[jon.partsch]

TL;DR

Will upgrading the cells in a dead Wasabi Power D-LI90 clone battery pack increase performance and lifespan???

Also, admin please move this to appropriate forum if this is not it.

Last year, I obtained an exactingly complete K1-ii kit with multiple lenses from a fellow forum member and dove head-first into FF shooting. The kit came with the original Pentax D-LI90 battery as well as four Wasabi Power clones. The clones initially held a small charge, but now are completely dead. The Pentax battery is going strong. I opened one of the Wasabi Power packs to discover that it contains two completely unlabeled 18500 lithium cells. Now, it is widely believed that these packs, even when new, don't yeild as many shots as the OEM packs, despite being labeled to have a higher capacity (2300 mAh vs. 1860 mAh for the OEM packs).

I've already gone ahead and ordered name-brand (Panasonic) 18500 cells to replace the unlabeled cells in the dead Wasabi packs. I understand that the OEM packs also use Panasonic cells. I could have purchased four new Wasabi packs for the same price as the Panasonic 18500 cells I ordered, but I am hoping that replacing the cells in the old packs will yield better performance and overall lifespan than new Wasabi packs. Am I barking up the wrong tree here? I guess the question is this: is the lower quality of the Wasabi packs vs OEM packs due to the cells they use or due to the other internal electronics. If it is the former, than I am sure my efforts will be worth it. If it is the latter than I am wasting a lot of effort and should have just bought new Wasabi packs.

~ Jon

Results are summarized here, below, for your convenience. There is, of course, more detail and discussion in the thread. In addition to the info in this thread, here are some other great PentaxForums threads on rebuilding battery packs and testing battery packs....

Rebuilding:
Rebuilding a pentax D-Li90 battery - PentaxForums.com

Testing and comparing:
Some Pentax D-LI90 Battery Charge/Discharge Measurements - PentaxForums.com
Capacity measurements of some 3rd party batteries - PentaxForums.com

Understanding the camera's battery meter:
The Pentax Battery Level Meter -- What it actually shows - PentaxForums.com



Battery pack rebuild #1 : Thread comment 36
Battery pack rebuild #2 : Thread comment 42
Battery pack rebuild #3 :
Battery pack rebuild #4 :
Bonus - new Wasabi pack test for comparison : Thread comment 46

TESTING RESULTS SUMMARY:

Rebuild attempt	1	2	3	4	*NEW* Wasabi BTR-DLI90-JWP
Old pack #	3	2			NA
Old pack brand and model	Wasabi Power, BTR-DLI90-JWP	Wasabi Power, BTR-DLI90-JWP			NA
New cells brand and model	Panasonic, NCR18500A	Panasonic, NCR18500A			NA
Fresh replacement cell voltage (new)	3.51v, 3.51v	3.51v, 3.51v			NA
New cells soldered into series	7.01v	7.02v			NA
Charger used	Pentax D-BC90	Pentax D-BC90			Pentax D-BC90
Pack external terminals prior to charging	0.10v	0.00v			7.82v (new from box)
Pack external terminals after a few minutes on charger	7.12v	7.14v			NA
Pack external terminals freshly charged	8.38v	8.36v			8.35v
Pack external terminals 24hr self discharge	8.33v	8.33v			8.30v
Pack external terminals 48hr self discharge	8.32v	8.32v			8.29v
Discharge cutoff voltage	6.0v	6.0v			6.0v
Discharge load	15 ohm	15 ohm			15 ohm
Initial discharge current	544 mA (roughly 0.25C)	540 mA (roughly 0.25C)			528 mA (roughly 0.25C)
Initial voltage drop under load	-0.20v (8.12v)	-0.24v (8.08v)			-0.38v (7.91v)
Measured capacity	1919 mAh	1942 mAh			1415 mAh
Pack external terminals resting voltage after test	6.65v	6.59v			6.58v

---

Last edited by jon.partsch; 04-22-2021 at 06:10 PM. Reason: Add testing results

[UncleVanya]

TL;DR

Will upgrading the cells in a dead Wasabi Power D-LI90 clone battery pack increase performance and lifespan???

