Inverter not converting 12V to 120V to run microwave oven

[alanmalk]

If you really, absolutely, want the total wire loss, you will need to do the same thing on the black wire. Measure from the negative inverter terminal to the negative battery post, and this time the + lead of the meter is on the inverter negative. The value really shouldn't be over 0.2 V. If it is then your new fuse may not solve the problem.


And since you are becoming comfortable being an electron detective, try measuring one side of the fuse to the other.


After today you can call yourself an expert at RV wire problems!

[Tonny LR]

Originally Posted by Perry Butler

A 4 AWG wire is way too small in my world. This could be your problem.

I used 2/0 wire running two feet for our 1,500 watt inverter.

I also used a 250a T fuse for our inverter. It was felt that 200a would blow too easily.

Food for thought,

Perry

Perry,
Thank you for your input on selecting a 250 amp T batteries terminal fuse. How do you flush mount it on the battery post since the buss bar with the center cylinder fuse does not look long enough to extend outside the edge of the battery? Would the center cylinder of the fuse creating a gap per pictures I saw on Amazon?

Tonny LR

[Tonny LR]

Originally Posted by alanmalk

If you really, absolutely, want the total wire loss, you will need to do the same thing on the black wire. Measure from the negative inverter terminal to the negative battery post, and this time the + lead of the meter is on the inverter negative. The value really shouldn't be over 0.2 V. If it is then your new fuse may not solve the problem.


And since you are becoming comfortable being an electron detective, try measuring one side of the fuse to the other.


After today you can call yourself an expert at RV wire problems!

Alan,
Thank you for being a wonderful teacher. I learned a lot from you.
I have 3 questions: 1) What do you mean by total wire loss? 2) How do you measuring one side of the fuse to the other?. The battery terminal fuse is square and enclosed in a plastic case? 3) Do you think a 4 gauge wire is not suitable for the inverter and need to be upgraded to 2 AWG. The distance between battery terminal and inverter is 63" which is 13" longer than the owner manual specified.

Tonny LR

[alanmalk]

Originally Posted by Tonny LR

Alan,
Thank you for being a wonderful teacher. I learned a lot from you.
I have 3 questions: 1) What do you mean by total wire loss?
Voltage drop = "loss". Total drop in the wires would be adding the drop in the red side (already measured) to the drop in the black side (which has not been measured). Just done for pure curiosity since we now know there is too much loss in just the red side.

2) How do you measuring one side of the fuse to the other?.
No extension cord needed, just put the meter probes on each side of the fuse, or as close as practical. Have the helper turn on the hair dryer. Read the voltage before the meter alarms. Wild guess = 0.5 V. (Note that by definition this V is already included in the 0.7 - 0.8 V that you already measured. Just another curiosity item.)

The battery terminal fuse is square and enclosed in a plastic case?
Probes as close to the case as practical - we're not after micro-volt precision.

3) Do you think a 4 gauge wire is not suitable for the inverter and need to be upgraded to 2 AWG. The distance between battery terminal and inverter is 63" which is 13" longer than the owner manual specified.
There are a couple rules of thumb: 1) No such thing as too big an inverter wire. Like having too much money. 2) To cut the wire voltage drop in half, go up 2 sizes. So for you, if you want to cut the voltage drop in half - in the actual wire mind you - go from 4 to 0. Important to keep in mind: We suspect a good % of what you measured (0.7-0.8V) comes from the actual fuse, not the wire. We just don't know as of today. But loss is loss, and any improvement counts in the long run, so go for it.

Remember, our bottom line is to fix the easiest and cheapest items first and see if everything works. But don't go cheap on the wire terminals. You can get high quality terminals added at most on-line wire sellers. They have the right tools to add those crimped terminals. They can also add sealed protection at each end - another small bonus. Another caution when pulling out the credit card: Look for "pure copper" wire ("oxygen free" - OFC is not needed), absolutely stay away from CCA - copper coated aluminum. Its cheap for a reason!
Tonny LR

More comments in blue.

