Giggy Box

[Sknuckles]

Does anyone know the max amperage circuit breaker that can be placed in the Giggy Box. My converter, WF 9855 AD, is 55 amp output and only has a 30 amp circuit breaker installed by the factory. The current 30 amp does trip often not allowing my batteries to fully charge. I do have a 50 amp circuit breaker in the Giggy box for another line. The converter manufacturer stated I should have 60 amps breaker. I dont think I can find a resettable 60 amp circuit breaker but I will try before installing a 60 amp breaker outside the Giggy.

Does anyone know the max amperage of the Giggy Box?

 

[NH_Bulldog]

The label on the inside of the cover identifies all circuits and breaker/fuse capacities. I wouldn’t deviate from what is listed on the label.

I have the same converter, but it is dark and raining at the moment so I cant tell you what is in my Giggy box, but I can take a look tomorrow.

I can’t put my finger on the specs off the top of my head, but I seem to recall when I was researching my inverter install that the Giggy box unlike a standard circuit breaker, doesn't have a single amp rating printed on it because its capacity is determined by the combined load of all connected devices and the associated wiring.

 

[Sknuckles]

Thanks

There isn’t a max amperage on my lid or the box. Thanks for your help.

 

[Viper02]

The MAIN BATTERY FEED breaker on the Giggy box is 150 amps.. the OUTPUT BREAKERS vary from 30 to 50 amps..

The converter should be wired to the power center BUS and battery feed

 

[JRTJH]

I believe the "max amperage" for the entire Giggy Box is what the Battery Cutoff Switch is rated. That's 150 amps @12VDC. Here's a wiring diagram for the Giggy Box showing how the battery cable comes into the box, splits to the breakaway safety device (always has power), splits to the solar system (also always powered on) and then to the BCO (max 150 amps) where it splits to two 50 amp (6-7) and two 30 amp (8-9) breakers with provision for an auxiliary (4) and two "optional" (10-11) which may not be used in some floorplans and one or both may be used in some floorplans, depending on equipment installed in the trailer.

I'm also including a tow vehicle/trailer wiring file that might shed some light on the question as well as the Giggy Box diagram illustration from that file.

Also, note that the Brock Box (used in fifth wheels) is similar to the Giggy Box (used in conventional travel trailers). In the larger fifth wheel lines, some have hydraulic pumps to power the slides/landing gear. In those trailers, I believe the factory installs either an 80 amp or a 90 amp circuit breaker for the hydraulic system. It is wired "alongside the Brock Box" and is not integrated into the actual Brock Box...

So, as far as I can tell, the "highest amperage rated component" in the Giggy Box is the 150 amp battery cutoff switch and the highest rated circuit breaker is 50 amps.

I would be reluctant to add any electrical wiring INSIDE the Giggy Box. That space is limited, there is a lot of potential for heat to be generated inside that space and adding any "high amperage wiring" to what's already there would/could present a problem if things "go south"... If it were me, I'd find a watertight automotive wiring box, mount it adjacent to the Giggy Box and install any additional wiring/circuit breakers in that new box. Any increase in circuit breaker amperage rating "inside the box" should be limited to the wire size on the circuit in question. Knowing Keystone, I'd suspect that they've used the smallest gauge wire for the circuit breaker for wiring "inside the Giggy Box", which would limit changing out a circuit breaker for a larger one to help prevent tripping when in use.....

Note: I downloaded this file from the internet and do not have any knowledge who initially provided it, so I can't give any "citation to the original poster"...

EDIT: Dinner and some family discussion interrupted my post and I see that ChuckS posted similar information during that time.

 

[NH_Bulldog]

The bigger issue is that the wire size dictates the fuse/breaker size. If it came with a 30a auto-reset breaker, then the wire size is likely 10 AWG. If you upgrade the breaker to 60a you will have to upgrade the associated wiring to 4 AWG. Otherwise, the wires could get too hot, melt the insulation and start a fire before ever tripping the breaker.

What situation are you finding yourself in that your converter is pumping out the full rated amps that would trip the breaker to start with? How many batteries, what size and what chemistry are they? Are they run down to nothing before trying to charge? Do you have any kind of solar setup?

 

[JRTJH]

Also keep in mind that the maximum output of your converter is 55 amps. THAT IS NOT THE CHARGING AMPERAGE !!! The converter output (max 55 amps) is "demand driven" based on how much DC power you need to power the demand being placed on the converter/DC power distribution panel. You will ALWAYS have some demand on the converter from things like lights, alarm systems, refrigerator, InCommand "standby voltage" as well as other potentials. The "battery charging amperage" is limited to "a maximum of what's left over after the immediate demand is satisfied"...

So, in theory, you will NEVER be providing more than a portion of that 55 amp converter output to your battery bank. To illustrate that, the cooling fan on the converter starts running at about 4-6 amps and increases in speed as the demand increases. You will seldom hear the cooling fan operating, even with a "nearly dead battery being charged"....

