# 3s / 4s lipo as launcher battery ?

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#### hartrockets

##### Well-Known Member
Hi all.

Has anyone used 3s or 4s lipo batteries as their main launch controller batteries.

Thanks

Pete

#### OverTheTop

##### Well-Known Member
TRF Supporter
If you are going to use these sort of batteries make sure the electronic protection circuit that is typically embedded in lots of LiPos does not cause you grief. They usually behave like a resetable electronic fuse I believe. You don't want the igniter getting half hot and then the battery tripping offline

#### Tonimus

##### Well-Known Member
I use them as the main batteries in my remote box. Works great. Lights everything right frickin' now. Just got to make sure all your components are sized right. The batteries I use can dump 250 amps all at once.

#### NateLowrie

##### Well-Known Member
Same here. I use a 3S 5000mah lipo with the QuickBurst launch system for my launch controller. It works great and kicks off anything I can throw at it. For ematches I can get 15 to light with 0.1 seconds of one another. If you want to use them for flight operations in a cluster buster type setting I would use 2-3.

#### georgegassaway

Been using 2200 mAh 3S Lipos for several years now. Often, older packs that have lost capacity for r/c plane flying but still plenty of punch for most rocket flying (other than clusters).

No problems. I will say if I was doing a cluster with normal ignitors, I'd prefer a 12V car battery.

I DO keep each launch battery LiPo in a "LiPo Safe" bag, so if the LiPo caught fire, it would be smothered inside the bag. Also the red ones as shown below, are a GREAT way to make the packs visible so people do not step on them. Lots on eBay at good prices. Example below:

https://www.ebay.com/itm/Mini-RC-Li...351979&hash=item2f08bc5bf5:g:0eoAAOSwA3dYdJrx

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#### KevinM

##### Well-Known Member
I agree with George on the utility 3S 2200mAh packs, including packs that nolonger have the "guts" for other RC applications. They're a convenient physical size and are readily available. I've got a radio-controlled launch-box of my own design that runs on 3S/2200's that don't have the stamina for RC helis anymore but they still work just fine for igniters. I use this primarily for starting rocket gliders, but I've also used it on many occasions to light-off other MPRs.

#### r12ski

##### Well-Known Member
Also, it's worth picking up a low voltage alarm. They are only a couple bucks. It tells you if the LiPo runs too low. If you run it down past a certain point you won't be able to charge it again.

BTW, anyone know the proper pairing for the Estes PS 1 Command Control launcher? It originally was set up to use either one or two of the old Radio Shack 7.2 volt NiCd RC car batteries.

I've been using a 2S 2200 mAh battery with it set on the single battery setting. It is nice not having the extra weight and there's plenty of room, which was a problem when you tried to squeeze two old NiCds in there. Makes for a great launch controller.

I just don't know how to convert NiCad to lipo. I have a couple 3C LiPos and would like to try using two of them for clusters.

#### BEC

##### Well-Known Member
I third George's comments generally. I am using an 11-year-old 3s pack of Kokam 3200s which originally was used in my electric conversion Sig Kadet LT-25 but which hasn't powered an airplane in years on my three-pad setup that I use with small groups. Instant ignition even with the new Estes "starters" and after a day's flying my Cellpro 4s chargers report the battery is still pretty close to full.

The panel I built for this does have LED's for continuity indication and a little piezo beeper for "armed" so it doesn't draw much power before firing an igniter....but that event is so short that the battery doesn't really even notice.

Now if I'd used this battery today at the club launch instead of the club's 12V garden tractor battery it would've needed a partial charge - we put up 124 flights and the old club panel uses incandescent lamps for both continuity and "armed" indication.

I also have a 3s 1200 ElectriFly pack in one of my Estes PSII controllers. This unit has even fired a copperhead for a TARC team. It gets used quite a bit as a loaner in the last couple of weeks before TARC scores are due.

So in short - it works great. But do take proper care of them. If you haven't been using them in RC for the past several years and don't have the right chargers don't cheap out there.

#### BEC

##### Well-Known Member
I just don't know how to convert NiCad to lipo. I have a couple 3C LiPos and would like to try using two of them for clusters.

NiCd/NiMh cells are nominally 1.2V each. A fully charged LiPoly is 4.2V though they are often rated /discussed as if they were 3.7V/cell. Better to use the full-charge voltage when substituting. So 2s is 8.4, 3s is 12.6V.

Without knowing the voltage ratings of the other bits inside that older Estes controller that's designed for two 6-cell NiCds I wouldn't do more than 2s lithium in replacing each pack. Even that might be pushing it depending what's inside. I think I have one in my old GSE collection....maybe I'll take a look and see if I can figure it out.

#### georgegassaway

Also, it's worth picking up a low voltage alarm. They are only a couple bucks. It tells you if the LiPo runs too low. If you run it down past a certain point you won't be able to charge it again.

BTW, anyone know the proper pairing for the Estes PS 1 Command Control launcher? It originally was set up to use either one or two of the old Radio Shack 7.2 volt NiCd RC car batteries.

I've been using a 2S 2200 mAh battery with it set on the single battery setting. It is nice not having the extra weight and there's plenty of room, which was a problem when you tried to squeeze two old NiCds in there. Makes for a great launch controller.

I just don't know how to convert NiCad to lipo. I have a couple 3C LiPos and would like to try using two of them for clusters.

As for the old Estes Command Control, I had one but not the Nicads. I modified the wiring to use the two 7.2V Nicad connectors (14.4 Volts) with a single power source, to be powered by a 12V battery. So I'm pretty sure it would be fine running off a 3S "11.1V" LiPo that is for practical purposes like using a 12V battery.

