tag:blogger.com,1999:blog-3993498847203183398.post2501899732970741958..comments2024-03-28T09:19:27.451+00:00Comments on RevK<sup>®</sup>'s ramblings: Battery SafetyRevKhttp://www.blogger.com/profile/12369263214193333422noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-3993498847203183398.post-4206332368738111462016-11-25T15:48:50.837+00:002016-11-25T15:48:50.837+00:00thanksthanksAnonymoushttps://www.blogger.com/profile/04571828795230778384noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-53295513322743685782016-09-22T08:06:17.973+01:002016-09-22T08:06:17.973+01:00thanksthanksAnonymoushttps://www.blogger.com/profile/04571828795230778384noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-85631126524510208402016-07-04T09:58:04.961+01:002016-07-04T09:58:04.961+01:00Well, testing, as someone else says, seems to sugg...Well, testing, as someone else says, seems to suggest no charging happens until it cools down anyway. The battery pack has separate per cell voltage checking, and has temperature reporting as well as in built logging of charges and discharges and flight time, so pretty comprehensive.RevKhttps://www.blogger.com/profile/12369263214193333422noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-15766218831880681572016-07-04T09:52:40.698+01:002016-07-04T09:52:40.698+01:00With regard to the battery protection circuits a l...With regard to the battery protection circuits a lot of cells (mobile batteries and some 18650's for example) have these. They is a widely used chip for this called the DC01. It has the following protection methods :-<br />1 - Turns off current flowing to the battery if it is over voltage.<br />2 - Turns off current flowing out of the battery if it is too discharged.<br />3 - Turns off the output if too much current is taken. Normally around 2-3A<br />4 - Turns off charging if too high a charge current is used.<br /><br />The discharge current limitation is based on the internal resistance of the switching MOSFET with 0.025R being a typical value and therefore it is difficult to use with equipment which is designed to have a high current draw so these often have more custom protection circuits.<br /><br />This chip does not do any temperature monitoring and this is always handled by completely separate circuitry.Gareth Bladeshttps://www.blogger.com/profile/01109177395639328580noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-54730974657818587352016-07-02T09:57:20.110+01:002016-07-02T09:57:20.110+01:00Which is what I would have expected. ThanksWhich is what I would have expected. ThanksRevKhttps://www.blogger.com/profile/12369263214193333422noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-21289572720860054432016-07-01T19:36:39.056+01:002016-07-01T19:36:39.056+01:00My P4 batteries refuse to charge if plugged in aft...My P4 batteries refuse to charge if plugged in after flight, as they cool they can then chargeAnonymoushttps://www.blogger.com/profile/16677452543166732638noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-58087446040927454762016-07-01T15:16:40.549+01:002016-07-01T15:16:40.549+01:00The Phantom 4 has all the bells and whistles. I am...The Phantom 4 has all the bells and whistles. I am pretty sure it reports each cell charge levels. I'll check next time I spin up the drone.RevKhttps://www.blogger.com/profile/12369263214193333422noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-76454038230414344552016-07-01T15:12:37.686+01:002016-07-01T15:12:37.686+01:00There are all sorts of circuitry the battery may o...There are all sorts of circuitry the battery may or may not have in it. Some have a thermistor to detect the battery temperture. Some have a full gas gauge chip with a 1 wire serial protocol, the chip knows how much charge is in the battery and it's voltage and current flowing and temperture. But either of these require a third contact for the data from the battery pack.<br /><br />Some batteries have safety trip circuitry in the pack (CE marking mandates this, but it isn't always present) which turns off the pack if too much current is drawn or the battery gets very very hot. The charger needs to know how to untrip these with a very slow initial charge at a lower voltage.<br /><br />Different batteries can quote differnent guidance because LiPo tells you nothing about the chemistry. Many are Lithium Cobalt, but there are quite a few other options eg. Lithium FerroSulphate. This site is a good place to see all the options, though the site layou leaves something to be desired:<br /><br />http://batteryuniversity.comOwen Smithhttps://www.blogger.com/profile/00890951742186614705noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-61170385923548086962016-07-01T14:26:44.496+01:002016-07-01T14:26:44.496+01:00It has separate section for air travel and says to...It has separate section for air travel and says to fully discharge.RevKhttps://www.blogger.com/profile/12369263214193333422noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-64341807058015778992016-07-01T14:25:29.319+01:002016-07-01T14:25:29.319+01:00"Transport" in this case means things li..."Transport" in this case means things like air travel, bulk transshipment, etc: the sort of thing where the battery might experience changes in air pressure, bumping around and the like. If you're just going out in the field with a drone this applies no more than it does if you're taking your phone on holiday with you.<br /><br />The battery system will know the battery is too hot *if* it has a temperature sensor close enough to the battery to monitor it. This is obviously true of fitted batteries in things like tablets but I'm not sure if the battery circuit's sensors and the battery are necessarily close together on the Phantom (I know nothing about it, since I will learn to fly drones at around the same time as I learn to fly by flapping my arms).Nick Alcockhttps://www.blogger.com/profile/06590610308528769844noreply@blogger.com