Li-ion charger

Got the same prob here in spain, with spanish RS, I'll have to create yet another yahoo acount, cos RS's IT dept is crap, and wont let me have the same account name/email address in two countries

martin

After logging in I sat watching a slow moving progress bar, after about 5 mins it opened a blank white html page!!!

I haven't opened a battery pack in a while, so I don't know about current technology. However, if you want to play it safe, you incorporate a cell protector chip in the pack:

as one of a few examples. Such chips used to be a requirement.

Initially, Sony wouldn't sell Lion cells without their protection chips. Eventually "bare" cells hit the market so I gather they dropped that requirement.

Thanks - lots of info coming in, including what I googled. From some of what I've read I'm beginning to think I need a long strip of flexiprint - so I can hang the battery being charged out the window!!!

A rhino?

Tim

-- Deep Fryer: a very philosophical monk. Website:

I'm not sure that Sony makes anything worth buying, anymore. Have you looked at their PCs? Every one I get my hands on is already half stripped.

My recollection is the average notebook computer battery could be made to explode like a stick and a half of dynamite. Many notebooks hide bits of the battery charger control software in the keyboard controller to kept it away from the hackers. Technically, every chipset has SMB control, but I don't know how many use the port to control the pack since it could be hacked.

Note that in this Dell fiasco, I blame the charger electronics. You will get crap cells from time to time and the charger should not charge crap. Period, end of story, no excuses, failure is not an option. Fool proof electronics is not simple.

In message , dated Sat, 9 Sep 2006, Tim Williams writes

No, a rhi-ino.

-- OOO - Own Opinions Only. Try

Baloney. The Sony cells blew up due to metal particles causing internal shorts. It actually had nothing to do with charging. Furthermore, there is no electrical means to detect this before it's too late. Even sensing battery temperature (which is done already) gives the warning too late. I'm afraid this is a case where the battery simply has to be made properly to avoid this. You can't blame it on the charger. Due the amount of money involved I'm sure Sony would have *loved* to blame it on the charger.

Now one thing the OP might want to know is that if you don't need to squeeze every ounce of run-time from the battery, you will get much bettery life (number of charge cycles) by charging to 4.1V (or lower) rather than 4.2V. Some, but no all charger chips allow this, so it would not be entirely crazy to roll your own charger. It really is only a current limited voltage source. If you want to be really nice to the cells you can add a charge timer and circuit to cut charge current to

The downside of lower charge voltage is of course less run time, so you have to decide about the tradeoff.

snipped-for-privacy@sushi.com wrote:

Most of the problems I've had with Sony kit were with their low-end products. Stuff from the mid- to high-end seems to be pretty well built IME.

A small operation can't buy 'bare' Li+ cells in the UK (nor all the EU, I believe). You have to show what protection you are applying and it has to be certified, which only makes sense for OEMs with the time and money (and expected shipments) to do such an exercise. If you are buying cell packs from a retailer (such as RS or Farnell) then they should have the protectors already in the pack. The protectors protect at a minimum against overvoltage events.

Cheers

PeteS

Thanks that's handy to know, although what I've read so far very small drops in charging voltage result in relatively large drops in charge capacity - but OTOH a lithium fire indoors is not an option!!!

Some simple effective charger designs and general lithium advice here:

Thanks - very interesting page.

It must be so high end that none of the stores around here sell it.

Since the Dell incidents the battery bin at the local tip has been the new home of an increasing number of Li laptop packs, all that I've opened so far had some circuitry but so far I've not been able to identify any chips to download the data sheets. If I persevere this situation may change.

Is that the African savannah's analog of the Everglades' newt-rino?

Tim

i believe seiko makes most of them , for datasheets see

Oh, and the shorts couldn't be detected? Hardly.

Oh, if only there was a law relating voltage, current and resistance. ;-)

It actually had nothing to do with charging. Furthermore, there

what