FYI: Any voltage drop, in any part of the system is lost power - vanished into the ether as heat. Like spilling good beer - worth crying over. And note that "weak" batteries have the same problem, lots of internal voltage drop - we still have not ruled that out. We are working on the "low" cost items first.

But as a broad generality - using an inverter to make heat, as in: coffee pots, toasters, microwaves, hair dryers, etc, is a very inefficient system. A lot of power is lost in the process. Use your stove when you can, stick wet hair out the window of a moving car, (if safe, and your wife doesn't mind the results), etc.

[RangerMan]

Originally Posted by Tonny LR

Perry,
Thank you for your input on selecting a 250 amp T batteries terminal fuse. How do you flush mount it on the battery post since the buss bar with the center cylinder fuse does not look long enough to extend outside the edge of the battery? Would the center cylinder of the fuse creating a gap per pictures I saw on Amazon?

Tonny LR

If you change the inverter/battery cable, don't forget to use the same size cable to connect your batteries. I changed mine to 2/0 also. Almost no voltage drop.

[Tonny LR]

Originally Posted by RangerMan

If you change the inverter/battery cable, don't forget to use the same size cable to connect your batteries. I changed mine to 2/0 also. Almost no voltage drop.

Thank you for your suggestion. May I ask what battery terminal fuse do you use on your trailer?

Tonny LR

[Perry Butler]

Originally Posted by Tonny LR

Perry,
Thank you for your input on selecting a 250 amp T batteries terminal fuse. How do you flush mount it on the battery post since the buss bar with the center cylinder fuse does not look long enough to extend outside the edge of the battery? Would the center cylinder of the fuse creating a gap per pictures I saw on Amazon?

Tonny LR

A 4 AWG cable is fine if you're just going by the math. However you need to introduce real world math that includes the fact that most have bad connections, bad crimps, too long of wire, fuses, switches, corrosion/vibration over time, etc., that all increase resistance. Those who include the realities of most installs will recommend a minimum of 2 AWG with a maximum run of six feet. Some feel a 1/0 is the minimun when accounting for real world losses. Again, your 4 AWG cable is fine in a perfect world, but just looking at your pictures you do not have a perfect world.

My T fuse holder does not go on top of the battery and does not have to if a larger wire is used. If you NEVER plan on going to lithium batteries an ANL fuse will work just fine. We use SiO2 batteries, so a ANL fuse would have protected our camper, but after having 2 sets of quality batteries fail (one dropped in transit to us lasted three months, the second was ruined when the WFCO decided to charge at 20.3 volts). I installed a T fuse and 2/0 cables becasue the increase in cost was within our discretionary income.

My wires were purchased from BatteryCablesUSA. There are many other battery cable vendors out there.

On the positive side, if I remember correctly, a 9" 2/0 AWG (00 AWG) cable is connected from the battery terminal to the T fuse holder, another 9" 2/0 AWG cable from the T fuse holder to the Blue Seas 4 position battery switch, and a two foot 2/0 AWG cable from the battery switch to our inverter.

On the negative side a two foot 2/0 AWG negative cable goes from the the inverter back to our Victron 712 shunt, with another 9" 2/0 cable from the shunt to the negative battery post. It's a clean, consistant install with clean crimps, no exposed wires at the crimps, and nothing hanging from or on top of the battery posts.

You can go cheap or you can just spend a few dollars ($100 ?) and your problem will be over. However, becasue of the realities of your install, your 4 AWG cable is just too small for long term use, even if cleaned up.

More food for thought,

Perry

[alanmalk]

Originally Posted by Perry Butler

A 4 AWG cable is fine if you're just going by the math. However you need to introduce real world math that includes the fact that most have bad connections, bad crimps, too long of wire, fuses, switches, corrosion/vibration over time, etc., that all increase resistance. ...


More food for thought,

Perry

And something else to chew on in his real world. It would appear that his current inverter has less tolerance for voltage drop than perhaps some other brands. That gives him no choice but to upgrade the system.

