Tough love for the industry's lithium addiction

[fmerkel]

I put LSD NiMh in my backup. Every 3-4 months I take 'em out, cycle 'em and put them back. This battery maintenance ensures I check the insides of the light on a routine basis. I've had backup lights.....seep.....ever so slightly, maybe 1/2 drop/dive, not a serious flood. Things appear normal, the light may even work for a good while, but ultimately some nasty corrosion sets in and ruins it.

 

[2airishuman]

Both NiCads and NiMHs give practically the same voltage through the whole discharge process, alkalines show a steadily dropping voltage. Now, while it's nice to have good, bright light through the whole charge, you can't see if the rechargeables are full or if they're five minutes from empty by turning on the light briefly. With alkalines you notice a clear reduction in light intensity when they're close to empty.

Lithium batteries also show a fairly steep output dropoff when nearly discharged. Alkaline batteries (and the similar carbon-zinc chemistry that predated them) are the only one where there is a significant variation in voltage between, say, 75% soc and 25% soc.

Also, NiCads have a noticeable self-discharge (NiMHs less so), while the self-discharge in alkalines is very, very low. Self-discharge isn't much of an issue for cells which are regularly drained and recharged, but it's very much an issue for cells which are just kept for backup.

Modern, high-quality NiMH cells (notably the Panasonic Eneloop ones but also other brands) have lower self-discharge than alkaline. They are also less likely to leak. They deliver more power (watts at once) then alkaline, but somewhat less energy (total watt-hours) at least for low-drain applications (particularly things like clocks and smoke detectors that are always on and run for a year). For dive lights that discharge the battery over the course of an hour or two, I can't imagine any benefit to alkaline over NiMH.

 

[fmerkel]

In my experience the probability of alka-leak on a backup light is not much different than flood probability. Both can destroy your light.
@2airishuman is correct about the discharge curves. NiMh simply works better in a high output dive light.

 

[Popgun Pete]

I had shared this on the Conception fire board; but it is better placed here. A lot of excellent information.
Safety Concerns with Li-ion Batteries – Battery University

That is a good reference. A problem that I have noticed is that there are poor quality lithium ion batteries around and fakes that pretend to be well known brands. If you are not very familiar with the real thing then it would be very easy to buy something that had no reliability or safety. The seller may not know either if you are buying an electronic good with the cells supplied as a switcheroo may have been pulled somewhere along the supply chain. Now I am no expert and about 3 years ago I had nothing that used an 18650 battery, but now I have lots of electronic gadgets that use them. Everything seemed fine at first, but then I found batteries were not holding a charge and some just refused to charge up. I did some research on the Web and decided to trash all the supplied "Ultrafire" (they may have been fakes) batteries and buy Panasonic and some Boruit batteries that tend to be supplied with higher value items from China. So far I have had two of the latter inexplicably refuse to charge which was exposed by using a Nitecore charger that really is smart in place of the no name intelligent chargers that would cheerfully pump juice in no matter what the state of the battery was which were supplied with the initial purchases. Regulations and enforcement is badly needed to weed out this clone and counterfeit equipment because you have no idea how dangerous it may be.

 

[hsinhai]

There has been a lot of talk about a potential bad battery or charger, has the sheer volume of devices been discussed? What is the best way to handle charging over 100+ devices concurrently?

cameras/strobes/video lights/torch/dpv/phones/laptop/pads means it’s common to have multiple extension leads plugged into outlets for the hundreds of devices/batteries charging. Chargers piled on chargers piled on chargers on the charging table means those covered run abnormally hot because not cooled by normal ambient air which could lead to a failure in a normally good charger.

I’m also curious about the capacity/rating of the electrical system? Excessive load can mean a voltage drop, manifests higher current, higher current means more heat. Back when installed the quantity of charging that happens now may not have been foreseen?

 

[Popgun Pete]

Overloading of the vessel's electricity supply would be protected by circuit breakers or fuses, smart chargers should take care of the charging rates of the batteries, but some chargers are smarter than others and a second stringer unit may have failed to control the charging or a bad battery gave up or a combination of both. Meets all current standards on a charger may be a deception if it is a knock-off unit or a replacement not from the original manufacturer. As I posted recently I just threw out a bunch of no name chargers and their 18650 batteries.

 

[telemonster]

There has been a lot of talk about a potential bad battery or charger, has the sheer volume of devices been discussed? What is the best way to handle charging over 100+ devices concurrently?

I’m also curious about the capacity/rating of the electrical system? Excessive load can mean a voltage drop, manifests higher current, higher current means more heat. Back when installed the quantity of charging that happens now may not have been foreseen?

You should be able to charge 100 devices on a 2 amp USB chargers (iphone, ipad, etc) from a 15 amp 117v circuit. That's a lot of cell phones, and they will only draw that much when they're empty. Of course larger scooter and pro video batteries might use more. Chaining power strips is really only an issue if you overload them, and small devices don't use a lot of power like a kitchen appliance or hair dryer. Laptop power supplies get a bit chunkier, 65 watts to 130 watts usually.

It was said the generator on the boat was 50KW, that's pretty nice. Quick calc is 3,333 iphones charging at empty assuming proper power distribution?

 

[rjack321]

There has been a lot of talk about a potential bad battery or charger, has the sheer volume of devices been discussed? What is the best way to handle charging over 100+ devices concurrently?

cameras/strobes/video lights/torch/dpv/phones/laptop/pads means it’s common to have multiple extension leads plugged into outlets for the hundreds of devices/batteries charging. Chargers piled on chargers piled on chargers on the charging table means those covered run abnormally hot because not cooled by normal ambient air which could lead to a failure in a normally good charger.

I’m also curious about the capacity/rating of the electrical system? Excessive load can mean a voltage drop, manifests higher current, higher current means more heat. Back when installed the quantity of charging that happens now may not have been foreseen?

Most lithium ion chargers are shockingly low power. 25 watts is actually fairly high. So you can easily run a dozen chargers off one 15amp outlet (120V * 15 amps is about 1800W) 25 x 12 is only 300watts and well within one outlet's capacity

 

[ThatDogDontHunt]

Does anyone have suggestions for a budget 18650 charger that is considered safe?

I have a single battery charger with no features and I am unsure if it is considered safe. It came included with my hog morph 1000 backup light.

 

[rjack321]

Does anyone have suggestions for a budget 18650 charger that is considered safe?

I have a single battery charger with no features and I am unsure if it is considered safe. It came included with my hog morph 1000 backup light.

I recommend the nitecore D2, they are only about $15
D2