[Solved] UPS Ever CDS 700 emergency power supply - short circuit during battery replaceme

Yesterday I replaced the battery in my old UPS. I wanted to remove the protection of the "+" connector on the battery with a screwdriver and unfortunately I came into contact with the device housing. A short cycle of a little balloon and the device didn't get up. I don't know what exactly burned out because you can't see the soot exactly. But this UPS could be used as an emergency power supply for the pump and gas furnace in the event of a power failure because it was equipped with a full sine wave. But before I get fixed, I don't need real-time power. Can I remove the necessary elements from this power supply, such as a transformer, inverter, etc., to get the full sine output after connecting the battery? Anyone have a schematic? Certainly in this electronics there are modules needed to detect the power state or the battery charge level, and for me it is unnecessary because such a system is an additional load for the battery. Can you do something like this "analog" or does it have to be a digital module? Or maybe it can be done with an arduino? I am completely green. I know how to convert AC to DC but I haven't done it the other way yet. Please help.

Check the fuses first. It's a bit strange, because by shorting the + battery to ground, you only short-circuit the battery, if the UPS was turned off at that time and the charging system was not working, then nothing should happen to it.

See also if the plate has not burned the mass path.

Hello

huluk wrote:

Check the fuses first.

Also check the plate from the print side. Perhaps there was some path burnt out.
best regards

I was looking, but I really can't see anything. In total, this power supply was bought on the Allegro for PLN 60, so I do not have a 100% guarantee that the error is operational before changing the battery. I am attaching photos of the board on both sides.

And the fuses are measured? Something reminds me that this UPS will not start without a functioning battery connected, if the fuses "popped", there is a break in the battery circuit and the UPS may not want to "start".

The tubular fuses are intact. I started looking for a broken circuit - did not find it. I plugged it in again and turned it on. It started to shoot and smoke in the marked place until the path came out of the tile. Does this mean that I have to make an additional bypass circuit with another wire?

Probably not. This path should not be followed by so large currents that it would burn out. Was it working properly for that moment after turning on the UPS? If so, you can measure the current flowing through it. A functional, charged battery was connected? There is probably a short circuit somewhere. You have to traverse the elements following its footsteps.

And here the problem becomes more complicated. The path branches out - one of them leads to some kind of chip. I suspect that it will be difficult to locate the fault. Coming back to my question, if the current can be rectified with a few diodes, maybe it can be easy to change direct current to alternating current using parts from this UPS. PS. I want a full sine wave.

The battery fuses are the two fuses on the board, green with the number 30, between the red and black battery cables.

My friend probably connected the UPS front panel to the board incorrectly, these UPSs do not like it. I've already done one Ever (a microcontroller shot). I don't know how - but it happened.

I made the same mistake - short circuit + to ground on the off upsie when replacing the battery. Teb ups probably does not have a protection system against such a case. Managed to fix the board (path connection and replacement of 30A fuses)? Are these regular 30A 32V automotive fuses?

Hello, I will connect to the topic, because maybe someone has managed to fix such a defect.
I broke my UPS similarly, but I'll add some data.
My UPS had cables with + and - crocodile clips led outside. It was connected to an external battery (under the photo / solar battery). Recently the crocodile clip fell off my clamp and touched the housing. The spark was heard. (the current flowed from the capacitor at the UPS input). Before reconnecting, I looked inside to be sure. I did not notice anything suspicious, so I connected the battery (so far nothing happened. After pressing the switch, the fuse burned out and exactly the same path as in the description above. I do not have a diagram, but I measured as much as I could and found two IRF1404 transistors damaged. So the path, I replaced the fuses, I replaced the transistors. After connecting, unfortunately, the effect is the same, i.e. after pressing the switch, the transistors fuses and this path. These transistors make me wonder because they are final and there is only a transformer behind them. it is 17v, it works quietly and does not heat up, so the secondary winding does not have short-circuits between the coils. Maybe someone has already managed to fix it, or maybe someone has a diagram, it would be a chance to go deeper.

Hello

mlak wrote:

These transistors make me wonder because they are final and there is only a transformer behind them

Rather, see what drives them. Because it is the wrong control of these transistors that is probably the reason for their damage. They're probably open all the time, which is why the fireworks.
best regards

I fell ... I bought a full sine converter. best regards