Also, admin please move this to appropriate forum if this is not it.

Last year, I obtained an exactingly complete K1-ii kit with multiple lenses from a fellow forum member and dove head-first into FF shooting. The kit came with the original Pentax D-LI90 battery as well as four Wasabi Power clones. The clones initially held a small charge, but now are completely dead. The Pentax battery is going strong. I opened one of the Wasabi Power packs to discover that it contains two completely unlabeled 18500 lithium cells. Now, it is widely believed that these packs, even when new, don't yeild as many shots as the OEM packs, despite being labeled to have a higher capacity (2300 mAh vs. 1860 mAh for the OEM packs).

I've already gone ahead and ordered name-brand (Panasonic) 18500 cells to replace the unlabeled cells in the dead Wasabi packs. I understand that the OEM packs also use Panasonic cells. I could have purchased four new Wasabi packs for the same price as the Panasonic 18500 cells I ordered, but I am hoping that replacing the cells in the old packs will yield better performance and overall lifespan than new Wasabi packs. Am I barking up the wrong tree here? I guess the question is this: is the lower quality of the Wasabi packs vs OEM packs due to the cells they use or due to the other internal electronics. If it is the former, than I am sure my efforts will be worth it. If it is the latter than I am wasting a lot of effort and should have just bought new Wasabi packs.

~ Jon

Attachment 529542

New wasabi packs in my k-3 gave nearly the same life as my Pentax batteries. Over time they lost a small amount but not as much as yours. I tend to not store them fully charged as this reduces lifespan.

I don’t know if they will be equal to the Pentax with the new cells. Your experimenting will inform us all.

[jon.partsch]

New wasabi packs in my k-3 gave nearly the same life as my Pentax batteries. Over time they lost a small amount but not as much as yours. I tend to not store them fully charged as this reduces lifespan.

I don’t know if they will be equal to the Pentax with the new cells. Your experimenting will inform us all.

I don't have any way to know how old these packs were when I got them. The fella' I got all this gear from, took *immaculate* care of his equipment. It all looked new. He labled the pack #1 through #4, so I am sure he took good care of them and rotated them appropriately.

One of the things that really frustrates me about almost everything that uses lithium batteries, is that there is no good way to limit the charging to prevent premature battery wear. If I could even just *see* the voltage while it is charging, it would help.

Opposite of NiCd and NIMH technology, lithium batteries benefit from many small charging sessions, and being kept as close to 50% charge as possible, while those other technologies benefit from full charge and discharge cycles. A "full" lithium cell is generally considered to be 4.2 volts. An "empty" cell is generally considered to be 3.0 volts. The 3.6 or 3.7 volts that is usually quoted as the nominal voltage is at about a 50% charge. I prefer to shoot for about 3.8 volts for my batteries when I am not using them, but this is tricky, because it means that I have to time the charging, or remove the battery from the charger every few minutes and check the voltage with my multimeter. I have found that my power tool batteries, when they drop to one bar, reach 3.8 volts after about 20 minutes of charging on their charger. I will probably figure out the same timing for my camera batteries and store them at 3.8 volts, only topping them off before I plan to use.

The charging limit and discharging limit (e.g. 4.2 volts and 3.2 volts) can be handed by circuits in the battery cells themselves (called "protected cells") and/or in battery *pack*, and/or in the charger, and/or in the camera/tool. I don't know how these limits are handled by the camera battery packs I am talking about here, other than that I know that it is not handled by circuitry in the battery cells as these cells do not have the "protection" circuitry.

[marcusBMG]

Rebuilding a pentax D-Li90 battery - PentaxForums.com

[jon.partsch]

Rebuilding a pentax D-Li90 battery - PentaxForums.com

@marcusBMG , I actually saw your post, and was partially inspired by it in my pending attempt to rebuild the Wasabi packs. The construction of the Wasabi packs seem to be a bit different from the OEM pack based on your example, and I am planning to solder in the new cells rather than spot weld. I have upgraded to a much more powerful PID-controlled soldering iron to make the attempt, and will have the dead cells to practice on first. I was able to cleanly separate the flat wire from the weld points on the terminals with a scraper blade, so I believe I should be able to just solder the new cells into place without any other consumable supplies.

