Powering notecard using D-cells: 2x3 or 1x6?


I am struggling with powering the notecard. I suspect that several of my other problems are somehow related to this.

Currently I am testing 2 x 3 (1.5V) D-cells of alkaline batteries. But it seems that these do not last very long before the power-surge will cause them to drop too low. I was pretty sure that having 2x3 (3 series times 2 in parallel) would have the current split between them, and they should handle 1A between the two for a good while. Do you think it would be better to put them all in series? In that case I need to regulate the voltage before passing it to the notecarrier, maybe with something like: Pololu - 5V, 3A Step-Up/Step-Down Voltage Regulator S13V30F5.

The reason that I would like to remain on alkaline batteries if possible is that this is going to be in an ocean buoy, and mixing lithium and ocean water is not great. And is more risky to handle when recovering (or found by someone else).

Do you otherwise have any experience with using super-caps to handle the GSM bursts? E.g. Super Capacitor - 10F/2.5V - COM-00746 - SparkFun Electronics, but I think this would require current limiting to not short everything…?

Thanks, Gaute

Hey @gauteh, I can follow-up with more details tomorrow, but we recommend using Tadiran batteries due to their ability to handle the high-pulses required by GSM. We have a specific model that we are in the process of getting into our online store, and I will follow-up as soon as I have more info to share.

Thanks a lot. An alternative would maybe be something like the super-cap charger in this schematic: https://cdn.sparkfun.com/assets/1/5/e/f/4/SparkFun_Artemis_Global_Tracker.pdf

Hi, just wondering if there was an update on the Tadiran battery model you recommend? We are looking at using one of their batteries (or equivalent like SAFT) or we may just go with a 3.7V 18650 battery pack.

Hey @dksmc thanks for following-up, and welcome to the Blues community, we are glad you’re here!

We have the Tadiran batteries ready to go, but are chasing down a few shipping-related requirements in order to ensure that we follow all the rules and regulations for sending these out. I hope we can get them up in the store within the next week.


Great! Thanks for the update.

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Just curious if this was every figured out? More of a reference then needing to buy direct. Thanks!

Yes @dksmc, the Tadiran battery we recommend is available in the store here: High Current Pulse Lithium Battery (3.6V) – Blues Wireless

Great! Thanks. Only problem is I’m in Canada haha. Still good info though.