RTK-SMA - replace BBR (ML414H_IV01E) - source & tips?

GPS/GNSS
1

Hi all,

I have an RTK-SMA board (SparkFun GPS-RTK-SMA Breakout - ZED-F9P (Qwiic)) with a backup battery that no longer keeps a charge and needs to be replaced.

It’s in a rover I built, so I really need a working battery for hot starts. Because of the usage, cold starting each time is a MAJOR PITA. :slight_smile:

From:

  1. https://cdn.sparkfun.com/assets/6/0/c/0/d/SparkFun-GPS-RTK-SMA-ZED-F9P_Board_Dimensions.png
  2. https://www.sparkfun.com/media/catalog/product/cache/6481a7e801770ff450b11f3cf63d7638/1/6/16481-SparkFun_GPS-RTK-SMA_Breakout_-_ZED-F9P__Qwiic_-01a.jpg

you can see that the battery is soldered to the board and has one tab at 10 o’clock and a second tab at 2 o’clock - which seems to run under the battery.

I found no docs listing the specific model # of the battery used on the RTK-SMA.

However, finally, after digging into the Eagle files for the RTK-SMA (specifically Qwiic GPS-RTK-SMA - ublox ZED-F9P.sch), I found that the battery is a SEIKO ML414H-IV01E.

I suspect I’m not the only one who is going to need to replace this battery … but maybe just the first.

Sparkfun doesn’t sell it and I don’t trust the one seller on Amazon who has 4 @ $19.78 each (plus shipping).

Does anyone have a source suggestion for this? Also, tips for removal & replacement? It looks like a tricky job.

Thanks!

PS - The RTK2 uses a different battery design (MS621FE-FL11E) - it looks like it would be much easier to swap.

2

Good detective work! You can readily trust Mouser or Digi-Key :slight_smile:

Remember to leave it trickle-charging (via usb) for ~24 hours the first charge once installed (to completely fill’r up!)

3

Hi Doug,

The MS621FE needs to be hand-soldered. The ML414H can be reflowed. That’s why we migrated to the ML414H…

Removal:

Use a scalpel or very small screwdriver to gently lift each side of the battery as you heat each contact with the iron. Swap between the two, lifting the battery seesaw fashion a little at a time, until you have a large enough gap to ‘break’ each solder joint.

Replacement:

Use your solder sparingly. Put a little on both pads, then place the battery, then press each contact down with the iron to create the joints - without adding more solder. It’s easy to create a short between the larger negative contact and the positive cell body if you use too much solder. Check with a meter afterwards.

Hope this helps,
Paul

1 Like
4

Definitely had to hunt for it. :slight_smile: Maybe listing it in one of the docs would be helpful to others in the future. But then, maybe this thread will help too.

Great! Links! Looks like $1.84 (battery) + $6.99 (FedEx ground shipping) + tax from DigiKey. And they have 15,000+ in stock so immediate shipping. $15.39 for four batteries (you know … just in case) and they’ll be in NC in 4 days. That works for me!! Just ordered.

Add in Paul (Mission Impossible) ZC’s super helpful soldering guidance (he’s truly a wizard), and I’m one happy camper.

No wonder I like SparkFun so much.

5

Paul, your guidance is without compare. You always increase my confidence level 10x. Thank you!