I've looked inside my garage remote control and I've discovered a 12v 27a battery. The voltage is very low, but the ampere are many, can it damage a person when is fully charged? Thanks
Can a 12v 27a alkaline battery damage?
The on each photo, the central part looks hand-soldered to me. On the last two pictures for example the excess amount of burnt flux is visible. Also while the components do no appear to be beautifully soldered, I don't see why they wouldn't work because they all appear to have electrical connections.
If nobody tried to hand-solder the components, it may be possible that someone tried to bake the card and may have added extra flux to the components to make the process go more smoothly. If that was the case, then we're probably not seeing the main damaged area. People usually bake cards when they believe that the solder balls on one of the BGA chips (and that's usually the GPU itself) are cracking and have bad connection. Unfortunately from what I've heard the only relatively cheap way of seeing the damage there is to make x-ray images of the card itself and even then not many people would go through the trouble of actually replacing a BGA component. The damaged capacitors also in my opinion support the baking idea since they can easily be overheated during the process and leak or explode.
If the card really wasn't "repaired" by someone else, then only thing that could in my opinion cause such problems would be really really bad overheating. There are stories of SMD resistors for example desoldering themselves because they heat up too much, but then again you have some problematic capacitors too.
Electronic – Could an electrically charged person damage an ESD sensitive component, that is isolated from ground, by touching it
While it is less likely to create hard-faults with Electrostatic Charge in a component that is not connected to any bulk surface to dissipate or equalise the initial impulse, it is still possible.
Say you are negatively charged compared to the chip, that means you have "excess electrons", so when you tough a pin of the device, that pin will be connected to your excess and will "want" to become the same charge. This induces a current. It may be shorter in duration and could be smaller than when the chip is "grounded", but it can be enough to kill it, depending on the chip's innards.
Even the over-charge on one pin compared to another can destabilise some constructs in Chips, especially MOS devices, sometimes even permanently.
Note about "Anti-Static" bags, There's a couple types:
- Pink Anti-Static: Not safe at all for ESD sensitive chips
- Black Dissipative: Very safe for ESD sensitive devices, but less so than the metal-foil ones.
- Metal Foil Conductive: Extremely safe.
The Pink bags are only anti-static: It does not create charge when rubbed by another surface. So they are nice in a shipment with several bags, to prevent static to build up, but a human-body zap can very easily go straight through the plastic to any chip.
The black dissipative actually conducts a bit of electricity, usually a few hundred kOhm to a MOhm per square of resistance, and they will dissipate any charge built up across it and human-body discharges are extremely unlikely to penetrate the bag to the chip, but high level discharges may still affect the chip.
Metal foil conductive: The name says it all, has a very low resistance per square. Some bags have the foil (or a micro-laser-perforated foil to allow some see-through) on the inside, some have an extra layer of dissipative material over it, to protect the metal film. It will be extremely hard to have any kind of zap go through the bag, as the foil will conduct it from one side to the other. Even high intensity discharges will have trouble getting through, with the exception of discharges that will vaporize the foil, since that will make the bag (and chip) explode. And of course a few below that level, but I wanted to conjure the image of an exploding ESD bag.
That's a 27A-size battery, not a battery capable of providing 27 amperes of current. The maximum current from that battery can best be described as "piddly", which is all a remote control needs.