[kaptain]

....
There is also a trickle charger (echo brand?) that steals a little current from the house batteries to maintain the start batteries even if the merge switch is not "engaged".
....

My understanding is that, for that to happen, the rear battery disconnect switch has to be at the ON position.

[Richard]

Yes , unless the echo charger is wired DIRECTLY to the chassis batteries.

[TJ Clark]

On topic in that I have swapped AGM's for lithium house batteries. Now I can't start my generator.
I have all my new batteries in the forward battery compartment.

I seam to have 100% functionality of the house side of things. Low volt lights, air compressor, inverter/battery circuits.

I don't have generator start.



Near as I can tell at this point the house batterie positive makes a direct shot to the inverter. In the same location as the inverter is a low volt buss panel, mounted high on the bulkhead between the bays. (see photo) On the main positive bus of that panel I had 3- 4/0 cables landing on it. I was not able to identify their other end of 2. One of the three has continuity to the house battery main bus positive, in the battery compartment, it also had battery equivalent voltage to ground.  

My method for finding both ends of any one cable is to attach a wire to one end with my volt meter to the other, set to ohms and then go around the coach looking for continuity. Is that mythology correct? 

It didn't occur to me until this morning that the generator might be taking it's power from that bus panel.  

I have disconnected many 4/0 battery cables around the coach. The isolator has had the house side disconnected. The merge solenoid has had the house side disconnected. I have abandoned in place all battery cables that I have disconnected. They have either been disconnected at both ends or had the visible end insolated. 



So I think my marching order need to find both ends of all these cables as Richard already told me. 

Is it reasonable for me to think I'll find an existing path of cables from the generator starter to the engine start batteries? 



Thanks.

[Gnawrocki1]

On topic in that I have swapped AGM's for lithium house batteries. Now I can't start my generator.
I have all my new batteries in the forward battery compartment.

I seam to have 100% functionality of the house side of things. Low volt lights, air compressor, inverter/battery circuits.

I don't have generator start.



Near as I can tell at this point the house batterie positive makes a direct shot to the inverter. In the same location as the inverter is a low volt buss panel, mounted high on the bulkhead between the bays. (see photo) On the main positive bus of that panel I had 3- 4/0 cables landing on it. I was not able to identify their other end of 2. One of the three has continuity to the house battery main bus positive, in the battery compartment, it also had battery equivalent voltage to ground.  

My method for finding both ends of any one cable is to attach a wire to one end with my volt meter to the other, set to ohms and then go around the coach looking for continuity. Is that mythology correct? 

It didn't occur to me until this morning that the generator might be taking it's power from that bus panel.  

I have disconnected many 4/0 battery cables around the coach. The isolator has had the house side disconnected. The merge solenoid has had the house side disconnected. I have abandoned in place all battery cables that I have disconnected. They have either been disconnected at both ends or had the visible end insolated. 



So I think my marching order need to find both ends of all these cables as Richard already told me. 

Is it reasonable for me to think I'll find an existing path of cables from the generator starter to the engine start batteries? 



Thanks.

TJ, 
I don't know about your lithium setup, but if you isolated it like I did because I went to a 48v house system you can connect the generator to the house batteries at the isolator after you know which wires go to where.
I believe on my coach the generator lead was found in the little fuse box above the original inverter.
My 48v system charges the engine 12v that now powers all 12v loads

[Richard]

That method of checking continuity and a long piece of wire will definitely work.

You said you disconnected many 12V positive cables. Hmmmmmmmm.

I would start at the generator looking with the ohm meter and the long piece of wire. Find the other end of that 12v cable.

Not exactly your era coach, but if you look at the schematic, it looks like Newell runs a 12 v lead to the compartment under the driver for the gen start, and a cable from that terminal to the panel you found in the compartment with the inverter. 

Newell2002 12V battery circuit.pdf Size: 496.08 KB  Downloads: 16

[TJ Clark]

I don't seam to see a starter on the generator. I have the Yanmar/Kolher. Looking from the front of the coach what side is it on?





EDIT:

I'm seeing how silly this question is in hindsight. But until I ask the silly question I don't know how silly they are.

[TJ Clark]

Thanks guys.

I remembered the starter is connected is connected via a solenoid. Then found the cable leading from the low volt bus panel above the inverter that runs all the way back to the rear engine electrical box. I used the one side of the merge solenoid as a bus to connect everything at that end. I used a bronze bolt to connect the genny cable to the start battery cable. a bit of shrink tube and tape should be good until I figure out a better solution. I think another bus terminal post or two is in order. Generator is running and stopping on command.



EDIT:

I did a volt and amp check on both battery banks. It's clear the genset is charging the chassis battery.

Again thanks for having this forum here. Thanks to all the folks that share their wisdom.

[TJ Clark]

So I found a low volt system that is not getting full power. My front window shades while getting power they are not getting full voltage or amperage.

I have not yet put a voltage meter on them but in activating the switches I get a slight sound, no movement and then silence. So some power it there. Nothing changes with the coach batteries on or off or the engine running. I also get a dash light "PRE HEAT".

I'm beginning to think I need a great huge diode at the end of my new coach lithium's and then connect everything back the way it was.


What are your thoughts for the next step of troubleshooting?


Thanks.

[TJ Clark]

Went back to the drivers seat and noticed the "PRE HEAT" light faintly glowing. The merge switch was in the center position. I activated that switch down and the light glowed brightly, back to center and back to faint, push it up and the light is out. KICKER the sun shades operate.


Thoughts?

[Richard]

TJ,

Look at the schematic I posted. It is clear that the power to the gen starter is connected to the house batteries. Your connection of the gen start cable to the chassis batteries is not how the system was designed. By doing so, you are inadvertantly back feeding a ground circuit. That’s why the preheat light is glowing when the switch is not activated.

I don’t know the reasoning behind the disconnections that you did. So I could be entirely in left field.

The only disconnection you have to do to prevent the alternator from charging the lithiums was the one cable from the house side of the merge solenoid to the isolation diode box.