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I want to have good power system for my van. I liked Jackery Explorer 240 . Price is good: $219.99. But the problem is that its capacity is only 16.8Ah and only 2 USB ports.

I can buy a more expensive option: Jackery Explorer 500. But its capacity is not much larger, and the price is itchy: $499.00. I have to spend $279 extra money for a small additional power (24Ah).

Therefore, I decided to consider the option to buy power banks. This option looks very good: Anker 325. The price is only $49.99 and I get 20,000mAh more power. For the same money I can take 5 such power banks (279 / 50 ~ 5 psc).

I will receive extra: 20 * 5 = 100 Ah. It looks like a good deal, doesn't it?

Another advantage of using power banks is that each device will receive its own guaranteed energy reserve. But I think that there are some hidden problems here, and not everything is so simple, what am I missing?

What are the disadvantages of this system?

Tamila Ambeon
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  • Can you clarify the ratings, there? When Charger 1 is rated at 16.8Ah and Charger 2 offers 'a small additional power (24Ah)' does that mean Charger 2, with 24Ah, offers a small additional power or Charger 2 offers an additional 24Ah, meaning 16.8+24 =40.8Ah – Robbie Goodwin Jan 22 '23 at 21:23
  • @robbie-goodwin I have shown the total capacity, thats means Jackery Explorer 240 has 16.8Ah total ($219.99), and Jackery Explorer 500 has 24Ah ($ 499.00), so if to be very precise, it turns out that you pay 279,01 more for (24Ah-16.8Ah)=7.2Ah – Tamila Ambeon Jan 23 '23 at 07:59
  • Thanks Tamila. So to be be clear despite those details, the comparison is simply between 16.8Ah and 24Ah? Is that right? – Robbie Goodwin Jan 23 '23 at 21:39

3 Answers3

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We start by making a list of all the loads we want to power, and the energy requirements they have. You need to know the difference between energy (watt-hours) and power (watts).

They are confusing you with different terms. Standard marketing ploy.

The "Amp-hour" spec you are reading is an attempt to give you energy capacity, but it needs a voltage to be useful information!

To get from amp-hours to watt-hours, multiply by volts.

For instance the $220 Jackery 240 is 16.8 amp-hours, at 14.4 volts - you multiply the two and get 242 watt-hours. So about 90 cents a watt-hour. Higher than I'd like to see, but typical for these "portable power stations" which are rip-off-y.

By contrast, the $50 Anker 325 has 20,000 milliamp-hours, which is a fancy way of saying 20 amp-hours. However, that spec is at only 3.5 volts. That means it actually has 70 watt-hours. That's 70 cents a watt-hour, which is better value but doesn't power anything but USB devices.

The Jackery can power small 120 volt AC loads as its power (watts) is limited... but only for a short time as its energy (watt-hours) is very limited.

VanLife really needs a bigger system.

Really, unless you're choosing to live like a homeless person, #VanLife calls for a proper, permanently installed 12V or 24V DC accommodation battery and solar system on the vehicle, powering all the living-space lighting and equipment. You don't want to sap the engine starting battery for those loads, because after a long boondock you might find you can't start the engine! 12 volt is easier to work with, honestly. And then you can get USB power off that battery system, as well as a large enough inverter to actually run refrigerator, microwave and the like. It can also provide power for very low-power fuel heaters such as the Dickenson.

This is more money than you are planning, but not a whole lot more, and you can do it in increments - get the battery now, then wire a cross-connection so it charges off the engine (but doesn't sap the starting battery), then get an inverter to run fridge etc., then add more battery capacity, then add solar, etc. You don't have to do the whole system in one go. You do need the skill to design a system, but info about that is all over the web.

By the way, 12/24V to 120V inverters are sold at every truck stop - Pilot, Flying J, Petro, that kind of place.

And getting from 12 volts DC to 5 volts USB is super easy - the adapters are sold at every gas station, convenience store, big-box and cell phone shop. In the US, they are easier to find than eggs.

