Good shop to buy YBOD CRP2 batteries?

PeteS

Well, as some chemist will no doubt point out soon, Lithium is "lively" in water of any kind. Apart from that I don't suppose there's much difference.

But if you have saltwater around your batteries, you have bigger problems than fizzy batteries.

__________________
Pete S.

http://www.steggle.co.nz

Every silver lining has a cloud

AD_ward9

This is not a post talking about what could be done. It is a post about, really done that, and here is what happens.

See the picture below: this is something I did 4 years ago and learnt the hard way why it is not a good idea.

I first did it just replacing the Inspo batteries by rechargeable Lithium batteries plugging in using cable, and plugging out to recharge, but the result was not good. I thought, perhaps if I build it really well, using a pcb, it will be cleaner and will work. All it did was highlight more issues with Inspo handsets. Here is what I learned in doing this:

1. Rechargeable Lithium batteries can explode. "Can" means "will". Pressurising them is a bad idea. Shorting them out is a very bad idea. There is a US Navy report on the APD batteries and rechargeables also carry the risk. When I design a rebreather controller, I keep batteries always at 1 atm. The Inspo does not. So, be careful. We do test batteries for use in rebreathers and have a nice teeny explosion proof chamber to do it in. Latest batteries (Lithium Ion Gel), in February this year (2006), leaked under pressure. If they leak, they can explode. Old types can do definitely explode.

2. If you replace the batteries by a rechargeable lithium ion, the battery resistance is actually higher depending on their charge state, surprisingly, and the Inspo handset computers do not have good regulators inside them. This means that when they read the PPO2 level with the solenoid on, they get a different reading then when the solenoid is off. My handsets below changed by 0.4 with the solenoid going on. I demonstrated this to Iain Middlebrook in 2001 and to a few others on this forum. APD are aware of the issue.

If you replace the plain wire by a nice power supply, the ESR of the caps is a problem: it is more than the original batteries, and will also cause more handset problems. You can tell I was getting desperate to get rid of those primary cells in the Inspo by this point.

3. I did my work on this using a red backlit handset. Never touch a unit with handset that are before the red backlit handsets (late 2000). Those have no watchdog and no brownout circuit. If you foul up their power, they hang and so do you. Powering off underwater after a hang to reset them causes a choice of cal (pure O2), or no cal (no O2). Nice touch. Experienced that choice also but took the bail out option.

Cheers,
Alex

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CharlieT

AP state in the Vision manual that the best battery is the Fujitsu CR-P2 and that is the battery type supplied with my new unit last September.

AP say the next best is the equilavent Energizer battery.

If you're willing to buy 12 batteries then I've found that Baruch Ltd in London, N18 can sell at £3.15 per battery inc Vat and I think also delivery.

Baruch Ltd was established in the early 1970's and my understanding is that they are the primary UK importer of Fujitsu batteries.

Their website is www.batterymasters.co.uk Tel: 0208 803 8899

At £3.15 each, we can all afford to use the recommended battery which must be better than our using cheap batteries with unsuitable decay characteristics?

I have supplied AP with the details of Baruch Ltd and I hope that they will at some future date be in a position to sell Fujitsu CR-P2's at a better price than £8.15 plus delivery.

If anyone lives nearish to me (Chiswick, London,W4) I am interested in sharing a 12 battery pack.