Help...LiPos...I have no idea what I am doing...

So for years I have only use 9v batteries and am looking to buy some LiPos but I have no idea what the options are out there. I look at this stuff and it's all Greek to me. I don't *think* I need some giant 8 battery charging $300 system or whatever that was I was looking at. Anyways, here's what I'd like to do with LiPo's:

- Eggtimer Quantum...I will someday shortly be the proud owner of one of these but their FAQ says 9vs won't work the WiFi (a key feature for me) because it's a bit of a battery hog. The FAQ says, "We recommend a 2S/7.4V LiPo battery, 300 mAH or larger" whatever that means. So I need something that size or larger...I guess.

- I have several standard alts that are perfectly happy to run off of 9v's so I could switch them to LiPo's but what do I need to be looking for?

- I really doubt I am going to need the ability to charge more than one or two at a time. I might fly one maybe two flights with a single rocket at a single launch leaving at least a couple of weeks to charge the batteries. Also on the charger I see some come with the ability to just leave the batteries in for a long time and be automatically discharged and charged to extend battery life. How necessary is that?

- Anything else I should be looking for?

Guess I am looking for something that is going to work for rocketry and if possible avoid unnecessary bells and whistles so recommendations are very welcome...

IMAX B6 Charger and no doubt you'll get recommendations of others. They don't have to cost a lot. I guess one of the keys is when you are going to let lipo's sit for a time to discharge them to like 50% capacity.
No problem with the IMAX as it has a "storage" setting that will either "charge up" the battery or discharge it to get to the acceptable level. Other chargers probably have the same.

I remember doing Nicads with a wall wart, an ammeter, voltmeter and potentiometer to set the current in the old days.

It's pretty easy to learn plus don't do a dead short with a lipo as they can destruct. Overdischarge? Pitch it and buy new. Kurt

Welcome to my favorite home for LiPo batteries HobbyKing https://www.hobbyking.com/hobbyking/store/__378__85__Batteries_Accessories-Turnigy_nano_tech.html

The Turnigy Nano-Techs are what I fly on all my Eggtimer products.

As for the charger spend the money to get a good one, I like the HiTec X1 AC+ its an AC or DC power capable charger so I can use it at home or in the field with my deep cycle trolling battery. It only does one battery at a time but it is a good unit.

As for 9V's I save them for my RRC3 as its a configuration that works so far everytime for me.

DAllen said:

- Eggtimer Quantum...I will someday shortly be the proud owner of one of these but their FAQ says 9vs won't work the WiFi (a key feature for me) because it's a bit of a battery hog. The FAQ says, "We recommend a 2S/7.4V LiPo battery, 300 mAH or larger" whatever that means. So I need something that size or larger...I guess.

Click to expand...

Here is a good page on "Understanding LiPo batteries" https://www.rchelicopterfun.com/rc-lipo-batteries.html Towards the bottom of the page it explains battery ratings and has some good general info on charging, etc.

I use these 2S 500mAH on my Quantum and on my Eggtimer TRS. https://www.ebay.com/itm/131644712658?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT They are fairly small and lightweight and have served me well so far.

Here's what I replied in another thread:

I've been happy with the batteries I purchased from Hobby King. This should link to there selection of 2S (2 cells - 7.4 volt) packs of all shapes and sized:

https://www.hobbyking.com/hobbyking/s...SortOrder=desc

You want something with a capacity of 500 mAh or greater.... the higher the number, the more capacity, the longer your Quantum will run!
Another critical is the C rating... you see something like 15-30C. This an output rating of the battery as a multiplier of it's capacity (C) so:

Example battery 1000 mAh Capacity
Rating - 15-30C
Sustained output = 1000 mAh x 15C = 15000 mA or 15 Amps
Instantaneous output = 1000 mAh x 30C = 30000 mA or 30 Amps

All of the above would far exceed the draw one would ever expect from a Quantum or most any deployment flight computer.

One other rating to look for, is a charge rating. It would be expressed in C as well, but would be low like the 1-5C range. The tells you the designed charging rate for the battery. You'll want to set your Li-Po charge to this calculated value or preferable lower.

Example:
Example battery 1000 mAh Capacity
Charge rating of 2C
Max charge current = 1000 mAh x 2c = 2000 mA or 2 Amps
at 100% efficiency, it would take 30 minutes to charge at that rate.... practically speaking, the batteries draw rate will decrease as it get filled and you'd be looking at more like 45 min to 1 hour from near 0% to 100%

When you go the Li-Po route, get yourself a Balanced charger as well. I purchased one of these, and have come to really like it: https://www.hobbyking.com/hobbyking/s..._GENUINE_.html
I power it with a universal Laptop brick I had with the correct connectors. You can also use it in the field from a 12v car battery.

I'm not an expert on these batteries, but I struggled to figure out the nomenclature detail above, so hope this helps.

