Second battery to run refrigerator

Holy Cow, wow, I just got this from Jackery… what a complete joke. Help, I need to send this piece back and get something that is properly engineered. I cant believe it. The most basic thing you would imagine and if you run it in pass thru charging they say you damage the batteries. looking now for an alternative on Amazon.
The email to Jackery
Hello,
Just purchased the 500. Wondering if it can do pass thru power…
In other words, when it is in the back of my truck and being charged from the bed outlet 120 supply, will it still be able to power my fridge via its 12 vdc output going to the fridge.
Also, how does the solar panel connect which is also supposed to arrive in a couple days.
The response from Jackery

Thanks for choosing Jackery and contacting us for your case.

The E500 supports pass-through charging. But we don't suggest, it will cause damage to battery life.

And here attached the picture of the Saga 60W to charge the E240.

Hope helps~ If you have any questions, please feel free to contact us.

 

I think this is just a function of lithium batteries in general. You can pass through charge, but you are building more heat into the battery. You have it discharging and charging at the same time. Both of those things make the battery hot. Heat is the #1 cause of degradation to lithium ion cells. So their statement may just be a general caution about the limits of the technology. I could also be wrong and this is just a piece of shit.

 

Here is what the manual states...

 

They need to make it clear in the manual then. They are misleading people. They need to design a proper charge controller to handle what the manual claims it will do. It should be possible to do a thermal incorporated sensor design that in some cases limits how fast you can charge if you are also discharging. They could use two banks and alternate with intermediate cooling, they could use a super cap to act as a 'buffer'. there are all kinds of engineering solutions they could pursue. instead they have lied to their customers. now I either buy the extended warranty and just use the thing or I send it back and look for another solution... but I also have to send the solar panel back as well... unless the connector is universal and I seriously doubt it is. frustrated. I wonder if other users that have done pass thru have noticed any decrease in battery performance??

 

Yea. Well it can. I think you are probably fine. The fridge doesn't pull a lot of power and it runs on a limited duty cycle. So majority of the time, you aren't charging and discharging at the same time. Even when you are, you aren't outputting max power while charging so I don't think you're going to damage the battery. But that's just my opinion based on knowing very little about this particular product.

 

Yea. I know there is a solution. But even at $250, this is still a budget minded solution.

It sounds like maybe you know more about the electrical solutions than me. If you aren't comfortable with it, then returning it is probably the best option. Finding a different solution that provides what you want might be difficult.

 

ok, right, sounds like you have been doing it for awhile and you have not had issues? how much power does your fridge draw? I suppose I could just get the extended warranty and see what happens. thanks for the confidence, I really don't have time to take steps back and was excited to use this hardware going forward. Maybe you are right and its more of a disclaimer, I know its hard to say really. I don't have time to call them, maybe I can try on thursday

 

is this what you mean by blue sea power port
https://www.bluesea.com/products/1016/12_24V_Dual_USB_2.1A_Charger

 

You seemed pretty sure that all of your engineering solutions would fix this. It seems like you are either just spit-balling about ideas you don't understand or you are plenty capable of deciding if you think this is really an issue. I'm leaning toward the latter.

I think the risk in returning it is that you might not find another product that actually solves this. I have the Dometic PLB40 and they state it can charge and discharge at the same time (and it does). But I have no idea if they solved this issue or just don't bother to mention it.

 

Now I am also wondering if this lithium battery will be safe to keep in the back of the truck and not catch fire or worse catch fire if my kids happen to be sleeping back there at night. A lead acid deep cycle would work for this as well but not be nearly as versatile but wont burn down the truck. After this BS from Jackery regarding pass thru I don't know if I trust their engineering anymore.

 

You are partially correct, I am an engineer but not an electrical engineer that specializes in battery and battery charging system. So yes, in a sense, i was just spit balling some concepts - just frustrated this unit has this clearly very undesirable 'feature'. I do know a lithium battery expert I can ping for a bit of feedback. will do that later.

good point about the risk in returning it. so far the best option might be to get the extended warranty, as the manual says it supports pass thru charging.

 

I used the one that has the cigarette plug, 2 usb's, and a volt gauge.

 

Since you are an engineer, you know this likely isn't an issue caused by engineering. I highly doubt the engineers there weren't aware of this, didn't know how to fix it and didn't want to implement it. This is just how consumer products are. Marketing and finance come up with the features, specs and cost target that are necessary to sell the product and make money. Engineering just makes that happen, even if we don't like the final result. I underlined cost because that trumps everything else in developing consumer products.

 

yes, all good points. For sure your right...
I did do a quick search on the Amazon question for this product and there must be a dozen hits for comments about folks doing pass thru charging. And it seems plenty of folks on this forum use it in pass thru. I don't think amazon offers an extended warranty but will check that may be the way to go if its available. Its apparently the norm for this product to be used in pass thru, but warning as there can be occasional issues with battery damage it seems. And likely caused by 'peak' operating extremes... either current draw, temperature of operation, battery age, etc limits to the technology you get for $500. your right, the perfect design would cost 3 or 4 times as much and no one would by it. one option is to go inside in a few years and just replace the batteries in there. I do that sort of thing all the time. most of the time its not too hard.

 

Yea, that's kinda what I'm thinking too. Since you probably aren't at peak output for extended periods while charging then you might never really have an issue. Also, if you get 3-5 years out of it, would you be all that disappointed? I bet you end up getting a lot of use out of it with no issues.

 

Jackery's statement "The E500 supports pass-through charging. But we don't suggest, it will cause damage to battery life." is merely pointing out the obvious, which is that there are many things that can degrade a battery at a faster rate. Simply using the battery will degrade battery life...the more you use it, the less life you'll get out of the battery. Like wise, running the battery to a very low percentage degrades the battery at a fast rate. IMO Jackery should have simply stated the pass thru option is supported, however it will tax the battery at a higher rate (i.e. degrade battery life) than non-pass-thru use, just like running the battery down to say 10% will tax the battery more.

If you're worried about degrading the battery, simple ensure the lithium battery is topped off every 3 months (or if using lead acid keep it on a smart charger 24x7x365) and never use to power anything. The battery will last many many years this way

 

I was on the fence too to use my Jackery 500 with pass through charging but I'm only taking one 4 to 5 day trip a year and most of my trips are just weekend long. I'm assuming and hoping I'm fine.

 

I've been using it this way for a while and have not had any problems. The Jackery has never felt hot. The fridge doesn't draw that much power. Perhaps they are just warning him of the possibility for liability reasons. I'm sure if I overload it with different devices and max it out I can get it to fail. But with just the fridge I have not had any issues. I'll pay more attention to it now to see if I notice any excessive heat.

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

 

Couldn't you get a multi plug for the 110 outlet in the bed, and run it to the Fridge 110v plug and to the Jackery? I don't know which fridge you have, but my Dometic always defaults to the 110v circuit when available. So as long as your fridge is plugged into both 12v and 110 it chooses 110 first, turn off truck and it would pull from the Jackery.

 

right on, thanks for that... how much does your fridge draw... wasn't it around 65 watts?