www.e-stim.net

Hello,

I opwn an ET 312, however, it seems to get a weak battery. Would everyone know where to buy a new and strong one?
Thanks in advance for information!
wiedehopf

Hi,
I've just changed the battery in my 312B - Looking around on the net I found Erostek's own replacement with the brackets handily pre fitted however it was quite pricey plus with shipping/possible? import duties on top of the price made it prohibitive ditto Happystim's.

Looking further on the net eventually led me to the type of battery required - I got this one off eBay UK for £15 including shipping (see attached pic)

Hopefully the same battery or something suitable should be available on e-bay in Germany/other countries.

Fitted and charged it overnight to 99% capacity and even after my first session with the new battery fitted (lasting around 45 min) it still showed a full 99% capacity

Also found this useful video (in German) showing how to change a 312 battery - [url]https://www.youtube.com/watch?v=y7SyuX9bXEE/url]

thanks a lot!!!

Hello from Germany to Germany,
I also dealt with this topic some time ago.
There is a very good guide to changing the battery on Youtoube in german:

https://www.youtube.com/watch?v=y7SyuX9bXEE

And on amazon.de I found this battery that should fit:

https://www.amazon.de/gp/product/B0071O ... XO6L&psc=1

Viel Erfolg!

Thanks a lot, that really helps!!!

Deltus1 wrote: ↑Fri Apr 14, 2023 11:32 am Hello from Germany to Germany,
I also dealt with this topic some time ago.
There is a very good guide to changing the battery on Youtoube in german:

https://www.youtube.com/watch?v=y7SyuX9bXEE

And on amazon.de I found this battery that should fit:

https://www.amazon.de/gp/product/B0071O ... XO6L&psc=1

Viel Erfolg!

i was looking all over at support info for this, this was a life saver.

To expand on this, for users in other countries, it looks like another comparable battery is this:
https://www.amazon.com/Casil-Security-R ... B07N7M4KR5
If that link breaks, or you're looking outside the previous locale's a search for
```
MULTIPOWER MP1.2-12 LEAD BATTERY LEAD GEL BATTERY 12V / 1.2Ah
```
found it for me.
the comparable battery specs are:
12V 1.2Ah
(L x W x H):
- Metric / mm / millimeters / sane parts of the world: 97 x 43 x 53
- Imperial / in / inches / freedom units cause 'murica: 3.82 1.69 x 2.28

hoping this helps people looking

A battery change is an opportunity to fix some ET312 bugs as well.

The schematic is here
https://github.com/openfuck/buttshock-e ... rboard.gif
It is a floating charge, the battery should have 12.5 to 12.6V
One can check when the old battery is removed.

* When the battery is full the current converge to 0, then the D4 voltage converges to 0 as well. Security alarms work like that, but they are never shut down.
* R7 is a 5% tolerance resistor.
* The LM2941 needs a minimum current to work properly (and not send a voltage too high). The tips and tricks is to use the resistors bridge to do that. Their values should be decreased to +-7.55K and 0.755K . A good idea is to buy a couple of standard E96 values around, for one of the R7 R8 resistors. After soldering the average one, and letting cool down for a couple of hours, a proper voltage measurement and an extrapolation can choose the good one.

It is also an opportunity to modify C21 and C27 from 1uF down to 150nF (see the other pictures). It is better for rapid changes inputs for "sport" audio3 inputs.