RCR123A (TF) strange behavior in RC-F4

I've purchased two RCR123A batteries to use in my Romisen RC-F4
They are the protected Trutfire ones (sku.8683 at DX)

What's strange is that I get SIGNIFICANTLY lowe output when I'm using the RCRs compared to primaries. I thought this was odd, so I went to meassure voltages and current draw (at battery). The results are baffling:

2 x CR123A (WF)
Voltage 5,09
Amps 0,83
Watts 4,22

2 x RCR (TF)
Voltage 7,64
Amps 0,13
Watts 0,99

Single RCR
Voltage 3,57
Amps 0,78
Watts 2,78

Output on 1 x RCR is about equal to output on 2 x Primaries (visually). I recon some of the power is lost in the regulating circuitry.

Are the RCR's bad or what?
Anyone seen anything similar?

T.

nakamoomin said:

Single RCR
Voltage 3,57

Click to expand...

It's my understanding that at 3.57v your RCR needs charging.

Zatoichi said:

It's my understanding that at 3.57v your RCR needs charging.

Click to expand...

Should have mentioned..
All meassurements are taken with batteries in flashlight (to account for all losses). The cells are freshly charged and cell voltage is 4,15.

T.

Oops, I have no idea then.

I thought I'd check the RCRs separately, to rule out a single bad cell.

Mixed (Primary + RCR #1)
Voltage 6,38
Amps 0,28
Watts 1,79

Mixed (Pirmary + RCR #2)
Voltage 6,36
Amps 0,28
Watts 1,78

Just for comparison:
Primaries
Voltage 5,00
Amps 0,83
Watts 4,15

2xRCR
Voltage 7,64
Amps 0,13
Watts 0,99

1xRCR
Voltage 3,51
Amps 0,80
Watts 2,81

Puzzling..
Looking at the amp numbers it seems like the RCRs internal resistance increases when used together with other batts.
This could be due to the protection circuits in the batteries or the voltage regulator in the RC-F4.

T.

nakamoomin said:

I thought I'd check the RCRs separately, to rule out a single bad cell.

Mixed (Primary + RCR #1)
Voltage 6,38
Amps 0,28
Watts 1,79

Mixed (Pirmary + RCR #2)
Voltage 6,36
Amps 0,28
Watts 1,78

Just for comparison:
Primaries
Voltage 5,00
Amps 0,83
Watts 4,15

2xRCR
Voltage 7,64
Amps 0,13
Watts 0,99

1xRCR
Voltage 3,51
Amps 0,80
Watts 2,81

Puzzling..
Looking at the amp numbers it seems like the RCRs internal resistance increases when used together with other batts.
This could be due to the protection circuits in the batteries or the voltage regulator in the RC-F4.

T.

Click to expand...

Fully charged ?? What RCR123A's are U using 3v or 3.6v

Because a 3v RCR should be about 3.6v and a fully charged 3.6v RCR should be 4.2v

So :

3.6v x 2 = 7.2v
4.2 x 2 = 8.4v
Primaries should be 6v +

What your quoting is all over the place ...

Make sure your running matched capacity batts ..
Fully charge a pair , Dont mix and match ...

+ Primaries can be up to 1400mA capacity , while th RCR are around 700mA , and possibly as High as 750mA capacity ..

So yes , primaries will give you better run time , but rechargeable ones will cost U less in the long run ....

If runtime is important - think about a 18650 flashlight . Runtime will be much better as capacity is around 2000 to 2500mA , and there are some new 18650 out that go 2800 to 3000mA ...

??? Sounds like a bad cell , youl have to isolate it .

I'll post a pic to show my method.



The cell voltage is around 4,2 for the RCR's (freshly charged), 2,8 for the primaries (some use).

I do the meassurements with batteries installed, Therefore some loss is to be expected (casing, points of contact, regulating circuitry etc).

I'm not sure how the voltage regulating of the light works, but I'll post a table recalculated for cell voltage (no loss)


2xPrimaries (used)
Cell voltage 5,75
Amps 0,83
Watts 4,77

2xRCR (faily freshly charged)
Cell voltage 8,25
Amps 0,13
Watts 1,07


As for runtime, I'm waiting for a 17670 which I intend to use for this light.

OK tried 2 x RCR123A 3.7v = o.44mA current draw
2 x PRCR123A 3.7v = o.44mA
2 x Primary RC123A = o.66mA
1 x 18650 = o.81mA

My R2 501B

Ok the simple explanation is , the higher the voltage , the lower the mA drawn .

Your primaries are 5.8v compared to 8.25 for freshly charged RCR , but yes o.13 is very low current draw , simply put , are you sure it can handle 8.4v , because depending on the driver , it could be like 6 volt or 7.2max input voltage ? Def some thing funny going on ... Its the batt or driver , could be something faulty with the driver and it simply cant deal with the higher voltage ...

old4570 said:

Ok the simple explanation is , the higher the voltage , the lower the mA drawn .

Click to expand...

Yeah, thats what I tought too, but the wattage should be about the same, no?

Anyway, I'll check the RCRs in another light and maybe buy another set of RCR123s to test.

Thanks for the help guys.

T.