Canon EOS 1n battery question

I have a Canon EOS1n. It's working fine with a 2CR5 battery. Recently, I bought a R2CR5 battery ie rechargeable lithium 6v and charger.
When I use this battery, the camera refuses to work. The"BC" starts flashing when I press the shutter release. The autofocus works, as does the display, the meter seems to work well - just the shutter won't trip and the transport doesn't operate. I've metered the voltage of the R2CR5 and it shows exactly 7v. My ordinary 2CR5 lithium non rechargeable battery shows 6.6v. I don't get it. Is the extra voltage somehow creating this fault? If I take out the R2CR5 and put in the 2CR5, it starts working again fine.
Any suggestions gratefully received.

PS, the EOS1n is a superb camera with very accurate metering and fast accurate focusing. I normally use Nikon (F5, F100, F2As, FE, FM) but I bought the Canon because the 85mm F1.8 EF Canon lens is so sharp.
I almost exclusively use the Canon with Kodak Tech Pan or Adox CMS20.(developed in Photographers Formulary TD3) The grain and sharpness is so good, many people fund it hard to believe the photos were taken on 35mm. No Leica lens I own is as sharp as the 85mm Canon lens. I also use my FD Canon 500mm mirror lens, with an FD to EF adaptor, which gives a 1.4x magnification. The results of this (effectively 700mm) lens are extremely good too

irivlin said:

Is the extra voltage somehow creating this fault?

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I'd suspect it's a voltage sag when your rechargeable battery needs to supply the power needed to operate the transport motor and/or shutter & mirror cocking actuators. It's a bit tricky to measure this as it needs to be done in-circuit and a regular DMM might not be fast enough.

Note that rechargeable lithium batteries will typically have some safety circuitry embedded into the package. The bare minimum is an overheating protection, but there may be more 'smart' controls present, including a current limiting circuit. Perhaps this is part of the problem, with the battery being exposed to momentary peak currents that exceed its protection circuitry's sensitivity.

That's a very interesting and thoughtful reply. Thank you for taking the time to respond. I guess there's nothing I can do about it. Pity, because that battery and charger was painfully expensive!
Ian

irivlin said:

that battery and charger was painfully expensive!

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I had a quick look; seems like you're right. I suppose LiFe technology hasn't reached the point where it's a low-cost commodity just yet.

Anyway, hold on and see if you get some more replies. Perhaps someone else has a useful insight to offer.

Thanks again. Yes, I'll keep my fingers crossed for some other replies. If the worst comes to the worst, I'll just keep feeding the 1n with non rechargeable batteries. Not the end of the world. It's such a nice camera to use though, that I'll probably get through loads of batteries.
Happy New Year,
Ian

I tried Lithium rechargeable AA batteries in an electronic flash unit. The batteries could not output enough Current flow to permit the flash to recycle as rapidly as using NiMH rechageable AA batteries. It could be that the regulation circuitry in your lithium batteries have a limit in the output Current flow, even though it can meet the Voltage needs.

In my limited experience with rechargeable batteries if it were my camera I would buy an ordinary Duracell none - rechargeable lithium battery new

In my limited experience with rechargeable batteries if it were my camera I would buy an ordinary Duracell none - rechargeable lithium battery new

benjiboy said:

In my limited experience with rechargeable batteries if it were my camera I would buy an ordinary Duracell none - rechargeable lithium battery new

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In the Nikon F100 I've found the Eneloop NiMH rechargeable AA batteries work well.