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Jim 75 · 05-21-2022, 09:49 AM

Hi Everyone, hope all are well. I have a 2012 MADP 4336, ALL Electric coach. Every since I have owned this new to me MH (purchased Apr 2021) I cant get the generator to start on house batteries. So with that being said, I find out these batteries have a date stamp dated 29-11-2010. Unbelievable right? So after testing many time (just voltage) decided to replace them. Load tested old ones after removal some border line, some dead-dead. Installed (8) new Crown AGMs, (charged up) STILL wont start!!

So to start the Gen. I start the big eng, soon as voltage comes up I hit the start button and it fires right off. Your wondering if I use the start procedure? YES I do...So when trying to start on house batts. the gen sounds like there is low batts. The starter is real slow, BUT, when I use the big eng. and hit the Gen start button, it turns over like it is supposed and it starts. I cleaned all cable ends, saw NO sign of corrosion. Did not check cable attachment at the starter as I`m to old to climb under to check. *^%^&*$@@(

So is there separate cables to the starter ?? Is there a relay/solenoid between?? Very frustrating after all this chasing to find the answer, SO HELP

PLEASE Thanks Jim

Skip426 · 05-21-2022, 10:40 AM

I can't provide any exact info for your coach ; but ; I'll comment on how Newmar laid out the battery power to the genset on my vintage Dutch Star .

From the coach battery positive post , within the first 3' of the cable that runs to the front of the coach is a 150 amp circuit breaker that protects the cable to a 12 volt power stud on the outside of the firewall above the genset .
Power stud is in the lower left of this picture .
The 12 volt circuit breaker is mounted on the chassis frame behind the battery tray . From pictures I've seen of battery banks on all electric coaches all I can say is you'll have to follow the cable and look for a C/B like the one in the second photo ; as I mentioned in the first three feet from the positive post .

MrMark52 · 05-21-2022, 10:42 AM

When you hit the Emergency start switch it ties the coach and house batteries together to act as 1 big battery. That’s what it sounds like your doing.

You need to confirm the proper wiring of the new AGMS’s (it’s probably right or there would likely be smoke).

But what I really think the problem is is that you’ve got some bad battery cables between the battery bank and the genset starter solenoid. Particularly corrosion inside of the battery terminal ends.
To test, attempt to start the genset - give it 20-30 seconds of attempt. Then promptly get out of the coach and CAREFULLY start feeling of all the battery cable terminations and cables in general.
Corrosion presents itself as heat in this situation. The reason for CAREFUL is metallic parts can get extremely hot in this type of test.

Mr JP · 05-21-2022, 11:17 AM

My generator spins over slowly also when using the house batteries and even when plugged in to 50amp service, but does start. I`ve cleaned all cables and checked all connections also.

Capt. Bill · 05-21-2022, 11:41 AM

Jim 75- I think you have a corrosion problem at your relays or ground on your Generator. Remove each one, brush it clean with a small stainless steel wire brush, apply dielectric grease & reinstall & tighten back down tight.

Also- next time try starting it at the generator- rocker starter switch8 on generator- and see if there's any difference?

Happy Trails

Pillbox · 05-21-2022, 11:45 AM

Check the ground cable from house battery to the frame.
Terry

USMCRET · 05-21-2022, 12:46 PM

How old are your chassis batteries, and are you sure the gen doesn’t use them for starting power? My old KSDP used the chassis’s batts.

PanJH · 05-22-2022, 06:11 AM

One our 2013 DS, the genset starts from the chassis batteries. There is a 40ft or so cable that runs from the rear of the coach to a stud located behind the front fuse/electrical bay. Then there is a short run from that stud to the studs on the genset. I found on our DS, hat the battery cable end at the chassis batteries was just touching the battery terminal. It wasn't bolted on!

Rev. Roy · 05-22-2022, 01:31 PM

When you said, "So to start the Gen. I start the big eng, soon as voltage comes up I hit the start button and it fires right off." that immediately said to me that the generator starts off the chassis batteries, not the house ones. Here's a test. Put a battery charger on the chassis batteries and try starting the generator before starting your engine. I am willing to bet it will start. If it starts, you'll need new chassis batteries.

twinboat · 05-22-2022, 02:00 PM

I would think that if he can start the main engine with the chassis batteries and the generator was also using them, the same batteries would start the smaller generator.

That leads us back to the house batteries starting the generator. Starting the main engine combines the healthy chassis batteries to the house batteries.

How about you post a picture of your house battery cable arrangement.

May be able to see any issues there.

Jim 75 · 05-22-2022, 07:04 PM

Jim 75 here!! First I want to thank ALL of you for your time and Info. helping me find the solution to my problem.

Having so many suggestions, let me update some of them.
I do hold the start switch to prime and warm first.
I have tried the Batt. Boost switch NO help.
I have tried the Rocker switch on the Gen. still NO.

If the chassis batteries (was told they were new ) will start the 450 HP diesel why wont they start the Gen. Unless they run a cable 43 ft to the Gen. This doesnt make sense to me??? Because using the BIG eng will start it real quick.
I will check tomorrow for a HOT cable / ground cable to the frame connection, and add a pic of old and new Batt.bank. Again many thanks---to be continued JIm

BrokeDown · 05-23-2022, 08:50 AM

My generator starts off it the chassis batteries. House batteries can be dead and the generator will start.

I would check the chassis batteries and all of the wires, terminals, etc from the batteries to the generator, both positive and ground.

Are your chassis batteries AGM or Flooded? If flooded, have you added (distilled) water lately?

-B

MrMark52 · 05-24-2022, 07:54 AM

You really, really, need to get the wiring diagram for your coach.

Kid Gloves · 05-24-2022, 08:30 AM

Quote:

Originally Posted by Jim 75

Jim 75 here!! First I want to thank ALL of you for your time and Info. helping me find the solution to my problem.

Having so many suggestions, let me update some of them.
I do hold the start switch to prime and warm first.
I have tried the Batt. Boost switch NO help.
I have tried the Rocker switch on the Gen. still NO.

If the chassis batteries (was told they were new ) will start the 450 HP diesel why wont they start the Gen. Unless they run a cable 43 ft to the Gen. This doesnt make sense to me??? Because using the BIG eng will start it real quick.
I will check tomorrow for a HOT cable / ground cable to the frame connection, and add a pic of old and new Batt.bank. Again many thanks---to be continued JIm

How else would the generator start if there were not cables running from the batteries to the generator?

Are the batteries located in close proximity to the engine? That’s one set of cables from the batteries to the starter. Are the batteries located some distance from the generator? Perhaps ~40’? That’s another set of cables.

It sounds as though your chassis batteries are healthy, as they are able to start the engine. The link between the batteries the generator appears to be somewhat compromised. It is unable to start the generator with the batteries at ~12.7V, but it is able to start it once the alternator is providing ~14.0V. Check the run from batteries to generator.