The WFCO converter/charger also has a built in charge profile that is designed to protect the battery from overcharging or from "high amperage charge damage"... You can read the theory of operation for your converter/charger here: https://www.wfcotech.com/support/operating-your-converter/

As an observation, the 8955 has two 40 amp "reverse polarity fuses" that protect/isolate the converter from the battery. I would suspect (you can confirm with WFCO if you want to pursue the data with their customer support) but I'd suspect that the "engineered in design" calls for a maximum of 40 amps "to or from" the battery and any amperage greater than that would potentially damage the converter/charger. Otherwise, they'd have 50 or 60 amp "reverse polarity fuses" in the system...

I'd suspect that the fusing in your Giggy Box is sufficient to provide maximum WFCO charge current based on the charging profile limitations in the system. Adding a larger circuit breaker may defeat the built in protection without providing any greater charge capacity to the battery.

 

[NH_Bulldog]

Good points John, I wasn’t sure about the relation of the reverse polarity fuses so I didn’t mention those, but on the OP’s converter (and mine), they are 35A each, which fully supports your thoughts.

 

[JRTJH]

You're right, Rob. His reverse polarity fuses are 35/35 amps. For some reason I had in my head that his converter/charger was the 8955, not the 9855.

 

[NH_Bulldog]

I was just out poking around in the camper getting information for the WFCO Tech (they are going to update and mod my existing auto-detect converter to force it to lithium only profile).

Anyway, I checked my Giggy (Brock) box and my converter is on a 50a auto-reset breaker

 

[LHaven]

The "battery charging amperage" is limited to "a maximum of what's left over after the immediate demand is satisfied"...

So, in theory, you will NEVER be providing more than a portion of that 55 amp converter output to your battery bank.

All solid information... but it just moves the question to, "why does he keep popping the charging breaker and how does he prevent that?"

 

[JRTJH]

All solid information... but it just moves the question to, "why does he keep popping the charging breaker and how does he prevent that?"

That's a great question and likely only will be answered by some thorough troubleshooting and deductive reasoning...

Could be anything from a loose/corroded connection, a shorted charge cable in the belly, a bad 50 amp breaker in the giggy box, a defective converter, a shorted cell in the battery (if it's an FLA type) or a defective BMS (if it's a lithium type) or ?????

 

[NH_Bulldog]

It definitely needs some research. He said his auto reset breaker in the Giggy box was 30A. I have the same converter and my Giggy box breaker is 50A. So my suggestion is to look at the converter and note the gauge of the wires, then go to the Giggy box and verify that the same gauge of wire is present, and what size bresker it is connected to. Then, based on distance and breaker size determine if he has the correct size wire for that breaker.

You cannot safely add a larger breaker than the wiring can handle.

What is important to note is that according to WFCO in regard to their 55A converter; “Rating includes charging and load”, so as I think John mentioned previously, only a portion of that 55A rated output actually goes to charge the batteries

 

[JRTJH]

The statement that the OP's charge line circuit breaker is 30 amps is a "puzzler"... The Giggy boxes are built "off the assembly line" and then installed "on the assembly line"... I would imagine that every Giggy box has the same configuration for that model/trailer line, but that does NOT mean that a Giggy box from another line didn't "find its way" to the wrong assembly line. And even with the correct Giggy box, it does NOT mean that the line workers connected the charge line to the correct circuit breaker inside the Giggy box.

Nor does the statement summarization, "My 30 amp charge line circuit breaker inside my Giggy box keeps tripping" mean any of the above IS the issue, but rather "one or more of the above COULD be the issue....

This one is not, IMO, one for someone who is "knowledeable of how a multimeter works" but is not "skilled in DC circuits, wire size, circuit breaker selection and specifically "RV DC wiring" to try to "wing it and see if it fixes the problem"......

 

[Joe Zig23]

Ok. So I too am putting in a 2000w invertor with auto transfer. I am moving batteries (200ah lithium) to the pass thru 2 ft from inverter and slicing into the provided AC loop. Battery to inverter cables are 2awg, the Victron charge controller will be wired to battery directly using same 10 awg wire as factory supplied. I will then run 6awg from battery to giggy box as factory supplied. there is no additional load at the giggy box. I believe that is a safe and proper way to wire it. Thoughts??

 

[NH_Bulldog]

2 awg is too small. You need at least 1/0 (if not 2/0) cables for Everything. I used 2/0 for my 2000w inverter. A=W/V (amps = watts divided by volts). So with a 2000w inverter, you need a minimum of 167a wire capacity, which is more than 2 awg wire can provide.

Please, unless you know exactly what you are doing, do not just wing it.

 

[Joe Zig23]

2 awg is too small. You need at least 1/0 (if not 2/0) cables for Everything. I used 2/0 for my 2000w inverter. A=W/V (amps = watts divided by volts). So with a 2000w inverter, you need a minimum of 167a wire capacity, which is more than 2 awg wire can provide.

Please, unless you know exactly what you are doing, do not just wing it.

Correct I missed typed 2/0 wire.

 

[NH_Bulldog]

Phew! In that case, you should be good to go.

When I did mine, I changed the cables between the two batteries to 2/0, and also from the batteries to the battery box lid and then on the positive side of the system, from the lid to the new 250a fuse to the new disconnect to the inverter are now all 2/0. On the negative side of the system I changed the chassis ground to 2/0 and also the cable from the battery box lid to the smart shunt and from the smart shunt direct to the inverter. Everything else I left at factory configuration since those loads didn’t change.