Recharge When?

[CaptnJack]

I'm not sure what their claim of available duty cycles has to do with sales; except that it would discourage me from buying their batteries. I assume these batteries are no different than those I'm accustomed to using. For those the rule is to use until failure unless in certain critical applications then to determine life in that application and schedule replacement before failure.

You two seem to be "Battery Authorities". From whence comes your expertise?

So you think 100x 100% duty cycles is admirable? I have 8yo NiMH batteries with upwards of 500 cycles on them and they still hold ~85% of rated capacity (4500mAh). Not discharging them below about 45-50% of capacity is the "secret" to long life. In scuba applications its easier to carry a slightly larger battery and use slightly less of its rated capacity per use. They don't really weigh anything in the water afterall and a slightly larger canister is generally not a major heartache (to a point). RC airplanes obviously have a different issue, they smoke through batteries using up 100+% of rated capacity every time as weight is critical and carrying even a slightly larger battery is not worth it . So they replace them every few months, they know that short battery life comes with that kind of duty cycle.

[airsix]

I'm no battery authority, just a guy concerned about getting the most out of my equipment. There's a lot of good info out there if you dig for it.

[Dashrynn]

I'm not sure what their claim of available duty cycles has to do with sales; except that it would discourage me from buying their batteries. I assume these batteries are no different than those I'm accustomed to using. For those the rule is to use until failure unless in certain critical applications then to determine life in that application and schedule replacement before failure.

You two seem to be "Battery Authorities". From whence comes your expertise?

To be fair, they are spot on. Just sometimes misinterpret ones words. When you spend countless hours researching your equipment or how to build your own, you learn a few things.

[ArcticDiver]

I'm not sure what their claim of available duty cycles has to do with sales; except that it would discourage me from buying their batteries. I assume these batteries are no different than those I'm accustomed to using. For those the rule is to use until failure unless in certain critical applications then to determine life in that application and schedule replacement before failure.

You two seem to be "Battery Authorities". From whence comes your expertise?

To be fair, they are spot on. Just sometimes misinterpret ones words. When you spend countless hours researching your equipment or how to build your own, you learn a few things.

True. Over the years I've learned a whole bunch about batteries. It all started because our aircraft batteries would often die in flight even though we were following mfg instructions. But, I really haven't spent a lot of time on scuba type batteries except I've discovered strange things that made me want to learn more. So far I've learned that a lot of people think they know a lot more than they really do. Hence, my questions here where people have a tendency to not overstate their knowledge.

Just for giggles: An alarm system I was installing for discouraging bears was powered by AA batteries. It didn't work with some brands of AA batteries but would with others. I chased that for a bit until it occured to me I should check the sizes. I found some brands positive terminal extends further from the case than other brands. The alarm maker had designed for a specific brand and it wouldn't work with any other. With the correct batteries the alarm did a good job.

[ArcticDiver]

I started this thread to get more knowledge about the kind of batteries that are used in scuba. There have been some good inputs from posters and I've gotten some more info from outside sources. Here is what I think I know as of now, subject to further factoids, of course. In scuba batteries are definitely a relatively inexpensive consumable.

-Lots and lots of misinformation that is passed for fact.
-Lots of tricks and practices that purport to eek out the last possible bit of energy from batteries. Those practices may or may not get more out of the battery. Most are not independently reviewed. Frankly, I've come to the opinion none of those things are worth the effort. Buy'em and use'em. Any possible savings are marginal at best when compared to total costs.
-Batteries have storage and in service lives. The lives are affected by many factors. One set of factors are the number of available discharge/charge cycles. For best use prevailing opinion seems to be to use each charge cycle fully before recharging. (Full use does not mean discharge so far as to damage the battery). Temperature is another factor. Keep batteries within their desgn temperature range during storage and service.
-Don't attempt to recharge a battery that is not designed to be recharged.
-It is better to remove load from batteries before recharging.
-When assembling battery packs it is worthwhile to balance individual cells within the pack.
-Different battery chemistries are more suitable for different uses.
-Read and follow the manufacturer's information before putting batteries into service.

My post is not a complete list, nor is it intended to be. After all a perfectly reasonable and effective way to treat batteries is as a consumable that a person buys, uses and discards with only thought for the correct size and type.

[Dashrynn]

I started this thread to get more knowledge about the kind of batteries that are used in scuba. There have been some good inputs from posters and I've gotten some more info from outside sources. Here is what I think I know as of now, subject to further factoids, of course. In scuba batteries are definitely a relatively inexpensive consumable.

-Lots and lots of misinformation that is passed for fact.
-Lots of tricks and practices that purport to eek out the last possible bit of energy from batteries. Those practices may or may not get more out of the battery. Most are not independently reviewed. Frankly, I've come to the opinion none of those things are worth the effort. Buy'em and use'em. Any possible savings are marginal at best when compared to total costs.
-Batteries have storage and in service lives. The lives are affected by many factors. One set of factors are the number of available discharge/charge cycles. For best use prevailing opinion seems to be to use each charge cycle fully before recharging. (Full use does not mean discharge so far as to damage the battery). Temperature is another factor. Keep batteries within their desgn temperature range during storage and service.
-Don't attempt to recharge a battery that is not designed to be recharged.
-It is better to remove load from batteries before recharging.
-When assembling battery packs it is worthwhile to balance individual cells within the pack.
-Different battery chemistries are more suitable for different uses.
-Read and follow the manufacturer's information before putting batteries into service.

