dropped your "flow" way down. Simple analogy, more power needed, bigger wire also needed. There are tables and formulas in the electrical code book, but we won't get into that here.

Hope this helps. Oh, normal house voltage at an outlet SHOULD be 115 to 120, and possibly as high as 125 vclts in modern houses. If you find that you have "low" voltage throughout your house, talk to a qualified electrician, or your local power company. There are things that can be done.

Also, on the batteries, age doesn't necessarily mean anything...to a point. I've had batteries last over 10 years, IF they are taken care of/kept charged up. What kills a battery is the number of charge/discharge cycles, plus sulphation of the plates.

[HOOK]

Too much resistance in the conglomeration of wires. IMHO