Any blueprints for a 9volt system?

[grim_piper]

I go on a two week camping trip every year and recharging kr808-d batteries is going to end up more trouble than it's worth.
I'd like to build a box that uses a 9volt and resistors to bring the voltage down to 3.7-4.7. Does anyone have any plans for such a device? I'll take the threaded part from a dead kr808 so I can use the carts. I do metalsmithing and wood work, so I'm going to build the box from scratch along steampunk lines. I just need to know what electrical rigging I need to get.
Any advice would be greatly appreciated.

 

[candre23]

When choosing batteries, it's the capacity (measured in milliamp hours, or mAh) that will tell you how long it will last, not the voltage. Most 9v batteries only have about (550mAh) 2-3x the capacity of a KR808 battery, and you'll lose some of that to the resistor you plan to use. You're much better off with a high capacity 3.7v battery than a 9v. One 18650 will last 2-3 days.

If you absolutely must use disposables, find a flashlight that takes 3 C or D cells. In series, three alkalines will give you 4.5v, and the Ds will be good for about 12000 mAh. You should get well over a week (but probably not two) on one set.

 

[grim_piper]

Hmmmm The 18650 seems a bit pricey for the woods and we run into the recharge problem again. The three D cells sound promising, but rather large.
Well, I'll keep searching. Any ideas or gentle nudges to blueprints would be appreciated.

 

[candre23]

On average, people seem to go through about 800-1000mAh worth of batteries per day. If you don't have the ability to recharge for 2 weeks, then you need to bring ~ 12000-14000 mAh (at 3.5-5v) worth of batteries with you. I suggested C or D cells because they hold a lot more energy than AAs or 9Vs. Whether you bring two sets of Ds or a whole bag full of AAs, your total power requirement for the trip is the same. If you go with 9Vs, expect to burn through about two per day.

 

[grim_piper]

You're right. My lantern gets by for well more than the two weeks on four D cells. I was just trying to get a smaller set-up. Thank you for the advice.
If I could ask one more favor, which method would you recommend for the C or D cells? I try searching, but my mind boggles quickly on here.

 

[candre23]

I'd just get a cheap 3D cell flashlight and do the standard flashlight mod. All you need is an battery connector of your choice (preferably sealed), a 3A pushbutton, and a couple inches of wire. Since you'll be outdoors, I'd definitely suggest sealing around the button and atty connector with some epoxy or silicone sealant to keep it watertight. It won't be pretty, but neither will you after two weeks in the woods. And the best part is, you're looking at less than $30 worth of materials, including enough batteries to last you a month.

 

[grim_piper]

Thanks for the links! That'll make things a lot easier. As to not being pretty after two weeks in the woods, you're not far off. It's a medieval S.C.A. event, so that means it's a two week drunken costume party. I'm a bagpiper.
You do the math.

 

[schaedj]

Back to the original question, though.... I have a virtually endless supply of 9V batteries. (Delivered as medical supplies, must be changed after limited use, so I have two new batteries every day)... I looked into making my own mod, but just am not skilled at the whole process. I take it from this thread that no one is interested because of the low mAh rating of the batteries? Has anyone tried or successfully made a 9v Mod? I sit in fron of my charger every day, wishing I had some way to use all of these batteries I'm throwing out, instead.

 

[candre23]

If you really wanted a 9v mod, the wiring would be exactly the same as a 5v mod w/ regulator. Just replace the two 3.7V batteries in series with one 9V.

 

[Israfil]

Thanks for the links! That'll make things a lot easier. As to not being pretty after two weeks in the woods, you're not far off. It's a medieval S.C.A. event, so that means it's a two week drunken costume party. I'm a bagpiper.
You do the math.

SCA? dang I didn't know there were any 2 week events coming up. Was just out at the Starcoffin event in pahrump nv. 3 days in a park, used a 3battery AA nicostick mod. (4bat box from radio shack) And just filled one of the pockets on my pack with extra double a's. Honestly it works a treat with 3 disposable AA in serial, even better now that I've added the TI PTN04050 to up the voltage to 5v. Make sure you solder the connections securely, if you are anything like me you'll drop it constantly when drunk and have a very hard time putting it back together...

Great to know others on here love times long past!

 

[grim_piper]

SCA? dang I didn't know there were any 2 week events coming up. Was just out at the Starcoffin event in pahrump nv.

I go to Pennsic in Butler, PA. The is a S.C.A. vapers group on here, just look in my profile.
Maybe I'll make my mod look like an extra drone on my bagpipe.

 

[nyx]

whatever you end up putting together, make *sure* you lock down all the connections with some epoxy or hot glue after you've tested it.. since you're not going to have access to an iron if something should come loose, i mean, go the extra mile when making it and ensure that nothing in there can move once the batteries are in place. vape on, and all the best.

 

[Israfil]

I go to Pennsic in Butler, PA. The is a S.C.A. vapers group on here, just look in my profile.
Maybe I'll make my mod look like an extra drone on my bagpipe.

That, sir, would be hilarious! I imagine you playing, taking a puff, then playing with vapor coming out... ^_^

 

[sjohnson]

Consider a solar battery charger and rechargeable batteries.

 

[j122068]

i would just hook a passtrough to the lantern bat with minor modifacations

 

[brandon555]

Back to the original question, though.... I have a virtually endless supply of 9V batteries. (Delivered as medical supplies, must be changed after limited use, so I have two new batteries every day)... I looked into making my own mod, but just am not skilled at the whole process. I take it from this thread that no one is interested because of the low mAh rating of the batteries? Has anyone tried or successfully made a 9v Mod? I sit in fron of my charger every day, wishing I had some way to use all of these batteries I'm throwing out, instead.

I rigged up a KR8 connector and 9 volt to a cheap toggle switch from wally world.

I'm still in the process of finding something to house it with. But, just messing around with it I found it worked awesome with cartos.

I thought they would burn up instantly, but even without any resistance the cartos operated better than they do on my Prodigy.