Shore power and generator

lets say you are running the inverter for the fridge ? or whatever
and you pull up and plug in to shore power
at the moment 120v is applied to the inverter-charger combo, it stops inverting and pulls in the 120v TS aka input relay, it might be micro seconds delay that you can't see but it shut off the inverter 120v out while doing the switch

in the reverse case, you are on shore power, and it fails
no incoming 120v, charging stops, invert comes on and TS relay drops out, to default to inverter power
in fact both TS switches change state, the house TS switch drops out the instant shore line power fails, before the invert TS changes state

the problem with the house TS and gnerator shore connection
is that it often fails by sticking one set of contacts
a 30 amp switch , switches (4) wires hot and neutral on each side gen/sp to the house input
a 50amp switch , switches (6) wires 2 hots and neutral on each side gen/sp to house input

when one contact sticks you end up with one wire from the gen and one wire from the sp connected to the RV
the gen becomes the path for the return side back to shore box
the gen is not in phase and cannot control the utilty input
it is forcefully tried to sync with utility power
the EMF forces involved are not trivial
this is a dangerous thing

usermanual
you type faster than I do

Kayteg1 wrote:

usersmanual wrote:

Kayteg1 wrote:
Well, as far as I know inverter/shore and shore/generator can be the same transfer switches.
Might be not, but definitely apples to apples.

There not and no its not comparing apples to apples
The worry some have here is (example) when on SP you have
120V coming in and lets say the hot water and the AC are running
now you start gen set and its expected to absorb a large load and may be a dangerous situation and very hard on the system(potentially)
your little low amp inverter TS switch is never subject to such loads
and its perfectly acceptable to start gen set while on invertion to charge the batterys
Like I said Two entirely different scenarios
and on top of that your inverter will not invert ever while on SP
even when its turned on
So as said NO the inverter system and how it operates is not in any way the same as the situation being discussed here
that being ""starting gen set while on LIVE shore power""

OK, I am curious. How 30 amp transfer switch on shore power is different from 30 amp transfer switch on inverter?

we are getting a little off topic but have you actually looked at the physical size of the main TS verses the little one in a inverter
plus when starting gen set to charge batterys the inverter will switch off the 120V power feed and all the power will be supplied though the main (large) TS system till the gen set is shut down
then the inverter will transfer back to 120V supply
it is as I opined a completely different system and works in a different environment
this is the way I understand the inverter system to be

usersmanual wrote:

Kayteg1 wrote:
Well, as far as I know inverter/shore and shore/generator can be the same transfer switches.
Might be not, but definitely apples to apples.

There not and no its not comparing apples to apples
The worry some have here is (example) when on SP you have
120V coming in and lets say the hot water and the AC are running
now you start gen set and its expected to absorb a large load and may be a dangerous situation and very hard on the system(potentially)
your little low amp inverter TS switch is never subject to such loads
and its perfectly acceptable to start gen set while on invertion to charge the batterys
Like I said Two entirely different scenarios
and on top of that your inverter will not invert ever while on SP
even when its turned on
So as said NO the inverter system and how it operates is not in any way the same as the situation being discussed here
that being ""starting gen set while on LIVE shore power""

OK, I am curious. How 30 amp transfer switch on shore power is different from 30 amp transfer switch on inverter?

Mile High wrote:

Effy wrote:

Mile High wrote:
I was reading the manual on the Onan autostart, and in one mode it actually starts and runs daily for two hours, right before quiet time (preset) to recharge the batteries for the night. It would do this as a hot transfer in both directions between the inverter and generator and it is completely automatic. I wouldn't necessarily call that an emergency use only.

Why would it auto start to charge batteries if you are plugged in to shore power. Doesn't that also charge the batteries? I may very well be missing something as my system is nowhere near this sophisticated.

That autostart sequence would be used for boondocking for the purpose of battery charging, but the high voltage power is still transferred hot between the inverter and generator for that situation. Not that the ACs are running, but potential for up to a 2800W load is transferred between two live feeds.

Makes sense, thanks for the explanation.

Effy wrote:

Mile High wrote:
I was reading the manual on the Onan autostart, and in one mode it actually starts and runs daily for two hours, right before quiet time (preset) to recharge the batteries for the night. It would do this as a hot transfer in both directions between the inverter and generator and it is completely automatic. I wouldn't necessarily call that an emergency use only.

Why would it auto start to charge batteries if you are plugged in to shore power. Doesn't that also charge the batteries? I may very well be missing something as my system is nowhere near this sophisticated.

That autostart sequence would be used for boondocking for the purpose of battery charging, but the high voltage power is still transferred hot between the inverter and generator for that situation. Not that the ACs are running, but potential for up to a 2800W load is transferred between two live feeds.

Kayteg1 wrote:
Well, as far as I know inverter/shore and shore/generator can be the same transfer switches.
Might be not, but definitely apples to apples.

There not and no its not comparing apples to apples
The worry some have here is (example) when on SP you have
120V coming in and lets say the hot water and the AC are running
now you start gen set and its expected to absorb a large load and may be a dangerous situation and very hard on the system(potentially)
your little low amp inverter TS switch is never subject to such loads
and its perfectly acceptable to start gen set while on invertion to charge the batterys
Like I said Two entirely different scenarios
and on top of that your inverter will not invert ever while on SP
even when its turned on
So as said NO the inverter system and how it operates is not in any way the same as the situation being discussed here
that being ""starting gen set while on LIVE shore power""

Well, as far as I know inverter/shore and shore/generator can be the same transfer switches.
Might be not, but definitely apples to apples.

Effy wrote:

Mile High wrote:
I was reading the manual on the Onan autostart, and in one mode it actually starts and runs daily for two hours, right before quiet time (preset) to recharge the batteries for the night. It would do this as a hot transfer in both directions between the inverter and generator and it is completely automatic. I wouldn't necessarily call that an emergency use only.

Why would it auto start to charge batteries if you are plugged in to shore power. Doesn't that also charge the batteries? I may very well be missing something as my system is nowhere near this sophisticated.

he was using a situation where hes not on Shore power ( a bit off topic but pretty obvious what situation hes referring to)so yes your missing something for sure

Kayteg1 wrote:
I am another one who want to see where transfer switches are danger?
When even wood spoon can be dangerous, for years I have been camping having 2600W inverter/charger with built-in transfer switch.
Often plug into 20 or 15 amp shore power, at the moment when AC was starting, or I put oven at the same time, the shore voltage would drop and inverter would instantly switch to battery power. When the draw stabilized few seconds later it would switch back to shore power.
In drastic situation transfer switch could be switching more than 10 times per hour.
During 10 years of using it never had a problem with the animal.

your trying to compare apples to oranges.two entirely different scenarios However I believe TS are safe and installed for a reason
look at the fact LOT OF US HAVE auto start gen start for when 120V gets goes off and gen starts automatically. so now gens running and the 120V comes back on grid etc

Mile High wrote:
I was reading the manual on the Onan autostart, and in one mode it actually starts and runs daily for two hours, right before quiet time (preset) to recharge the batteries for the night. It would do this as a hot transfer in both directions between the inverter and generator and it is completely automatic. I wouldn't necessarily call that an emergency use only.

Why would it auto start to charge batteries if you are plugged in to shore power. Doesn't that also charge the batteries? I may very well be missing something as my system is nowhere near this sophisticated.