Hi all, long time blog follower, first time posting on the forum (and registering..).
I'm having an issue on which I can't find a lot of information, so where else is a better place to ask than here?
I've been experimenting with two different DC DC Converters in series: one regulates the voltage of a (sealed lead acid) battery and protects it against deep discharge (by shutting off the load of the converter..). The second (in series) is a straight of the market DC-fed laptop charger (Kensington). This last one feeds a laptop.
Why 2 converters?Well, most manufacturers of laptops protect their hardware by adding an "ID pin" so you can't use a charger that is not licensed... As I'm not intending to mimic the ID pin myself, I've resorted to a mainstream supplier.
What's the issue?Ever since I've started experimenting, I have the issue that my battery starts to swell up.
![Banging Head |O](https://www.eevblog.com/forum/Smileys/default/bangheadonwall.gif)
I've never "seen" it happen: it was only after a couple of days I was informed the system was no longer working well. The load never exceeds the maximum specified current of 8A and I've used the same kind of batteries for months now on a single DC DC Converter setup (so similar to the situation above except without the store-bought laptop-charger)
I'm afraid (and not experienced enough with DC DC Converters) that putting these two converters in series is causing some oscillations or something. I was hoping that someone on the forum can tell me:
- Have I been doing a naughty "no-no" by putting these two in series
- How can I make sure the converters are NOT interfering so I can run another test (and wait for the batteries to swell up or not)
Thanks in advance!