Goal Zero as second battery

[bhayes423]

I'm starting to game plan some electrical upgrades in my GX460 and wanted some opinions before I go down a dual battery route.

I've got a X2 Power Group 31 battery that has been running my Dometic CFX3 55im no problem for 2 days without moving. I'm adding a Garmin Powerswitch and pods around my rig so I don't want to have everything running on my starter battery. I already own a Goal Zero Yeti 500X and one of their 100W panels so this is what I was considering:

- Mount Goal Zero in the back and plug my Dometic fridge into it for power.
- Simultaneously charge my Goal Zero via 100W panel on roof and 12v charging cable that goes in the outlet my fridge was previously on.
- To prevent the Goal Zero from draining my starter battery I'd disconnect and plug into my Garmin Powerswitch so I can turn it on / off.

We may charge a phone or bluetooth speaker periodically but that's it. We aren't famous YouTubers looking to charge 3 drones and 5 cameras every day. As a backup I carry a NoCo as well. Would love for this route, or something similar, to work and use the money saved to get an Alu Cab awning.

What do ya'll think?

 

[K1mj]

So the 100W solar panel (if that is the nominal rating) will probably yield 50W in direct sunlight at ideal conditions. When you consider that you won't have ideal solar conditions 24h a day, in a scenario where you are parked and have the fridge running on the Yeti and solar panels deployed you are still going to have a negative charge on the battery. The current that the fridge is drawing is greater than the charge it's getting and it will drain it. The solar panel will just slow that process a bit. Now it's great that you have a Li-ion battery so that you can drain it more (compared to agm) but it is only 46.8 Ah so you will most likely be in a situation where you have to keep using the 12v car outlet to charge the battery. The main problem that I see here is the load that you are still putting on your main battery, it might be doing fine now but you are making its life shorter and risking getting stranded if for example you forget to unplug the battery?
In my experience, a larger second battery equipped with a DC to DC charge controller like Redarc or Projecta is much better. You can put in a 100Ah battery and never have to worry about draining your main battery. Plus, when the second battery has had its life you just replace the battery and not the entire system as opposed to using a Yeti.
If you want to keep the wiring simple there are battery boxes that have the charge controller and the outlets and you just put in your own battery. Think of it as a goal zero with a replaceable battery.
All that being said, if you really don't want to wire anything for the short term I think charging your Yeti at home and using it at least to partially power the fridge is still better than putting all the load on the main battery alone.

 

[bhayes423]

So the 100W solar panel (if that is the nominal rating) will probably yield 50W in direct sunlight at ideal conditions. When you consider that you won't have ideal solar conditions 24h a day, in a scenario where you are parked and have the fridge running on the Yeti and solar panels deployed you are still going to have a negative charge on the battery. The current that the fridge is drawing is greater than the charge it's getting and it will drain it. The solar panel will just slow that process a bit. Now it's great that you have a Li-ion battery so that you can drain it more (compared to agm) but it is only 46.8 Ah so you will most likely be in a situation where you have to keep using the 12v car outlet to charge the battery. The main problem that I see here is the load that you are still putting on your main battery, it might be doing fine now but you are making its life shorter and risking getting stranded if for example you forget to unplug the battery?
In my experience, a larger second battery equipped with a DC to DC charge controller like Redarc or Projecta is much better. You can put in a 100Ah battery and never have to worry about draining your main battery. Plus, when the second battery has had its life you just replace the battery and not the entire system as opposed to using a Yeti.
If you want to keep the wiring simple there are battery boxes that have the charge controller and the outlets and you just put in your own battery. Think of it as a goal zero with a replaceable battery.
All that being said, if you really don't want to wire anything for the short term I think charging your Yeti at home and using it at least to partially power the fridge is still better than putting all the load on the main battery alone.

Thanks for the input!

I think my OP was a little confusing.. the Goal Zero has two inputs and would only charge off the car when it's turned on, then automatically switch to solar when the car is turned off. We only stay put at a max two days before driving again so I'm hoping the Goal Zero w/ solar panel can handle that. I've got a buddy selling one of their 100W Nomad panels we could use to double up.

My eventual goal is to build my own dual battery box w/ Redarc down the road but wanted to make my Goal Zero stuff work for now.

 

[lhoffm4]

Doubling up your goal zero with panels and alternator charging is a good idea, especially if you don’t already have panels. My Bluetti EB70 will expedite charging if I have both panels and the unit plugged into the trucks 12v system. I imagine the goal zero will do the same? The controller should throttle down as the charge reaches full. I have been playing with my DIY 200ah LiFePO4 bank in the same way, going back and forth between panels and using one bank to charge the other while getting topped off by either the panels or power brick for the EB70. I also played with an AC/DC converter I got for the diesel heater to be able to play with a generator or AC through a battery bank for the heater. TheEB70 is quite versatile with all the accessory cords, the way it’s controller works. If I were not knee deep in building a SoGen around the 200ah bank, I’d be looking to acquire one of the larger commercial Bluetti SoGen offerings. Too rich for my blood at one shot tho, so it’s DIY for me and should end up around 1/4 to 1/3 retail. I should have totally went for the 300ah LiFePO4 pack tho, and would recommend that to anyone building their own SoGen...

 

[leeloo]

With a goal zero 500 and the solar panel you should be able to power the fridge for a few days no issues, with relatively good weather. The goal zero has an aprox 40 amp battery inside. I have a 50 amp one, at sundown it was full, in the morning it was aprox. 75 % full, running a 40 l engel fridge and charging a phone / tablet .
The issue with goal zero type devices is the very long charge time from 12v plugs, actually solar charges them faster. This why I went with a simple Lifepo4 and a DC to DC charger. Cost is about the same if not lower, but takes some skills to install it. If I start the engine in like 15-20 min I will be at 95% full..
You need something bigger and more panels if plan to power a lot more things, but for a fridge and some phones, it will do..