Rewiring Generator to Chassis battery bank

[96 EVO]

Well, I think you have done a great job, solving your problem 👍!

Nice clean install!

As far as having a battery out front, American car builders did that for decades!

[Paul J A]

Put a Motorcycle battery up by the Genny, and use power from the FRB to charge it. Adequate CCA's to spin the Genny.

[96 EVO]

14 minutes ago, Paul J A said:

Put a Motorcycle battery up by the Genny, and use power from the FRB to charge it. Adequate CCA's to spin the Genny.

Not me!

I have no luck getting any lifespan out of motorcycle, or lawn tractor batteries!

[Paul J A]

51 minutes ago, 96 EVO said:

Not me!

I have no luck getting any lifespan out of motorcycle, or lawn tractor batteries!

In what application(s) ?

[96 EVO]

Well, motorcycle and zero turn mower.

Even putting them on a 1.5A battery maintainer for a couple of days a month, I'm lucky if I get a couple of yrs service out of them 😖!

[Trevor and Laura]

I copied the idea from someone else who had used an Optimum gel battery, had tried for the same as our Fiat 500 toad, but something didn't fit, the grp 26 was from Canadian Tire, maintenance free, 3 year free replacement, 540cca, not too expensive. Now with some solar likely never to be needed.. but without the solar and battery switches off both banks discharged down to around 12.2v, measured at the batteries after a couple of weeks when in storage. That was enough to start the ISL, thankfully, maybe the gennie with a bigger cable at the front, but maybe not.. I was not of a mind to try and find where the power was going then and certainly not now. The chassis batts were new in June. 

Think I know enough to realise that there is good reason to be nervous of the electrical systems in our lovely Dynasty, Bella.. I have no trouble adding something simple though.

3 weeks ago I had to switch out our Big Boy, shut off the battery disconnects, good, no volts on those big terminals but there was very close by to its mounting screws, put tape on the socket and then decided to play safe and kill the battery grounds. Saying this because there was quite a spark from the house side when reconnecting, may have been some solar charging, or??

[96 EVO]

26 minutes ago, Trevor and Laura said:

  Saying this because there was quite a spark from the house side when reconnecting, may have been some solar charging, or??

Mine has given a healthy spark every time I've replaced my house batteries, even though all power shut off, and no solar!

From what I've been told, it has something to do with the inverter. 

[Trevor and Laura]

That is good to know, thanks Ben.

[Tom Cherry]

4 hours ago, Paul J A said:

In what application(s) ?

I have gone through a LOT of engines (Generators, Lawn Tractors, Stationary Home Generators and such) and learned a lot.  I had a 3 year old Deere lawnmower battery fail.  The JD shop foreman told me NOT to waste my money letting him repair the crappy "charging" circuit on the Kohler Engine...would have been over $400 to pull the top of the engine off and it could "blow up" in a few months.

I then started using "Battery Tenders".  There are MANY brands.  Some here ended up using the same ones that I used.

These are 1.5 - 2.0 Three Stage (Not the CHEAP 6/12 Chargers) maintainers.  Here is a link to the one that I use now....and several have used them with great success. Northern Tool also sells them.

https://www.amazon.com/BatteryMINDer-Model-1500-SmarTECHnology-Motorcycles/dp/B00D7HZ6FC?pd_rd_w=dWd01&content-id=amzn1.sym.904ca806-5e87-42cf-86b8-c792f6d660bd&pf_rd_p=904ca806-5e87-42cf-86b8-c792f6d660bd&pf_rd_r=5X7DDKZDG00VCCV324KQ&pd_rd_wg=czS8I&pd_rd_r=5fa691c6-f47e-4d28-9376-98cd56edea89&pd_rd_i=B00D7HZ6FC&psc=1&ref_=pd_bap_d_grid_rp_0_1_ec_t

BatteryMINDer 1500: 12 Volt-1.5 AMP

I got 10 years out of the Duracell "Batteries Plus" cranking (sealed Lead Acid) battery for my John Deere (14 HP).  I use another one for the Portable Emergency Generator.  I have one more that I use to keep the "Jump Pack"/Air Compressor battery charged.  They are GREAT.  There is a Battery Tender that is weatherproof....I have used them. The Batter MINDER also defulfonates and improves the life.  The BatteryTender ones don't, but I had one hung under a screened porch floor and it works great.

