Lipo batteries

[Drumbo]

Lithium polymer batteries are the technologically evolved versions of traditional Lithium-ion batteries, so let’s try to understand lithium-ion technology first. Li-ion batteries are widely used in today’s consumer electronic devices because they offer three major advantages over traditional rechargeable batteries.

No Memory Effect – Memory effect, in short, refers to the battery’s loss of capacity due to partial discharge cycles. Li-ion batteries do not suffer from memory effects. These batteries are designed to be recharged without the need to fully discharge/drain them. In fact, this process of fully discharging before a charge cycle, also known as deep-cycling, should not be performed during regular usage as you risking doing more harm than good to the battery cells.

Got this from Wikipedia, any comments on this?

 

[Slackware]

the drawback is they are very picky about voltage and current when being charged, and are not content with just venting.

 

[Drumbo]

I was taught that they had a non linear charge rate and didn't like being recharged when half full. This is news to me. Once I've flown with a battery, even if half charged, it gets discharged and recharged fully as soon as the discharge cycle is complete. A mate who "had" a Parrot Bebop destroyed his battery in less than a month. After every flight, regardless of remaining capacity, got recharged. Could this be the reason?

 

[John Locke]

I was taught that they had a non linear charge rate and didn't like being recharged when half full. This is news to me. Once I've flown with a battery, even if half charged, it gets discharged and recharged fully as soon as the discharge cycle is complete. A mate who "had" a Parrot Bebop destroyed his battery in less than a month. After every flight, regardless of remaining capacity, got recharged. Could this be the reason?

Your practice of discharging fully before recharge is counterproductive. That wears out the battery sooner, not to mention wasting your time.

A battery rated at 200 full discharges will last for over 400 half discharges, with same end result. That's what the Lipo battery makers say.

 

[TimboZero]

A lipo is a li-ion, however where all lipos are li-ion not all li-ion are lipo.
Essentially the difference is the polymerisation of the electrolyte.
All the lithium chargers I have used over the last 10+ years use a dual charging method. They will initially charge with a constant current until the battery reaches nominal voltage (4.2volts per cell) when it will switch to constant voltage to 'top off' the last 20 or so percent.

 

[TimboZero]

John Locke is correct, or very close to. A lithium battery with a cycle life of 200 charges refers to full cycles and should do 400 half cycles (800 quarter cycles etc). In reality it will more than likely only do 380 half cycles (for example) as the oxidisation that causes battery failure wouldn't be half that of a full cycle but close enough for discussion.

 

[With The Birds]

I was taught that they had a non linear charge rate and didn't like being recharged when half full. This is news to me. Once I've flown with a battery, even if half charged, it gets discharged and recharged fully as soon as the discharge cycle is complete. A mate who "had" a Parrot Bebop destroyed his battery in less than a month. After every flight, regardless of remaining capacity, got recharged. Could this be the reason?

One of the best ways to shorten the lifespan of LiION chemistry is to keep it at full charge. There is no benefit to deep cycling a healthy pack (some swear to the benefits of deep discharge to balance cells but I haven't managed to save any of the dodgy packs I have had over the years with this method. Balance charging individual cells in non DJI packs seemed to have some success). The concensus for best lifespan and performance is to charge to around 50% after use and fully charge just before flying.

 

[TimboZero]

Whilst a stored lithium battery will lose more capacity when fully charged than partially charged (40% is considered the best long term storage capacity) it is not a huge deal. At 25 Celsius a 40% charged cell will have 96% capacity after a year, at 100% charge this drops to 80% capacity. At near frozen temperatures this difference drops drastically to only 4% (98 and 94% respectively) after a year.

 

[TimboZero]

The real killer is where cell voltage drops below 2.5volts

 

[Sith77]

Oddly I was just having this discussion's today. The whole battery chasing your charge level thing to keep at 60 and allow to dissipate to 50 yaada yadda I'm pretty sure is a little over top and old school thinking. The new LiPo - Lithium batteries arre much better built and the only real maintenance needed should be deep cycle. I've always used Deep Cycle process for everything , portables, cell phones , anything electrical. My battery life has all been great on my devices.

 

[John Locke]

The new LiPo - Lithium batteries are much better built and the only real maintenance needed should be deep cycle.

Can you point us to where you learned this? Or is this your opinion?

DJI has quit recommending deep cycle maintenance. Must be for a reason.

 

[Sith77]

Here was the first spot on the owners manual for the P4P where they tell you how cycle . They reference it a few times throughout. But they do also acknowledge the batteries interval decharge , now mind you this just my opinion Ive had my share of multiple devices out there and never once had a battery issue with loss of life etc..... But hea I'm to the DJI family ND just got sUAS today !! Very happy. Had Firmware up, software update no fly zone upades . First flight hoping for tomorrow weather permitting

 

[With The Birds]

Oddly I was just having this discussion's today. The whole battery chasing your charge level thing to keep at 60 and allow to dissipate to 50 yaada yadda I'm pretty sure is a little over top and old school thinking. The new LiPo - Lithium batteries arre much better built and the only real maintenance needed should be deep cycle. I've always used Deep Cycle process for everything , portables, cell phones , anything electrical. My battery life has all been great on my devices.

LiION do not need to be deep cycled- you are only wearing them out faster by increasing your cycle count unnecessarily.

Laptops, cell phones and other devices are less likely to show the effects of increased internal resistance than the battery in your phantom, this is simply because they are subjected to a significantly lower current delivery demand in normal use.

 

[John Locke]

Here was the first spot on the owners manual for the P4P where they tell you how cycle . They reference it a few times throughout. But they do also acknowledge the batteries interval decharge , now mind you this just my opinion Ive had my share of multiple devices out there and never once had a battery issue with loss of life etc..... But hea I'm to the DJI family ND just got sUAS today !! Very happy. Had Firmware up, software update no fly zone upades . First flight hoping for tomorrow weather permitting

That's interesting they put this into the P4P. It's also interesting they didn't say how often to discharge to 8%. You certainly don't want to do that every time you fly, however that's implied, with no guidance on frequency. Originally this was a process that was recommended every 10 charges (I think), then it was removed from manuals. The forum consensus has been there is no proof this "Calibration" discharge routine helps battery life at all.

 

[Sith77]

It is interesting , my brother has a P4 and we were discussing that discharging because he said his manual didn't say anything about having to do that process .