NiMHi Battery Dilemas

[Sid]

Probably spelled that wrong. OK I got this 18 watt PRO 14 cannister HID . So anyway the SLA battery is shot so I was looking at getting some NiMHi packs, and they got some 12 volt (10-1.2 D-Cells) knocking out 9500 mAH, and since I got that big cannister, I could just stuff two packs in parallel, giving 19000 mAH or about 500 min burn time on 18 watts. BTW this will cost 150.00. So here are the problems/ideas:

Will 12 volts off these packs fire the light? I think so since 12 volts SLA works, or do they run >12 volts on some of the packs being sold out of the diveshops

That can is 10 positive empty, and 5 lbs neg with a 15 lb SLA, so it will be positive with the two NiMHi packs.

I wouldn't mind losing burn time and going to 9500 mAH on a single pack but it is rediculous the cost of cannisters, so I'm kicking around the idea of just potting the battery pack in pure silicone inside a metal cylinder (beer can) and having an EO connector sticking out and no switch, just plug in and it fires. Maybe some type of industrial electrical enclosure is out there that I could put a bulkdhead switch in, gotta look today.

Might want to get the size/weight down if I can get an acceptable cannister, what are the packs like on the helios etc, ie cell size, number cells and voltages.

Any experience with putting packs /cannisters together would be appreciated. I'm just get sick of buying lights for 1200.00, yeah I know only need a battery, but WTF low on money and feeling creative.


Thanks, Sid

[Jordan]

That was a hacker post (just before this one) that got banned and removed. Judging by your comments, you feel the same about it as I... tj

[Gary]

Will 12 volts off these packs fire the light? I think so since 12 volts SLA works, or do they run >12 volts on some of the packs being sold out of the diveshops

The NiMH battery packs I have seen have either 9 or 10 cells in series and either works fine. I have 10 cells in series usually charging to about 14V and better burn time and ability to fire up then the 9 cells (I'd think).

[THE TICK]

We are wondering why such an entity would go to the trouble to move and attempt to secure this site, and then leave it basically open to all invasive acts.

Stop your evil ways hacker! You face The Tick!

[nwade]

Sid, I put a single 10 "D" cell pack (as you described) in my Pro 6 can to drive an 18 watt HID. I don't know the dimensions of the Pro 14, but two of those preformed 10 cell packs would not have fit in my Pro 6.

I found that in order to fully charge the pack you have to fool the MAHA MH-C777 charger I'm using by unplugging the pack at the end of the charge cycle, and then plugging it back up to restart the cycle. (usually three cycles total to be sure).

One of the issues with NiMH batteries is sensitivity to heat, and the MAHA uses a thermal sensor that you attach (it's magnetic) to the pack while charging. I've never noticed any overheating while charging mine, but I have read that that can be a problem. Thus, it may be that fully encasing the battery pack in what amounts to a thick insulation layer may increase your risk of heat damage to the battery.

FWIW the burn test I did with mine ran well in excess of two hours ; I cut it off at 2 hours 25 minutes, and the voltage level was still holding strong. Good luck with your project, and I'm looking forward to a SID report on the outcome.

[Gary]

One of the issues with NiMH batteries is sensitivity to heat, and the MAHA uses a thermal sensor that you attach (it's magnetic) to the pack while charging. I've never noticed any overheating while charging mine, but I have read that that can be a problem.

I don't think the 777 charger will ever charge the larger battery pack fast enough to cause it to heat up significantly.

PATCO sells large NiMH battery packs for thier suit heaters and they make chagers for them as well. If you want to check out what they have for big NiMH chagers: http://patcoinc.com/NiMH.html

[crazyduck]

Sid, hey there hope life has been treating you right. Go easy on the nut kicking I was laughing so hard I thougt I was going to need to ice.

Just a few things-
When soldering the batteries please be careful, this is not the most forgiving process. Get the sucker tacked and get off the heat soon as possible. Have you thought about using Silver Solder?

I have noticed that the single stacked sealed “d” cells “tend” to blow a cells in the middle of the stack. I have seen two different OMS tubes that blew single cells in this configuration and they both were in the middle of the cell stack. (I don’t know why.) However, I have not seen this problem with the double “A” cells that are built into bundles. Someone else can cover on the possible pros and cons.

Rebreather geeks have had to solder batteries together for sometime for the electronics on the MK15 and 15.5. So that might be another source on how folks are doing it.

Some manufactures have woken up to upgrading systems and will offer the service and a pretty good rate. I would consider contacting someone and telling them what you have and you want to convert to NiMH and what can they do. Hey, if nothing you could see what your time is going to cost you.

Custom Divers in the UK have a awesome design and great over pressure valves, something to have a look at. They had GREAT 40watt LED lights at Dema. Awesome backup lights.

I am going to have my Diverite MLS/ 10 watt HID converted from SLA to Nimh. I want to get rid of that massive canister and go to a wreck series. I have a mini canister for my other HID light and it ROCKS.

If you need to reduce the size of your can drop in PVC pipe as a spacer. Also I have found that soft weight can be put into the PVC pipe section if your need extra weight.

Later, Andrew

[OFG-1]

http://www.4cbradio.com/mh-2d110.htm

Greetings
Look at these that I am drooling over. 11,000 mAH

I called the manufacturer, and was told that you could discharge these at 5 amps. I can run my 55 watt quartz for about two hours on 10 cells.

[Dwain]

http://www.4cbradio.com/mh-2d110.htm

Greetings
Look at these that I am drooling over. 11,000 mAH

I called the manufacturer, and was told that you could discharge these at 5 amps. I can run my 55 watt quartz for about two hours on 10 cells.

I know where to get my new NiMH batteries from now...
Had a canister flood a couple of months a go and now my current Nimh Battery pack stays about 1.6 volts below a full charge.
Lost a bit of life.

[Sid]

All, thanks for the ideas/comments....This is what I was thinking of getting (should have linked it in the original post), and they got a charger shown at the bottem of the page, all welded/soldered or however they connected them together. I think two of these packs would fit in a pro14 can (to get the weight up and use the volume) and like I said in parallel it would burn 19000 mAH on an 18watt light > 500 min (just estimated from 9000mAH going 250 min on EE website)....off to look for a can. Thanks Sid


http://www.batteryspace.com/index.as...ROD&ProdID=988