You need 120 VAC, but you just leave them plugged in.  When we were travelling for several months, I used one on one car in the garage and ran a "lamp cord" jumper cable over to the other car.  Both Cars were fully charged.

These have a THREE phase, like our Magnum, circuit and will NOT overcharge or burn up a battery.  The cheap 6/12 low amp chargers just keep pumping out juice and burn them up.

Ben, I think, is talking about a 12VDC to 12VDC Charger that may have the 3 phase or controlled charging.

Many folks will actually use the BatteryMinder and plug into the MH's inverter and use to to charge or keep charged the Chassis Battery when they have 120 VAC in storage, but NOT a BIRD system.

 

On 11/20/2023 at 8:09 PM, 96 EVO said:

Well, I think you have done a great job, solving your problem 👍!

Nice clean install!

As far as having a battery out front, American car builders did that for decades!

Right you are...on both.  Trevor did a GREAT job.  Yes, Car manufacturers put batteries up front, sometimes under a floor panel in the interior (WAY BACK WHEN) or in the trunk.

As LONG as the Cabling is correct (sized for the Length of Run and the Max Amps) all is well.

What we have here is a problem.  The cables from the FRB studs as well as ground were puny....way undersized.  Monaco made a Boo Boo.

SO, I applaud Trevor's workmanship and the way he wired it in.  However, in reality, new Cables (2/0) for less than $75 would have, based on all we know and other "electrical experts here", have solved it.

 

[96 EVO]

13 minutes ago, Tom Cherry said:

  The JD shop foreman told me NOT to waste my money letting him repair the crappy "charging" circuit on the Kohler Engine...would have been over $400 to pull the top of the engine off and it could "blow up" in a few months.

 

 

Ha!

My zero turn mower has a 20hp, single lung Kohler engine!

Other than my hotrods in years gone bye, probably the thirstiest motor I've ever owned! 

[Tom Cherry]

10 hours ago, Newcsn said:

@Ivylog Just ran across your pic of the new compressor/battery mount. What brand of compressor is that? And, do I assume correctly that the battery is to start the genset? If so, I’ve been considering doing the same & would value feed back on wiring & components necessary to put a genset starting battery up front w/ short cable runs. Will the alternator on the genset charge this battery/how do you keep it charged?  Thanks

If you want the WHOLE story and the rationale as to WHY most Generator starting issues were the fault of Monaco in undersized wiring and why upgrading the wiring should eliminate the need....

Some folks have done an excellent job, be it all expensive, and added an upfront battery.  However, at least 80 plus percent of the Dynasty owner never have an issue. Monaco GOOFED.  Upgrading the Wiring to the Generator (where the Starter gets its power) is the most simple and cost effective solution.

There is NO rhyme or reason as to why the majority don't have an issue, but correcting Monaco's GOOF should eliminate the need for an upfront battery.

[Tom Cherry]

56 minutes ago, Ivylog said:

Yes the battery is #4 on the engine side mounted next to the generator. Tied into the engine’s lug on the outside of the FRB so charged by the engine’s alternator. I find mixed results the my 10K has its own alternator… don’t see one on it.

Air compressor is off EBay.

The ONLY way to know is to pull the Model Number and download that manual. There were several of the earlier 10K's that DID have an Alternator....and then Onan dropped that or it was a special model. Typically, the 12.5K's DO have them... BUT, wired properly?  Who KNOWS.  The wiring issues were not understood until a realistic evaluation of current capacity and wire size...see my other post.

And, again, the "won't start and need an Aux Battery" issue only impacts a small number...I was way low when I estimated that 80% do NOT have an issue.  NOW, when it gets REALLY COLD...maybe, but if your Engine will crank, that means that the Starting or Chassis batteries are OK. BUT, if you underwire it...like Monaco DID...you will have an issue. One of the nicest Aux Battery projects was a dream.  REALLY GREAT workmanship. BUT, if you look at what he did...he upgraded the wiring to the Genny.  BINGO....that would have probably started the Genny with what he had...

