# Portable Power Source for 12v launcher

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#### strikeanywhere45

##### New Member
Hey everyone. I'm considering getting into mid-power rocketry with the Initiator Starter Kit. Only problem is I don't want to have to be tethered to my car and the Interlock controller (as well as every other 12v controller) require a car battery. I've heard of some people creating custom cases for motorcycle batteries but that adds the cost of the battery and the charger. I was just wondering what some of y'all were doing to get your rockets off the ground other than the car battery, or if you're happy just using the car battery. Thanks.

#### kandsrockets

##### Well-Known Member
I have been using a ryobi 12v rechargable drill battery for the last 2 years with no problems. I have even fired cluster of 12 bp motors and all lit perfect.

#### MarkII

I use something like this, only mine doesn't have the emergency light or air compressor. I got it a couple of years ago at Radio Shack. It was on clearance, and I paid something like $26 for it. And to be perfectly honest, I did actually buy it to launch rockets, and not to jump start my car. I just clip the two cables to the two corresponding battery connectors on my Interlock Controller, and launch away. I have never even gotten the battery as much as half-drained. It is a sealed lead-acid battery, so it loves to be charged. Mine weighs about 8 lbs. As long as we are talking about the AT Interlock Controller, let me suggest a slight modification to make it much more versatile. The mod is simple: At Radio Shack, pick up: • a small spool (or partial spool) of 18-gauge speaker wire (two conductor) • a pack or two of bullet connectors, in the size appropriate for 18-gauge wire (the kind with the red covers) • a pack or two of micro-clips • a pack of heat-shrink tubing or a can of liquid insulating tape You will also need wire cutters, a wire crimping tool, a soldering iron and some lead-free silver solder. I used the red and black stranded 18-gauge speaker wire from RS. When you get home, take out your Interlock Controller and your pair of wire cutters and clip off that not-very-adaptable Interlock Clip, about 8" or so back from the clip. Now take the cut ends of the leads coming from the controller and the leads coming from the Interlock Clip, and separate them for about 2" back from the ends. Remove some insulation from each lead and install a pair of bullet connectors (one of each, a male connector and a female connector) on the two leads coming from the controller, and install another pair on the Interlock Clip leads. Use the crimp tool to crimp the connectors onto their respective leads, and then slip a short length of heat-shrink tubing over the red sleeve of each connector, overlapping some of the wire lead right behind it, and heat them with a heat gun or hair drier until they shrink down and form tight seals around the joint where the wire lead enters the connector sleeve. (If you bought liquid insulating tape instead, brush some onto this same area.) Now you are no longer limited to using just the Interlock Clip with your controller. Go ahead and make a pair of micro clip leads by cutting a length of the 18-gauge speaker wire, soldering on a pair of microclips onto one end and a pair of bullet connectors (remember, one male and one female) to the other end. When you want to use micro clips (which will be most of the time), just plug the attachment into the connectors on the controller's leads, and disconnect them on plug in the Interlock attachment when you are launching with Copperhead igniters. If you terminate each pair of conductors (strands or wires) in all of your leads with one male bullet connector and one female connector, you will be assurred of always being able to connect everything to your controller's leads. I also used the plans shown at Rocketry Online's InfoCentral to make various clip whip configurations, and I terminated the trunk leads with bullet connectors, so that I can just plug the whips into the Interlock Controller's leads and have solid connections all the way to the clips. MarkII Last edited by a moderator: #### DAllen ##### Well-Known Member Another almost free option is to use a used car or motorcycle battery. I have cats and loads of those Tidy Cat plastic bins the kitty litter comes in. I also have a small car and the last time I had the battery changed I kept the old one. I put the battery on a charger and for little launches like up to an AT first fire it works fine. Then I put the battery in one of the kitty litter bins and it has a nice little lid and provides *some* containment just in case the battery decides to leak and also provides a nice little handle to carry it around. I also often place a power inverter on it at large launches to charge camera batters, let the kiddos watch movies on the portable DVD player, etc. (If you were at LDRS27 and saw a red Sable with a kiddy litter bin next to it...that was mine, lol) The advantage of this is then I know for a fact I am not draining the power on my car. -Dave #### RocketT.Coyote ##### Well-Known Member I started out using motorcycle and lawn tractor batteries when they could be had on sale. Gel cells are more compact and are low maintenance. Emergency automotive jump kits contain them. Tower Hobby sells the 12v gel cells to power starter motors and fuel pumps for RC planes. Some of these even come with a charger unit. I charge mine with a solar panel. #### Peartree ##### Cyborg Rocketeer Staff member Administrator Global Mod I haven't built mine yet but since we already have a (huge) 12V deep cycle marine battery that we use for electricity when camping I'll probably use that since its already paid for... #### Verna ##### Well-Known Member Great choice! We have used that exact model now for 8 years. Yes, 8 years, the same one and it's great for clustering too. We've used it for watching tv when the power is out, a flashlight and to air up the car tires. We tried a gel pack... once... and there is no comparison to the jump battery pack for power, kick, or charge life. Recharges quickly too. Verna #### luke strawwalker ##### Well-Known Member Hey everyone. I'm considering getting into mid-power rocketry with the Initiator Starter Kit. Only problem is I don't want to have to be tethered to my car and the Interlock controller (as well as every other 12v controller) require a car battery. I've heard of some people creating custom cases for motorcycle batteries but that adds the cost of the battery and the charger. I was just wondering what some of y'all were doing to get your rockets off the ground other than the car battery, or if you're happy just using the car battery. Thanks. These are just about the handiest things ever invented for rocketry... https://www.overstock.com/Auto-Parts/2-in-1-Power-Station/3356658/product.html You can find these locally at most of the big box stores, auto parts stores, farm/ranch stores, tool stores, and such. Prices vary but they can be had for a little under$40 if you really look. Handiest thing since sliced bread.