Harper - Reinstate Monica
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  • Thanks for your explanation! These marketing tricks are really confusing. My idea is to create 2 separate power systems. The 1st one will be for low-power devices that I can power from a USB cable (for example: phone, camera, LED lamp). The 2nd system will be separate for electric stove, heater etc... That is why I intend to use power banks for the 1st system. And what is needed for the 2nd one, I don't know yet, because I haven't made a list of the necessary devices yet. Do you think this approach with 2 separate systems makes sense, or is it better to combine everything into one? – Tamila Ambeon Jan 18 '23 at 11:34
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    Building 2 systems is more expensive than one. The big cost is the battery. You can easly and cheaply step down from 12V to 5V for all your USB needs. – Christian Jan 18 '23 at 12:52
  • @christian I understand this and I am ready to invest more money. And do you see any other disadvantages here, apart from financial ones? – Tamila Ambeon Jan 18 '23 at 12:58
  • You also lose a lot of power when transferring power. You probably shouldn't charge the Anker direkt from a solar panel, because it isn't made for that and decreases the lifetime drastically. But if you charge your Anker power bank from a Jackery Explorer, you will get probably more than 20% loss for the conversion and discharging/charging, so you need probably >92Wh input to charge the 74Wh. And there are losses inside the Jacery too, so its very likely you will need > 100Wh from the Jackery Battery to get 74Wh into your Anker power bank. (All ballpark numbers) – Josef Jan 18 '23 at 13:09
  • @josef how did you find out about the 20% loss? Please explain the losses in more detail – Tamila Ambeon Jan 18 '23 at 13:15
  • @TamilaAmbeon it's just a ballpark number, but [Anker](https://support.anker.com/s/article/Why-does-the-power-bank-discharge-quickly-when-charging-other-devices) says it's even higher! If you want an more in depth explanation why and how power is lost here, you should start a separate question. But the short summary is: stuff will heat up. – Josef Jan 18 '23 at 13:39
  • @Josef why does it reduce the lifetime? – user253751 Jan 18 '23 at 15:03
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    The isolation/charging/solar bit of the system also gets somewhat pricey. The all-in-one box systems (like Jackery and others) come with it, so that should be factored in to the perceived relative costs. But one can bootstrap over time, going from a low voltage cutoff on the start battery to a full house system in increments. But then many of those increments get tossed as you upgrade... – Jon Custer Jan 18 '23 at 15:13
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    @user253751 because solar doesn't deliver a constant current. The amount changes, because the sun is not shining exactly the same amount on your solar panels constantly. Solar power banks expect this, and have charging controllers and batteries to handle that. USB power banks are designed to be charged with a USB power adapter delivering the power to charge constantly without fluctuations. Constantly switching charging on and off harms them. – Josef Jan 18 '23 at 15:14
  • @Josef evidence that this harms the power bank? – user253751 Jan 18 '23 at 15:15
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    @user253751 try it yourself. You can have the evidence in a few weeks of charging a power bank with a small solar cell. I have destroyed more than 10 power banks this way! – Josef Jan 18 '23 at 15:18
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    Without a charging controller, your solar panel will also put out varying voltages. Check the specs on a panel and you will likely find that your "12V" panel may put out 24V or more, depending on illumination conditions. – Jon Custer Jan 18 '23 at 17:07
  • @Tamila well just having power banks for USB devices is fine. In our household we probably have a dozen of them :) So it's a good start that is compatible with a bigger built-out system. Since your goal is a respectable system, I wouldn't mess around with Jackery, Goal Zero or any such overpriced "solar+12V+120V+USB" type deals. That one you mentioned is for running a laptop for a couple hours, it can never run a fridge or microwave. You probably want a physically installed "just a battery" and add the other stuff modular. – Harper - Reinstate Monica Jan 19 '23 at 01:04
  • Isn’t it also that powerbanks cannot be used in UPS mode (i.e. charging and discharging at the same time)? None of these I have document that as possible (one even warned off it)… – mirabilos Jan 19 '23 at 02:34
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    @mirabilos Yes, but I also have several reports from users that their unit is designed for that and does it. It's perfectly possible to build a unit to do that, just adds very slightly to manufacturing cost. – Harper - Reinstate Monica Jan 19 '23 at 03:30
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    @Harper-ReinstateMonica - I have a larger all-in-one system which complements my built-in system in my truck. It is perfectly capable of running my full-size kitchen fridge just fine in an all-day power outage, and fully recharges in the summer with a portable solar panel. An all-in-one is not a bad start, and several people I know didn't bother to go further since it met their needs. – Jon Custer Jan 19 '23 at 14:15
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The Jackery Explorer 240 has a 240 watt-hour (16.8 Ah, 14.4 V) lithium-ion battery. The Anker 325 Power Bank has a 20 Ah battery, but the voltage and wattage isn't specified. Since it only has USB-A output and they are coy about watt hours I suspect it contains a single 3.7 V cell, which would have a capacity of ~ 3.7 V x 20 Ah = 74 Wh. You would need 3 of them just to match the capacity of the Jackery Explorer 240.