 

[Newcsn]

11 hours ago, Tom Cherry said:

The ONLY way to know is to pull the Model Number and download that manual. There were several of the earlier 10K's that DID have an Alternator....and then Onan dropped that or it was a special model. Typically, the 12.5K's DO have them... BUT, wired properly?  Who KNOWS.  The wiring issues were not understood until a realistic evaluation of current capacity and wire size...see my other post.

And, again, the "won't start and need an Aux Battery" issue only impacts a small number...I was way low when I estimated that 80% do NOT have an issue.  NOW, when it gets REALLY COLD...maybe, but if your Engine will crank, that means that the Starting or Chassis batteries are OK. BUT, if you underwire it...like Monaco DID...you will have an issue. One of the nicest Aux Battery projects was a dream.  REALLY GREAT workmanship. BUT, if you look at what he did...he upgraded the wiring to the Genny.  BINGO....that would have probably started the Genny with what he had...

 

Thanks @tom cherry & @ivylog ! I must be one of those “lucky” Dynasty owners that has the genset start issue. I’ve checked all batteries (8 house & 2 new chassis - no bad battery & all fully charged) & cleaned all terminals.  Genset attempts to start but only grunts a couple times. However, when the main engine is running the genset will crank right up! 

It would appear the “undersized cables” may be its issue. From a cost & labor perspective it would seem much easier to install a battery setup similar to Ivylogs - as opposed to running heavier cables the length of the coach.  And, our 10 KW does have an alternator on it - I’ve replaced its belt.

Am I missing something on the “cost & labor” side of the equation? Thank you!

[Paul J A]

3 hours ago, Newcsn said:

Thanks @tom cherry & @ivylog ! I must be one of those “lucky” Dynasty owners that has the genset start issue. I’ve checked all batteries (8 house & 2 new chassis - no bad battery & all fully charged) & cleaned all terminals.  Genset attempts to start but only grunts a couple times. However, when the main engine is running the genset will crank right up! 

It would appear the “undersized cables” may be its issue. From a cost & labor perspective it would seem much easier to install a battery setup similar to Ivylogs - as opposed to running heavier cables the length of the coach.  And, our 10 KW does have an alternator on it - I’ve replaced its belt.

Am I missing something on the “cost & labor” side of the equation? Thank you!

YEP! I would do as Dick Bell did.

16 hours ago, Tom Cherry said:

If you want the WHOLE story and the rationale as to WHY most Generator starting issues were the fault of Monaco in undersized wiring and why upgrading the wiring should eliminate the need....

Some folks have done an excellent job, be it all expensive, and added an upfront battery.  However, at least 80 plus percent of the Dynasty owner never have an issue. Monaco GOOFED.  Upgrading the Wiring to the Generator (where the Starter gets its power) is the most simple and cost effective solution.

There is NO rhyme or reason as to why the majority don't have an issue, but correcting Monaco's GOOF should eliminate the need for an upfront battery.

"However, at least 80 plus percent of the Dynasty owner never have an issue."  Tom, is that your estimate or ???

[Tom Cherry]

3 hours ago, Newcsn said:

Thanks @tom cherry & @ivylog ! I must be one of those “lucky” Dynasty owners that has the genset start issue. I’ve checked all batteries (8 house & 2 new chassis - no bad battery & all fully charged) & cleaned all terminals.  Genset attempts to start but only grunts a couple times. However, when the main engine is running the genset will crank right up! 

It would appear the “undersized cables” may be its issue. From a cost & labor perspective it would seem much easier to install a battery setup similar to Ivylogs - as opposed to running heavier cables the length of the coach.  And, our 10 KW does have an alternator on it - I’ve replaced its belt.

Am I missing something on the “cost & labor” side of the equation? Thank you!

Mark,

Did you read or scroll and scan the link that was provided. TECHNICALLY this should have been posted on the topic that was current.  TOO MUCH HOUSEKEEPING TO DO...so it stays here.

Look at the PRINT. You do NOT need to run cables to the rear. Look in the let side. The Genset has #2GA cables. That is being fed off a 4/0 cable. The issue is what Monaco ran to the Genset. That is a fairly short run. The most elegant "SS Installation" that was on the other thread or was posted before had at LEAST 2/0 cables from his NEW, UPFRONT Generator Battery...there was also an issue in keeping it charged.  I can't recall all the details, but that was the gist of it.

