Altus Telemetrum replacement battery

I think these used to be available at the Altus webstore but can't find them. It is a LiPo 900 mAh 3.7 v. I think they used spark fun batteries but couldn't find it on that website either. Anyone know of a source for this battery with the correct connector (and polarity!) for the Telemetrum?

Atlasboy said:

I think these used to be available at the Altus webstore but can't find them. It is a LiPo 900 mAh 3.7 v. I think they used spark fun batteries but couldn't find it on that website either. Anyone know of a source for this battery with the correct connector (and polarity!) for the Telemetrum?

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Have you sent a message to them through their website store? https://shop.gag.com/contacts/

If they can't get you one I bet they can help you find one.

Good luck.

I did and they got right back to me. I ordered two 3.7v 850 mAh from Sparkfun. But, I've got to follow bdale's one-sheet on removing the circuit board before I use them. Doesn't look to bad.

Atlasboy said:

I think these used to be available at the Altus webstore but can't find them. It is a LiPo 900 mAh 3.7 v.

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Just to keep everyone up to date, Keith is talking to various producers of LiPo cells about making some for us with the right cable and no protection circuit board. I suspect we'll put some sort of announcement out on our list and/or here when we have flight batteries in stock again.

In the meantime, any of the single-cell (3.7 volt) LiPo cells from SparkFun will work, though we do recommend removing the protection circuit board as documented on our web site.

Be careful of other LiPo cells used for radio control toys, as many of them use a similar connector but with the polarity reversed!

Hi guys

I just destroyed my Telemetrum battery trying to remove the protection. The positive tab looks aluminium and there was a tiny bit of solderable mertal that looked tacked/soldered to it and it was so brittle it just fell apart. I cannot solder to the bit that is left and totally frustrated. Looking at the datasheet they are 1C discharge is this correct? Most of the batteries on HobbyKing are at least 20C which certainly changes the amperage. I know you guys are coming to THUNDA and I doubt you will be bringing lipos with you lol but can you offer some idea of what can be used in replacement that can be found on Hobbyking or other that can post to Australia.

Cheers

Chris

The batteries without the current limiting circuit can be had from the Altus Metrum store. Apogee sells them too.

You can also get them from HobbyKing.

3.7 volt single cell lipo for altimeter alone or with ejection charge use.

https://www.hobbyking.com/hobbyking...6&v=&sortlist=P&LiPoConfig=1&CatSortOrder=asc

Pick one with wires so you do not have to solder to the battery. Below is a 950 mah version for ~$4.

https://www.hobbyking.com/hobbyking...6&v=&sortlist=P&LiPoConfig=1&CatSortOrder=asc

Here the line for 7.4 volt 2 cell lipo battery packs.

https://www.hobbyking.com/hobbyking...y=86&LiPoConfig=2&sortlist=P&CatSortOrder=asc

Here's the 2 cell version of the single cell unit above for ~$7

https://www.hobbyking.com/hobbyking...950mah_2S_25_50C_Lipo_Pack_AR_Warehouse_.html

None of these batteries have control circuits inside. Instead of cutting and rewiring the connectors simply consider getting a wired mating connector and reversing the polarity with the wires at the altimeter terminal board. This way you can still use the hobby chargers and disconnect the batteries easily for the altimeter.

Bob

I also have them in stock

One can very carfully remove the wires and switch polarity on the micro jst connectors that are reversed. Kurt

Thanks to the guys with stock answering too. I have had problems in the past ordering lipos from overseas with postage and the like. Especially when I need this by March. I'm in Australia not the US for postage with Lipos.

My concern with the batteries above are their C ratings. At least from the Data Sheet on the one Chris' Supplies, Altus Metrum themselves, and Apogee use all show a C rating of 1C. These above all have high discharge C ratings of 20 to 70C. I don't know what the firing circuit on the Telemetrum is rated to but I want to stay under that. You take C rating multiply by mAhr and you get what that battery is happy to deliver all the way to discharge. For example

1S 3.7volt 130mAhr 20C battery

3.7 volts stay the same

.13 Ahr X 20 = 2.6amps continuous.

if it has 850mAhr and 40C then

.850 Ahr X 40 = 34amps continuous. OUCH:y: I assume that is more than the Telemetrum can handle.

When the igniter circuit is on and there is a micro second short that is a lot of current flowing.

Keith,, Bdale???

V2rocketeer said:

Thanks to the guys with stock answering too. I have had problems in the past ordering lipos from overseas with postage and the like. Especially when I need this by March. I'm in Australia not the US for postage with Lipos.