Jack

I have a Quantum. Here's what I went with for charging and powering.

Charger: https://smile.amazon.com/dp/B00XC62FFC
Battery: https://smile.amazon.com/dp/B017I90XJ8

The batteries are 850 mAh, but they're still pretty light at about 40 g. I'm not worried about minimizing weight. I believe the Quantum used around 30 mAh (memory here), so you can keep your Quantum powered on for around a day on a fresh battery. No worries there when your rocket sits around waiting for a launch window. Plus, they're cheap at $18 for two batteries. You'll have an extra for backup deployment or a gps.

Oh, and don't forget you'll need extra JST connectors to screw in or solder to the board so you can connect the battery. Your local electronics ship should have that, or you can buy these cheap.

Connectors: https://smile.amazon.com/dp/B00EZH92JE

ksaves2 said:

IMAX B6 Charger and no doubt you'll get recommendations of others. They don't have to cost a lot. I guess one of the keys is when you are going to let lipo's sit for a time to discharge them to like 50% capacity.
No problem with the IMAX as it has a "storage" setting that will either "charge up" the battery or discharge it to get to the acceptable level. Other chargers probably have the same.

I remember doing Nicads with a wall wart, an ammeter, voltmeter and potentiometer to set the current in the old days.

It's pretty easy to learn plus don't do a dead short with a lipo as they can destruct. Overdischarge? Pitch it and buy new. Kurt

Click to expand...

I agree with this, but be careful- there are a lot of knock off B6 (and other) chargers out there. I bought one myself on purpose (Hobbyking.com lists them as knockoff, which is kinda nice), but it didn't work. Thankfully I was able to exchange and went up a bit (like $30 total) for a real charger.

Hoo boy,

Remember one thing with lipos, bigger is not necessarily better. Search out the threads on lipos here and there are discussions about choosing the appropriate
capacity. Yes, if powering a tracker, bigger gets you more runtime. If powering an altimeter, bigger might toast some of the output components on the board
if the ematch shorts. I limit my on time (if possible) to 1 second. Example: A Raven can run on a single 1S lipo with a capacity of 160mah just fine.
Yeah, I wouldn't want to let it sit on the pad for hours or in cold weather but for a single flight, it works fine. Above all, follow the manufacturers recommendations and if one wants to do something different, drop the maker an email or ask other users what they fly. Kurt

This one rocks. I've used it on the EggTimer Quark, Stratologger CF, and RRC2 and RRC3, as well as powering an EggFinder GPS. Cheap as dirt, rock solid performance, and small/light enough to fit into the Landru/Missile Works/Additive Aerospace sleds. No complaints at all.

https://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=28646

When ordering, check to make sure you select the US East or US West warehouse. Sometimes they're out of stock, so the only option is another warehouse, or the International warehouse (which sucks).

For a charger, I have a B6 and power supply left over from my RC car racing days. Still one of the best/fastest/easiest chargers out there. Pay the money for a real B6 and never look back.

As an alternative, look into a second hand charger from a local RC shop or race club or even a local flying club. RC guys tend to be gear guys, and change often, so they have lots of 'last year's stuff' laying about.

https://www.hobbyking.com/hobbyking...ancer_Charger_LiHV_Capable_US_Warehouse_.html


I have charger like that I'm happy with , has balance and storage modes

Assuming they're for Eggtimer Rocketry altimeters, you don't have to worry about the battery being "too big". The optoisolator/BJT architecture in our deployment circuitry provides automatic current limiting, so you'd really have to try hard to blow out a transistor. Conversely, if it's for a Quark you can use a small 1S LiPo, as long as it will put out 5A (that's 5x what most ematches draw, our recommended safety margin). If you aren't sure, multiply the mAH rating by the "C" rating, and if it's at least 5,000 you're good to go. For example, a 350 mAH LiPo with a 20C rating is good for 350 x 20 mA, or 7,000 mA (7A) and would be fine.

ksaves2 said:

Hoo boy,

Remember one thing with lipos, bigger is not necessarily better. Search out the threads on lipos here and there are discussions about choosing the appropriate
capacity. Yes, if powering a tracker, bigger gets you more runtime. If powering an altimeter, bigger might toast some of the output components on the board
if the ematch shorts. I limit my on time (if possible) to 1 second. Example: A Raven can run on a single 1S lipo with a capacity of 160mah just fine.
Yeah, I wouldn't want to let it sit on the pad for hours or in cold weather but for a single flight, it works fine. Above all, follow the manufacturers recommendations and if one wants to do something different, drop the maker an email or ask other users what they fly. Kurt

Click to expand...

Just remember to wire your ematches in series. Or was it parallel...........:duck:

Buckeye said:

Just remember to wire your ematches in series. Or was it parallel...........:duck:

Click to expand...

(DAllen goes and looks for clips from the infamous Mythbusters 360 rocket swing episode...)