The Jackery Explorer has a 200 W 110 V AC outlet, and it can be charged by a solar panel or from the car's electrical system. These extra features could make it more useful than the Anker 325 power banks. However it only has 2 USB outlets. You could probably plug a USB power adapter with multiple outlets into the cigarette lighter socket to get more USB outlets, though this would be an extra expense.

If you only need to charge USB devices then Anker 325 Power Banks might be the better choice, especially if you might want to use them separately.

However for general purpose use I would go for the Jackery Explorer 240, because it can also power 12 V and 110 V devices. The solar panel option could also be useful, and recharging it might be easier. Of course if you already have those functions in an existing charging station then they would be redundant (which may not be a bad thing).

Bruce Abbott
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tl;dr forget about power banks or small portable power supplies if it's for a van

I'm late to the party, but since I'm a #vanLifeForLife guy, I decided to second what Harper said.

I want to have good power system for my van.

You're doing what is called an XY problem. The stuff you linked to is good for an occasional biking/hiking trip to the wilderness. The specs are too low for anything even remotely serious (like a couple of days off-grid or powering even a stronger laptop for gaming for a couple of hours etc.) If you have a van, the proper-ish way (browse through the campervan discussion forums if you don't believe me) to do it is like this:

  • get a solar setup, at least 200W and preferably about 500W (depends on the amount of space on the roof you have and funds), I have 2x 330W peak/250W avg solars myself; you need a large headroom here since during dark days you'll only get some 10-20% of the max power.
  • get a solar DC-DC converter + inverter (I have this one, but obviously you can find similar one for US voltages etc.), I suggest getting one with at least 1kW of actual power, since that will allow you to power virtually everything you need that uses mains voltage, including heaters and things with engines like normal fridges etc. IMVHO, 1400/2000W one is the best match for regular van or campervan,
  • get some solid AGM or hybrid AGM/gel batteries (I have 2x 12V * 100Ah = about 2400 Wh top), with proper fuse setup you can not only charge them from the solar converter but also power things directly from them (since they basically act as a buffer on the output of the solar charger). There's a lot of stuff for 24V (or for hybrid 12V/24V) since that's the standard voltage for trucks and buses; (you can go for LiFePO4 or other stuff like that instead, but that will increase your bill at least 2x, maybe even 4x due to all the electronics you need for them)
  • if you want to have 12V supply, get a 24V->12V step down (they are very small, cheap and very efficient); alternatively, get a 12V battery, wire it to your car's alternator through a proper kit which will make you load your main battery first and start charging your secondary battery only after the main one is full and remember that you can still use a dedicated mains voltage 12V battery charger straight from your inverter if you need it.

That's a setup I've been using for some years, without a slightest problem. I've been powering power tools, computers, home electronics, heaters, fridges etc. from it without any hiccups. On sunny days, the batteries are fully loaded after about 5 hours in the sun, so if I drain them before going to sleep, in summer I have 100% just as I wake up. This setup also allows you to use mains power directly (i.e. my inverter has this option, since it has a xformer and a rectifier built in) in emergency or if you need to charge your batteries quick when you're low on sun.