I did a lot of research on this.  SO, make up two new cables....the GROUND has to also be larger, and run them directly to the Genny. BE CAREFUL when you torque down the bolts on the ONAN.  They are BRASS...but using coming sense will work.

Hope this clears it up.  

2006 Dynasty High Current Drawing.pdf

39 minutes ago, Paul J A said:

YEP! I would do as Dick Bell did.

"However, at least 80 plus percent of the Dynasty owner never have an issue."  Tom, is that your estimate or ???

See my post explaining WHY there is an issue and why there are problems on SOME units.  NOT ALL. I can't explain that. BUT, yes, 80% is my estimate. We only have had maybe 15 - 20 members (my rough memory count) that have issues. In addition, many of them were Camelots and lower.

SO, let's put it another way.  Of all the Dynasty and ABOVE (Imperial, Executive, Navigator & Signature) owners....only a FEW have had issue. Maybe it is where the tried to start the Genny. One member did a great job in adding a battery. BUT, he was way up north and it was way below freezing.  He DID also replace the cables from the FRB or wherever he put in the Battery. I really think that if he had run new cables (2/0...is what I THINK he used), that it would have started fine. I guess that if he disconnected his aux battery and ran Jumper Cables from the 4/0 Stud to the positive in his setup, we would know. 

We have 1950 CCA from the Starting (Chassis) Battery.  Run that on a 4/0 cable up front.  THEN, stupidly, use a #2GA cable to the Genny.  BIG TIME VOLTAGE DROP. 

That's my logic and my "guestimate". I don't know if there is a POLLING option, but again, that is what I remember.

Hope that explains it... 

[Newcsn]

4 hours ago, Tom Cherry said:

I did a lot of research on this.  SO, make up two new cables....the GROUND has to also be larger, and run them directly to the Genny. BE CAREFUL when you torque down the bolts on the ONAN.  They are BRASS...but using coming sense will work.

Hope this clears it up.  

Thanks @Tom Cherry - and sorry for the add to your "housekeeping"! Cleared up! Happy New Year!

[Tom Cherry]

On 12/30/2023 at 5:19 PM, Newcsn said:

Thanks @Tom Cherry - and sorry for the add to your "housekeeping"! Cleared up! Happy New Year!

Not a problem….just let it ride.  A search will find it.  Try the cables first….then if that don’t work….good luck.

MODERATOR EDIT.  Moved all the posts that related to the Generator and Starting ISSUES to this thread...they do NOT exist on the old AUX AIR COMPRESSOR Topic.

[det944]

This is a great read and analysis. I've been having this very issue with my 2006 Dynasty despite NEW chassis batteries. I've tried all the recommendations like cleaning all the connection studs including the brass connections on the genset. I have not seen any significant corrosion or pitting on any of the connection so the voltage drop based on reduced gauge cable from the frb makes sense. I guess it's time to invest in some proper cable crimpers door 2/0 cable. Any recommendations would be welcomed. Thanks all that have contributed to this discussion! Very informative!

 

[amphi_sc]

9 minutes ago, det944 said:

This is a great read and analysis. I've been having this very issue with my 2006 Dynasty despite NEW chassis batteries. I've tried all the recommendations like cleaning all the connection studs including the brass connections on the genset. I have not seen any significant corrosion or pitting on any of the connection so the voltage drop based on reduced gauge cable from the frb makes sense. I guess it's time to invest in some proper cable crimpers door 2/0 cable. Any recommendations would be welcomed. Thanks all that have contributed to this discussion! Very informative!

 

It has been a good discussion about GENERATOR starting issues, genset cables, etc, but not obvious that when researching generator issues we will need to find this discussion under the topic of "aux air compressor for air leveling".  Just say'n

[Tom Whitlow]

https://www.harborfreight.com/hydraulic-wire-crimping-tool-64044.html

I use these from Harbor Freight.  But I bought them a while back at less than half the current price.

