Has anyone upgraded to a QD 8000 from an LP unit

[polar76]

Considering doing this on my 97 CC Allure.
Nothing but problems with the 6500W LP unit,
We like our coach but fed up with lack of reliability of the generator.
so new diesel generator on different coach.
Anyone done this and what issues came up..?

[CA_Traveler]

I certainly agree that the OPs wiring may be acceptable for the gen upgrade. But I don’t know his wire size, length or how much voltage drop would be acceptable to him. This is why I said in my very first post on this thread I said “You may need to replace the wiring…”. It’s so simple to check the wire gauge, estimate the length then run one of the free wiring calculators and then determine if the voltage drop is acceptable. Arbitrary statements without knowing the basic information is just that arbitrary.

My prior MH used a larger neutral from gen to ATS to CB panel for the QD 7500. So they understood the need for that MH and did not compromise with lower gen voltage at the main CB panel.

[polar76]

Thanks guys for all the input.... I was surprised over the back and forth between CA Traverler and Mile High, but thought it to be interesting...
Haven't decided to do this yet but have been looking into it. Might just by a new coach due to the cost of the upgraded and other things that need to be done.
Love my Country Coach but gotta look at the overall picture on cost.
The generator install would run close to $10k or more and I would have to have a shop drop the diesel tank and add pickup lines for the fuel.... just sayin it's going to be expensive.

Thanks again will give update on decision in the next few weeks.

[MrWizard]

That is exactly what is being pointed out
Rewiring is not needed, a neutral wire heavier than the hot wires is not needed

[BigRabbitMan]

MrWizard wrote:

he already has a 6500 LP generator

A 6500 LP generator is identical to a 7000 gasoline generator. The reduced energy in LP vs gasoline caused a de-rating to 6500 for the same unit. My unit says 7000 on the outside, but due to my changing it to LP it is now a 6500 unit.

All of that means that he would be wired for 7000 watts even though he has a unit rated at 6500. His upgrading to 8000 max output would be only a 14% increase in MAX available current. I have never used the maximum output of my generator.

[MrWizard]

i want to add something here , food for thought

he already has a 6500 LP generator

thats what ? 28 amps per leg, 56 amps max possible full load, on the neutral
in a strickly 120, 120 parallel in phase windings

8000w another 5amps per leg, a max possible 10amps increase on the neutral

do you really thing, the wiring is so weak, so undersized, that it is NOT going to handle that increase ?

I don't

[Mile_High]

That's fine with me. You kind of started out condescending to everyone on the post, but I can sit back and listen if you want to explain it.

[CA_Traveler]

Typo, should have been Mile not Mike.

I'm willing to start again and go into more depth if we're both willing to stop the personal posts on what each of us know. Agreed?

[Mile_High]

So in other words you really can't explain why nobody cares about what the neutral carries other than you. Not even the manufacturers see it your way.

I would like to believe what you are saying and I would like to understand, but when I open mine up I'm just not seeing anything that would support what you are saying - at least in terms of the upgrades you are saying are required to operate the 8,000QD. You may have a higher background knowledge, but on the ground I'm not seeing where what you are saying is actually engineered that way.

Who is Mike anyway 🙂

[CA_Traveler]

Mike,

Initially I just wanted to correct some of your mis statements. But we’ve gone beyond that and it’s clear that further depth is out of your wheel house. You can have the last word.

[Mile_High]

CA Traveler wrote:
Mike,

It's not theory - it's basic AC Circuits 101. Have you researched this to where you now understand the QD 8000 has a maximum 66A on the neutral and the RV 50A circuit has a maximum of 50A on the neutral?

I don't find anything from Onan that supports your theory Bob, but Onan isn't real open about publishing the install manuals. What I do know, is the Engineers that designed my coach didn't see it necessary to do anything special for the 8000 QD, so I'm sure the OP will be fine not upgrading the wiring or transfer switch. I have the same 50amp rated lugs on my transfer switch that he does on his, and the wiring gauge, including the neutral, coming from the shoreline is the same going to the CB. I don't see where the generator wire size is any larger than the others either. My personal opinion is you are trying to prove a point that has no difference on the outcome.

[CA_Traveler]

Mike,

It's not theory - it's basic AC Circuits 101. Have you researched this to where you now understand the QD 8000 has a maximum 66A on the neutral and the RV 50A circuit has a maximum of 50A on the neutral?

[Mile_High]

CA Traveler wrote:
Mike, You've just demonstrated that you don't understand a 120/240V circuit like the 50A RV. That's OK because we all have to learn.

Just so you know both hot's and the neutral are the exact same wire size. The secondary winding on the utility transformer is a single phase center tapped winding and the center tap is the neutral. Due to this type of circuit the center tap or neutral wire carries the difference in amps of the two hots. ie If one hot has 30A and the other 20A then the neutral has 10A. A 120/240V 50A RV circuit neutral does not carry the sum of the two hot lines. Hence none of the 3 wires will carry more than 50A due to the 50A CB on the hot lines.

The QD 8000 has 2 33A 120V circuits and it's common neutral does carry the sum of both of the hot wires. Hence the wiring needs to handle 66A all the way to the CB panel.

Here is what is wrong with your theory - My 8,000K gen is mated to a Surge Guard Model 41260 ATS with contactors rated at 50A FLA.

[Mile_High]

CA Traveler wrote:
Mike, You've just demonstrated that you don't understand a 120/240V circuit like the 50A RV. That's OK because we all have to learn.

Just so you know both hot's and the neutral are the exact same wire size. The secondary winding on the utility transformer is a single phase center tapped winding and the center tap is the neutral. Due to this type of circuit the center tap or neutral wire carries the difference in amps of the two hots. ie If one hot has 30A and the other 20A then the neutral has 10A. A 120/240V 50A RV circuit neutral does not carry the sum of the two hot lines. Hence none of the 3 wires will carry more than 50A due to the 50A CB on the hot lines.

The QD 8000 has 2 33A 120V circuits and it's common neutral does carry the sum of both of the hot wires. Hence the wiring needs to handle 66A all the way to the CB panel.

So you are saying the neutral wire size for an 8000K generator needs to be larger than that for the 50A 240 pedestal shore line to the CB. I think you are totally over thinking this.

[CA_Traveler]

Mike, You've just demonstrated that you don't understand a 120/240V circuit like the 50A RV. That's OK because we all have to learn.

Just so you know both hot's and the neutral are the exact same wire size. The secondary winding on the utility transformer is a single phase center tapped winding and the center tap is the neutral. Due to this type of circuit the center tap or neutral wire carries the difference in amps of the two hots. ie If one hot has 30A and the other 20A then the neutral has 10A. A 120/240V 50A RV circuit neutral does not carry the sum of the two hot lines. Hence none of the 3 wires will carry more than 50A due to the 50A CB on the hot lines.

The QD 8000 has 2 33A 120V circuits and it's common neutral does carry the sum of both of the hot wires. Hence the wiring needs to handle 66A all the way to the CB panel.