Currently have one flooded trojan house battery in my 1999 Coachman Class B that also has a onan 2800 genny. Almost impossible for me to get to the existing battery for maintance and I want more battery power. I know I could use my generator for 120v power but HATE the noise but don't want to take genny out as is useful sometimes.The plan is to do a stepped upgrade. 1st stage: put in four AGM 6v lifeline batteries, a trimetric 2025 rv monitor with 500 amp shunt and upgrading my magnetek 7345 controller with maybe powermax boondocker. (which controller isn't 100% decided.) I know I don't know everything about this 1st step but I think that there isn't too much modification necessary.2nd stage: when budget can afford, I want to incorporate a 2000 - 3000 pure sine inverter. I know there are different ways to accomplish this but at present I am favoring the installing a 30 amp receptacle from the inverter on the outside of the van and plugging the shore power plug into this when I want to run 120v off batteries.I know I have to not have the converter charging the batteries when the inverter is running. ...which I think would be happening if the shore power is plugged into the inverter 30 amp receptacle. Question: would it work to just use the "disconnect" switch that currently exists when I use the inverter?I am sorry if this is explained somewhere. I have spent a lot of time looking at the info here and other places. It probably has been answered but I either missed it or didn't clearly understand what was being said. Thank you very much for any help, Mary my email is: dancermm@comcast.net

The battery disconnect switch would not work for that, since the converter would still get its 120v from the inverter. You need to switch off the converter.The 7300 is a decent converter for when on shore power. We kept ours for that, and got the PowerMax deck mount as an additional charger, mounted close to the batts, for use when fast charging is needed on generator, to reduce gen time.You can mount the new converter right beside the new big inverter and they can share the same short, fat wires to the battery so you don't need two sets of those. Just go across between the inverter and charger then on to the battery bank.We also do the whole house by plugging the shore power cord into the inverter and can run the microwave, TV, etc. Works great.To isolate the 7300, which usually is on the same breaker as the receptacles you still want to work, you have to find the black wire coming up from below to the breaker and snip that, insert a switch, and then you can leave the breaker on so the receptacles work while the converter is switched off.The new deck-mount converter can just be unplugged from the 120, unlike the hard-wired 7300.

I suspect that your current disconnect switch is wired to disconnect the battery from the system, but not disconnect the converter. You need to devise some way of disconnecting the 120vac from the converter input when that 120vac is being supplied by the inverter. There is probably a circuit breaker that you can trip.

As long as you have the generator for big stuff like microwave and hairdryer I would encourage you to consider a smaller 150w-300w inverter for the small stuff. Small transfer switch can power the one circuit you need to plug stuff in without powering up the converter.

NWLady wrote:I know there are different ways to accomplish this but at present I am favoring the installing a 30 amp receptacle from the inverter on the outside of the van and plugging the shore power plug into this when I want to run 120v off batteries.This is how I did it although I'm certain the angry at anything but a sub-panel crowd will show up to poo poo on my setup. Regardless, it works and doesn't need a contractor (to replace the walls that you'll have to tear down to run new wires to your sub panel...yes that's what you'd HAVE to do in my rig to use a sub panel...even my old rig would've required this but no one elses does apparently) nor an electrician to implement.

Thank you everyone. Good ideas and info. like Mena661, I don't want to have to tear things apart to the walls. I am a nurse not an electrical engineer so putting in switch and the like is doable for me. My generator works great but I really dislike having to start it up any time I want to use the micro so trying to set things up so I can run the micro a little off the batteries. Being able to rewarm my coffee in the micro is such a sweet luxury. Thanks again.

need help with install of inverter in Class B

11 Replies

pianotuna
Nomad III
Oct 26, 2013
Hi NWlady,

The big fat #2 wire only needs to go to the inverter.

I used the largest size that would fit my inverter.
NWLady
Explorer
Oct 26, 2013
Thank you everybody for your help. Gives me more things to consider. I went from 2 to 4 batteries because I did read that two was minimum for that type of load even for short periods. I was planning on replacing the existing 6 wire with 4 but maybe I need to consider doing #2.

I was leaning towards the PD 4645 or 4655 because it is a staged charger but maybe I need to contact lifeline or get more info on lifeline AGM battery charging needs. ....or look at the universal batteries.

I sure do appreciate everyone sharing their ideas and experiences.
pianotuna
Nomad III
Oct 24, 2013
Hi NWLady,

Currently the "best bang for the buck" on a PSW inverter is the Prowatt 2000 PSW $355.00

Lifeline units are VERY specific in their charging parameters. It may be better to consider Universal AGM instead.

