Circuit breaker or Current protector to protect Energizer XP18000A batteries

I have quite a number of XP18000A batteries that often got overheated (usually while the batteries
are supporting my  Macbook Retina  or  Thinkpad X61 or X230), causing the batteries to be

There's warranty for it but after changing them too many times, the supplier became reluctant
to change them though it's still within warranty period.  I have something like 5 of them to
rotate them around while waiting/arguing with principal Tennrich to get the burnt ones replaced.

Is there any device out there that could detect "over-current" & sort of cut off to protect the
XP18000A?  Got tired of sending them for warranty replacement.  There's 2 occasions when
I don't watch videos/movies, the XP18000A got burnt too but in almost all cases, it's video
playing that got the XP18000A burnt (feeling extremely hot to touch)

This thread is not meant to discredit / soil Tennrich products but to explore ways to reduce
my frustrations.

For Hyperjuice batteries, I have used units which works till today : they have built-in mechanism
to auto cutoff when there's overcurrent & I just need to plug in the charger & this will remove
the auto cutoff mechanism.   Hyperjuice is too expensive though & I'm glad I got those used sets
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JohnBusiness Consultant (Owner)Commented:
How do you hook said batteries into your ThinkPad X230 (I have that machine)?

I think I would be inclined to use a current limiting device. A resistor is a simple minded current limiting device.
If you short-circuit batteries they burn.
I had (acer) laptop that plainly short-circuited own battery and the external power at times and they burned out.
Why dont you buy over spec battery inside laptop?
Gerwin Jansen, EE MVETopic Advisor Commented:
Do you have an adapter that fits the MacBook MagSafe converter?

The battery itself must be fitted with such a protection, it is rated at 19v / 3.5A - if you try to use more it should disable the output, or at least limit to 3.5A.
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Davis McCarnOwnerCommented:
Apple has sued everyone who tries to make a magsafe connector for patent infringement.  If you are using the auto/air adapter from apple to connect the XB18000A batteries, the battery may be choosing to run at 12 volts as it "autosenses" the proper voltage.
How are you connecting to the MacBook?
Also, from what I have found online, it looks like there is a thermistor that blows due to overheating which is not necessarily due to drawing too much current.
sunhuxAuthor Commented:
> MacBook MagSafe converter
Yes, I used one of these.  

I connect to the Macbook using one of those adapters that the battery supplier provide &
it burns.  Then I got one of those direct from the battery to Magsafe2 cable adapter from
eBay & still burn the XP18000A batteries.   The Hyperjuice ones are Ok so far.

However, I have an old XP18000: it never burn despite that it felt very hot on the surface
after powering a laptop playing videos/movies

But it's not just the Macbook that burns the XP18000A, even my X230 & X61 burns quite a few of
those XP18000A.

The thermistor sounds interesting.  Can I just get a spare thermistor & replace it myself?  Of course
the XP18000A is so well-sealed that I have no idea how to open it up yet
JohnBusiness Consultant (Owner)Commented:
even my X230 & X61 burns quite a few of those XP18000A.   <-- My X230 is very easy on power, so the batteries you are using must be hopelessly underpowered (and under voltage?).

I use the large battery in my X230 and it is good for four hours. Try something like that.
Davis McCarnOwnerCommented:
Thermistors (in this case AKA thermal fuse) look like little bottle rockets; but, the only way to get a part number would be to dig one out.

And yes, back in the dark ages, it was easy to crack open a battery and change the bad battery.  Now; though, they're so thoroughly sealed shut that they have to be cut open with a small saw.

I'd figure out how to check the voltage that the XP1800's were deciding to use.  It ought to be the 19v; but, they could also decide to put out 12v which would up the current and the heat.
Gerwin Jansen, EE MVETopic Advisor Commented:
When do you connect the xp18000 exactly? When the laptops' batteries are full or when they are empty? If you connect while empty, the laptops will take a charging current which could be the cause for the high temperatures. If so, I would connect the xp18000 when laptop is full and when xp18000 runs out, disconnect and use laptop battery until empty.
A resistor is a simple minded current limiting device.

