BCD436HP/BCD536HP: Trickle Charger Mod

[Rred]

No, I had seen them while looking for replacements a couple of years ago, no idea what's being sold now. A fast look at Digikey doesn't show anything above 2.45 now, maybe someone got religion?

I realize the two products (from any supplier) will come from different lines, but seeing Tenergy fall so short of what I had expected from them (good reviews) I just crossed them off my list. The idea is "this vendor isn't backing up what they are claiming" or "this vendor isn't looking to long term performance" and that tends to cut across all product lines.

Quality control and customer service, from anyone these days, are all too rare.
The few I find, I treasure.

 

[jonwienke]

I'm pretty sure the NiMHs you saw were rated pretty optimistically, and that's why they aren't being sold any more. Even with good brands like Eneloop, the extra capacity (~2400mAH) cells tend to fail after fewer charge cycles than standard (~2000mAH) cells.

So far my experience with the Tenergy Li-ion cells has been good. Fit & finish is good, and 13 hours of run time is significantly better than anything I ever got with NiMH batteries. If you have a link to 14500 Li-ion cells with solder tabs that have a brand name that doesn't sound like a saturday morning anime villain, i'll take a look and possibly comparison test them against the Tenergy cells.

 

[jonwienke]

I just finished a second runtime test. Everything was the same as the previous test, except this time I had the internal GPS turned on. Total time elapsed between unplugging the scanner and low battery warning was 11 hours, 43 minutes, 1 second. And that was with more activity than yesterday. I'm really liking the Li-ion battery mod.

 

[jonwienke]

Some pics of the battery pack.

In place. Please forgive the kinda ugly electrical taping job:
https://1drv.ms/u/s!ApJIS-l4xqPtgupLAqnrXRfzZQXtIQ

Pulled out. Note the absence of the standard battery compartment terminals. The battery pack connector fits in the slot where the + end of the top bettery used to go:
https://1drv.ms/u/s!ApJIS-l4xqPtgupFd6_n5pI-rzU8Ig

 

[KK4JUG]

I heard a rumor that they'll put that in the new HP3.

I heard the rumor from my cousin's bail bondsman whose nephew cuts the hair of the guy who lives next door to one of the janitors at Uniden so it must be true,

 

[jonwienke]

Now I just need to figure out a way to mod the battery compartment door so I can put 5 or 6 cells in the battery compartment, rather than just 3.

 

[jonwienke]

Recharge time with the Li-ion mod and completely discharged batteries is about 2.5 hours if the scanner is off, and about 3 hours if it is on. If the batteries are partially charged, recharge time is proportionally less.

 

[jonwienke]

I decided to try an alternate approach. I figured out a way to reconfigure the battery terminals so they connect in parallel rather than in series, which allows individual 14500 batteries to be used rather than creating a soldered-together battery pack. It make it easier to carry spare batteries, replace defective cells, and to get the battery door closed.

https://1drv.ms/u/s!ApJIS-l4xqPtgu4XMEdm2IIsIIsabw

I'm currently running tests on the EBL cells to see how they compare with the Tenergy cells.

 

[jonwienke]

The testing is complete. Total elapsed time from unplugging the charger to low battery warning (set to 3100mV) was 13:36:05, about 1 minute longer than the Tenergy cells, which is not a statistically meaningful difference. Here are some photos of the reconfiguring of the battery terminal connections from series to parallel:

https://1drv.ms/f/s!ApJIS-l4xqPtgu4kYS9-xNBTH0PVig

 

[jonwienke]

I made one final refinement to the Li-ion battery mod. I connected the +5V input on the Li-ion charger board to the V_USB pad on the 436 display board. Doing that has several advantages:

1. Charging time is decreased, because the entire output of the charger board (current limited to ~1000mA) is used to charge the batteries. The power needed to run the scanner bypasses the charging circuit, rather than passing though it. USB current draw during charging increases from a maximum of ~1000mA to ~1200mA as a result. The batteries are charged at a maximum of ~1000mA, rather than ~800mA. Maximum charge time is ~3.5 hours starting from completely discharged batteries. Batteries charge to 80% in ~2.5 hours.

2. It is easier to tell when the batteries are fully charged, since the scanner isn't a constant load on the charging circuit. The indicator LED will turn green when the batteries are fully charged, instead of staying red until you turn the scanner off.

3. Either USB jack can be used to power the scanner and charge the batteries, so you can operate the scanner with a mini-USB or micro-USB cable. But only the factory USB jack can be used for programming and serial data.

The only disadvantage is that the serial / mass storage menu will still pop up when you apply power to the new USB jack, even though it has no data functionality.

 

[jonwienke]

double post