Used Canon batteries from MPB?

nnowak wrote:

R2D2 wrote:

nnowak wrote:

R2D2 wrote:

nnowak wrote:

For example, you could have a battery that was only used in the camera once, but spent a year sitting on the charger constantly getting topped up to 100%. The battery would look like new with barely a mark on the contacts, but performance would be dramatically degraded.

This is entirely false, and does not apply to these lithium ion chargers at all (like it would to older technologies such as NiCad and even NiMH). Simple Li-ion battery chargers for safety’s sake do not have a float or “trickle” charging function. They shut off charging current entirely when peak voltage is reached. If this is not done, then lithium batteries will over-charge, burst, and/or ignite. Bad bad bad.

Reread what I wrote. Nowhere did I suggest that lithium batteries would be trickled charged.

LOL, you're trying to backtrack from what you posted earlier.

So, in your mind, "getting topped off" means trickle charging, but your use of "topping charge" means something completely different. I am not backtracking, you are just trying to misconstrue my words because you want to be argumentative.

No.  What YOU wrote earlier was the very definition of “trickle charging.”  Go re-read it.

You went and created a cause and effect relationship: “Constant topping up” resulting in “Dramatically degraded performance”.

I’m simply correcting this bad information.  It’s absolutely not how these Li-ion battery chargers work.  “Constant topping up would be dangerous!

You used the word "CONSTANTLY." That's how the old trickle chargers work. THAT is what would cause the "dramatically degraded" performance that you wrote about. If not worse effects! Bad bad bad.

No, I used the word "constantly" because the charger won't just top up the battery one time, it will do it over and over whenever the charge drops a bit.

Perhaps english isn’t your native language.  I’ll help… Webster defines “constantly” as [Continuously over a period of time, Always].  You’re now backpedaling to what would be referred to as “intermittently!”  In any event, a (very) intermittent topping charge would not dramatically degrade performance!  You are wrong on both these counts.

But that's not how these Canon Li-ion chargers work. Instead they have a "topping charge" that triggers at typically 3.5 volts, and it takes a looooong time for these batteries to self-discharge to that level!

A typical lithium battery at 3.5 volts would be beyond 50% discharged. The charger will kick in long before the battery every gets that low.

Instead, after the Li-ion battery has self-discharged over the course of several months down to the trigger voltage of the Canon charger, it’ll kick on again for a short while to bring the battery to full charge, and then shut off again.

This would not damage the battery any more than any normal charge/discharge cycles would during that time. In fact fewer cycles would likely occur!

You are wrong is in your suggestion that the battery can sit on the charger for several months before it will be topped up again.

The self-discharge rate for these batteries is Very Low. You’re still thinking in terms of old tech. Heck, I have Li-ion battery packs that have been sitting for over a year unused and still measure over 3.7 volts per cell!

I don't know what battery your are referring to, but all of my Canon batteries are roughly double that voltage. If you have a LP-E12 sitting at 3.7 volts, you killed that battery.

I am guessing you are talking about primary cells, which will behave differently from a camera battery with multiple cells connected to a protection circuit with a built-in balance function. Regardless, judging the charges state of a lithium cell based on a measured voltage is relatively meaningless due to the flat voltage curve of a lithium cell. A measurement of 3.7 volts could be anywhere from 40% capacity to 90% capacity. Only at the extreme ends of charge/discharge will a voltage measurement be remotely meaningful.

I just checked a genuine Canon LP-E12 I have sitting around and it was at 8.0 volts (4.0 volts per cell). After using it in the camera for a few minutes it dropped to 7.6 volts (3.8 volts per cell). The genuine Canon charger took 40 minutes to bring is back up to 8.2 volts (4.1 volts per cell).

The charger will kick in to top up the battery much sooner than that. You're roughly off by a factor of ten.

Definitely not. You're just pulling numbers out of thin air (I sanitized this last bit ).

Like your 3.5 volt number?

Getting the last few percentage of charge into a lithium battery is one of the hardest things for a lithium battery. Charging from 98% to 100% does similar wear and tear to charging from 25% to 100%

Yet Canon's batteries are still rated at 500 charge cycles even with this charging regimen. Give it up, your argument simply holds no water.

I’d recommend everyone spend some time at the Battery University website. They’re an excellent battery info resource, esp important for the newer chemistries nowadays…

https://batteryuniversity.com/article/bu-409-charging-lithium-ion

If MPB had the equipment to do a full load test on each battery and reported a % for remaining life, then they might be worth considering. As it is, you are buying a complete unknown.

But you don’t know if they do or they don’t! It’d be good instead to get a definitive answer from them (and from Canon Refurb for that matter). A good job for you?

R2

Whether or not MPB tests their used batteries is irrelevant if they do not post the test results for each battery, or at least publish a minimum threshold that every battery must attain. A battery from MPB could 10 years old with a 50% capacity or a year old with 98% capacity. There is no way of knowing aside from purchasing the battery and doing your own testing

A minimum threshold would be nice. It's why I thought you should research that (maybe after boning up on Li-ion technology?).

Can't research something that does not exist. I went to MPB's page for these used batteries and there is nothing posted. Feel free to do your own research.

I for one have never had an issue with my camera batteries. I treat them well, and they treat me well back. Amazing things actually.

And I am guessing none of these were used batteries purchased from MPB.

R2

I just did a very quick google search and one of the first hits was the Nikon D850 manual with the following warning:

"Continuing to charge the battery after it is fully charged can impair battery performance."

I am sure if I spent more time searching, I could find a similar warning in a Canon manual.

It’s very obvious your battery knowledge is lacking.  I already gave you the best tool (link to B.U. above) to further your knowledge.  Li-ion chemistry isn’t something that you want to get wrong.  Go bone up on it (or at least quit spreading false information).

R2