[leekil]

Opposite of NiCd and NIMH technology, lithium batteries benefit from many small charging sessions, and being kept as close to 50% charge as possible, while those other technologies benefit from full charge and discharge cycles. A "full" lithium cell is generally considered to be 4.2 volts. An "empty" cell is generally considered to be 3.2 volts. The 3.6 or 3.7 volts that is usually quoted as the nominal voltage is at about a 50% charge.

I mostly use my batteries until the camera stops working, and this doesn't seem to have impacted the battery life. I haven't noticed any older batteries as having significantly less life than newer ones, though there could be some absolute difference.

[jon.partsch]

I mostly use my batteries until the camera stops working, and this doesn't seem to have impacted the battery life. I haven't noticed any older batteries as having significantly less life than newer ones, though there could be some absolute difference.

@leekil , I don't know what the camera's cutoff voltage is (I assume this is being handled by the camera), but it would be easy to check the voltage of the battery with a multi meter once the camera shuts down. Are you using Pentax packs or third party packs? My concern is specifically about the quality of the Wasabi Power packs. I still have the 12-year old pack that came with my K5 and it still seems to be working fine, so this might not be as much as a problem with the Pentax packs.

I believe that overcharging is usually more of a problem than over-discharging as the charging is often controlled by cheap charges that don't have a reliable high-voltage voltage cutoff. Generally, a lithium cell should be able to stand at least 300 *full* charge-discharge cycles before capacity degradation is noticeable. I believe that many cells are rated at 500 cycles. By not fully discharging and/or not fully charging the pack, the lifespan can be extended to many thousands of cycles. Again, I believe that over-charging (and especially storing batteries in a fully-charged state) tends to be more of a problem than fully-discharging in the camera.

Based on the reviews and the anecdotes I have read, it sounds like many have experienced significant capacity degradation with the Wasabi packs after less than 300 cycles (mentioning, for instance, significant degradation after only a few months).

[marcusBMG]

@marcusBMG , I actually saw your post, and was partially inspired by it in my pending attempt to rebuild the Wasabi packs. The construction of the Wasabi packs seem to be a bit different from the OEM pack based on your example, and I am planning to solder in the new cells rather than spot weld. I have upgraded to a much more powerful PID-controlled soldering iron to make the attempt, and will have the dead cells to practice on first. I was able to cleanly separate the flat wire from the weld points on the terminals with a scraper blade, so I believe I should be able to just solder the new cells into place without any other consumable supplies.

Right - I should have actually read your post through to begin with,..

To ans yr orig qq: the battery performance is due essentially entirely to the cell quality. Those wasabi cells are almost certainly generic no-name chinese ones (and all too often the indicated capacity is mostly marketing). Replacing with panasonic ones the performance and longevity will reflect the quality of the panasonic cells.
The electronics in the batteries are IMO essentially the same and pretty simple: just a simple control board that I don't see doing much more that the usual short circuit, temp monitor, charge/discharge protection with an element of balance charging, and esential communication with the charger. The pcb should work the same with all Li IOn cells - no reason why not.
As far as soldering goes, it's not really high power you need but the right solder, the right tip and, especially, good flux! In fact too much power could be very bad - increasing the risk of heat damaging the battery. I suggest a hoof shaped tip, a good quality lead free* solder and I have had good results with a thin smear (fingertip) of standard plumbers flux paste. Check out some of the YouTube videos.
*actually with some nickel strip/nickel plate I have had better results with lead solder - you just have to experiment.

[jon.partsch]

Right - I should have actually read your post through to begin with,..