My post is not a complete list, nor is it intended to be. After all a perfectly reasonable and effective way to treat batteries is as a consumable that a person buys, uses and discards with only thought for the correct size and type.

Read this, you will see how newer lithium ion batteries react to different discharges. This is mostly a comparison of different name brand batteries with some questionable types that reflect assumptions.

http://lygte-info.dk/review/batteries20 ... %20UK.html

[ArcticDiver]

I started this thread to get more knowledge about the kind of batteries that are used in scuba. There have been some good inputs from posters and I've gotten some more info from outside sources. Here is what I think I know as of now, subject to further factoids, of course. In scuba batteries are definitely a relatively inexpensive consumable.

-Lots and lots of misinformation that is passed for fact.
-Lots of tricks and practices that purport to eek out the last possible bit of energy from batteries. Those practices may or may not get more out of the battery. Most are not independently reviewed. Frankly, I've come to the opinion none of those things are worth the effort. Buy'em and use'em. Any possible savings are marginal at best when compared to total costs.
-Batteries have storage and in service lives. The lives are affected by many factors. One set of factors are the number of available discharge/charge cycles. For best use prevailing opinion seems to be to use each charge cycle fully before recharging. (Full use does not mean discharge so far as to damage the battery). Temperature is another factor. Keep batteries within their desgn temperature range during storage and service.
-Don't attempt to recharge a battery that is not designed to be recharged.
-It is better to remove load from batteries before recharging.
-When assembling battery packs it is worthwhile to balance individual cells within the pack.
-Different battery chemistries are more suitable for different uses.
-Read and follow the manufacturer's information before putting batteries into service.

My post is not a complete list, nor is it intended to be. After all a perfectly reasonable and effective way to treat batteries is as a consumable that a person buys, uses and discards with only thought for the correct size and type.

Read this, you will see how newer lithium ion batteries react to different discharges. This is mostly a comparison of different name brand batteries with some questionable types that reflect assumptions.

http://lygte-info.dk/review/batteries20 ... %20UK.html

Yes, there are several charts like that around. I don't really pay much attention to them because except for cell size I've found the manufacturers change their products over time and those charts are out of date. A person could spend a lot more time and energy chasing out of date specifications that if they just followed the device's instructions. In venues other than powering scuba devices if those details are important they can be measured in the field or gathered from the manufacturer at the time.

[Jeff Kruse]

It’s best to recharge LA, NIMH, and Li after every use. Do not use them “up” or to their full runtime. Always recharge after every use if you can.

Li should be stored at 40% charge for long term storage.

[ArcticDiver]

It’s best to recharge LA, NIMH, and Li after every use. Do not use them “up” or to their full runtime. Always recharge after every use if you can.

Li should be stored at 40% charge for long term storage.

And we are back to one of the disputed practices. Those who believe charge cycles are more important say to use every cycle as much as is practical. That doesn't imply running a battery to 0, or "flat". Others don't. Definitely recharge as soon after use as practical and try to do the recharge when the battery is not under load. Frankly, I don't think considering their cost, both outright and as part of the overall diving budget it matters much. Start off with fully charged batteries; when they are too weak to power the device; remove them from the device or turn it off; recharge and start all over.

As far as I know all batteries should be stored with partial charge. Even lead/acid batteries once they have the acid added should be stored with some kind of charge. Prevailing opinion seems to be that internal resistance will discharge a battery so it is not necessary to discharge a battery to any specified level prior to storage.

Again, this thread has been useful to me. Thanks for the input and the research it prompted.

[airsix]

I'd encourage you to develop specific practices for different chemistries. You cannot create a universal battery policy that works equally well with all types. For example, your statement about storage charge/self-discharge. I have lithium rechargeables that will loose less than 10% of their charge during a full year on the shelf. My sealed lead acid batteries would be irreparably damaged after a sitting that long without maintenance. Nihm would also be fully or nearly fully discharged by that point, however they would likely be undamaged. They are each unique and should be treated as such for best performance.

[Jeff Pack]

[ArcticDiver]

No question each chemistry should, for maximum performance, be treated indidvidually. I can take that one step further and comment that each battery application should be treated individually. Not only that but a user cannot trust the device, vs. the battery, manufacturer to have made the best decisions about battery selection and use.

But, this thread was focused on scuba style batteries and applications. I wanted to see if there was a significant hole in my knowledge. I found there was. I've filled it with the knowledge that the batteries we use in scuba are so cheap and so forgiving that it just isn't worth sweating over them unless you are one of those people who gets satisfaction from doing so. The big thing is when going on a trip be sure to have enough batteries, or to make sure there are adequate recharge facilities and you have the proper chargers