Strobe with low power sleep mode?

I'm looking to do an underwater timelapse with 3 strobes. I'm used shooting timelapses above the water and I've learned there are many strobes that use a lot of power even when they're sleeping. Some strobes have excellent low power sleep modes, such as the nikon SB28 flash, but I haven't seen this flash used in any underwater setting. Ideally I'd like to get a week or so out of my flashes as 99.9% of the time they're just sitting there not being used, but I don't know if underwater strobes have good sleep modes. Thanks in advance!

1) How long would your underwater strobe stay powered on and ready to be used if you left it on and connected to the camera?

2) Does anyone have or know where I can find the current draw of their flash when it's power on and in sleep mode?

3) Are there any known or specific flashes that have a good low power deep sleep mode so that they can sleep drawing little power when they aren't being used but then be used the instant they are needed and then go back to sleep?

I do not think any underwater strobes have a "sleep" mode. The sea &sea ysd1 has an auto power off feature after 30 minutes of inactivity, but you have to flip it off and and on to reactivate it.

Most (all?) strobes have indicator led(s) that draw current any time they are turned on. Any time i have forgotten to turn off a strobe the batteries were dead the next morning, but that would have been after a dives worth of pictures, so the batteries would have been half used already.

I do not think any underwater strobes have a "sleep" mode. The sea &sea ysd1 has an auto power off feature after 30 minutes of inactivity, but you have to flip it off and and on to reactivate it.

 

Most (all?) strobes have indicator led(s) that draw current any time they are turned on. Any time i have forgotten to turn off a strobe the batteries were dead the next morning, but that would have been after a dives worth of pictures, so the batteries would have been half used already.

Thanks for the info! I'm thinking I might just take a flash I know to have a good sleep mode and stick in a cheap underwater flashlight housing like the Princeton Tec Sector 7. It will take a bit of testing to make sure there is no water leaking if I leave the housing underwater for a week but whats the worst that could happen?

To workout standby battery life measure current draw by putting a multimeter in series with the batteries, might be fiddly but should work(battery door off). Then compare against you're battery's mAh.

I think your into custom case/extra battery and custom circuit's.