| day |
notes |
hours |
| 18 |
Check on the state of the battery in the Garmin GPSmap 296 - flat. The device works fine when connected to external power, but the battery won't charge; it has again fallen below the minimum level to be recognised by the charging circuitry. Likewise the replacement battery that I got a while back is also showing a "Battery missing" message. Open up the battery pack to have a look at the cells in it. They are marked ICR18650-24B Samsung. Do some online research and find that similar cells are available for purchase, with various Ah capacities. The -24 suffix indicates 2400mAh.
Prise up the circuit board on the top of the cells to get at the welded connexions. Take pictures for reference. Peel the connexion strips off the ends of the cells, taking care not to strain the other ends of the strips on the circuit board. Those are soldered, so it seems possible that the connexion strips could be soldered to new cells; there is no way I could weld them! Peel off the joining strip at the other end of the cells. |
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| 20 |
On eBay, order 2 Samsung 18650-30Q cells (ie 3000mAh). Then, thinking about the need to charge them properly before fitting to the Garmin battery case, order a Li-ion charger (which actually comes with 4 more cells, of unspecified capacity). |
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| 22 |
2-off 18650-30 cells delivered. They do not show any manufacturer name, but have pink sleeves and a prefix IMR, which apparently indicates a slightly different chemistry to ICR. Check voltage and they both show about 3.6V.
Also receive from eBay a safety notice about the type of cell I have purchased, but it appears to be just a warning about the danger of improper charging of individual cells outside of a battery pack with proper management, or of storing in a way that might cause short-circuits. |
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| 23 |
Li-ion charger and 4-off 18650 cells 3500mAh received. They are Multpow brand and claim to incorporate "Re/Discharging Protection Circuit". Check voltages - all between 3.96V & 3.99V so pretty healthy.
Put the IMR18650-30Q cells in the charger to bring them up to full charge, which completes in a few hours. Next put a couple of the Multpow cells on charge; they charge much more quickly and there is time to do all 4 before bedtime. All cells showing just over 4.1V after charge. |
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