[Tom Cherry]

3 hours ago, amphi_sc said:

It has been a good discussion about GENERATOR starting issues, genset cables, etc, but not obvious that when researching generator issues we will need to find this discussion under the topic of "aux air compressor for air leveling".  Just say'n

YOUR VOICE WAS HEARD.  I did not have time to do this last week....too busy. NOW all are moved....

Comment @Tom Whitlow post. I chose to purchase the lowest cost...but highest rated Crimper on Amazon. That was several years ago.  I THINK I paid around $67 and it was FINE.  It is NO longer available....but for $75, here is what is the most popular. It has the same number or maybe more dies for different sizes. I ordered all the cables and fittings from Amazon. I now have 4/0 fittings that I can use to repair any of the HIGHEST current...I also purchased 2/0 fittings.  I have some lengths of different size cables as well.  SO, in my SPARES, I HOPE to be able to effect repairs.

Buy the one that you think is best...but think ahead and get fittings that you will need.  Check the "terminal" diameter as well as the Size that they work for. They are slightly pricey....but what we paid for these behomothes.....the cost of having the RIGHT fittings (Cable Size) and the RIGHT Diameter (Monaco used different diameters on the SAME Cable ends) is a small price...compared to running around and finding a Welding Shop.  NAPA will make cables, but they are usually much smaller...so if you need to repair a GOOD 4/0 cable, then this crimper and the fitting will do it.

Thanks for the link.

Here is the highest rated one for $75 that would be comparable to the one that I bought.

HYCLAT 16 Tons Hydraulic Wire Crimping Tool Battery Cable Lug Terminal Crimper With 13 Pairs of Dies, 9AWG to 600MCM Crimping Tool

[dandick66]

Ok, I know you’re not supposed to beat a dead hose, but I came up with an idea for the sluggish generator cranking.

For background, the cable running to the generator is 2/0.  It was set up to start from the house batteries.  I moved the cable to the chassis batteries and saw no difference in the starting.  Tom mentioned about running a cable from the 4/0 FRB stud.  However, my coach has a 2/0 running from the chassis batteries to the FRB and a 2 gauge (not 2/0) running from the house batteries to the FRB.

I considered adding another battery just for starting the generator, then I came up with this thought.  What if I ran a 2/0 cable from the 2/0 stud on the FRB to the generator?  Then I would have 2, 2/0 cables for starting the generator.  It would be cheaper and less maintenance than adding a separate starting battery.  
 

Thoughts and comments appreciated. 

[96 EVO]

Would basically be the same as holding the boost switch every time you start the gen.

On second though 🤔, wouldn't you be permanently tying your two banks together?

Edited February 4 by 96 EVO

[Tom Cherry]

4 hours ago, dandick66 said:

Ok, I know you’re not supposed to beat a dead hose, but I came up with an idea for the sluggish generator cranking.

For background, the cable running to the generator is 2/0.  It was set up to start from the house batteries.  I moved the cable to the chassis batteries and saw no difference in the starting.  Tom mentioned about running a cable from the 4/0 FRB stud.  However, my coach has a 2/0 running from the chassis batteries to the FRB and a 2 gauge (not 2/0) running from the house batteries to the FRB.

I considered adding another battery just for starting the generator, then I came up with this thought.  What if I ran a 2/0 cable from the 2/0 stud on the FRB to the generator?  Then I would have 2, 2/0 cables for starting the generator.  It would be cheaper and less maintenance than adding a separate starting battery.  
 

Thoughts and comments appreciated. 

Let's go through this again.  Maybe I gave TOO MUCH information.  The issue has always been on the Dynasty and UP.  OR AT LEAST THE BULK of the complaints and they were on the 10's and 12.5KW's.  NOW if you go back to the prints for the Dynasty, there is a 2/0 Cable from the FRT RUN BAY "Stud" to the Genny. THAT is where the problem is.  The solution, for most Dynasty and UP owners is to FIRST replace that 2/0 Cable.  Some have added a battery and then actually RUN larger cables to the Genny.  YES, of course if you run larger cables to the Genny and have an up front battery, it WILL not see the Voltage Drop. 

Again....this is MEMORY....but I DID check the Dynasty....YES, a 4/0 cable....the a puny 2 gauge cable to the Genny.  DUH.....run a 2/0 will definitely improve it....but one probably does NOT need a 4/0...but COULD.  The OTHER thing....you have GOT to also upgrade the GROUND cable....so it sized the same. Sounds simple...but sometimes the simplest, and yes...it happens to me...is NOT obvious....especially if one has their mind made up.

THAT is the solution for the Dynasty.

NOW...as to @dandick66 YES.  Monaco was inconsistent....GOD FORBID....in their wiring, especially large cables. See the above, for the DYNASTY.  Your Diplomat ain't like the Dynasty.  SO, YES, run a 2/0 from the Chassis Stud (4/0 if I read correctly). Next up.  UPGRADE the Negative. 

NOW, as Ben Pointed OUT..... You are JUMPERING your Banks.  NOT GOOD.  SO, back to your situation.

I would do this first...and then run the NEW cable from the FRB Stud...It is a 4/0 going in.  The shorter 2/0 will be better than the long 2/0...  PLUS you have a CRANKING battery, NOT a deep cycle...so your Chassis should work better.

MY QUESTION (Hunch and BEEN THERE)...  If you saw NO improvement....that here is an issue somewhere.  MY Genny starting issue was NOT in the cables. 

Remove BOTH Negative Ground studs behind the Battery box (one for Chassis and one for House). Clean thoroughly. 

Do the SAME for the Genny Negative up front. We do NOT have your prints...so I am ASUMMING that you have a 2/0 GROUND.  Never trust a GROUND.  Clean it.  Folks have spent considerable time chasing issues...and ran new grounds.  OPPS...turned out the FIRST Front Chassis Ground was "tainted".  They LOOK FINE. My Genny would NOT start.  It was simple. The House had a corroded (you could NOT see it), but I did a lot of OHM Measurements...and found the bad ground on the House.  Took 5 minutes to fix.  NO ISSUES since 2015..

OK...if that doesn't work....put in the new cable from up front.

I would also tell you to check the buss where the 2/0 cable is hooked up.  YOU NEVER KNOW...

You are GOOD to GO...

 

3 hours ago, 96 EVO said:

Would basically be the same as holding the boost switch every time you start the gen.

On second though 🤔, wouldn't you be permanently tying your two banks together?

@96 EVO

Ben, I think these will be combined...but YES, you are right.  I just pulled our prints again.

I think the solution to your issues, assuming you still have them...and also assuming the MONACO wired our MH's the same.  We ONLY have a 1/0 Cable from the BACK to the front Genny. 

BUT, we have TWO 2/0 Cables (each has a 200 Amp Fuse).  If you wanted to simply rewire yours, then there are TWO suggestions...

First...simple.  I would CHECK the Ground on the House Bank, as the Chassis Bank as well.  A bad ground on the House (STUD) shut off my Genny. 5 minutes to fix.  BUT...

If you want the optimum.  Then run a NEWS 2/0 cable from the FRONT Chassis Stud to the Genny.  Also replace the 1/0 Ground with a 2/0.  THAT should easily fix it.

NOW...the ULTIMATE.  Purchase a Blue Seas Battery Selector Switch. They make one that allows OFF, BATT 1, BATT 2 or BOTH.  Put that sucker in BOTH....if it don't start....your Starter needs some looking at. Personally, I think there is a high resistance connection...and a swap to the FRB and using a 2/) cable will fix it....unless you DO find a Ground Stud issue.

That's my take....unsolicited...but seem logical after I pulled my High Current Print...  It sure works great for my Hydraulic slide.  I have it on a selector switch....and I DID find that the House Battery Switch has a "wee tiny issue". That is the HALF volt drop I have chased for years. It will be fixed...and then if I ever have an issue....pour both banks to the hydraulics...

[dandick66]

3 hours ago, Tom Cherry said:

Let's go through this again.  Maybe I gave TOO MUCH information.  The issue has always been on the Dynasty and UP.  OR AT LEAST THE BULK of the complaints and they were on the 10's and 12.5KW's.  NOW if you go back to the prints for the Dynasty, there is a 2/0 Cable from the FRT RUN BAY "Stud" to the Genny. THAT is where the problem is.  The solution, for most Dynasty and UP owners is to FIRST replace that 2/0 Cable.  Some have added a battery and then actually RUN larger cables to the Genny.  YES, of course if you run larger cables to the Genny and have an up front battery, it WILL not see the Voltage Drop. 

