LiPo vs Rechargeable Lithium 123

[Nick Odell]

The LiPo battery in a tiny remote controlled helicopter toy has failed. I can tell it's failed because it has blown itself up like a party balloon! I was surprised at how low the capacity was - 200mAh was printed on the side. I've now replaced it with a similar 350mAh LiPo battery.

I was just wondering how the performance of these LiPos compare with a more conventional rechargeable lithium 123 cell. The 123 only weighs

4g more than the LiPo yet seem to have many times the storage capacity so presumably there must be some reason why they aren't used in this application. Any thoughts?

Nick

[Andy Burns]

I thought CR123 were /not/ rechargeable?

[The Natural Philosopher]

123s are about 50% heavier and have lower terminal voltages (3.3 v 3.7 average) although they are more bombproof

I think they are LiFePo technology

[The Natural Philosopher]

A123

[Theo]

I don't know what you mean by '123 cell' (as mentioned a CR123 is non-rechargeable. The company A123 Systems made lithium iron phosphate for EVs etc, probably a bit large for you!), but possibly the amount of current that can be drawn. A drone is going to take much more continuously than a camera.

Theo

[The Natural Philosopher]

model planes will fly on 123s. They are better than Nixx. But LIPO is simply better than either.

[Nick Odell]

I've been using rechargeables like these:

cameras for years.

I'm not sure of the correct prefixes or suffixes for them so I deliberately avoided that. They weigh about 14g and have a capacity of about 1500mAh compared with the LiPos I have which seem to be just over 10g and, as I said 200/350mAh

Nick

[Nick Odell]

At 70g vs the 14g of the ones I've been using, I wonder if we are talking about the same thing?

Nick

[Nick Odell]

In what respect better? Are the LiPos better able to sustain a high current drain? It was my suspicion that they might not be equal to several minutes sustained flight that made me ask the question rather than lash one up in the helicopter body.

Nick

[Nick Odell]

I have an electronic balance which measures in 0.1g intervals and is accurate to +/- 0.1g (according to reference weights). The 123 cells each weigh something between 13.8-14.0 grammes, the little helicopter LiPo about 10.2g.

These 123s say Li-ion and 3.7v on the sleeve.

Nick

[The Natural Philosopher]

Apples and oranges - you have about 5 Wh there. (3.3 x 1.5) And I am certain they don't weigh 14g

40g is more like it

This 5Wh LIPO pack

weighs in at 26g

[The Natural Philosopher]

I would weigh your cells. They are NOT 14g. At that capacity they HAVE to be around 2 oz - 40g+

[The Natural Philosopher]

more energy to weight and as much power to weight

Well I've had nearly half an hours sustained flight out of LIPOS. Not an a chopper tho

[The Natural Philosopher]

If these are rechargeable 'CR123 equivalents' they certainly weigh a lot more than 14g - and they are not 3.3v LiFePo technology they are 3.7 v Li-ion...

[The Natural Philosopher]

FURTHERMORE if they are 1500mAH they are almost certainly NOT rechargeable viz:

"Non-rechargeable CR123A batteries have nominal voltage of 3.0 volts and capacity around 1500 mAh. Shelf life of the best CR123A brands is usually in the 7-10 years range, making these batteries excellent choices for standby devices like EDC flashlights, security devices, military applications and similar.

Non-rechargeable CR123A batteries also tolerate high drain currents, which is very important for high-power devices and for devices that require plenty of power for relatively short periods of time.

Rechargeable CR123A batteries (or RCR123A batteries) usually have voltage in the 3.6-3.7 range and capacity in the 500-800 mAh range. Note that rechargeable 3.0 and 3.3 volts batteries are also present on the market."

[The Natural Philosopher]

well you had better get theme gold plated. They appear to be, if truly

1500mAh, somewhat akin to pixie dust,

Either your scales are borked, or they are not 1500mAh, or they are not rechargeable

150mAh at that weight ...

Are you sure you had the scales on grams and not oz? 1.4 oz i could believe

And I can barely believe 10g on a 200mAh LIPO either One cell maybe.

[Paul]

I saw an article about RC cars, showing the "best" batteries available. You get effects like this:

Storage Max-Current 1500mA 20000 ma 3000mA 10000 ma

The reason a low capacity battery was fitted to the helicopter, could be to enhance available peak current flow. Making short trips work better.

The peak current is not stamped on the battery. They only stamp the capacity on them (3500maH for Panasonic, compared to "10000maH" for a chinese one :-) ). You need the datasheet or website, to get the max-current value.

You need to find vendors with complete tables of batteries for sale ("capacity" batteries versus "current" batteries), to discover how the specs and size, influence results. One site I checked, one of the results was entirely unintuitive. (One of their "current" batteries was just horrible max-current.) Then you need accurate weight values, to decide whether they're good for the job.

Paul

[Brian Gaff (Sofa]

Off the shelf availability? Brian

[Andy Burns]

In the same way of measuring 18650 cells, a CR123A size is a 16340 cell.

I have a Fenix torch that takes a 26650 cell, it has a Fenix branded cell 4800mAh (98g), according to my BT-C3100 charger, that capacity is accurate.

Fenix sell various sized Li-ion cells, including a 16340 (19g), but only with a capacity of 700mAh

The mAh/g is better for the larger cells, obviously the metal casing is dead weight, surface area to volume ratios and all that, which is one advantage to LiPo with their flimsy "bags".

So I'd doubt any 16340 cell that claims 1500mAh capacity, if Fenix could make one with double the capacity, why wouldn't they?

Did I squint and read on the photos that they have a minimum voltage of

2.75V? That seems quite low for Li-ion.

[The Natural Philosopher]

I suspect these are cheap chinese cells that actually have reject 150mAh inside :-)

1500mAh is for a primary cell and even those weigh more.

I think that what is printed on the sleeve bears no resemblance to reality at all.

Anyway total confusion because these are not the A123 Lifepo but LI-ION in a C132 size,any if they really weigh 14g, there is no way that they are 1500mAh.

I found some similar discontinued on amazon with rather bad reviews.