Canister Light Battery Upgrade

[WillAbbott]

I have a Dive Rite MLS 1, halogen (MR16) that I got really innexpensive used... was going to build a whole light, but buying one for around $100 I said forget it...

Anyways, these lights use a Sealed Lead Acid Battery pack, which works fine.

Recently my runtimes have seemed short, that aside...


I was thinking it might be cool to upgrade to NiMh. I was guessing given the size of the battery in there now, and the space available, that it would probably be possible to get 12volts and much higher Ah than 7.

What I need to know, is how to figure out what I need for batteries, etc...

As well as how to make a battery pack, is it possible to get that shrink wrap type stuff used on pro battery packs.


it seems like most NiMh batteries are rated in mAh instead of Ah, if memory serves 100mAH is 1Ah??? Correct?

I seem to recall the batteries will have to be wired up in series parralell, is there a website or something which shows how this is worked out? I don't recall how series and paralell, and the combination work.

Basically I'd like to see about wiring up 2 packs (depending on how many Ah I get out of them) and modifiying them to work with the light (easy part, just put new connector on the wiring)

I'm pretty mechanically inclined, just don't know much about the electrical side in Ah, Volts, etc.

Thanks.

<edit> also, I'm aware I will need a new charger, is there a certain plug that comes on chargers standard? or do they need modification to the plug one plans to use, or can you get them in different plug styles.

Also, I'll try and get dimensions on the current battery, or the inside of the canister, if someone wants to try and figure out what I can fit in there...

My guess is given the size of NiMh canister with similar Ah ratings, I could easily fit probably 4-8 of thier battery packs in this canister (depending on the light) which should mean if wired correctly, I can have the same size canister, but vastly increase burn time.

Longer burn time is of course the goal, currently I have a 50watt bulb, and 7Ah battery, which provides around 40min to 1 hour burn time (lately seemed like 40mins is about the normal, battery may need replaced)

 

[Boogie711]

Apparently, the standard recommendation is finding a copy of Vance Harlow's Dive Light Companion.

Disclaimer - I have NOT read it, and have no interest in building my own light. But many people swear by it.

 

[Diver0001]

I have a Dive Rite MLS 1, halogen (MR16) that I got really innexpensive used... was going to build a whole light, but buying one for around $100 I said forget it...

Anyways, these lights use a Sealed Lead Acid Battery pack, which works fine.

Recently my runtimes have seemed short, that aside...


I was thinking it might be cool to upgrade to NiMh. I was guessing given the size of the battery in there now, and the space available, that it would probably be possible to get 12volts and much higher Ah than 7.

What I need to know, is how to figure out what I need for batteries, etc...

As well as how to make a battery pack, is it possible to get that shrink wrap type stuff used on pro battery packs.


it seems like most NiMh batteries are rated in mAh instead of Ah, if memory serves 100mAH is 1Ah??? Correct?

I seem to recall the batteries will have to be wired up in series parralell, is there a website or something which shows how this is worked out? I don't recall how series and paralell, and the combination work.

Basically I'd like to see about wiring up 2 packs (depending on how many Ah I get out of them) and modifiying them to work with the light (easy part, just put new connector on the wiring)

I'm pretty mechanically inclined, just don't know much about the electrical side in Ah, Volts, etc.

Thanks.

<edit> also, I'm aware I will need a new charger, is there a certain plug that comes on chargers standard? or do they need modification to the plug one plans to use, or can you get them in different plug styles.

Also, I'll try and get dimensions on the current battery, or the inside of the canister, if someone wants to try and figure out what I can fit in there...

My guess is given the size of NiMh canister with similar Ah ratings, I could easily fit probably 4-8 of thier battery packs in this canister (depending on the light) which should mean if wired correctly, I can have the same size canister, but vastly increase burn time.

Longer burn time is of course the goal, currently I have a 50watt bulb, and 7Ah battery, which provides around 40min to 1 hour burn time (lately seemed like 40mins is about the normal, battery may need replaced)

depending on your canister size you can make or have a pack made with 8000mAh (8ah) D-cells. 10 such cells make 12 volts at 8ah in a pack that weighs just shy of 2kg. There are similar C cells if you have a small canister but i'm not sure about the discharge characteristics. Take a look at this website: http://www.batteryspace.com to get an idea of what is out there.

If you make it yourself you have to find batteries with tabs on them for soldering or you can damage the battery with the heat of the soldering iron in the process of assembly. The shrinkwrap stuff just goes around and you heat it with a blow dryer to make it shrink.

IN my case I found a place that would sell me what I needed and they only charged me $5 to put it together and test it for me. Take a look around maybe you can save yourself some work.

R..

 

[WillAbbott]

depending on your canister size you can make or have a pack made with 8000mAh (8ah) D-cells. 10 such cells make 12 volts at 8ah in a pack that weighs just shy of 2kg. There are similar C cells if you have a small canister but i'm not sure about the discharge characteristics. Take a look at this website: http://www.batteryspace.com to get an idea of what is out there.

If you make it yourself you have to find batteries with tabs on them for soldering or you can damage the battery with the heat of the soldering iron in the process of assembly. The shrinkwrap stuff just goes around and you heat it with a blow dryer to make it shrink.

IN my case I found a place that would sell me what I needed and they only charged me $5 to put it together and test it for me. Take a look around maybe you can save yourself some work.

R..

Thanks for the help...

The bad news is this is looking like a more expensive adventure than I thought, around $60-100 for the batteries, and another $60 for charger...

