I hope you'll be able to help. First of all this is a bit of a complex one that I'm struggling with. I wear hearing aids, both of which use removable, rechargeable batteries, charged only by a charger plugged into an AC outlet.

Short version: I'm looking to try and see if it's possible to charge my batteries using a USB outlet, presumably USB C or USB PD (meaning I can use a battery bank to do so, and I don't have to spend my life tethered to an AC outlet).

Long version: I'm profoundly deaf, (basically, without hearing aids I hear sod all) and I'm an outdoor person. I love to spend long periods of time outdoors, exploring and doing things that involved a prolonged period of time away from regular AC outlets. This means that I don't always get to recharge my hearing aid batteries due to their power supply being AC (UK plug). Hearing aid manufacturers aren't renowned for being modern and keeping up to date with modern charging capabilities. I'd love to know if it's possible to charge my current set up using a USB C/USB PD battery bank, with the help of an adapter/converter; I just simply don't know enough about electronics to feel comfortable in making the decision. I swear to God, if anyone is able to help me understand this or make it possible, you will have honestly changed my life and I'll be forever grateful to you.

The specifications on the plug for the charger to my hearing aid batteries reads as follows:
Switching Power Supply
Model: S018BAM1200100
Input: 100-240V ~ 50/60Hz 500mA
Output: 12V - 1000mA

If there's any more information you need, just let me know. Again, I appreciate anyone's help with this in any way.

Many thanks!

  • 1
    \$\begingroup\$ You should be able to use a regular 12V 1A battery bank for this. Plenty of those available, unless the hearing aids have some proprietary plug? \$\endgroup\$
    – Jeroen3
    Aug 12 '18 at 10:47
  • \$\begingroup\$ What kind of hearing aid batteries do you have that need 1-A charging supply? Just curious... \$\endgroup\$ Aug 13 '18 at 2:44
  • 1
    \$\begingroup\$ Detachable cochlear implant batteries :) \$\endgroup\$
    – H. Thomas
    Aug 15 '18 at 17:18

Something like this or this should work just fine for you (but see the entire lineup, you might like different model more).

The only problem with 12V power banks is that they tend to be rather on heavy side, which can be a burden while hiking.

I think you should also explore solar power alternative. While smaller solar panels won't be able to provide 1A charging current they still should be able to charge hearing aid battery. But even bigger panels are often lighter than 12V power banks. And you can hang them on your backpack and charge on the go.

Finally there are combination power bank + solar panel models. These are heavy but versatile. Many of them have built-in LED light and rugged body, which is extremely useful outdoors.


If you want to reuse your existing power bank, there are DC-DC "boost" modules that can convert 5V into 12V. Like this one or this one for example. They are cheap and they work. However keep in mind, that inside your power bank there is DC-DC already, producing 5V from battery voltage. This dual conversion reduces efficiency of the power bank. The bank with 12V output does this conversion only once.

Furthermore, to get 1A at 12V you need to draw at least 2.5A from 5V power bank. You need to make sure yours can provide this much. And you can calculate how long it can do that. For example 8,000 mAh bank can give you only 3 hours charging. If this is enough for your needs then OK.

This is the reason I suggested solar power in the first place. When you have no way to recharge power bank on a long trip you are back to square one. But if you have solar panel you do not need to worry. So, check out combination devices too (one, two). At least with them using converter module makes more sense, despite efficiency loss.