Again....this is MEMORY....but I DID check the Dynasty....YES, a 4/0 cable....the a puny 2 gauge cable to the Genny.  DUH.....run a 2/0 will definitely improve it....but one probably does NOT need a 4/0...but COULD.  The OTHER thing....you have GOT to also upgrade the GROUND cable....so it sized the same. Sounds simple...but sometimes the simplest, and yes...it happens to me...is NOT obvious....especially if one has their mind made up.

THAT is the solution for the Dynasty.

NOW...as to @dandick66 YES.  Monaco was inconsistent....GOD FORBID....in their wiring, especially large cables. See the above, for the DYNASTY.  Your Diplomat ain't like the Dynasty.  SO, YES, run a 2/0 from the Chassis Stud (4/0 if I read correctly). Next up.  UPGRADE the Negative. 

NOW, as Ben Pointed OUT..... You are JUMPERING your Banks.  NOT GOOD.  SO, back to your situation.

I would do this first...and then run the NEW cable from the FRB Stud...It is a 4/0 going in.  The shorter 2/0 will be better than the long 2/0...  PLUS you have a CRANKING battery, NOT a deep cycle...so your Chassis should work better.

MY QUESTION (Hunch and BEEN THERE)...  If you saw NO improvement....that here is an issue somewhere.  MY Genny starting issue was NOT in the cables. 

Remove BOTH Negative Ground studs behind the Battery box (one for Chassis and one for House). Clean thoroughly. 

Do the SAME for the Genny Negative up front. We do NOT have your prints...so I am ASUMMING that you have a 2/0 GROUND.  Never trust a GROUND.  Clean it.  Folks have spent considerable time chasing issues...and ran new grounds.  OPPS...turned out the FIRST Front Chassis Ground was "tainted".  They LOOK FINE. My Genny would NOT start.  It was simple. The House had a corroded (you could NOT see it), but I did a lot of OHM Measurements...and found the bad ground on the House.  Took 5 minutes to fix.  NO ISSUES since 2015..

OK...if that doesn't work....put in the new cable from up front.

I would also tell you to check the buss where the 2/0 cable is hooked up.  YOU NEVER KNOW...

You are GOOD to GO...

 

@96 EVO

Ben, I think these will be combined...but YES, you are right.  I just pulled our prints again.

I think the solution to your issues, assuming you still have them...and also assuming the MONACO wired our MH's the same.  We ONLY have a 1/0 Cable from the BACK to the front Genny. 

BUT, we have TWO 2/0 Cables (each has a 200 Amp Fuse).  If you wanted to simply rewire yours, then there are TWO suggestions...

First...simple.  I would CHECK the Ground on the House Bank, as the Chassis Bank as well.  A bad ground on the House (STUD) shut off my Genny. 5 minutes to fix.  BUT...

If you want the optimum.  Then run a NEWS 2/0 cable from the FRONT Chassis Stud to the Genny.  Also replace the 1/0 Ground with a 2/0.  THAT should easily fix it.

NOW...the ULTIMATE.  Purchase a Blue Seas Battery Selector Switch. They make one that allows OFF, BATT 1, BATT 2 or BOTH.  Put that sucker in BOTH....if it don't start....your Starter needs some looking at. Personally, I think there is a high resistance connection...and a swap to the FRB and using a 2/) cable will fix it....unless you DO find a Ground Stud issue.

That's my take....unsolicited...but seem logical after I pulled my High Current Print...  It sure works great for my Hydraulic slide.  I have it on a selector switch....and I DID find that the House Battery Switch has a "wee tiny issue". That is the HALF volt drop I have chased for years. It will be fixed...and then if I ever have an issue....pour both banks to the hydraulics...

I think I need to better explain what I have and what I want to do.  My generator is connected to the RRB bus (chassis batteries) with a 2/0 cable.  There is another 2/0 cable running from that bus to the FRB.  I was thinking of running a new 2/0 cable from that stud on the FRB to the generator.  I would then have 2, 2/0 cables running from the RRB chassis bus.  The banks would not be connected unless I pushed the boost switch.