Second battery to run refrigerator

I believe the ports on the Jackery will turn off after a certain amount of time if power is not drawn from them.

 

Right, hell yea, that should work. I think some of us on here were trying to keep all at 12 volts as that avoids a couple inverters which are slightly less efficient. but the idea you propose here eliminates the issue with pass thru being as much of a problem. I will definitely test this out and let yall know how it runs/operates. thanks for the idea, I had gotten my head in a corner and this might be a way out. that's why you guys rock!!

 

I'll have to check the draw when it turns on. When not in my tacoma it's in the garage. I usually fill it up the night before a trip and let everything get to temperature in my garage before I load it in the truck for a trip. So everything is pre-chilled. I'll set it up later in the garage and set the temp to the lowest possible setting so it will kick on full blast and I'll see what the draw is.

Edit: After some more experience with the Jackery 240 I learned a few things about it. Make sure to read these two post if you are thinking about the 240

https://www.tacomaworld.com/threads/second-battery-to-run-refrigerator.673769/page-10#post-24053033

https://www.tacomaworld.com/threads/second-battery-to-run-refrigerator.673769/page-9#post-23905664

 

Good point, might be a reason to keep a small device connected just to not have to fiddle with it, even a frekin light bulb, certainly a phone charging or a GPS or something.
I will have to look up that number, it might have been 10 watts, I think your right.

 

right on, I will post some numbers as well. My fridge is supposed to draw 75watts when on. It arrived yesterday and I just got it turned on. with it empty it seemed to turn on for about 5 min every 20 min. so a pretty low duty cycle.

 

45w when it's running.


0-1w When its idle.


I've never had it turn off on me so I'm not sure if it's true that the Jackery will shut off if there is no draw. I heard that the bed outlet does shut off with no draw after a while. But that has never happened either with the Jackery plugged in. So not sure what the other post is about...

Edit: It shut off on me see this post https://www.tacomaworld.com/threads/second-battery-to-run-refrigerator.673769/page-10#post-24053033

Also this post if you are thinking about the 240
https://www.tacomaworld.com/threads/second-battery-to-run-refrigerator.673769/page-9#post-23905664

 

I have heard that before about the outlets on some of the portable power stations and large jump pack/battery packs shutting off if not in use, so I'm not completely surprised. I have one good sized Gooloo jump pack that you have to press the power button on to start charging things via the USB ports, but our old, smaller gooloo always seemed to feed power to the ports. I'm wondering if it's because the new/larger one has "smart" fast charge usb outlets. Maybe they drain power when not in use?

 

I've had the fridge since 2014 and never bought a slide because they were too expensive and it really didn't improve anything in my old jeep. But for the truck I really wanted one because of the tailgate. I put it up on https://camelcamelcamel.com/ and got a low price alert back in march so I jumped on it. I'm pretty happy with it. I don't think I would have saved much building my own DIY fridge slide. If you are interested you can see my setup here https://www.tacomaworld.com/threads/high-speed-low-drag.673276/ . It's not much but I take my time and think a lot before I do anything.



Edit: You got me thinking if DIY would have been cheaper. found this https://forum.ih8mud.com/threads/homebrew-fridge-stove-slide-combo.604751/ . I still think the price I paid was fair though. I don't think they are worth the $300 they ask for them.

Edit 2: After some more experience with the Jackery 240 I learned a few things about it. Make sure to read these two post if you are thinking about the 240

https://www.tacomaworld.com/threads/second-battery-to-run-refrigerator.673769/page-10#post-24053033

https://www.tacomaworld.com/threads/second-battery-to-run-refrigerator.673769/page-9#post-23905664

 

oh that is pretty reasonable, some of the heavy duty slides I saw were 10 times that. I agree, I think I would just pay the 200 to 300 as I don't have time to tinker as much as I used to. thanks for sending that link, that would likely work well for me too. good deal I reckon. thanks

 

I added a second battery to run accessories, including fridge... Later I added solar... I have to say, having the added reserve of a second battery for winching, night lighting, fridge running, electronics usage / charging and the solar to top off the battery the next day within hours without turning on the truck is pretty awesome... If all you're doing is a fridge... You can add solar to your main battery and that will be more than enough to keeps things good.