Mine has a cigarette lighter receptacle that can be used with a double male ended cigarette lighter plug in the car for charging, and also if you buy a cig liter end in the auto parts section of your designated store, you can wire that directly to your controller and plug the controller into it directly for launching. I personally have 'battery charger clips' on my launchers, so I just use the jumper cable ends on the battery jumper box and clip them directly onto the charger style clips on my launcher, and it works fine. These things can deliver a LOT of power. We launched a couple weeks ago with it and then I boosted off one of the club guy's cars when the lights in the hatchback killed the battery in his Expedition. I also used it to boost off the tractor battery on a cold morning this Monday so I could load hay to haul to the cows, and haven't even charged it. All that and the indicator says it's still fully charged!

You can slip this past the boss (wife) as a 'safety expense' by keeping the thing in the trunk of the car-- that way if you accidentally leave the headlites on, you've got a way to boost your own car off without needing to bum a jump off somebody else. Of course, you want to make sure it's well charged for her when she might need it, so you can 'conveniently' pull it out for use on launch day and then recharge it and put it back that evening.... very handy! Plus you'll score bonus points for being concerned about her safety, and it doesn't have to come out of the space program appropriations (hobby rocket fund)...

Win win situation... OL JR

#### MarkII

##### Well-Known Member
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You can slip this past the boss (wife) as a 'safety expense' by keeping the thing in the trunk of the car-- that way if you accidentally leave the headlites on, you've got a way to boost your own car off without needing to bum a jump off somebody else. Of course, you want to make sure it's well charged for her when she might need it, so you can 'conveniently' pull it out for use on launch day and then recharge it and put it back that evening.... very handy! Plus you'll score bonus points for being concerned about her safety, and it doesn't have to come out of the space program appropriations (hobby rocket fund)...

Win win situation... OL JR
If your wife is like mine, then she probably won't mind if you borrow the car starter for a little extracurricular use, as long as you still have it available (and fully charged) for her when she needs it. Women don't worship tools the way that men do.

MarkII