New to modding...safety?

[westy78]

I stumbled across Russ interviewing Mamu & Steeljan on Clickbang yesterday and then found the Milo tutorial--wow, thanks Mamu!--and a bunch of other fascinating threads. I am now considering my first build; I have been reading extensively on battery chemistry & protection etc. and have a few questions about safety:

1) If using a DNA20D, is the use of a separate master switch desirable for safety, or would you consider the board's on/off feature sufficient protection when the device is in your pocket or on your bedside table?

2) Anyone have a good source for a collapsible spring type "fuse" device (in quotes b/c I don't know if it could be considered a proper fuse)? I have been searching but haven't come up with anything actually available on a vendor's site.

3) If using a blade fuse, where does it want to be located in the circuit (specifically in a wood box mod that isn't likely to short in the same mode as an all-metal tube mod)? As close as possible to the positive terminal? Is this overkill if the box is wood and everything is thoroughly tested and well-built?

4) How can one know whether the Evolv dna charger is reliable and won't overcharge as compared to a reputable external charger? Does it have a good track record? I haven't found anything bad about it so far. I am leaning toward using an IMR 18650 so excluding an on-board charger might be an acceptable trade-off for safety.

I hope these aren't loaded questions; I'm just hoping to take advantage of others's opinions/experience before taking the red pill and jumping down the rabbit hole of modding. Thanks!

 

[bapgood]

Westy, welcome to the ECF modding forum. Compared to a lot of folks around here I still feel like a rookie, but I will give your questions a shot.

#1 - IMO a master on/off switch is not needed for the DNA20D, it is more of a luxury/peace of mind feature (more in answer 3). The DNA20D doesn't really have an on/off function. It has a fire button for vaping and a lock function (5 clicks on the fire button) that locks out operation of the fire and wattage adjustment buttons, for pocket transport/etc.

If you are panning on having the 18650 removable then IMO there is no reason for a master on/off switch.

#2 - I'm not sure what you are referring to here. But I believe mamu typically uses PTC fuses, along with a lot of others modders based on breaktru's parallel PTC fuse concept.

#3 - To my knowledge I'm the only one that has used a blade fuse, at least the DNA20D mods I have seen on here in the ECF battery mods forum. Their are a couple of reasons why I went this route, the biggest reason was to easily be able to disconnect all power to the DNA20D for tinkering/emergency situations along with the protection the fuse gives.

I tend to be less careful then I should be at times and I had a couple of mishaps due to me not being careful when I had power to the DNA20D. Now with the blade fuse, I can solder everything up and get everything secured in its place and then energize by inserting the fuse. Also I pull it out first thing before I start tinkering with an existing mod.

I place the fuse between the battery positive and the DNA20D and DNA charger (if its not hooked the DNA20D) positive, so it segregates the battery.

#4 - This is a good question, and I don't have a good answer. I have never heard anything negative about the DNA charger and I have used them on several different lipo batteries without a problem. I can say that the DNA charger can handle a large capacity battery as I just finished charging my 6000mah lipo from dead. It took about 13 hours to fully charge, and nothing got hot/etc.

 

[westy78]

Thanks for the very helpful response! I'll post a little more about the design I'm working on as it comes together.