Need help with Jackery and Pc1100

[MILT]

I need help. My jackery 240 is too small to power my fridge for the weekend. I’d like to add a pc1100 battery with the AAL bracket in the rear storage compartment. I need ideas on connecting the two. Right now the jackery is hard wired to the rear 12v plug for charging. On the summer when camping I’ll use a jackery solar panel.

so I want to add a pc1100 to add battery life to the jackery.

The main question is do I need a charge controller like a red arc connected to the pc1100 battery?

as I see it I could:

1) charge the pc1100 through the jackery manually with a 12v plug. This means I need to manually turn the charge on feature on the jackery. When I want to use the pc1100 I can then switch cables and put the pc1100 to the input side of the jackery

2) through-put the pc1100. Connect the pc1100 to the rear 12v plug and then connect it to the jackery. The pc1100 charges and then the jackery charges. The only issue I see is that with solar I need to then figure out how to through put charging from the jackery to the pc1100

Any thoughts?

TIA for help

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[lashlee]

There's a lot of different ways to get to what you want, some will be easier and some will be more expensive, and typically it's one or the other. The simplest solution is to sell the 240 and buy a larger model. I have a friend with a similar end goal as you (though using a Goal Zero) that can power the fridge for a few days, and use a Zamp 100 amp solar panel.

The biggest issue with adding the battery is the Jackery might not work well in that configuration, and the 12v outlet in the back doesn't have the wiring to support charging a potentially dead battery. You don't necessarily need a Redarc DC-DC charger (and they work awesome in certain situations) but you do need to use larger wire and some sort of battery isolation device to keep the under hood battery from draining while the PC1100 is being drained. Certain Goal Zero units offer the option to add one of their "battery packs" but packaging can get tight. I can't tell from the Jackery site, but in your case I would look at buying a bigger unit.

 

[MILT]

I appreciate the reply. While I should get a bigger unit than the jackery, I have yet to find anything that doesn’t take up significantly more space.

my new thought:

I have the rear 12v plug fused for ignition only. I guess that’s how I will isolate the pc1100 from the main battery. I know it would be smarter to run heavy gauge wire from the battery to the back, but I’m thinking that the pc1100 is getting trickle charged while the pc1100 is trickle charging the jackery. The jackery is then powering devices.

if I add a dc-dc charger then I can solar charge the pc1100 without have to reverse charge from the jackery to the pc1100.

does this seem reasonable?

 

[lashlee]

The amount of charge that is sent to the PC1100 will be based on the charge in the battery, the output of the alternator and the draw on the battery and you will have no way of knowing or controlling that, which will likely overload the wiring for the rear 12v plug and hopefully blow the fuse before it does much more damage to your Jeep. To do it properly, without buying a larger unit, you need to run bigger wires to the PC1100, at a minimum. The 12v rear outlet is not designed for what you're trying to do, hence the reason not many other people have any experience with doing it this way. Even AAL offers a large wire kit for the rear battery for this very reason, trust me that you don't want to rely on the rear 12v outlet to power the battery.

One of the Redarc BCDC-1225 will give you the option of using solar, but it's real benefit is that its keeping the PC1100 fully charged from the moment you start the Jeep so the solar can work much more efficiently since it's not fighting an uphill battle.

To do it right, dismiss the rear 12v outlet, run a 4awg wire (fused at both ends) and wire up the battery properly. Redarc recommends at a minimum 6awg wire if you're wiring up one of their units so 4awg help future proof your rig. If a DC-DC charger is out of the question for now, you can use a high current relay to isolate the two batteries to keep you from running down the battery under the hood.

 

[MILT]

Thank you. Based on your info I’ll do it right the first time and run heavy gauge cable to the pc1100.

appreciate the help

 

[lashlee]

Good luck and let us know how it turns out. The Goal Zero that I set up for a customer works great with his ARB fridge. The Goal Zero has the vehicle integration kit that allows it work like the Redarc piece and charge while he is driving to the campsite. Once there, with the fridge still hooked up he can charge at up 10% per hour with solar. Once you get the PC1100 wired in properly you'll appreciate the convenience. You can wire to the front battery and it will charge and drain them both at the same time, or you can use a large relay to isolate the PC1100 from the front battery when the key is in the off position.

 

[JLeco2022]

I was up in the air about using the jackery boxes, instead i went to a LiFePO4 battery from Dakota lithium, made up my own connections and have no issues with my dometic fridge running for a few days before it needs a charge. there is a few ways you can do it cheap to charge off the alternator if you don't want to charge off solar, it really depends on the setup you want vs need. however my system is completely independent of the jeeps 12v system, if needed i run a jumper from the rear 12v cig plug to the battery in my rear space where the battery is located.

 

[Ratbert]

if needed i run a jumper from the rear 12v cig plug to the battery in my rear space where the battery is located.

Won't that drain the higher voltage battery (lithium) to the lower voltage battery (the Jeep's AGM)?

 

[MILT]

I’ve got a 60w solar panel. I’ve used that to power my jackery. My problem is that my fridge draws a lot so on a hot day I’m lucky to get the jackery to last 1 day. I’m also lucky if I have a sunny day for charging. I like the jackery for portability—I pull it from the Jeep to charge phones or run a diesel heater from the tent. Getting rid of that is a no go.

I like my fridge because it’s small, despite its inefficiencies. I was hoping to simply charge a pc1100 to keep the jackery topped off—via solar or Jeep power.

was hoping to avoid the PITA of running large cable the length of the Jeep but it appears the best, safest way to go

 

[JLeco2022]

Won't that drain the higher voltage battery (lithium) to the lower voltage battery (the Jeep's AGM)?

no i have diodes in my system, the power can never go the other way

 

[Ratbert]

no i have diodes in my system, the power can never go the other way

I'm no EE, but I thought that it wouldn't flow from lower voltage to higher. You'd need a DC to DC converter to do that and to keep the alternator from shutting down.

But, of course, I'm no expert.

 

[lashlee]

There are a lot of ways to make a dual battery setup work. One way, like @JLeco2022 is doing is with a jumper and a diode. Another is using a high current relay, another uses a battery isolator or a DC-DC charger. I've installed almost every variation over the years and they all have their pros and cons, it just depends on your specific situation.

 

[JLeco2022]

As @lashlee said every system should be built on what the end game is, I don't like putting any inverters to 115 in my system because of the about 30% loss, every system has pros and cons, all depends on how much you want to spend vs cheaper bypasses imo

 

[Viking Jeeper]

There are a lot of ways to make a dual battery setup work. One way, like @JLeco2022 is doing is with a jumper and a diode. Another is using a high current relay, another uses a battery isolator or a DC-DC charger. I've installed almost every variation over the years and they all have their pros and cons, it just depends on your specific situation.

There are lots of ways but I would suspect if using two aux batteries it would be best for them to be the same.

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