[RangerMan]

Originally Posted by Tonny LR

Thank you for your suggestion. May I ask what battery terminal fuse do you use on your trailer?

Tonny LR

I did not replace the 200a ETI installed fuse but I did move it to a fuse holder. I used a 1/4 x 1 inch copper plate as a bus to connect the battery terminal to the fuse in the holder. Cut the copper plate to 3 in and drilled 5/8 in holes for the terminals on the battery and holder.

The bus will handle anything likly to pass thru the connection. I've since thought about replacing the ETI installed fuse with a 'T' but not done anything yet.

Credit to tdf-tx for the ideas. Search for his mods on this. The best!

[John in Santa Cruz]

FWIW, my 2000W Renogy inverter came with cables that were made up of 2 #4 each in parallel, about 4 feet long. the length was nearly perfect to reach my main battery bus bars, each of my batts has #4 plus and minus wires to the bus bars, with 150A ANL fuses fuses inline with each plus. The inverter has run just fine on a high wattage coffee maker, and my wife's big hair dryer on high.

[Tonny LR]

Originally Posted by alanmalk

And something else to chew on in his real world. It would appear that his current inverter has less tolerance for voltage drop than perhaps some other brands. That gives him no choice but to upgrade the system.

Alan,
Thank you for the detailed instructions/tutorial of your previous post. I am in the process of finding out a suitable and high quality fuse, 1 or zero gauge pure copper wire and connectors. I can afford to spend high $ for quality products. I want to do it right the first time. We have been thinking of upgrading to a ETI 23 feet, but with the aluminum frame which has not been tested and no service department; we are tabling the idea for now and decided to keep our 19' classic.
we are the original owner. So it may take me a while do the next test again.

Tonny LR

[Tonny LR]

Originally Posted by RangerMan

I did not replace the 200a ETI installed fuse but I did move it to a fuse holder. I used a 1/4 x 1 inch copper plate as a bus to connect the battery terminal to the fuse in the holder. Cut the copper plate to 3 in and drilled 5/8 in holes for the terminals on the battery and holder.

The bus will handle anything likly to pass thru the connection. I've since thought about replacing the ETI installed fuse with a 'T' but not done anything yet.

Credit to tdf-tx for the ideas. Search for his mods on this. The best!

Thank you for sharing your information which is every helpful.

Tonny LR

[Tonny LR]

Originally Posted by Perry Butler

My wires were purchased from BatteryCablesUSA. There are many other battery cable vendors out there.

On the positive side, if I remember correctly, a 9" 2/0 AWG (00 AWG) cable is connected from the battery terminal to the T fuse holder, another 9" 2/0 AWG cable from the T fuse holder to the Blue Seas 4 position battery switch, and a two foot 2/0 AWG cable from the battery switch to our inverter.

On the negative side a two foot 2/0 AWG negative cable goes from the the inverter back to our Victron 712 shunt, with another 9" 2/0 cable from the shunt to the negative battery post. It's a clean, consistant install with clean crimps, no exposed wires at the crimps, and nothing hanging from or on top of the battery posts.

Perry,
Thank you for taking time to sharing your knowledge. I appreciated your guidance and will follow some of the instructions.

Tonny LR

[John in Santa Cruz]

its challenging finding a suitable crimper for 0 and larger gauges. I think the one I prefer using only goes up to 2 gauge (and has jaws for 2,4,6,8). odd gauge wire like 1 is rare.

watch out for 'chinese wire gauge' stuff on the likes of Amazon. I try and find made-in-USA pure copper, fine stranded cable. The WindyNation stuff on Amazon seems good quality, its what I used for all the heavy gauge runs on my battery/etc upgrade.

https://www.amazon.com/gp/product/B01MD1XRSL/

(1/0 is 0. 2/0 is 00). Note that SKU has 10 feet each black and red 1/0, plus 10 1/0 3/8" tinned copper ring terminals, suitable for making up to 5 total cables.

this crimping tool and cable cutter were very useful (oh, this crimper does go up to 1/0).
https://www.amazon.com/gp/product/B00MVE48Z6

this hydraulic crimper is junk
https://www.amazon.com/gp/product/B06XR8BY65
(its dies are metric sized, not AWG, and its awkward to use)

[tdf-texas]

Here is a link to my battery cable replacement project.
https://www.escapeforum.org/forums/f...les-19164.html

I've done this change for a number of friend's Escape trailers with good success in fixing the inverter trip problem. 4 ga wire for the inverter wires is just not big enough.