Since there is limited space, I'd consider an 8D AGM. There are good reasons to avoid external connections on six volt batteries under large loads (200 amps is definitely in that category).

If you attempt to use the existing battery disconnect switch with a 200 amp load you will let out the "magic blue smoke". The wire feeding the switch at 200 amps may act like a fuse and burn out.

Large inverters do better with short runs of thick wire to the battery.

I plug my shore power cord into an outlet powered by the inverter.
I disconnect the converter, and set the fridge to propane only.

I added an auxiliary shore power cord for just the converter, so when I have only a 15 amp source of power I can do "double conversion" and run the RV from my inverter--while charging the battery bank from shore power. It's great for times that I don't have access to the shore power breaker box.

NWLady wrote:
Currently have one flooded trojan house battery in my 1999 Coachman Class B that also has a onan 2800 genny. Almost impossible for me to get to the existing battery for maintance and I want more battery power. I know I could use my generator for 120v power but HATE the noise but don't want to take genny out as is useful sometimes.

The plan is to do a stepped upgrade.

1st stage: put in four AGM 6v lifeline batteries, a trimetric 2025 rv monitor with 500 amp shunt and upgrading my magnetek 7345 controller with maybe powermax boondocker. (which controller isn't 100% decided.)

I know I don't know everything about this 1st step but I think that there isn't too much modification necessary.

2nd stage: when budget can afford, I want to incorporate a 2000 - 3000 pure sine inverter. I know there are different ways to accomplish this but at present I am favoring the installing a 30 amp receptacle from the inverter on the outside of the van and plugging the shore power plug into this when I want to run 120v off batteries.

I know I have to not have the converter charging the batteries when the inverter is running. ...which I think would be happening if the shore power is plugged into the inverter 30 amp receptacle.

Question: would it work to just use the "disconnect" switch that currently exists when I use the inverter?

I am sorry if this is explained somewhere. I have spent a lot of time looking at the info here and other places. It probably has been answered but I either missed it or didn't clearly understand what was being said.

Thank you very much for any help, Mary my email is: dancermm@comcast.net
BurbMan
Explorer II
Oct 24, 2013
This guy had issues getting his microwave to run off an inverter which apparently is a common problem. Long thread but worth a read if you are going to all this trouble primarily for the microwave.
BFL13
Explorer II
Oct 24, 2013
AGMs vary as to what charging profile is both safe and suitable. PowerMax along with most converters is ok with AGMs or Wets but ISTR people here say Lifeline AGMs are unusual, so I don't know for them. The AGM guys can answer that.
NWLady
Explorer
Oct 24, 2013
BFL - thanks for the great info and idea.... and the actual info of what I need to find....and snip... and insert. My new batteries will be AGM. Does the powermax, you speak of, do a good job for AGMs? I will look into your ideas. Thank you very much. mary
NWLady
Explorer
Oct 24, 2013
Thank you everyone. Good ideas and info. like Mena661, I don't want to have to tear things apart to the walls. I am a nurse not an electrical engineer so putting in switch and the like is doable for me. My generator works great but I really dislike having to start it up any time I want to use the micro so trying to set things up so I can run the micro a little off the batteries. Being able to rewarm my coffee in the micro is such a sweet luxury. Thanks again.
mena661
Explorer
Oct 24, 2013
NWLady wrote:
I know there are different ways to accomplish this but at present I am favoring the installing a 30 amp receptacle from the inverter on the outside of the van and plugging the shore power plug into this when I want to run 120v off batteries.
This is how I did it although I'm certain the angry at anything but a sub-panel crowd will show up to poo poo on my setup. Regardless, it works and doesn't need a contractor (to replace the walls that you'll have to tear down to run new wires to your sub panel...yes that's what you'd HAVE to do in my rig to use a sub panel...even my old rig would've required this but no one elses does apparently) nor an electrician to implement.
time2roll
Nomad
Oct 24, 2013
As long as you have the generator for big stuff like microwave and hairdryer I would encourage you to consider a smaller 150w-300w inverter for the small stuff. Small transfer switch can power the one circuit you need to plug stuff in without powering up the converter.
OnaQuest
Explorer
Oct 24, 2013
I suspect that your current disconnect switch is wired to disconnect the battery from the system, but not disconnect the converter. You need to devise some way of disconnecting the 120vac from the converter input when that 120vac is being supplied by the inverter. There is probably a circuit breaker that you can trip.

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need help with install of inverter in Class B

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