Batteroo says $2.50 Batteriser sleeve gives battery extended life

[saypat]

anybody hear of this? Experts care to chime in on it?

Batteroo says $2.50 Batteriser sleeve gives battery extended life

[Strick9]

From Reddit…

Well, this is the old joule thief concept made small. A joule thief boosts a voltage from a lower to a higher by a flyback circuit that uses a inductive kickback. It can also be built in.

Caution, fully draining batteries become more likely to corrode through the zinc casing and the alkaline battery fluid can wreck the equipment circuit by etching it away.

The Joule Thief connects to the depleted battery draws a current from it through a coil, then interrupts the current very very quickly with a FET switch (which has no diode drop). When the current is interrupted the magnetic field in this coil collapses. The energy stored in the collapsing magnetic shows up as a voltage spike, which is gathered in a smoothing capacitor. This all happens many times per second and the smoothed spikes are engineered to be at ~1.5 volts. Eventually the battery drops too low, maybe down to 0.3 volts or so and the inductive spike falls off below 1.5 volts. For very low current devices these joule thief circuits can run down to near zero volts as long as the turn-off is very rapid = a high spike.

Yes, pretty much. It really doesn’t do what they claim, however.

Most devices will shut down when the batteries drop to about 1.0 V/cell, give or take a bit. It’s true that there is still energy left in the batteries, which can be extracted with the right load.

However, the amount of energy available below about 1 V is small. This is no secret; you can get a data sheet for an alkaline cell, and discharge curves are widely available from many sources. It depends on several things, but it looks like you could get maybe 10% more energy from a battery drained to 1.0 V. To claim you can get 8x the power is just not true. I can’t imagine why anybody would claim that.

So you want to extend your battery life by 10? Hold on; it’s not that simple. If you use a boost converter to produce a constant 1.5 V from the battery, it will have some loss. 90 efficiency would be pretty good. So draining 10% more energy from the battery and then losing 11% of it in the converter does nothing.

OK, if you want to get really clever, you can design a low-loss switch that connects the battery directly to the output until it gets down to 1.0 V, and then start a boost converter. But that’s getting kind of complicated.

Bottom line: this doesn’t work. It’s easy to show that it doesn’t work; you don’t have to try one to see. The people who say that it works are either confused or lying.

[HKJ]

It may help a bit with devices that can only run on alkaline but not on NiMH because the voltage is to low (This kind of devices are designed by manufacturers that did not read the battery specifications).

This is typically low power devices and the question is if the boost converter has low enough power consumption to extend the battery life time.

[mhanlen]

I saw this. It looks really cool, for people who use alkalines. I have a ton of old partially used batteries that these might be good for. Of course i don’t know what I would use those batteries in.

[DavidEF]

@HKJ

It may help a bit with devices that can only run on alkaline but not on NiMH because the voltage is to low (This kind of devices are designed by manufacturers that did not read the battery specifications).

This is typically low power devices and the question is if the boost converter has low enough power consumption to extend the battery life time.

Hey, I never thought of that. So, this device might allow me to use my Eneloops in devices like remote controls and game controllers that wouldn’t normally work at the slightly lower voltage. I’ve always wondered why such a low drain device as a remote would consider 1.4v to be a “dead” battery.

[HKJ]

@DavidEF

So, this device might allow me to use my Eneloops in devices like remote controls and game controllers that wouldn’t normally work at the slightly lower voltage. I’ve always wondered why such a low drain device as a remote would consider 1.4v to be a “dead” battery.

That might be a possibility.

I wonder if it can handle remove controls, the peak current can be fairly high, but only for a short fraction of a second.