I have to disagree with John on the crimper - I have used the hydraulic crimper that he linked for years and it not junk. The crimper dies are sized in metric - just use the linked table to convert. (hint, I printed the table out and taped to the inside of the crimper case).
https://crimpingtools.com/blogs/blog...t-to-square-mm

[John in Santa Cruz]

the problem is, AWG gauges are in between metric gauges. the hydraulic one would probably be easier to use if you have a bench vise to hold it, then you can pump it with one hand while you hold the cable with the other. with the long arm mechanical crimper I posted, I would rest one arm on my thigh, the other arm in my armpit (while sitting down), then I could hold the crimp in one hand and the cable in the other until I started the crimp, then use one hand to finish the crimp while still holding the cable in the other. obviously, if you have a helper, that would be easier. By the time I finished my wiring board, I had probably made 100 crimps of various gauges.


(before the inverter was added, so yet more wires... also, when I added the inverter, I upgraded the two ANL fuses from 100A to 150A)

[Tonny LR]

Originally Posted by John in Santa Cruz

its challenging finding a suitable crimper for 0 and larger gauges. I think the one I prefer using only goes up to 2 gauge (and has jaws for 2,4,6,8). odd gauge wire like 1 is rare.

watch out for 'chinese wire gauge' stuff on the likes of Amazon. I try and find made-in-USA pure copper, fine stranded cable. The WindyNation stuff on Amazon seems good quality, its what I used for all the heavy gauge runs on my battery/etc upgrade.

https://www.amazon.com/gp/product/B01MD1XRSL/

(1/0 is 0. 2/0 is 00). Note that SKU has 10 feet each black and red 1/0, plus 10 1/0 3/8" tinned copper ring terminals, suitable for making up to 5 total cables.

this crimping tool and cable cutter were very useful (oh, this crimper does go up to 1/0).
https://www.amazon.com/gp/product/B00MVE48Z6

this hydraulic crimper is junk
https://www.amazon.com/gp/product/B06XR8BY65
(its dies are metric sized, not AWG, and its awkward to use)

John,
Thank you for sharing your knowledge. Now, I can start forming my equipment list.

Tonny LR

[Tonny LR]

Originally Posted by tdf-texas

Here is a link to my battery cable replacement project.
https://www.escapeforum.org/forums/f...les-19164.html

I've done this change for a number of friend's Escape trailers with good success in fixing the inverter trip problem. 4 ga wire for the inverter wires is just not big enough.

I have to disagree with John on the crimper - I have used the hydraulic crimper that he linked for years and it not junk. The crimper dies are sized in metric - just use the linked table to convert. (hint, I printed the table out and taped to the inside of the crimper case).
https://crimpingtools.com/blogs/blog...t-to-square-mm

Hello Tom,
Thank you for your posted info. I had followed your mod before and I respect your electrical knowledge and expertise. I have been waiting for you to chime in. I will follow the posted link to do battery terminal wires replacement. Thanks again.

Tonny LR

[alanmalk]

Originally Posted by Tonny LR

...
I am in the process of finding out a suitable and high quality fuse, 1 or zero gauge pure copper wire and connectors.
...
Tonny LR

If 1 gauge is your target wire you can try these folks:
https://www.batterycablesusa.com

They will also do the assembly of end fittings if you desire.

[John in Santa Cruz]

I bought this Class T 225A fast-blow fuse holder, Blue Sea brand, to replace my ANL fuses, along with some AWG 1/0 wire and 3/8" ring terminals, with the idea of redoing my battery mains but I have yet to convince myself its worth doing.



p.s I have L or XL hands per my glove size.