My concern with the batteries above are their C ratings. At least from the Data Sheet on the one Chris' Supplies, Altus Metrum themselves, and Apogee use all show a C rating of 1C. These above all have high discharge C ratings of 20 to 70C. I don't know what the firing circuit on the Telemetrum is rated to but I want to stay under that. You take C rating multiply by mAhr and you get what that battery is happy to deliver all the way to discharge. For example

1S 3.7volt 130mAhr 20C battery

3.7 volts stay the same

.13 Ahr X 20 = 2.6amps continuous.

if it has 850mAhr and 40C then

.850 Ahr X 40 = 34amps continuous. OUCH:y: I assume that is more than the Telemetrum can handle.

When the igniter circuit is on and there is a micro second short that is a lot of current flowing.

Keith,, Bdale???

Click to expand...

Most lipos CAN supply more than their C rating. They just sacrifice themselves in doing so. Don't worry about getting a battery with too high a C rating.

V2rocketeer said:

Thanks to the guys with stock answering too. I have had problems in the past ordering lipos from overseas with postage and the like. Especially when I need this by March. I'm in Australia not the US for postage with Lipos.

My concern with the batteries above are their C ratings. At least from the Data Sheet on the one Chris' Supplies, Altus Metrum themselves, and Apogee use all show a C rating of 1C. These above all have high discharge C ratings of 20 to 70C. I don't know what the firing circuit on the Telemetrum is rated to but I want to stay under that. You take C rating multiply by mAhr and you get what that battery is happy to deliver all the way to discharge. For example

1S 3.7volt 130mAhr 20C battery

3.7 volts stay the same

.13 Ahr X 20 = 2.6amps continuous.

if it has 850mAhr and 40C then

.850 Ahr X 40 = 34amps continuous. OUCH:y: I assume that is more than the Telemetrum can handle.

When the igniter circuit is on and there is a micro second short that is a lot of current flowing.

Keith,, Bdale???

Click to expand...

I run a 25C 3S LiPo pack on the pyro power input for my TeleMega's and it works great. Just make sure the igniter duty cycle isn't set too high, the default setting works great.


Sent from my iPad using Rocketry Forum

The MOSFET we use, a Vishay SI7232DN-T1-GE3, is good for 10 amps continuous, and 40 amps pulsed. The former is a thermal limit, which means that the package will get really hot and fail if you pull more than that much current through the device continuously. Given that we fire the pyros for 50ms, the effective limit is somewhere between 10 and 40 amps; probably north of 20 amps.

A typical ematch is about 1 ohm or so; that's going to limit the current to 4 amps or so, if you use a single cell lipo. If you used an external 12V lipo, and found an ematch that was less than one ohm, *and* you configured TeleMega to fire for multiple seconds, then you might be able to get over the thermal limit of the device.

Oh, we also track the battery voltage and shut the firing circuit down when it droops to the point that you might brown-out the CPU on TeleMega, EasyMini and TeleMetrum v2.

In other words, you're gonna have to try pretty hard to get beyond what the board's firing circuit can handle.

Be careful of other LiPo cells used for radio control toys, as many of them use a similar connector but with the polarity reversed!

Click to expand...

I'm not sure this is really an issue, granted I'm no LiPo or JST expert. That said I own Altus Metrum products as well as Featherweight AV Bays and a Power Perch which utilize the rc toy batteries that HobbyKing sells. The connectors used by Altus Metrum are JST PH connectors and can be sourced from Sparkfun. The pins are 2 mm apart.

https://www.sparkfun.com/products/9914

The connectors used by Parkzone and Kyosho that are also present in some of the Featherweight products utilize a JST but I think it's a JST SH, not PH connector. Regardless of exactly which JST it is the pins are 1 mm apart. Sure, the polarity is reversed on the two connectors but they aren't interchangeable due to the difference in pin pitch.

I've searched HobbyKing and haven't been able to find a LiPo that supports JST PH connectors. If you're looking to make replacement batteries for any Altus Metrum products I reckon the best bet is to source JST PH connectors and then use them with generic HobbyKing LiPos. That stated I will say the comment made by Stuart_F on the SparkFun JST PH page is correct, the fit with the loose female connectors is too snug and will need to be filed down.

Below is a picture of some of the products that have said connectors. As you can see the pitch between the Altus Metrum products and batteries is twice the distance of the Featherweight products.

Thanks for posting this comparison. Am searching for the 1.25mm pitch sockets on Ebay so I can connect up the 180mah battery to the
Raven without using the perch. The connectors are available for the Altus Metrum products BUT the polarity is reversed. Not a big deal.
Simply, pry up the little tab and pull the wire out of the plug and switch them. Viola', instant compatibility. That's how I got it to work with the
Easy Mega. Kurt