Salvo/LM 21w HID replacement battery

[Mattleycrue76]

Recently I have seen a big reduction in burn time on my 21w salvo HID to the point where it usually dies about half way into a second 1hr dive. I was wondering if anyone has had any luck replacing bad cells or ordering replacement packs from places like battery space.com. Oh yeah, it's a Li-Po battery, 10Ah. Does anyone know the voltage for these?

[Mattleycrue76]

specifically this one looks alot like the OEM one that came with the light.

http://www.batteryspace.com/highpowerpo ... prate.aspx

[Nwbrewer]

That's because that is the OEM one...

Check the voltage with a volt meter after it's charged. If it's around 14 or so, that one is definitely right.

[Geek]

I do believe Marc put up a Salvo for sale that has 2 battery's, maybe he would sell you one of them?

[Mattleycrue76]

Well after searching high and low for a replacement battery pack and not finding one that would definitely fit my can I got on the phone with the guy at battery space who convinced me to just buy the individual cells and rebuild the pack myself. Since I was a little unsure about the wiring and had heard horror stories about lithium packs gone wrong, I enlisted the help of NWbrewer to ensure a second ( much more knowledgeable) eyes on the project. It took us about 30 -45 minutes to rebuild two complete packs and in hindsight it's project I'd easily feel comfortable doing myself in the future. Total cost per pack was about $110 including shipping.

[Raydar]

Well after searching high and low for a replacement battery pack and not finding one that would definitely fit my can I got on the phone with the guy at battery space who convinced me to just buy the individual cells and rebuild the pack myself. Since I was a little unsure about the wiring and had heard horror stories about lithium packs gone wrong, I enlisted the help of NWbrewer to ensure a second ( much more knowledgeable) eyes on the project. It took us about 30 -45 minutes to rebuild two complete packs and in hindsight it's project I'd easily feel comfortable doing myself in the future. Total cost per pack was about $110 including shipping.

How old was the original pack?

What are you using for cell-balancing?

[H20doctor]

a place in everett that builds packs.. Jake should have told you about it.. Evergreen sumthing... Bad jake.. Bad bad ..

[Nwbrewer]

How old was the original pack?

What are you using for cell-balancing?

Ray,

Both packs were pretty old, but the main problem with Matt's was that all 3 cells were swollen, I think they got wet at some point. There was some corrosion on one of the terminals, and some on one of the solder tabs.

The battery configuration in the sealed LM/Salvo cans has the thin foil like solder tabs on the bottom, between the cells and the bottom of the can. So every time the can got bumped, dropped whatever, these were getting pinched between the cells and a flat delrin bottom. That's where Joe's failed, one cell the tab had completely broken off, and another was awfully close.

We used the original PCB for cell balancing.

A Kraky, I did tell both Matt and Joe about that place, but they won't touch an existing Li-ion pack. I guess that should have told us something....

[Raydar]

Both packs were pretty old, but the main problem with Matt's was that all 3 cells were swollen, I think they got wet at some point. There was some corrosion on one of the terminals, and some on one of the solder tabs.

That could do it. This guy goes into other reasons for swollen cells: http://barnson.org/node/1842

The battery configuration in the sealed LM/Salvo cans has the thin foil like solder tabs on the bottom, between the cells and the bottom of the can. So every time the can got bumped, dropped whatever, these were getting pinched between the cells and a flat delrin bottom. That's where Joe's failed, one cell the tab had completely broken off, and another was awfully close.

Interesting. Wonder why they did that. Easier to package? (Not knowing what the inside of the Salvo light looks like.)

We used the original PCB for cell balancing.

The reason I asked is that we ran into this with the lights. It seems that a lot (many or most?) of cell balancing PCBs have small circuits with limited capacity. (in the neighborhood of 30mah, IIRC) Which is OK for smaller packs like cell phones. But when we're talking a 10,000mah battery pack, it's practically worthless. :(

[Nwbrewer]

Interesting. Wonder why they did that. Easier to package? (Not knowing what the inside of the Salvo light looks like.)

We used the original PCB for cell balancing.

The reason I asked is that we ran into this with the lights. It seems that a lot (many or most?) of cell balancing PCBs have small circuits with limited capacity. (in the neighborhood of 30mah, IIRC) Which is OK for smaller packs like cell phones. But when we're talking a 10,000mah battery pack, it's practically worthless. :(

I'm not sure why they did it either, seems like a bad idea, but I think it was to keep the can as short as possible, but I think with a little effort they could have come up with something better. All we did was replicate what was done on the original, I'm not confident enough in my knowledge of EE and Li-battery chemistry to try and invent a new wheel. Probably blow up my garage.

LM makes some strange choices in the electronics of their lights, still trying to figure out why they still use the old Ostar LED's, unless they have HUGE pile of them sitting around, it wouldn't be that hard to switch to a more efficient LED with a better beam output.

The cells were these - http://www.batteryspace.com/highpowerpo ... roved.aspx

And I believe the balancing/protection circuit was this one - http://www.batteryspace.com/pcmwithequi ... limit.aspx

How is progress coming on the new light? I expected that I'd be seeing them around the sound by now.

Jake

[Matt S.]

Cool, I love fixing stuff for cheap!

There is a lot of fun stuff at HobbyKing. Dive lights aren't the only things that use big batteries. For example, here is an 8 Ah 11.1V lipo battery for $44. (This battery is also rated for a vastly higher discharge rate than you'd need for a dive light.)

http://www.hobbyking.com/hobbyking/stor ... duct=16225

But note that it has a balancing tap, not a built in balancing circuit. Hobby chargers have balancers built in, rather than building the balancer into every battery. It also will not have any over-discharge protection built in because in a model plane or car, that feature is built in to the speed control in the model or simply left to the user to manage.

If I was trying to replace a battery the cheap and lazy way, I might use a battery like this, but charge it with my existing balancing hobby charger and figure out a safe run time to prevent over-discharge. Building a new pack from Batteryspace parts is definitely the superior approach, though.