You can then easily use car USB chargers (nowadays easily available as hybrid 12V/24V devices) or regular mains ones, depending on your preference. Efficiency of this setup is at about 80-90%, depending on the exact load, so there's nothing to really worry about.

If you're tight on cash or space, you can reduce this setup heavily (e.g. just use just a single solar panel matched with a single 12V AGM battery and use a cheap/small MPPT DC-DC converter which has USB charging ports built in). That would still be better than any intergrated/proprietary system, because you will be able to easily upgrade it.

You can buy those electronics from China or Chinese resellers for a fraction of the price of the usual US setups, including shipping. You can reuse old car batteries if they're still in workable condition if you're really in a pinch.

Worst case scenario, just use regular car USB chargers and if your car battery is running low, charge it from somewhere or drive a couple of circles around the neighbourhood to charge it from the engine.

spamove
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  • Can you give me some links to campervan discussion forums? Don't get me wrong, I appreciate your response and your experience, it's just becouse I still have a lot of questions and I want to ask them specifically in the relevant forums. – Tamila Ambeon Jan 18 '23 at 16:50
  • https://community.smallmotorhome.co.uk/forum/camping-discussions/cars-and-light-vans-adapted-for-camping , https://www.motorhomefacts.com/ , https://www.camperteam.pl/forum/viewforum.php?f=396 etc. Just google for it, but it's heavily country/region dependent. There's also a lot of YouTube videos on how electricity for off-grid or hybrid on-/off-grid van conversions can/should be done. You can of course use any solution you'd like, even power banks or portable PSU you mentioned, but if you're planing to do it good, they are simply not the way to go, due to many reasons. – spamove Jan 18 '23 at 17:00
  • @TamilaAmbeon and, to reiterate, if you just need USB charging for short trips, just use a 12V USB car charger of your choice. Your van car battery is at least ~600Wh, so as long as you have a charger that monitors the battery voltage (or as long as you monitor it yourself) so that you don't spoil the battery with discharging it too deeply or use the charger mainly while driving, you will be good. – spamove Jan 18 '23 at 17:07
  • thank you! Can you tell me this many reasons, that make such an approach wrong? – Tamila Ambeon Jan 18 '23 at 17:09
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    @TamilaAmbeon My point is that those Jackeries are basically useless at their price point. Their only redeeming quality is that they are portable. 16Ah 12V power supply with 200W constant output is too little even for a strong laptop (my Legion would kill that supply if I'd do anything serious on it, since it's basically weaker than the battery it has built-in :D), not to mention a desktop computer. You can maybe use it to charge a phone for a day or two, but that's basically it. Your car already has a battery that's a couple of times stronger. It also has some other useful stuff (alternator). – spamove Jan 18 '23 at 17:15
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    also, the solutions with integrated battery will need to have the battery replaced in just a couple of years (if you're lucky) or even months (if you're unlucky). Integrated MPPT is good, but it's useless if you don't have solars. OTOH, solars with low power are also basically useless, since you'll be waiting hours or days to charge your batteries. For light hiking those low-power solutions might be OK, but if you have a van, you have a roof that's a perfect place to get free electricity for you. Good panels will give power for decades (about 80-90% base power after 20-30 years). – spamove Jan 18 '23 at 17:22
  • Now I understand you, thanks for the explanation! Can you tell me from your own experience, how often you ran out of power with your setup? (2x12V * 100Ah + 2x240W solars). How long do your batteries take to charge in winter, on dark days? – Tamila Ambeon Jan 18 '23 at 17:40
  • Let us [continue this discussion in chat](https://chat.stackexchange.com/rooms/142151/discussion-between-spamove-and-tamila-ambeon). – spamove Jan 18 '23 at 17:45
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    The essential point, just to spell it out, is that lithium batteries are most useful when you have to *carry* them. They have high specific energy + energy density. But they are *expensive*. If you can truck the battery around, almost any other chemistry is superior. – Lawnmower Man Jan 18 '23 at 21:42