Here's a post some of you might find interesting.
I recently acquired an E-trac and it cames with 1600, 1800 and alkaline battery packs. All of these have been used, some more than others (presumably), but I have no idea as to their life. Anyways, I decided to charge them up using the stock Minelab "trickle" charger and test their capacity and performance under load.
Below is a chart where I have the alkaline pack, except it's loaded with eight AA 4th generation Eneloop (Panasonic) cells. The picture makes it clear that it's performance is amazing. Not only does it exceed the rating capacity of 2,000 mah per cell, but it has a pretty flat discharge curve.
As for the 1800 E-Trac pack by Minelab, it did ok. Assuming it's at least a few years old, it still has plenty of life left.
A few notes about the testing.
1. All discharge tests were at 200mah. This exceeds what the E-trac will pull on a consistent basis during normal operations.
2. The discharge test ended when the pack had an overall voltage of 8.4 volts. The E-Trac manual implies that 8.4v is some sort of important point in the pack's discharge cycle. I've concluded that this is when the battery bar starts to blink or when the automatic shutdown kicks in.
3. The Eneloop test used 4 cells that were about 4-5 hours off the charger and 4 cells that were abour 5 minutes off the charger. This charger was a single channel charger and charged the cells at 300mah (per cell).
4. The 1800 pack was about 55 hours off the charger before discharge testing began. In case you're wondering that had an effect on the overall capacity, but not by much.
5. When the cells in the 1800 mah pack dumped...they DUMPED. I iniitially suspected it had some sort of auto-cut off. But I don't think that's the case because the cut off is so high voltage-wise (about 9.5 volts) and the 1600 pack (also an OEM product from Minelab) did not have a discharge curve that had such asn abrupt termination. Instead, the 1600 discharge curve looked similar to the Eneloop curve in SHAPE only, ie the curve as it approached the 8.4v cutoff point was gradual, not abrupt. Anyways, I suspect that this 1800 pack is an accidentally created matched pack. Or, there could be 1 or 2 cells that are dumping fairly early, but the overall discharge curve of the 1800 is fairly close to the Eneloop pack. So I'm not 100% sure what's going on here.
6. So how does this data relate to run times? Well, the E-Trac manual says the 1800 pack should get 16 hours of run time. That equates to about a 112.5mah current draw. Assuming Minelab is being generous here (which they probably are), let's assume an actual current draw (during normal use) of 135mah (a 20% current draw "adjustment"). Assuming that's the case, then this 1800 pack I tested should get about 10 hours and 20 minutes of run time and the Eneloop pack would get about a 14 hours and 45 minutes of run time. If we used Minelab's numbers, then the run times are 12 hours 20 minutes and 17 hours and 35 minutes, respectively.
7. These discharge tests were completed using the CBA III (which is no longer in production and has been replaced by the CBA V).
P.S. In no way am I affiliated with West Mountain Radio.
I recently acquired an E-trac and it cames with 1600, 1800 and alkaline battery packs. All of these have been used, some more than others (presumably), but I have no idea as to their life. Anyways, I decided to charge them up using the stock Minelab "trickle" charger and test their capacity and performance under load.
Below is a chart where I have the alkaline pack, except it's loaded with eight AA 4th generation Eneloop (Panasonic) cells. The picture makes it clear that it's performance is amazing. Not only does it exceed the rating capacity of 2,000 mah per cell, but it has a pretty flat discharge curve.
As for the 1800 E-Trac pack by Minelab, it did ok. Assuming it's at least a few years old, it still has plenty of life left.
A few notes about the testing.
1. All discharge tests were at 200mah. This exceeds what the E-trac will pull on a consistent basis during normal operations.
2. The discharge test ended when the pack had an overall voltage of 8.4 volts. The E-Trac manual implies that 8.4v is some sort of important point in the pack's discharge cycle. I've concluded that this is when the battery bar starts to blink or when the automatic shutdown kicks in.
3. The Eneloop test used 4 cells that were about 4-5 hours off the charger and 4 cells that were abour 5 minutes off the charger. This charger was a single channel charger and charged the cells at 300mah (per cell).
4. The 1800 pack was about 55 hours off the charger before discharge testing began. In case you're wondering that had an effect on the overall capacity, but not by much.
5. When the cells in the 1800 mah pack dumped...they DUMPED. I iniitially suspected it had some sort of auto-cut off. But I don't think that's the case because the cut off is so high voltage-wise (about 9.5 volts) and the 1600 pack (also an OEM product from Minelab) did not have a discharge curve that had such asn abrupt termination. Instead, the 1600 discharge curve looked similar to the Eneloop curve in SHAPE only, ie the curve as it approached the 8.4v cutoff point was gradual, not abrupt. Anyways, I suspect that this 1800 pack is an accidentally created matched pack. Or, there could be 1 or 2 cells that are dumping fairly early, but the overall discharge curve of the 1800 is fairly close to the Eneloop pack. So I'm not 100% sure what's going on here.
6. So how does this data relate to run times? Well, the E-Trac manual says the 1800 pack should get 16 hours of run time. That equates to about a 112.5mah current draw. Assuming Minelab is being generous here (which they probably are), let's assume an actual current draw (during normal use) of 135mah (a 20% current draw "adjustment"). Assuming that's the case, then this 1800 pack I tested should get about 10 hours and 20 minutes of run time and the Eneloop pack would get about a 14 hours and 45 minutes of run time. If we used Minelab's numbers, then the run times are 12 hours 20 minutes and 17 hours and 35 minutes, respectively.
7. These discharge tests were completed using the CBA III (which is no longer in production and has been replaced by the CBA V).
P.S. In no way am I affiliated with West Mountain Radio.
Attachments
Last edited: