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Using Lipo batteries StrataloggerCF

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ColumbiaNX01

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I bought 2 new StrataloggerCF for a new project. I am wanting to run Lipo batteries. If I had more room in the avbay I would use 9 volts. What type and size lipos have you guys been using in these altimeters?

I looked in the manual all it says is to use a battery anywhere between 4 and 16 volts. It says you can use a lipo but does not say what size and kind. I contacted Perfect flight. They were not very helpful. The pretty much said I can use a lipo but they recommend 9 volt. When I asked where I could get one that they recommended they said since they don't sell lipos they don't recommend any. That is convenient!!! LOL

They did say in a email that a 2S 125-150mAH lipo would work. But the issue is I have not found any 2 cell lipo batteries with that amperage.

That being said with the CF being out a while I assume there are guys out there running there CF's with lipos.

Thanks, Andrew
 

manixFan

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Those the same ones I used at BALLS on 3 flights. The are smaller and lighter than 9 volts but the wires are a bit unwieldy (really the extra balance plug). I really like the size and form factor over a 9 volt. They are inexpensive enough that even if you only use them 4-5 times they are still less expensive than 9 volts. Buy at least one bag each of male and female connectors:

https://www.hobbyking.com/hobbyking...tail_10cm_Length_10pcs_bag_US_Warehouse_.html
https://www.hobbyking.com/hobbyking...tail_12cm_Length_10pcs_bag_US_Warehouse_.html

and maybe some of their silicone coated wire:

https://www.hobbyking.com/hobbyking...AWG_Silicone_Wire_1m_Black_US_Warehouse_.html
https://www.hobbyking.com/hobbyking...20AWG_Silicone_Wire_1m_Red_US_Warehouse_.html

I bought this charger for both those and other much larger Lipos we use. This one is an AC unit since we already had other DC 12 Volt chargers:

https://www.hobbyking.com/hobbyking...ell_S60_AC_Charger_US_Plug_US_Warehouse_.html

Those links are to the US West warehouse. You might try East depending on where you live.

You also need to read up on Lipos and how to safely handle them and especially how important it is to not over-discharge them and storage voltage levels, etc.

Good luck,


Tony
 

mpitfield

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Below are several links, in no particular order, that may help you in gaining some knowledge on using LiPos with altimeters in general. There are more threads if you dig through the forum, these are just some that I have been involved with. In brief, I use the SL100 and SLCF on several rockets and the batteries I use, are a 1S 250 mAh 20C LiPo. The "C rating is important with a LiPo as it dictates the max current your altimeter can draw, and if you have a short, the lower C rating and lover voltage will help mitigate damaging your altimeter.

As you will read, there are some who prefer a 2S for comfort. However I can tell you from both experience and quite a bit of ground-testing that the 1S will more than do the job for these altimeters, despite the 4-16V requirement and the 3.7 voltage rating on a 1S, which is actually 4.2 volts when fully charged. The batteries are also cheap enough that you can pick up a 1S and do your own ground testing to give you the confidence before you make a decision. If you're not comfortable then grab a 2S, but just be aware that the extra margin does come with a higher probability of damaging your altimeter. At least in the case of the SL100 and SLCF, which were not designed for LiPos.

There are some altimeters, like the MARSA54 just to name one, that have circuitry protection built into them and were specifically designed for LiPos, but sadly this seems to be the exception and not the rule.

https://www.rocketryforum.com/showt...earch-of-the-Perfect-LiPo&highlight=mpitfield
https://www.rocketryforum.com/showthread.php?130296-Ravens-and-LiPos&highlight=mpitfield
https://www.rocketryforum.com/showt...ut-do-direct-on-altimeter&p=710673#post710673
 

mikec

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I second that - have the same batteries from Sparkfun, no issues firing deployment igniters.
Be warned that these lipos have current limiting built in, so depending on what your deployment requires, you may or may not have a problem.
 
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matthewdlaudato

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Be warned that these lipos have current limiting built in, so depending on what your deployment requires, you may or may not have a problem.
Yes - if I'm reading the data sheet correctly, the typical over current protection threshold is 4.5A, not a problem for the fireworks style igniters I use, but higher draw igniters could misfire. Ground test.
 

watermelonman

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They did say in a email that a 2S 125-150mAH lipo would work. But the issue is I have not found any 2 cell lipo batteries with that amperage.
That H means we are talking capacity, not strength. You could give it a 2200mah battery without worry.

As others have mentioned the C rating is important for max currant.
 

ColumbiaNX01

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That H means we are talking capacity, not strength. You could give it a 2200mah battery without worry.

As others have mentioned the C rating is important for max currant.
Ok thanks. How low of a C rating do you want for a SLCF? I have seen the different C ratings on the batteries.
 

Johnly

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I use 7.2V 400mA batteries with a 20C discharge rating, but install a 1.5 ohm current limiting resistor to protect the FETs on the CF.

John
 

ksaves2

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I use 7.2V 400mA batteries with a 20C discharge rating, but install a 1.5 ohm current limiting resistor to protect the FETs on the CF.

John
Where to install and what size resistor? 1/8watt? 1/4watt? 1/2 watt? It never ceases to amaze me how fliers are having successes with the Lipo chemistry.
I have a teeny, tiny 180mah 1S Lipo I'm running in a minimum diameter with a Raven. Tested the ematches and they pop with authority fine.

I can appreciate if a 7.4V or high "C" rating can fry the output transistors if one is not careful but the other concern with a low capacity battery is a long wait
on the pad at a large launch and impairment of the LiPo chemistry in cold temperatures. If one is a polar bear flier, the non-rechargeable 9V Lithium cells have pretty good performance at low temperatures and I've heard suggested to wrap a chemical hand warmer about a battery in the ebay to keep it at its peak at low outside temps. Kurt
 

MikeyDSlagle

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You put the resistors on the return side of the charge. I have only just started with electronics in my rockets myself but the way I did it:
I built the resistors right into my sled. I ran each resistor (one for the drogue, one for the main) across the pins on a terminal block. Now I can hook the return lead to the block, then a jumper from the the other screw to the altimeter. If a 9v needs to be used, I can bypass the resistor altogether. I'll try to get some pics if need be.
I think mine are 1/4 watt, don't know how right that is though.

Mikey D
 
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