  • \$\begingroup\$ Thank you, I really appreciate your feedback. I’ll have a look into those.8 guess because I’m already using battery banks to charge my iPhone etc and some of the battery banks have usb PD (which I’m aware can deliver up to 100w output in some cases) it seems silly that I can’t utilise that in some way. Is there no converter/adapter that would be possible to convert the power delivered by this USB PD socket to the appropriate output needed by the charger? \$\endgroup\$
    – H. Thomas
    Aug 12 '18 at 14:12
  • \$\begingroup\$ Yes, it is easy to reuse your existing power bank. See an update in the answer. \$\endgroup\$
    – Maple
    Aug 12 '18 at 17:01
  • \$\begingroup\$ A solar panel is not great advice. A solar panel needs a battery and MPPT charger to store the energy. You cannot connect a solar panel directly to the hearing aid charger. A 12V panel does not output 12V. Voltage ranges from 0 to 20+ volts depending on the amount of irradiation received. \$\endgroup\$ Aug 12 '18 at 17:23
  • \$\begingroup\$ @Misunderstood First, you do not need "MPPT charger" if MPPT is built into panel itself, as is the case with Goal Zero devices I linked to. Second, the combination devices I suggested provide power form the battery, not solar panel. They output exact voltage they are designed for. \$\endgroup\$
    – Maple
    Aug 12 '18 at 17:56
  • \$\begingroup\$ Okay you got me there. I did not follow your link and assumed you were referring to just a solar panel. Still when an inexpensive small (e.g. four 18650 cells) fully charged battery pack will do the job well for an extended period of time, a solar panel is a superfluous waste of money. Especially on a cloudy day. \$\endgroup\$ Aug 12 '18 at 18:01

Any regulated 12V battery or battery pack will work fine. Your car battery with a cigarette lighter adapter would be ideal.

You will still need the charger. The 1000 mA spec on the power supply is more than sufficient to power the charger. You can very likely use a battery with less than a 1000 mA output. I manufactured a product that used about 300 mA but included a 1000 mA supply because it was the same cost as a lower current supply and more readily available. I did not use it because the device required 1000 mA. That said 1000 mA is easily achieved by most 12V Li-ion battery packs.

If away from your car for extended periods of time, if your battery bank is a regulated 12V it will work fine. By regulated I mean it outputs 12V regardless of the battery voltage.

If you need to purchase a new battery pack I would recommend one that uses 4 18650 batteries with a buck/boost (step down/step up) regulated 12V output so no matter where the battery voltages are in their discharge cycle, they will provide a 12V output. Many battery packs charge up to their maximum voltage then discharge to a much lower cutoff voltage and therefore would be of limited use. Just because a battery pack is labeled 12V (nominal) does not mean it outputs 12V.

Depending on your type of battery you may be able to take some spare primary (non-rechargeable) with you.

Thanks for the question. I may need a hearing aid soon with about 70% loss. I cannot watch a movie without closed captioning. I now know to choose a hearing aid that uses both primary and secondary (rechargeable) batteries. But for now I can usually get away with smiling and nodding my head.

  • 1
    \$\begingroup\$ Glad I can be of help in return- another piece of advice, look for one that is at least splashproof. Getting caught out in the rain or having an unexpected splash of water is so taken for granted. \$\endgroup\$
    – H. Thomas
    Aug 12 '18 at 18:52
  • \$\begingroup\$ I believe the OP does have the charger. The 12 V 1 A is an input to his charger, if I understand the situation correctly. So any simple 12-V battery pack will do the job, he just need a proper cable. \$\endgroup\$ Aug 13 '18 at 0:19
  • \$\begingroup\$ @AliChen yes I agree. I was saying his charger likely does not need for the battery to provide a full amp. It's just that a 1 amp power supply is the easiest for the manufacturer as far as cost and inventory control. \$\endgroup\$ Aug 13 '18 at 2:53


I have the exact same problem as you are having. I cannot live my life knowing I'll be forever constrained to a wall outlet to charge my hearing aid device. I even contacted Cochlear about this and they said do it at your own risk.

I performed a electrical test of how much wattage the battery charger consumes (Not using the USB port that the base station have). I have estimated that the battery consume roughly 0.6 to 0.7 watts which will consume 2.4 ~ 2.5 watts for all four batteries at once. (Currently I only have three batteries to test with, but I did test how much wattage it consume per each batteries at a time). The max total, including the base station, would take about 2.6~2.7 watts for four batteries.

My estimation would be that a simple 5v 1a (Should provide 5 watts) USB bank should be sufficient to charge the battery for four hours. The charger based does require a initial idle power of 0.3 watt.

I do plan on building a small USB power converter to meet the necessary requirement specification to charge just the battery itself. I do need help figuring out where I could buy the outlet for the charger base station. Once I figure that out, I'll assemble a quick and simple USB to power port jack to power the device.

If I can get all of this working, I'd be glad to share this solution with you! Hope the information above helps!


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