But I did that a long long time ago, so do not recall the exact details. What you want is to have the two Nicad connectors to be in series when the wiring is modified, so the circuit will be expecting as much as 14.4V. If you just hooked up to the first one, or wired the two in parallel, then you'd be feeding about 12 volts into a circuit internally for 7.2 volts, and probably fry the continuity if not more. I forget whether it had a slide switch to choose a single Nicad pack (7.2V) or two Nicad packs (14.4V). If it did, I'd either glue the plastic part of the switch to the 14.4V setting, or glue some cover over it so it would not get accidentally moved to 7.2V.

#### BEC

##### Well-Known Member
BTW, anyone know the proper pairing for the Estes PS 1 Command Control launcher? It originally was set up to use either one or two of the old Radio Shack 7.2 volt NiCd RC car batteries.

I've been using a 2S 2200 mAh battery with it set on the single battery setting. It is nice not having the extra weight and there's plenty of room, which was a problem when you tried to squeeze two old NiCds in there. Makes for a great launch controller.

I just don't know how to convert NiCad to lipo. I have a couple 3C LiPos and would like to try using two of them for clusters.
OK - I found the NIB Command Control I got off of eBay in my "gather up old GSE" phase a couple of years ago. According to the instruction sheet, the range of the LED battery level meter is 6.5v to 19V. Later in the instructions are words to the effect that even with two NiCd packs selected, all the LEDs won't likely light up (and they wouldn't - even hot off a peak charge you only see - briefly - 1.6V per cell so you'd just barely be at 19V for a few minutes before they cooled down).

So - it seems to me that once you get past the <sarcasm>lovely</sarcasm> Tamiya connectors inside you could very safely use a 2s LiPoly pack in place of each of the NiCds it was designed for. Just take them out to charge them on a proper LiPoly charger rather than trying to use the inputs in the controller. I would NOT use 3s batteries in both sides, but it sounds from my read-through that if you set the switch in the 7.2V position and plugged a 3s battery into the first position it should work.

I found one 2s 2200 mAh ElectriFly pack in my airplane battery collection that comfortably fits in one side and I have the means to make an adapter to go from the faux-Deans Power Plug on that battery to Tamiya so I don't have to commit surgery on the launch controller's wiring. I just wish I had two of those batteries.

Since I bring out "classic GSE" for our Classics-themed September club launch (including a 1966 ElectroLaunch) I should get this Command Control set up with a pair of matching 2s packs and we can use it for the E-G rockets that may turn up at the launch. In practice it'll probably be fine on one 2s pack, but it would be nice to have the full capability of the unit.

While George has some interesting thoughts in the post just above, based on a read-through of the instructions I don't think it would be a good idea to fix the switch in the 14.4V setting as one of the LEDs would be on all the time unless you unplugged the battery when you're not using the controller. It's also kind of awkward since that's the middle position for the three-position switch. But since you've been using the controller, you know that already.....

#### r12ski

##### Well-Known Member
It was easy to get past the Tamiya connectors. I just used these. All my batteries are XT60. That's also where I got the low voltage alarm.

As for the charger. I didn't cheap out. I went with one of the combos from ProgressiveRC.

I have a couple of those same 2s 2200 ElectriFly packs. Maybe I'll try it with two and see if it will light four solar ignitors in your standard cluster formation.

The Command Control and the Power Plex launch pad are my standard GSE when I'm not at a club launch. I know I used it to light a CTI F36. Haven't had a chance to test it on anything bigger because I didn't have the field. As it was, that F36 put my Arreaux in a tree which I have yet to locate. (See signature) But I've recently moved and may have access to some real fields again.

#### BEC

##### Well-Known Member
Cool. I ordered two Zippy 2200s and these: https://hobbyking.com/en_us/xt60-to-tamiya-battery-adapter-2pcs-bag.html to put my Command Control into operation for our Classics launch next month.

It looks like you found some less-expensive adapters (well, three instead of two for about the same price). All my more-than-10A airplane stuff has Anderson Powerpoles (which started back when the late John Sermos was marketing them to electric RC airplane guys with his name on them as a way to get power-wasting Tamiya plugs out of airplanes).

When I pretty much dropped out of airplanes to get back into rockets it was just when the various flavors and sizes of bullets, plus Deans Ultras and AstroFlight's proprietary connectors were all choices....but before there were XT-anythings from HK. I went looking for some XT-60s to make my own adapters (I have a few of the Tamiya plugs) but decided to just let HK make 'em for me.

Glad you have a good charger. That's really the most important piece of the entire LiPoly puzzle. And I'll bet that they've gotten consistently better than the early lithium chargers that I used to test and write about for RC Groups. Long ago I had a column called "Recurring Charge" over there - before the Ezone site was kind of phased out and all articles were just stuck in the discussion fora.

The instructions for the Command Control imply that you can fire a four-Solar-igniter cluster on one NiCd pack. If that really works, then one modern LiPoly would do it, too. Using both should pretty much melt those suckers.

That's a cute little low voltage alarm. Based on my experience launching rockets with my old Kokam 3200 packs, you'd have to launch on the order of a couple of hundred rockets before something like that would be needed. But it can't hurt.

#### BEC

##### Well-Known Member
Just to close this out....here is what I ended up with using two Zippy 2200s. Fully charged, this setup pegs the internal LED voltmeter when the "both batteries" selection is made. We shall see how well it works on 9/9.

#### Tonimus

##### Well-Known Member
Anything worth doing, is worth over-doing.

#### dhbarr

##### Amateur Professional
Anything worth doing, is worth over-doing.
Finally, a real engineer! Fix it till it's broke!