To ans yr orig qq: the battery performance is due essentially entirely to the cell quality. Those wasabi cells are almost certainly generic no-name chinese ones (and all too often the indicated capacity is mostly marketing). Replacing with panasonic ones the performance and longevity will reflect the quality of the panasonic cells.
The electronics in the batteries are IMO essentially the same and pretty simple: just a simple control board that I don't see doing much more that the usual short circuit, temp monitor, charge/discharge protection with an element of balance charging, and esential communication with the charger. The pcb should work the same with all Li IOn cells - no reason why not.
As far as soldering goes, it's not really high power you need but the right solder, the right tip and, especially, good flux! In fact too much power could be very bad - increasing the risk of heat damaging the battery. I suggest a hoof shaped tip, a good quality lead free* solder and I have had good results with a thin smear (fingertip) of standard plumbers flux paste. Check out some of the YouTube videos.
*actually with some nickel strip/nickel plate I have had better results with lead solder - you just have to experiment.

@marcusBMG , that's my hope! I can see the ICs on the PCB, but haven't investigated to see if I can determine what the ICs do. I'd have to more fully disassemble the pack and try to find codes on the ICs with a magnifier, but am waiting until I am ready to solder in the new cells before I disassemble the old pack further.

The odd thing to me is that Wasabi Power is probably *the* major third party battery pack maker for cameras. They both advertise a higher capacity than OEM packs *and* say "Premium Cells from Japan" right there on the pack. I highly doubt these claims, but don't know how they get away with it. Every review or video that I have seen that semi-scientifically compares the Wasabi packs head to head with Pentax pack show that the Wasabi packs don't hold as much charge, so the mAh capacity claims seem to be bogus at least.

---------- Post added 03-31-2021 at 01:32 PM ----------

The new Panasonic cells that I ordered are NCR18500A. I believe these are the exact same ones that are in the OEM Pentax packs, but they are rated at nominal capacity of 2040 mAh rather than the 1860 mAh of the Pentax packs. I wonder if Pentax is limiting the charge capacity of the cells to increase their longevity. If so, that is really a good thing! That may be one reason the Pentax packs seem to have such a long lifespan compared to the competition.

~ Jon

[marcusBMG]

nominal capacity of 2040 mAh

These quoted capacities are usually for a full discharge to the lowest V allowed by the specs - often 2.5v. it is common I think for the internal control circuitry to cut off at higher V eg 3v. This would account for the discrepancy.

[jon.partsch]

These quoted capacities are usually for a full discharge to the lowest V allowed by the specs - often 2.5v. it is common I think for the internal control circuitry to cut off at higher V eg 3v. This would account for the discrepancy.

Ah! that makes total sense! The rated cutoff voltage for the cell from the manufacturer's (Panasonic's) website is 2.5v. Do you have any idea whether the charge/discharge cuttoff (in real wold use) is handled by the componants on the battery pack's PCB, or by the charger/camera?

[marcusBMG]

Low battery alerts and then cutoff in use: power management software in the camera i would think.
Charging: don't know, I haven't taken a charger apart. In any case charging seems to be a commonality, with any number of ic controllers that do a similar c-A and c-V job to 4.2v/cell like tp4056's. Wouldn't be surprised to find one in both the charger and teh battery.

[stevebrot]

Those wasabi cells are almost certainly generic no-name chinese ones

I would note that Blue Nook used to claim their cells were Made in Japan. That claim is missing from the current Wasabi Power Web site.

They both advertise a higher capacity than OEM packs *and* say "Premium Cells from Japan" right there on the pack.

I just checked and yes, the Wasabi battery in my K-3 does indeed say "Premium Cells from Japan". Go figure...


Steve

[stevebrot]

Low battery alerts and then cutoff in use: power management in the camera i would think.
Charging: don't know, I haven't taken a charger apart. In any case charging seems to be a commonality, with numerous ic controllers that do a similar c-A and c-V job to 4.2v like tp4056's.

And I would guess the cutoff is based on sag-on-demand rather that resting voltage. I just tested one of my Wasabis that failed to power on with my K-3 a few days ago and it tests 7.6V this afternoon.


Steve

[marcusBMG]

I just tested one of my Wasabis that failed to power on with my K-3 a few days ago and it tests 7.6V this after noon.

You may find that the camera wil now turn on... but probably not for long.