Rechargeable batteries for Inspo

Garry Whyke

Has anyone ever looked into using rechargeable batteries for the inspo?

Can you get rechargeable CRP2's? Can they be used in the Inspo?

Cheers

.......... Garry

Doorduijn, Niels

Garry,

The use of rechargeable batteries in a rebreather is not recommended. The problem is that when rechargeable batteries become empty, they fail instandly, unlike normal batteries which will gradually deteriorate. As a result, the low battery warning on your unit will not work with rechargeables.

See the inspiration list archives for more details (given the price of the batteries, you are not the first to come up with this question).

Rgs,

Niels Doorduijn

AD_ward9

This is not true.

The following tone is not meant to be disrespectful to anyone, other than to manufacturers who do not use rechargeable batteries. "You" refers to them, not to you Neils. Hope you do not mind.

Just look at your mobile phone. They have a battery life indicator. Seen when it goes to zero, your phone does not work? It does not go from full to zero in a single step. Mine takes a day. This is not difficult to do: Maxim and Linear Tech have made it so easy even Noddy can get this one right.

An eCCR should never use a primary cell. There is no way on earth one can get the things through SIL 4 requirements for EN61508.

I replaced my Inspo head with one with rechargeable batteries in 2001. Works fine. Still works fine. It is piece of cake to get this right. I have posted pictures of it on this forum before.

Alex

NB: For members in the USA, Noddy is a British children's puppet, whose head is made of wood and does not think too well. The new computer animated version is rubbish compared to the hand drawn cartoons ... one area where technology still has a long way to go to beat a guy with a pencil and paintbrush.

Gill Envy

I generally have had the impression the neil's perspective is correct in terms of appropriate application but perhaps i'm wrong. i also understood that all rechargable batteries loose some charge each day even if they are not used.

I would like to hear specifics on what types of rechargable batteries gradually run down as apposed to suddenly drop off and hold a charge for long periods of time without decay. Nicad and NMH's drop off suddenly and my expereince has shown that they don't always take a reliable charge. I would need a lot of convincing to shift my conclusions. I just think if there is one place where you don't want to push it on a rebreather it is in the supply of juice to the electronics that control the PO2. If there is some new fangled rechargable battery (lithium ion?) available as a CRP2 that can keep up with the demands of the solenoid and give fair warning before it goes tits up, it's news to me...and it would be good news so please do tell.

__________________
Gill Envy

...Because I wasn't born with gills!
><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>

Faceless

I think Alex is referring to a totally different apporach here.
Current Inspo controller is totally unaware about current battery state
and moreover, power supply is not fail-safe.

So, IMHO the easisest way in terms of making power more reliable would be two simple steps:
Power supply should be consist of two/three/four complelety separate battery sets, each good enough to operate entire unit on it's own, with failover option between them. During predive checks controller measures battery capacily, and if capacity of ANY battery set drops below 15 hours then just refuse to activate/warn user/do some other alarm thingies.

AD_ward9

You are right: Nicad and NMHs are not the way to do it. Your phone uses Li Ion. It is not very new, and is the only sensible thing to use: everything else has a memory effect and is too big.

We found some Li Ion Gel batteries that withstand being saturated at 1400msw in helium and blown to the surface in one second. As a further measure put them in silicone oil, not wax, so they will not on-gas helium.

The onboard charger circuit is on the DL Open Revolution pages. Use a Nokia phone charger, not yet another charger to lug about - the number of companies who think their skills are best applied reinventing the battery charger never ceases to amaze me.

To Faceless: thanks. Spot on, except for power up when the Inspo does check the battery voltage. If the battery is low, it does not let you proceed, if if it reset due to a battery bounce when you are underwater. Green blobbed.

Alex