Understanding the generator wiring

[moonlitsouls]

Hey guys , so ive been doing some upgrades to the electrical system of my eagle cap 811 , im in the process of installing a victron multiplus inverter charger

As i learn more about the camper wiring and 12v electrical in general , i contacted eagle cap to ask them what the source was of two particular wires. They told me these two wires were actually coming from the generator

Ive attached a photo of these two wires , and a wiring schematic from eagle cap for reference ,

Shore power / generator power runs through a transfer switch and then to the ac panel

But , these two wires are not actually on the diagram (likely because its just an optional add on)

Here's what's confusing me

These wires from the generator were actually previous wired directly onto the battery (I've since moved them to pos/neg busbars

Apparently these wires turn ON the generator by way of the 12v switch located in my control panel section so to speak , its just the simple Onan start / stop switch to turn on the gen

So how does this work exactly ? The switch turns on the generator , but why do we need two 4awg wires running from the battery to the generator ?

the power from the gen should be going from the gen to the transfer switch to the ac panel

[noteven]

Yes you can put panels on top of one another on a truck camper

Link to video

[moonlitsouls]

pianotuna wrote:

moonlitsouls wrote:

mkirsch wrote:

moonlitsouls wrote:
But i think i got it now , these wires simply power the starter motor to my generator , then the output goes through the transfer switch , all that made sense to me. It never occured to me the gen needed a power source to start up

You connected them back to the battery, right? You want a direct connection to the battery for these. No fuses. No bus bars.

Morning , I run these off my busbars, I moved everything to busbars.

You think i should move them back?

No.

If you decide to move them back, have a circuit breaker or catastrophic failure fuse near the battery.

The other possibility would be too small wire to the buss bars. I think that is probably unlikely

my main battery positive runs through a 100a fuse , all good. the gen start up wires are pulling power from the positive and neg bus

[pianotuna]

moonlitsouls wrote:

mkirsch wrote:

moonlitsouls wrote:
But i think i got it now , these wires simply power the starter motor to my generator , then the output goes through the transfer switch , all that made sense to me. It never occured to me the gen needed a power source to start up

You connected them back to the battery, right? You want a direct connection to the battery for these. No fuses. No bus bars.

Morning , I run these off my busbars, I moved everything to busbars.

You think i should move them back?

No.

If you decide to move them back, have a circuit breaker or catastrophic failure fuse near the battery.

The other possibility would be too small wire to the buss bars. I think that is probably unlikely

[moonlitsouls]

mkirsch wrote:

moonlitsouls wrote:
But i think i got it now , these wires simply power the starter motor to my generator , then the output goes through the transfer switch , all that made sense to me. It never occured to me the gen needed a power source to start up

You connected them back to the battery, right? You want a direct connection to the battery for these. No fuses. No bus bars.

Morning , I run these off my busbars, I moved everything to busbars.

You think i should move them back?

[mkirsch]

moonlitsouls wrote:
But i think i got it now , these wires simply power the starter motor to my generator , then the output goes through the transfer switch , all that made sense to me. It never occured to me the gen needed a power source to start up

You connected them back to the battery, right? You want a direct connection to the battery for these. No fuses. No bus bars.

[3_tons]

moonlitsouls wrote:

3 tons wrote:
Wow!…How do you fit nearly 1000w on top of a truck camper??

3 tons

wait , you mean im not supposed to put them on top of each other? 🙂

Oh, I think I get it - it’s in a sandwiched thermionic generator configuration, right??

3 tons

(p.s. my EC 995 would be so lucky - lol)

[moonlitsouls]

3 tons wrote:
Wow!…How do you fit nearly 1000w on top of a truck camper??

3 tons

wait , you mean im not supposed to put them on top of each other? 🙂

[3_tons]

Wow!…How do you fit nearly 1000w on top of a truck camper??

3 tons

[moonlitsouls]

pianotuna wrote:
Nice equipment choices.

Will you go the auto generator start route?

hello , i dont think so, id like to use the generator for only emergencies. I have almost 1000w of solar so im hoping that covers all my needs.

[pianotuna]

Nice equipment choices.

Will you go the auto generator start route?

[moonlitsouls]

3 tons wrote:
I think you may be over-thinking it a bit…JMO

You didn’t mention whether or not you have a onboard genny?…

If not:

Since the Victron has it’s own built-in ATS switch (priority, shore or gen power), consider simply re-routing your shore power cord to the Victron, then from the Victron to the Main panel…

If so: Re-route the Shore power / Genny ATS output from the main panel to the Victron (and complete as mentioned above)…

Having said that, with an inverter you may also want to consider adding a sub-panel so that the inverter cannot inadvertently power up the OEM converter-charger (resulting in a’round-robin’ affair…), refer (passive power sensing-switching), water heater (or say, other wasteful consumers) etc…

Feel free to PM me for more ideas

3 tons

Hey 3 Tons , yes its an onboard onan generator , i included a wiring schematic.

But i think i got it now , these wires simply power the starter motor to my generator , then the output goes through the transfer switch , all that made sense to me. It never occured to me the gen needed a power source to start up

[3_tons]

I think you may be over-thinking it a bit…JMO

You didn’t mention whether or not you have a onboard genny?…

If not:

Since the Victron has it’s own built-in ATS switch (priority, shore or gen power), consider simply re-routing your shore power cord to the Victron, then from the Victron to the Main panel…

If so: Re-route the Shore power / Genny ATS output from the main panel to the Victron (and complete as mentioned above)…

Having said that, with an inverter you may also want to consider adding a sub-panel so that the inverter cannot inadvertently power up the OEM converter-charger (resulting in a’round-robin’ affair…), refer (passive power sensing-switching), water heater (or say, other wasteful consumers) etc…

Feel free to PM me for more ideas

3 tons

[moonlitsouls]

KD4UPL wrote:
Those wires are likely to power the starter motor to crank your generator to get it started. They have nothing to do with controlling it. They have nothing to do with it's output.

Thanks for the reply , im also confused about the connection between the switch and the wires , is the switch wired to the gen itself , then the gen uses these wires to pull power from the battery to start up?

[KD4UPL]

Those wires are likely to power the starter motor to crank your generator to get it started. They have nothing to do with controlling it. They have nothing to do with it's output.