Resistor are a very poor, inefficient current limiter mainly used for older circuits, and shouldn't really be used on modern DC-DC voltage regulator circuits.  If you had an older circuit, you'd have to know how to correctly size the resistor to match the impedence of the laptop and you'd need one of the larger wire wound ones to withstand the wattage the larger current would produce and therefore waste power in resistor heat.  On modern DC-DC circuits, both the battery unit and the laptop will compensate for the extra load and you'll have more power being pushed out from the XP18000A.

It ought to be the 19v; but, they could also decide to put out 12v which would up the current and the heat.
It's not current that determines heat, it's wattage/power.

Watts = Volt x Amps
19 V x 1.0 A = 19 Watts.
12 V x 1.6 A = 19.2 Watts.

Those are approximately the same power and same heating at around 19.0 Watts of power.  I rounded to give cleaner numbers that you can still basically multiply in your head.  Your laptop would draw the same power at either voltage.  There may be a little extra heat from the voltage controlller circuit, but it wouldn't be that much more on today's modern DC to DC voltage regulator circuits.  They're very efficient compared to the old transformer technology.

They generally don't let you open the modern cases because Lithium batteries need precise charge cycles to extend their life and prevent explosions from overcharging and prevent undercharging to maintain battery life.  Putting in different battery capacities would change that.

Thermistors and thermal fuses are actually 2 different things.  A fuse would just blow open and disconnect the circuit.  You don't want to keep replacing them.  A Thermistor changes resistance based on the temperature, and there are 2 kinds, negative temperature coefficient and positive temperature coefficient.  You most likely need one with a positive temperature coefficient.  It also has to be sized correctly for the correct voltage and temperature.  Overheating is actually bad for the life of the batteries.  You shouldn't just replace the thermistor without knowing the exact specs and the unit probably doesn't use a thermistor.

It sounds like you got underpowered units or they've overstated their capacities on the newer units.  Maybe they're meant for lower power draw laptops.  How hot do the units get?  Is this the Energizer brand XP18000A?
Only XP18000/A and new model XP20000 can support laptop. XP18000 (5V/1A, 10.5V/2A, 19V/3.5A), XP18000A (5V/2A, 12V/2A, 19V/3A) may support one laptop and one USB devices at the same time. XP20000 (5V/1A, 5V/2A, 19V/3A) may support one laptop and two USB devices (1A, 2A) at the same time.

It may not be using a more expensive DC-DC regulator and it might just be tapping the cells at 2 points for the laptop power  Each Lithium cell is nominally about 3.7 Volts, so they may be using 3 cells for the 10.5 V setting (really 10.6V) and 5 cells for 19V (really 18.5 V)   The 12 V setting may use some voltage limiter, which may explain your heating.  This may also explain the lower current rating at the lower voltages.

The more expensive hyperjuice is probably using a DC-DC circuit, which is why it's more expensive.

I don't see the current rating, but the lenovo shows 14.4V as the adapter output.
Output: 14.4 V dc

Macbook 13" power supplies output 16.5V at a maximum of 3.65 A

Those are voltage mismatches, but that should be ok.  The circuits on the laptops will convert the voltages back to the voltages they actually use, but this does mean a little extra work from the XP 180000A and on the Laptop.  It should still be plenty of power.  It suggests the newer units are using lower quality parts and they should fully honor your warranty.

If Gerwin's suggestion isn't your case:

Rather than taking apart the entire unit and trying to find a difficult to match thermistor, you might want to just attach a thermal switch to the output line and just cutting the power when the temperature rises to a certain point.  This would be an easier external attachment, requiring only cutting the cable and adding wires to the switch and taping the switch to the unit.  Don't cut the entire line, just cut one of the 2 cables inside the sheath and add extra wire, if needed, to connect the thermal switch.  There are thermal switches for different temperatures.  You should figure what temperature you want to trigger and buy the one you need.

