50 amp controller on 30 amp trailer

[RJJ]

I am the process of thinking about some upgrades... I will probably need to install a 2nd AC unit on my 30 amp FC26U which means an upgrade to a 50 amp electrical system. But first, I want to upgrade my batteries and want a better charge controller. I will also go solar at some point, but right now, I'm just looking to consider preparation for the upgrade to the 2nd AC. Can I install a 50 amp charge controller on a currently 30 amp system? Or will I create problems I don't need? I guess if I have to, I'll add 200 watts of solar for the new batteries, but the additional AC won't happen until my next trip to JC (months away...) Thanks for your learned advice. 👍

[markdoane]

I think you need 50 amp AC (alternating current) for your two air conditioners.

The 50 amp DC (direct current) charge controller is for your future solar system. They are on different electrical systems.

There is no need to match the DC amp rating of the charge controller to the AC amp rating.

[RJJ]

Originally Posted by markdoane

I think you need 50 amp AC (alternating current) for your two air conditioners.

The 50 amp DC (direct current) charge controller is for your future solar system. They are on different electrical systems.

There is no need to match the DC amp rating of the charge controller to the AC amp rating.

Well, duh... of course. I was mixing my systems. Thanks for setting me on a better path. Much appreciated.

[steverino]

Originally Posted by RJJ

Well, duh... of course. I was mixing my systems. Thanks for setting me on a better path. Much appreciated.

Most Airstreams ship from the factory with 45 or 55 amp converters. Many people swap the OEM single-stage converter to multi-stage, which are easier on the batteries. In general, the only reason to increase converter capacity is if you were to add more batteries or replace them with significantly bigger batteries. In that case, you would probably want more than 200 watts of solar as well.

[RJJ]

Originally Posted by steverino

Most Airstreams ship from the factory with 45 or 55 amp converters. Many people swap the OEM single-stage converter to multi-stage, which are easier on the batteries. In general, the only reason to increase converter capacity is if you were to add more batteries or replace them with significantly bigger batteries. In that case, you would probably want more than 200 watts of solar as well.

Good to know. Thanks!

[gklott]

How will you get the new wiring from the second A/C unit down to your power panel?

Also, when you upgrade your A/C load center, insist on all branch circuit over current protection devices (OCPD, i.e., breakers) being combo AFCI and GFCI. The National Electric Code specifies this today in nearly all residence spaces. Am so glad we've done that when upgraded from 120V 30A to 240/120V 3-pole 50A service.

As you may have read on other forum posts, recommend using 105C stranded wiring throughout your trailer - like Ancor Triplex Cable, 12/3 Part # 131310. I do not recommend traditional Type NM-B Romex cable, which is 90C, for trailer wiring. If you use the trailer in the hot SW, recommend consider going from 12 AWG to 10 AWG (Ancor 131150) for the roof-mounted A/C.

73/gus

[A W Warn]

Originally Posted by RJJ

I am the process of thinking about some upgrades... I will probably need to install a 2nd AC unit on my 30 amp FC26U which means an upgrade to a 50 amp electrical system. But first, I want to upgrade my batteries and want a better charge controller. I will also go solar at some point, but right now, I'm just looking to consider preparation for the upgrade to the 2nd AC. Can I install a 50 amp charge controller on a currently 30 amp system? Or will I create problems I don't need? I guess if I have to, I'll add 200 watts of solar for the new batteries, but the additional AC won't happen until my next trip to JC (months away...) Thanks for your learned advice. ��

Just wondering why you need a second air conditioner? If you were out west were temperatures get really hot, I would understand.
My 34' lives in central FL, 80+ miles south or Orlando. It does fine with one 15k btu. Even in August when the temperatures hover around 100F, inside the trailer will maintain mid to upper 70's.
My 25' Safari has a 13.5k btu unit. It does fine in these conditions too.

add edit:
If you do add a second AC unit, it is not necessary to modify the existing wiring. Some people add a second power inlet that only powers that second AC unit. In other words, the second AC unit is on a separate power cord. Since most campground power pedestals have a duplex outlet in addition to 30 and 50 amp RV outlets, this works fine and is a lot less costly.

[RJJ]

Originally Posted by gklott

How will you get the new wiring from the second A/C unit down to your power panel?

Also, when you upgrade your A/C load center, insist on all branch circuit over current protection devices (OCPD, i.e., breakers) being combo AFCI and GFCI. The National Electric Code specifies this today in nearly all residence spaces. Am so glad we've done that when upgraded from 120V 30A to 240/120V 3-pole 50A service.

As you may have read on other forum posts, recommend using 105C stranded wiring throughout your trailer - like Ancor Triplex Cable, 12/3 Part # 131310. I do not recommend traditional Type NM-B Romex cable, which is 90C, for trailer wiring. If you use the trailer in the hot SW, recommend consider going from 12 AWG to 10 AWG (Ancor 131150) for the roof-mounted A/C.

73/gus

Thank you, Gus. I'm having the 2nd AC installed at JC, and will mention this recommendation to them.

[RJJ]

Originally Posted by A W Warn

Just wondering why you need a second air conditioner? If you were out west were temperatures get really hot, I would understand.
My 34' lives in central FL, 80+ miles south or Orlando. It does fine with one 15k btu. Even in August when the temperatures hover around 100F, inside the trailer will maintain mid to upper 70's.
My 25' Safari has a 13.5k btu unit. It does fine in these conditions too.

add edit:
If you do add a second AC unit, it is not necessary to modify the existing wiring. Some people add a second power inlet that only powers that second AC unit. In other words, the second AC unit is on a separate power cord. Since most campground power pedestals have a duplex outlet in addition to 30 and 50 amp RV outlets, this works fine and is a lot less costly.

AW, thanks for your input. The 2nd AC would be for my travels in southwest summers - AZ, NM, etc. 100-126 degrees... BUT, I won't make a final decision until after this summer's testing of my current 1 AC set up on my 26U. I live in FL, too.

[RJJ]

To everyone who contributed to my continuing education.

I so appreciate this site and the experience and expertise of its members.