Northwest Dive Club

To the mods, Hope this doesn't break the rules but I need member input. I am not advertizing just looking for input to see if it is something I want to take on.

If I were to come up with an extended burn time model that would be the same as the current model but could do 5 hrs on high would it be of interest at a $100 above the current price? It wouldn't be off the shelf battery packs like the present but they would be Li-ion so no self discharge. These would be custom batteries that cost over twice what I am paying now and require a more expensive charger as well that I have to stock so I am wondering if the outlay would be worth it.

I could use a good cannister backup light, but 4 hr minimum burn time, 5 even better.

Depending how many cells, balance leads would be nice too.

For a simple 3S,11.1V configuration, balance leads wouldn't be necessary if the packs had internal PCBs for protection. Newer battery chemistry available in 18650 cells is much safer these days. I have several packs and canisters that use these cells, and they never get warm during charging.

I think that longer burn times with the same size or smaller canister would make these great lights for travel and cave diving.

I am not in the market for a new light, but 4+hrs is pretty much a minimum burn time for me. So I would think to be competitive with some of the other lights on the market you might want to offer something with 5hrs.

GearHead wrote:For a simple 3S,11.1V configuration, balance leads wouldn't be necessary if the packs had internal PCBs for protection. Newer battery chemistry available in 18650 cells is much safer these days. I have several packs and canisters that use these cells, and they never get warm during charging.

I think that longer burn times with the same size or smaller canister would make these great lights for travel and cave diving.

They have PCB's and fit in the standard canister.

Would it be possible to upgrade an existing light to this better battery system, or does it require a whole new light?

dwashbur wrote:Would it be possible to upgrade an existing light to this better battery system, or does it require a whole new light?

This would be my questions as well - particularly since for some reason my battery packs are only giving me one dive before going disco ball. I have made do by changing out batteries between dives, but it would be nice if I could set it up to last the whole day.

Of course buying a newer light is also an option.

dwashbur wrote:Would it be possible to upgrade an existing light to this better battery system, or does it require a whole new light?

Yes it is possible. it doesn't require modification to the light. However it's a little more expensive because there is no offset for the cost of the original battery and charger. The problem is that these are custom built for me and require lead time for build and I have to order in quantity which makes it expensive to keep them in stock.

I think this would be a fantastic idea. I've wanted a dusty light, but I've enjoyed the 5 hour burn on my light monkey even if it isn't as bright. So my vote is yes, it would be worth it.

Tom Nic wrote: This would be my questions as well - particularly since for some reason my battery packs are only giving me one dive before going disco ball. I have made do by changing out batteries between dives, but it would be nice if I could set it up to last the whole day.

You are using the stock charger? If so, try using the 0.9A setting. As batteries age the internal resistance goes up. The termination algorithm used depends on the amp setting and battery condition. You may be getting premature termination.
I've got a couple stock batteries with 60+ charges on them over 2 years old and doing just fine. Mostly charge at the 0.9 setting.

The light also lasts a lot longer on medium with little perceived difference in output. On low you will notice it but the light last a whole lot longer. Here's some specs for reference:

NiMh-5000mA (newish battery) Start = 8.04v 48 hours after charging.
Amps - Watts - Volts
Hi 1.77 - 13.6 - 7.87
Med 1.13 - 8.8 - 7.87
Lo 0.6 - 4.6 - 7.89

Notes - 5000mA is 5.0A. Divide the Amp draw into the capacity to get run time....approx. There is probably a 10-20% operational loss.
NiMh will lose ~10% of it's charge within 24 hours of initial charge. This is normal.
No matter what the manufacturer claims unless it's a damn fine battery the capacity will be less than spec. Capacity is also determined by using a draw current that is generally way lower than it would be used in a real world situation. I have found the 5000mA batteries actually have about 4800mA when new.

Thanks Fritz, That explained it better than I could. there are battery chargers out there that will do a better job than the stock one but they are costly and not really plug and play. In general the slower the charge the longer it will last so patience is definitely a virtue when charging batteries.

fmerkel wrote:

Tom Nic wrote: This would be my questions as well - particularly since for some reason my battery packs are only giving me one dive before going disco ball. I have made do by changing out batteries between dives, but it would be nice if I could set it up to last the whole day.

You are using the stock charger? If so, try using the 0.9A setting. As batteries age the internal resistance goes up. The termination algorithm used depends on the amp setting and battery condition. You may be getting premature termination.
I've got a couple stock batteries with 60+ charges on them over 2 years old and doing just fine. Mostly charge at the 0.9 setting.

I will definitely give this a try. I've been using the high setting (there are 2 on my charger).

I was getting two full dives plus on a battery pack, then all at once they started going disco ball about 20-30 minutes into the 2nd dive. I thought it was the battery pack - bought a new one - same thing. Thought perhaps something was draining power inside the light?!? Beyond my paygrade to check / test for that. I've made do, but if that is the fix that would be awesome.

Appreciate the suggestion.

Tom Nic wrote:
I will definitely give this a try. I've been using the high setting (there are 2 on my charger).
I was getting two full dives plus on a battery pack, then all at once they started going disco ball about 20-30 minutes into the 2nd dive. I thought it was the battery pack - bought a new one - same thing.
Appreciate the suggestion.

Having a new pack do that would probably indicate either an issue with the charger, or with the light itself. The strobe is a low voltage indicator. I suppose whatever does that could get whacked out. Rich might be able to help more. I don't know the electronics of the driver.

The charger itself could be at fault, not fully charging the battery. Therefore it goes into strobe mode.
It's a pretty simple unit. My much better radio control chargers confirmed solid operation on my 2 Tenergy units. Now I just use that because it's simpler.
If you could either try someone's known good fully charged battery, or known good charger on your current battery(s) you could probably sort that out. Or have someone with a good light and charger charge your battery and take it out for a test.

Note - An uncharged battery will stay cool while charging. As it nears full it should get warn (not hot, never hot). If it never gets warm but the charge stops it's not fully charged. If it gets hot it's overcharged. Heat damages the battery over time.

You should have gotten about 2+ hours on high from a good stock pack, about 3+ on medium.

Tom, you live very close, No excuse for not coming over and to let me check things out for you.

Dusty2 wrote:Tom, you live very close, No excuse for not coming over and to let me check things out for you.

Fixed

The deed is done new packs on order. Any further inquiry's PM me please. Don't want to cause the mods heartburn.

You could build a 4s li-ion battery pack. If you have a power supply you could test it on a bench before shelling out the coin >.> that's just something I've done in the past for my builds.

So when is kasi gonna jump in?