50º C or 122º F
45º C or 113º F
40º C or 104º F
sunhuxAuthor Commented:
With this same manufacturer's XP18000A, it never burn/overheat while with their newer (& higher
wattage), it never fails to overheat (after 1 hour of continuous movie watching on Macbook Pro,
X230, X61)  while I'm watching a video (Youtube,

In all cases, the batteries of the laptops are partially charged so I'm certain it has to do with video
/movie watching drawing too much power too fast
sunhuxAuthor Commented:
Correction, should be XP18000  (the newer model is XP18000A):
> With this same manufacturer's XP18000A
Davis McCarnOwnerCommented:
Both of them "autosense" what voltage they are supposed to supply and if they decide to use a lower voltage, the current goes up accordingly.  We have no control over the autosensing excepting which adapter causes the battery to choose the right voltage and using a voltmeter to measure the voltage is the only way to know.
There is no autosense, all laptops have same power regulator that adapts between 12 and 24V
sunhuxAuthor Commented:
The manufacturer Tennrich has declined to honour the warranty on the
grounds that the manner I (mis)used the XP18000A is the cause of the
DC 5V, 2.1A / DC 12V, 2A / DC 19V, 3.5A
My very basic laptop says 19V 3A
I dont see how one banks on powerbank that says it can charge 3 such average devices...
Marketing lies.  They probably meant 1 laptop, 1 cell phone, and 1 tablet.  Although your laptop says 19V 3A, it probably won't ever draw 3A, unless you have everything running and plug in all USB devices, so it can support the extra cell phone and tablet on the USB ports.
Electric company will not notice if you draw .5 or 1.5 A from wall socket for 1s. Limited battery pack certainly will...
Davis McCarnOwnerCommented:
OK, I dug in a little last night; but, had other responsibilities that kept me from posting......

The setup listed on Tennrich's website is inadequate for many of the MacBook Pro's.  Apple says the airplane adapter needs 15 volts at 5 amps (75 watts) and the setup from Tennrich provides 19.5 volts at 3.5 amps max (68.25 watts) IF your adapter is using the blue tip.
Tennrich manual:
Apple Airline adapter:,d.dmo

Further, the airline adapter was discontinued by Apple and does not work properly on newer MacBook's.

What I have to assume is happening is that both laptops have discrete videos (probably NVidia something) and watching the movies engages that video in both which significantly increases the power consumption, causing the battery to overheat.

With the actual model numbers of both laptops and some testing, I could prove this is what's happening.

XPal/Tennrich/Energizer's documentation is woefully inadequate and makes claims that are not supportable.  A 17" MacBook Pro would probably not even run on the XP18000A and the 15" model would be an overload. Pursuing that may be a crazy waste of time (though it ought to be winnable).

I think I'd dump the product and post a bunch of bad reviews on the web.

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Thumbs up for last line ;)
Macs do not need that much power and should be able to draw from lower power supplies when needed.  I've used the 45 Watt MacBook Air Chargers just fine on the 15" Macbooks that should be using the 80 Watt Chargers.  You only need the 80 Watts if you're running at peak power and need to recharge the battery at the same time.  With the 45 Watt charger, the laptop will either just recharge the battery, if you're not running anything, or switch to power only mode and stop recharging the battery when it's running full CPU and GPU.  The adapters just run a little hotter and doesn't burn out.

I've never really tested with other brands because they don't generally use fully interchangeable connectors with different power ratings on PC laptops.  They're all over the place.  I have swapped and Thinkpad 570, T21, and HP Omnibook chargers, but those all had enough power to power each other, even with different current ratings.  They were all overpowered to power additional docking stations, so they never had problems with just the laptops.  They usually change adapter tips when the voltage ratings change.

I suspect the supposed higher capacity of the newer XP 18000A uses lower quality circuits to get them out cheaper.  Designed correctly, it should not allow the battery to overheat or burn out.  These packs are supposed to have circuitry to compensate for the load and have a current limiter.  All lithium battery packs are supposed to have them.  They probably started out ok with the earlier XP 18000, but kept the basic specs while going with cheaper circuitry that didn't properly limit current.  Your only work-around may be the thermal cutoff switches if you want to keep them, or just saving them for the USB charging ability.

Basically, their marketing materials lied about the capability.  You should definitely give them a bad review.  They shouldn't be allowed to use substandard technology in the hopes that you overlook it.
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