Manufacturers saving a few cents on wire

dougrainer wrote:
When I see posts like this, how come NOBODY ever questions HOW Jayco connects the wire to the Battery? I am talking about a 30 amp ATC fuse holder with 14 gauge wire pigtails.............

A while back I bought a bunch of supposed 10AWG ATC inline fuse holders. They were 12 gauge SAE at best, and SAE wire gauge is 6 to 12% thinner than AWG

I had acquired them to bypass the original HVac blower motor fuse, which like many vehicles, the whole circuit is underwired, and for other things. The original fuse holder had melted before my ownership of the vehicle and the previous owner had used a glass inline fuse holder instead, which lasted me all of 3 or 4 months before melting.

It worked for about 7 months, and one day with blower motor on speed 3 of 4, I started smelling burning plastic, and turned off blower motor. I later found the fuse holder was completely melted around the 20 amp fuse.

Later I got '8 AWG' Maxi fuse holders and when installed on this circuit, no more issues, not to say that these are built any better, but at least 8awg can wick away the heat from the fuse tang connection better. Where that wire joins inside the plastic molding is a huge resistive point.

Not too long after that the blower motor started squealing, and the speed switch lever itself had been getting hot. On inspection I found The wires entering it were charred. I replaced everything including resistor pack, and used 8awg overkill from speed switch to new blower motor, and the amount of air the motor moved on high was at least 20% more and no more issues.

More recently I decided to use a 40 amp 21khz PWM motor speed controller instead of the resistor pack for speed control, and ran a new 8awg power feed to dash so I can power it with Key not in the ignition. I've not yet tested the voltage reaching the motor now, but it has to be considerably higher, and the amount of air exiting the vents at highest speed, has improved yet again.
I feel better the whole underwired original circuit is basically offline, but still functional, all I have to do is open the glove box and switch an anderson powerpole, but see no reason to do so.

I actually wish I did not bother rebuilding the speed switch and part of the Hvac circuit, but just went for the PWM motor speed controller at that point.

Infinite fan speeds engine on or off , ignition on or off, and much less wasted amperage bypassing the resistor pack speed control. The blower motor is not as efficient as my other methods( computer fans) for exchanging outside for inside air when parked, but it is a very nice option to have.

The vents are vaccuum operated and will revert to windshield/defrost and floor, rather than the dash, about 5 minutes after engine shutdown.
Where the air exits, as well as the position of the blend door, affects amp draw of the motor.

Twice, I have had to open up the new blower motor as the brushes got stuck inside their holders, the second time I reduced their dimensions. Nice quality control there.

Anyway, almost all the inline fuse holders I have purchased are problematic even on circuits well below the wire rating, and some Rv manufacturer using these inline from the converter is criminal batterycide incompetence.

I now make my own inline ATC fuse terminals with 10AWG and 10-12 insulated flag terminals, or lesser flag terminals on lesser wire. I crimp then solder then slide the insulation back over the terminal, then Use Amazing goop around the flag terminals to form a one piece body.
I trust these, and they are low profile and way better than any purchased inline fuse holder with the two extra connections required to butt splice them into the wiring.

I have employed the other '10 awg' ATC fuse holders on other circuits that rarely see more than 10 amps and only briefly, but they will be phased out.

Unfortunately they do not sell 8awg flag terminal quick connects in order to grasp the tangs of a Maxi fuse, and I have had to use the older inline 8awg fuse holders on my new 8awg dash feed, but intend to phase it out at some point.

The Blower motor draws 50% more current when it gets 14.5v vs 12.6v and spins way faster too, and I doubt the original circuit ever fed it more than 10.5v even when the alternator had system voltage upto 14.9v.

Same topic, different product.

I have a soft sided cooler I can't store flat because the velcro straps that hold it down are 1/2 inch to short.

Manufacturers RVs to be yanked from the factory to an RV park then towed from park to park until age disassembles it. I had to build Quicksilver from scratch in order to get a wilderness grade RV. Thank God Crown had to build the bus to federal specs. Conversion was insanely expensive even using salvage parts and surplus salvage sailboat wood and surplus space shuttle and SR71 wiring.

Toyota did and still does use a wire that is too small on the heater blower motor. They have been a failure point since the 2005 model year.

RoyF wrote:
10-guage wire will carry 55 amps, according to the charts. You can check the output of your converter, but I would be surprised if it is rated at more than 55 amps.

You might wanna rethink that. #10 ga is only good for 20 amp @15'

55 amp would require #4 at 15'

I checked 4 different 12 volt wire charts.

#10 will never carry 55 amps on any wire chart. If you have one that does I would like to see it. #10 will never carry 55 amps for any distance.

When I see posts like this, how come NOBODY ever questions HOW Jayco connects the wire to the Battery? I am talking about a 30 amp ATC fuse holder with 14 gauge wire pigtails. Kind of like having a 1 inch water line connected to a 1/4 inch hose to the input of your house. Kind of negates the purpose of getting all the power you should require. You need to replace the input fuse system to your battery also. Jayco runs a 12 gauge wire from the positive battery post 2 feet to a 14 gauge 30 amp ATC fuse with the pigtails about 4 inches long in and out. Also, I don't think Jayco runs a dedicated GROUND wire to the Converter. The ground goes from a Chassis frame stud below the Converter area to the Frame. Doug

As long as you are pulling new wire... go with #4.

(replace the entire charging loop with similar rated connections)

At 12V, 3% drop is WAY too much loss, period.

Folks need to stop propagating this bad information, those charts simply cannot be applied to 12V, they are designed for 120V AND HIGHER where 3% IS NOTHING TO LOSE!

Example, 14.4V at your converter results in .432V drop at 3% so now your batteries are only seeing 13.968V which is nothing more than a trickle charge!

Using 3% chart WILL result in disappointing results.

Nope, you NEED to be shooting way below 1% which in my eyes results in an unacceptable loss of .144V at 14.4V which your batteries will only see 14.256V..

I used 1/0 and have less than 6ft for both pos and negative between my converter and batteries..

Go BIG or don't bother, otherwise your converter is nothing more than a trickle charger after the wire eats up all of your voltage in heat loss.





You've gone to the other extreme and it just adds to the confusion. Voltage drop is a product of wire resistance (it's gauge), wire length, and how much current you try and push though it. Your size is great if you want to charge at 100amps/hour. For the rest of us a 10amp/hour rate is more than adequate when plugged into shore power overnight. Just for the record any charging voltage over 13.5 will charge the battery.

wolfe10 wrote:
Tell us what amp converter you have. With that, the length of the wire run (positive + negative) AND (an important AND) using a 3% voltage drop chart you can get the answer very quickly.

https://www.westmarine.com/WestAdvisor/Marine-Wire-Size-And-Ampacity

At 12V, 3% drop is WAY too much loss, period.

Folks need to stop propagating this bad information, those charts simply cannot be applied to 12V, they are designed for 120V AND HIGHER where 3% IS NOTHING TO LOSE!

Example, 14.4V at your converter results in .432V drop at 3% so now your batteries are only seeing 13.968V which is nothing more than a trickle charge!

Using 3% chart WILL result in disappointing results.

Nope, you NEED to be shooting way below 1% which in my eyes results in an unacceptable loss of .144V at 14.4V which your batteries will only see 14.256V..

I used 1/0 and have less than 6ft for both pos and negative between my converter and batteries..

Go BIG or don't bother, otherwise your converter is nothing more than a trickle charger after the wire eats up all of your voltage in heat loss.

On edit..

Found an online voltage calculator which WILL show you real results, much better than a chart..

Plug in 14.4V and you can change the current and wire size along with length..

HERE