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storyarc
Explorer
Jan 31, 2020

Disconnect/Shut off converter when inverter is on

I recently got 600W of solar, two 12V 100ah gel batteries, 40amp charge controller, and 2500W inverter installed on my travel trailer. The guy who installed the system disabled charging via the converter so it wouldn’t create a loop when my inverter is on. He did this because there was no switch to physically turn off the charger when I want to turn on the inverter.

The problem is that I’m currently in Oregon and solar input is seriously low. We’re at a campground and our batteries are almost dead because there’s very little sunlight and charging via the 30 amp shore power is disabled.

1) How do I add a breaker/switch for the charger to my electrical panel so I can charge my batteries with shore power when my inverter is off?

2) I have a 35 amp converter charger. Can I just get a 35 amp breaker and have it installed?

40 Replies

  • DrewE wrote:
    35A is the output of the converter; the current at the 120V input will be considerably less than that.

    The basic solution is indeed to reconnect the converter with a switch or breaker dedicated to controlling it. Exactly how that might work depends some on what exact style of converter it is, whether you have extra space in your AC electric panel, and that sort of thing. One possible solution is to simply hook it up with a normal household light switch wired in to turn it on and off.

    Depending on how old the converter is, it might be worth considering upgrading it to a modern multi-stage converter if you expect to be using it much.


    I don’t expect to be using it much, maybe once or twice a month. We’re full-timers. We’ll mostly be boondocking in sunny areas. We’ll only be staying in RV parks or campgrounds once or twice a month.

    But we’ll be in the Pacific Northwest for 4-5 months a year, from late spring to early autumn, and we should still have a few days or weeks of rain during that time period. We will likely be utilizing campgrounds and RV parks more often during those months, to keep our batteries topped off.

    The converter is a 12-year-old three-stage converter. Is it worth changing it out for what I’ll be using it for?
  • BFL13 wrote:
    You have come to the right forum! :)

    So first give us the brand and model of the 35 amp converter so we can know how it gets its 120v. Some you just plug in and others are "hardwired".

    A 35 amp converter means only 35 amps DC. Its 120v input requires only a 15a circuit.

    On your 120v breaker panel, there should be one marked "CON" that might be sharing with some other 120v thing like "Receptacles" If the converter has its own breaker, that can be the switch.

    Your "gel" batteries are probably AGMs. There is a difference in how to recharge them. Confirm what you have there.

    Two 100ah batteries are not enough to run that 2500w inverter to run anything big like a microwave. OK for TV sets etc. Needs two more batteries for a MW.

    600w of solar is a lot with only two batteries as "storage". You can recharge them quicker than four batteries, but then you can't last as long between sunny days. (As is the situation)


    There’s no breaker labeled “CON”. There’s only one labeled MAIN and another labeled GENERAL. Don’t know what that means. If I don’t have one, can I just have a breaker for the converter installed? I have two open slots for additional breakers in the converter. The model is made by WFCO and model number is WF-8935AN with plastic.

    The gel batteries are Renogy gel batteries. They’re supposed to have more cycles than AGMs, but they’re not as expensive (or efficient) as lithium.

    I agree. I do need more batteries. We’re headed back to Southern California soon, where I had the solar system installed. When we were down there, we were almost always running on the float charge. We’ve never reached full charge since we arrived in Oregon last week. So I don’t need more batteries now, but I will when I get down to So Cal.

    And we don’t run the microwave much, so I’m not concerned about that.
  • Hi! Thanks so much for the replies! We’re on the road right now. Didn’t expect people to reply so quickly. We will look at all these replies when we’re stationary later tonight. Thanks!
  • "The problem is that I’m currently in Oregon and solar input is seriously low."

    With 600 solar watts recharging batteries with 200 AHs? You must be parked in the Oregon Caves.
  • Connect the converter to the AC power with a CB that IS NOT the inverter output.

    Lot's of questions about your installer. :h
  • How is your inverter wired into your 120v circuit breaker panel
    Did he add a new 30amp outlet for your shore cord to plug into?
    Did he run new wire to the breaker box from the inverter
    Or
    Did he install a transfer switch between shore cord and the inverter

    The inverter output side must be disconnected from the house wiring when using shore power

    Do Not plug into shore power until you know it is safe to do so, you risk damage to the inverter even if it is turned off, if it is not physically/electrically disconnected from the breaker panel and shore power
  • Why would any reputable installer do that?

    What do you mean 'gel' batteries?
  • 35A is the output of the converter; the current at the 120V input will be considerably less than that.

    The basic solution is indeed to reconnect the converter with a switch or breaker dedicated to controlling it. Exactly how that might work depends some on what exact style of converter it is, whether you have extra space in your AC electric panel, and that sort of thing. One possible solution is to simply hook it up with a normal household light switch wired in to turn it on and off.

    Depending on how old the converter is, it might be worth considering upgrading it to a modern multi-stage converter if you expect to be using it much.
  • You have come to the right forum! :)

    So first give us the brand and model of the 35 amp converter so we can know how it gets its 120v. Some you just plug in and others are "hardwired".

    A 35 amp converter means only 35 amps DC. Its 120v input requires only a 15a circuit.

    On your 120v breaker panel, there should be one marked "CON" that might be sharing with some other 120v thing like "Receptacles" If the converter has its own breaker, that can be the switch.

    Your "gel" batteries are probably AGMs. There is a difference in how to recharge them. Confirm what you have there.

    Two 100ah batteries are not enough to run that 2500w inverter to run anything big like a microwave. OK for TV sets etc. Needs two more batteries for a MW.

    600w of solar is a lot with only two batteries as "storage". You can recharge them quicker than four batteries, but then you can't last as long between sunny days. (As is the situation)
  • Hook the convert back up to the circuit breaker. Use the circuit breaker to turn the converter on and off.

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