**edit: think about this... For the price of a second Northstar batt and dual system wiring / relay and connection, you can get a pretty sweet solar setup... Just saying... If money is a thing, keep this in mind... If money isnt a concern, forget all of this and buy a raptor lol

 

Thanks for that input. I still might end up going that route. I am talking to Jackery about the warning regarding the units inability to do pass thru charging without damaging the batteries. If I had known this beforehand I wouldn't have purchased it. The reviews say you can do pass thru as well as their manual, but now they tell me it does damage and that they are working on a 'fix'. Not sure if it is a new version of firmware or hardware or even batteries, not sure yet. At this point I don't have much time left. thanks for the input... appreciate it.

 

Exactly. if i was staying for longer periods of time, I’d probably just run solar to the main. Dual battery systems get expensive in a hurry. Especially to do them the right way.

 

Did they specify "how" it damages the battery? A pass thru is no different than running solar to a battery that is powering something like a fridge at the same time. I agree it seems like a huge flaw if they are now saying this isn't possible.

I'll put in another plug for the Dometic PB40, it can pass thru without issue. I love the fact that you can run a solar panel straight into it without the need for a seperate solar controller. The only downside to the PB40 is that it doesn't have a built in inverter, however it can support up to a 150W inverter via the 12V DC outlet. I carry a 150W pure sine wave inverter on the off chance I might need it. That said, the purpose of the PB40 in my set up is purely to run the fridge and random DC power needs.

Cheapest place to get the PB40 is thru CampingWorld. Their normal price is in the $750 range and on occasion (esp Black Friday time frame) they run 20% off coupons which puts it in the $600 range. Otherwise REI sells them and utilizing their 20% off put it at $680...their normal price is $850. The PB40 is LiFePO so it'll take thousands of charge cycles vs the Jackey's lithium ion which will top out in the 500 range of cycles

 

Pass through charging isn't a simple feat with Li batteries. Less expensive Li battery packs like the ones being discussed are made from individual cells and require some sort of BMS to balance them constantly. Circuitry to make this happen isn't trivial. Most cheap BMS cards will do one thing at a time, in or out..... To get this capability you will have to fork out the cash for a real battery: Bioenno, Renogy or Battleborn.

ETA....
The jackery 500 is actually a 21v pack. It uses step-down circuit to get 12v nominal output. That is fine, aside from being inefficient (heat waste) and it also severely limits DC current draw (to 10a). It also makes charging more complex.. Li ion batteries are much cheaper than LiFePo4, which is why the unit costs less. Li ion batteries are 3.6v each, whereas LiFePo are 3.2v. The jackery probably uses 6s Li ion to get to 21v. LiFePo4 is better suited to 12v applications, because 4s is right in the 12v sweet spot. A 4s LiFePo4 is simpler to charge as well, because charge input (14.4) is much closer to power out (13.5). The more I dig into the design of that jackery pack, the less appealing it becomes.......

 

...add the Dometic PB40 to that list as well

 

I can't tell for certain, but I think the PB40 uses Li ion cells as well. It has a max current draw of 15A, which leads me to believe it uses step down and a higher voltage Li ion pack. Dometic is also extremely overpriced, IMO.

That current draw limit is a deal breaker to me, because I frequently need to run 30-40 amp things. I have tested my home made LiFePo4 battery to 60a....

 

PB40 is LiFePo4, here is the description from the Dometic site:



It has a max current draw of 15A per outlet simply because it is limited to the 12V socket outlets and there is no inverter or Anderson output connections

 

@perkj is doing a pretty good job touting the PLB40 and I’ve already mentioned it too, but I’ll add it’s worked great for me so far. Since my truck has the factory inverter which I’ve only used once or twice in four years, I don’t miss it on the PLB and it really helps the PLB stay small and light. I’m a real tightwad but I think it’s worth the money.

 

Ah. Ok.

And it probably only has room for skinny wiring inside the box.

It's still pricey for a 40ah battery. Just a couple more Benjis and you're into 100ah battery range.

 

true, but when you say 100ah range you're talking cost of a 100ah battery only, not a complete package that includes charge controller, battery monitor LCD, ports (both input and output), AC changer, etc etc. $600 for the complete package IMO is well worth the money given that it will last for thousands of charge cycles. I liked it so much, I bought two

I suggest having a look at a PB40 in person. Extremely small and a near work of art.