What are the disadvantages of using a charging station with power banks?

Question

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?

Answer 1

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.

Answer 2

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).

Answer 3

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.