The good news is, this looks like I could make a battery pack for my light which would double, or tripple the Ah of my current battery, depending on the cells used. I just rough fit 10 normal (non rechargable) batteries in the bottom of the canister, with room to easily stack a second set of 10 on top, and actually a rough estimate, that if configured properly, I could fit 30 C cells in the canister, which would yeild 12Ah, if D cells were used, I would say, 20 would be the max number, which would give about 18Ah.

Thanks for the help, I think I've got a handle on this now...

Now the question is, do I want to spend the money on doing this, and do it myself, or can I find an inexpensive place who can build a pack for me, to the dimensions required.

By the way, the canister has a diameter (inside) of about 4.5 inches, and an inside height of about 6inches, with some room to spare for the the current battery connector on the lid (a rigid rectangular peice, not wire)

 

[ronrosa]

Funny you posted this. I am currently doing almost the exact same thing.

batteryspace.com had a special on a 12v 4ah nimh pack based on 10 "C" cells for $25. 4ah is really lower than what I need, but I figured it would be a worthwhile test for $25. I bought the pack and charger for $85.

Pack worked great with my 50 watt halogen. Burn times exceeded my 8ah SLA battery and lamp held it's color much better. 100 watt halogen proofed to be too much and battery pack cutout on it's thermal safety.

batteryspace.com quoted me $98 for a 12v 9.5ah pack based on 10 "D" cells. I plan on ordering the pack today.

Only difference between you and I, is I want a small canister/pack. 9.5 ah is enough for my needs. I'm having the pack built in a 3-3-3-1 arrangment creating a long thin cylinder that should fit into a canister with internal dimensions of 2.75" x 9". AUL makes a slightly longer canister with the same diameter.

You may want to be careful about wiring the packs in parallel. You'll get more amp hours, but proper charging may be a challenge. How do you ensure the packs get charged equally ?

 

[in_cavediver]

Here's one more option you may not have thought of. Look for a Dive Rite 10 watt HID lighthead and stick with the 7AH SLA. I have a similar light using the 7AH battery but with a 10 watt MR11 HID and I get burn times in the order of 5 hours. The light output is very comparable to the 50 watt halogen.

As for the issues with NIMh packs. First, making them isn't all that difficult. If you are handy with a soldering iron and a heat gun, then it's really just a matter of thinking the design through. An combination of batteries in series and parallel should work fine. Charging them also should not be an issue. A thermistor is used to monitor the cell temperature during charging and any NiMh charger should be able to recharge the pack

Mike

 

[ronrosa]

As for the issues with NIMh packs. First, making them isn't all that difficult. If you are handy with a soldering iron and a heat gun, then it's really just a matter of thinking the design through. An combination of batteries in series and parallel should work fine. Charging them also should not be an issue. A thermistor is used to monitor the cell temperature during charging and any NiMh charger should be able to recharge the pack

Mike

I don't have actual experience with charging parallel packs, but the company I bought my pack and charger from doesn't recommend it. Here is a quote from their website.

"Why is putting batteries in parallel a bad thing?
-------------------------------------------------------
Discharging NiMH or NiCD in parallel is not a problem. Charging however is. When Ni based batteries are being charged their voltage rises until they are nearly full, then the voltage drops. 'Smart' chargers take advantage of this to detect when the batteries are full. It's called negative delta V detection. If two strings of cells are in parallel while being charged and one string fills first its voltage will drop and 'hog' all of the charge current. This will result in overcharging/overheating. "

Halycon's larger NIMH packs are parallel and I know a few diver's have homemade packs in parallel.

I guess if the charger has a thermister that would prevent overheating/overcharging of the "hot" pack, but what about the other pack ? Will the parallel pack be fully charged ? I don't know.

Lucky for me 10 "D" cells in series provides enough amps and burn time for my needs.

 

[DeepScuba]

Yeah guys, I kicked this around all last year. I came to the conclusion that the cost/reward wan't even close to being worth it. I stuck with the SLA 12V/7ah.

If I did anything it would be what in_cavediver said. It's the way to get good burn time, but the HID ain't cheap either. So I'm "stuck" with a 35W Halogen bulb. No biggie. If I want to lessen the burn time I can move up to 50W. 35W is fine for me. I've had the guy on the boat tell me just how much HE can see when we're doing night dives down below!

 

[ronrosa]

Yeah guys, I kicked this around all last year. I came to the conclusion that the cost/reward wan't even close to being worth it. I stuck with the SLA 12V/7ah.

I have an AUL canister light with both a hardwired lamp/lid and a wet connect lamp/lid.

I plan on keeping the wet connect lamp and use it with a smaller NIMH battery/canister.

I'm not there yet, but my estimates for the NIMH battery/canister I'm planning on are:

9ah NIMH pack/canister: 3 1/4" x 10" canister, 1hr burn time w/ 100watt halogen, cost of battery, canister, & charger, $360-$460.

8ah SLA pack/canister: 5"x8" canister, 20 minute burn time w/ 100 watt halogen. Sell battery, canister, lamp, charger on Ebay for $150-$200.

For me, diving with the smaller canister on my hip, plus more than doubling my burn times is worth the additional dollars. I shoot video, so I need the 100 watt bulb. A 35 watt won't cut it.

 

[DeepScuba]

I've used 2 35W Halogens for video, and it hasn't worked out to badly. It gave about 35-40mins as I recall, of burn time. And was in blacker than black mud-soup.

I could have used 2 50W I guess, but it would have been a quick shoot.

2 100W would be a dream!

I considered a 2 battery system that would work, but it's damn heavy on land as it is right now. (I mount the battery pack under the video housing.)

For the $$$ you still can't beat Halogen. Cheap, who cares if it floods, Home Depot has all your parts!

My big question has always been, at what discharge rate can you run with those NiMHs? I cringe a bit when I see the SLA's running even 50W bulbs.