MK 15.5 battery

Gibbon

Try looking more carefully at the picture.

You might notice the words "Saft" & "Lithium"

Niels Doorduijn

Jason,

Would it not work this way:

2 * (1 * 9V + 3 * 1,5V = 13,5) = 27V ?

I.e. use four batteries for each side?

Niels

koputai

Well you can't actually SEE any of those words on the battery! Having never seen them before I assumed they were alkalines, just like the set is designed to use.
The use of lithium batteries is a strange choice as at the current draw of the Mk15.5 electronics, the lithiums have a shorter life than alkalines, and cost a lot more to boot.
Typical current draw with one LED lit is 40mA, two LED's lit (alarm on) is 67mA, and the solenoid draws in excess of 200mA.
Lithiums just don't like that sort of current draw and will fail very quickly, you'd be lucky to get ten hours out of them.

Jason.

Niels Doorduijn

Jason,

Do you recon it is possible to replace 8 of the 1.5V cells by 2 6V cells (using alkaline cells)? Or would this somehow affect the way Colkan's secondary measures the cells?

Rgs,
Niels

jvos

Sorry for the confusion. They are Saft 3.6 v lithium cells. 28.8v dc., center tap 14.4v dc. I have about 15 hours on these so far. No sign of change yet, they still measure about the same under load.

heyydude

Jason has a point - the "standard" Mark 15/15.5 uses a 24v 5 watt solenoid. This is coupled to an electronics which consumes power like it is going out of style. The Primary display has 6 incandescent lamps which are rated at 10v but receive up to 14.7 volts (with a fresh battery) so they are bright enough to shine through the decal on the front of the display.

We've used a lot of the Saft batteries (the original HH was powered by 2 of the 1/2 AA models) and I never would have guessed that they'd be a good source for driving the Rev. G analog stuff.

That is, unless Jvos has one of Will and I's original Rev 1 Digitals...?

The Rebreather Website used to have a page up there that I wrote back in the dark ages on how to build your own battery for a Mark 15 - I'll ask Paul Eliott if he still has it.

By the way - the original Mark 15/15.5 used to get 6 hours (yes, you're reading that correctly) out of a huge battery pack which was NOT rechargeable. BioMarine used to charge $50 each for these batteries back in '93. So you had to be either a dedicated CCR diver or a very rich CCR diver back then...

Kevin Juergensen
Juergensen Marine, Inc.

Mung

I have a company called strikealite (UK) make the batteries for me. The electronics in my mk15.5 are standard Juergenson. the batteries are standard AA alkaline. 9AA in series (1 12v +ve and -ve) and then parallelled together to drive solenoid. This is a direct copy of the batteries supplied in my colkan unit.

Regards

heyydude

The power consumption of the Smithers/Juergensen Gen 1's are significantly lower than the original Rev. G analogs. The way to REALLY reduce power consumption of these sets is to install a wattmiser solenoid. We used to stock 24v .65 watt units, but when we developed the HH, we changed to the lower voltage models.

On my original rig, I went from 6 hours per battery to over 40, just by changing the solenoid.

Today's solenoids consume a lot less juice, which is why you have rigs powered by smaller battery packs for longer periods of time. The Hammerhead gets the same amount of hours of diving (6) out of a single AA Alkaline that the Mark 15 used to get out of a $50 battery pack (18 "AA" Alkalines assembled in a pack from BioMarine).

Progress is cool...

Kevin Juergensen
Juergensen Marine, Inc.

Doorduijn, Niels

Kevin,

Do you know whether the Wattmeister is still being produced?

Rgs,

Niels