Surefire Defender Upgrade

[HKsig]

Never go cheap on Li-ion batteries as they can be dangerous. For my Nitecore P36 flashlight I use Simon (Panasonic made) 18650s 3400 mA batteries. Double protected and at $35 a pair from Amazon. Also my charger is a Nitecore D2.

[dcphoto]

I would recommend against using unprotected batteries. First, any protection built in to a $10 drop in unit is dubious at best. Second if there is no protection circuit built in to the unit you could easily over-discharge the batteries damaging the cells, possibly to the point of ruining them. The worst thing you can do is let them drop below 2.5 volts and since they have no protection, it can happen easily. If they go below 2 volts they can become completely unusable, and most "smart" chargers won't try to charge them. I try not to let my IMR cells go below 2.9 volts to be safe, and fully charged they should be 4.1-4.2 volts.

I'd suggest picking up AWs RCR123A batteries instead. They're more expensive up front, but will easily offset the cost in a short time. The protection circuit will prevent over-discharging them, over-charging and IIRC they prevent a charger from charging with too much current. I've been using AWs in my EDC light for about 2 years now. They each get charged every two weeks (alternating), so I figure I've saved about $100 in 123 primary cells since I switched.

I know I rambled a little, so please forgive that; and forgive me if you know all this already.

Thanks for your advice. I am still researching batteries.
The drop in LED is supposed to be rated to 18V, so I figured it would handle two of the AW batteries.
I read [on the website] that the unprotected batteries were a "safer chemistry".
What is the capacity of the AWs RCR123A that you use?
AWs seem to be difficult to locate. Where do you buy them?

Last time I bought 16340s (RCR123A) I got them from Four Sevens. You can also buy them directly from AW at the http://www.candlepowerforums.com marketplace. I don't have a link to his most recent sales thread, but google can help you find it. It's cheaper to buy directly from him, but takes much longer to get them since they're shipped internationally.

IMR is a safer chemistry, but LiCo with a protection circuit is equally safe. Plus, it's better to run multi-battery lights with protected cells. If you'd like more info I can write another post about it later, when I have a little more time. If you'd like more info about batteries check out http://www.hdssystems.com/Content/LightFaq/. Scroll down to "What are rechargeable lithium-ion batteries?" and you'll have an explanation better than anything I can provide.

[WildBill]

Thanks dcphoto! You have been very helpful. BTW what is your EDC flashlight?
I have noticed that some lights designed for CR123 do not recommend RCR123.

[dcphoto]

Thanks dcphoto! You have been very helpful. BTW what is your EDC flashlight?
I have noticed that some lights designed for CR123 do not recommend RCR123.

My EDC is an HDS Tactical custom with the high CRI LED, flush button, and 123 battery compartment. I finally settled on this light after trying nearly 25 other lights that didn't meet my needs. Fortunately I was able to sell most of those lights to be able to afford the HDS.

Some flashlights don't recommend the RCR123 because they aren't designed to handle the higher voltage of the rechargeable. A primary 123 is 3 volts at full capacity. A RCR123 is 4.2 volts when fully charged. Some other manufacturers don't recommend them because of the reputation early lithium batteries had for shorting internally (or from damage) and explosively venting. This was long before modern chemistries and protection circuits were available, but the stigma has remained. Finally, a rechargeable battery is not ideal for a tactical light. They can't provide as much power at low temperature; they will slowly discharge whether they are used or not (the protection circuit uses a tiny amount of power, and they have internal losses); they have less total capacity compared to a primary cell.

For those reasons I don't put rechargeable cells in my dedicated, but rarely used, "fighting" flashlights. Meaning my nightstand light and gun mounted lights all use primary cells. Since my EDC is for everyday uses, and I go through so many batteries, it gets a rechargeable.

P.S. My family normally uses 50-60 123A primary cells a year, so I buy them in bulk from Battery Station. The website is straight from the 90's, but the business is legitimate. I normally place my order over the phone because they don't have provisions for the discount I get on the site. I've ordered other products from their site without any issue.

[WildBill]

My EDC is an HDS Tactical custom with the high CRI LED, flush button, and 123 battery compartment. I finally settled on this light after trying nearly 25 other lights that didn't meet my needs. Fortunately I was able to sell most of those lights to be able to afford the HDS.

Thanks again. I am learning more than I intended. I remember when I thought Maglites were the ultimate flashlights.

[MONGOOSE]

My EDC is an HDS Tactical custom with the high CRI LED, flush button, and 123 battery compartment. I finally settled on this light after trying nearly 25 other lights that didn't meet my needs. Fortunately I was able to sell most of those lights to be able to afford the HDS.

Thanks again. I am learning more than I intended. I remember when I thought Maglites were the ultimate flashlights.

[dcphoto]

My EDC is an HDS Tactical custom with the high CRI LED, flush button, and 123 battery compartment. I finally settled on this light after trying nearly 25 other lights that didn't meet my needs. Fortunately I was able to sell most of those lights to be able to afford the HDS.

Thanks again. I am learning more than I intended. I remember when I thought Maglites were the ultimate flashlights.

I still keep a few maglites (and a sundry of other lights) of various sizes around. They're virtually bomb-proof and are bright enough for most tasks. I've just settled on the HDS as my EDC.