[SeaHag]

I just came across this section of the forum and it looks like there are several members here who know a thing or two about lighting systems...so what I need should be easy to address.

I have this old light system that I have not used for a decade and it saw relatively light use when I was actively night riding...But the old Ni-Cad battery is long dead. I looked it up and they sell a replacement Ni-Mh battery in a water bottle now for $70; but I'd like to see if I could build my own battery pack to meet my needs for less money.

The battery pack is rated at 6-Volt and 5AH and as you can see here: Cygolite Night-Explorer Lights Reviews

I have a nice large frame mount pack to hold my creation. If you guys don't have any ideas for me, I guess I'll hit up the local batteries plus. I figured I'd use the charge wires from the old battery as they are simply soldered to the terminals...but now that I think of it, would there be a problem charging a Ni-Mh battery pack with the old and slow Ni-Cad charger? If so, perhaps I should have some kit that uses standard batteries I can put in my home charging station that takes everything from AAA and 9V to 4 D cells.

 

[SeaHag]

This is what the dead battery looks like:

Elk 0650 - Rechargeable Sealed Lead Acid Battery 6 Volts/5Ah

 

[borrower]

What kind of burn time did you get from your old 5Ah battery, and how does that compare with what you want? A lot has changed in batteries over the last few years.

Plus, can I suggest you post an actual picture of your battery? It's not clear if you've got a nicad or a SLA unit.

 

[mattthemuppet]

ditto what borrower said. Either way, if you do rebuild the battery with NiMh, it shouldn't be too hard to do but you will need a new charger. For the money that you'll spend on the larger tabbed NiMh batteries plus a new charger, you'd probably be better off building up a Li-ion pack (2series2parallel for 7.4V). It would overvolt the bulb similar to a 7.2V NiMh pack, which will shorten bulb life quite a lot (1000h+ to ~100h) but will make it quite a lot brighter. 4 protected 18650 Li-ion cells, plus MS charger from Geoman would run to ~$40 and give you ~4.8Ah for considerably less weight (~200g) than the original battery.

 

[ThinkBike]

I think it's great that you want to get back into night riding. As far as doing it economically with the light you've got, just get a new SLA battery. It won't cost you much out of pocket and you won't need to get a new charger and batteries. You won't overvolt the bulb, so you'll save money buying new bulbs.

When you're ready to jump into LED lights, you'll have the money you saved by not trying to modify your old light.

For every dollar you put into your old light, that's a dollar you no longer have to invest in a new LED system.

mattthemuppet was right to suggest Lithium Ion 18650 cells. The best cells have the highest power to weight ratio of any of the other battery type typically used with LEDs.

 

[mattthemuppet]

actually, thinking about it and what ThinkBike wrote, you'd be better off spending $50 on a Magicshine from DealExtreme. There's nothing that can compete with it (even repairing an old light) for the money.

 

[SeaHag]

I think it's great that you want to get back into night riding. As far as doing it economically with the light you've got, just get a new SLA battery. It won't cost you much out of pocket and you won't need to get a new charger and batteries. You won't overvolt the bulb, so you'll save money buying new bulbs.

When you're ready to jump into LED lights, you'll have the money you saved by not trying to modify your old light.

For every dollar you put into your old light, that's a dollar you no longer have to invest in a new LED system.

mattthemuppet was right to suggest Lithium Ion 18650 cells. The best cells have the highest power to weight ratio of any of the other battery type typically used with LEDs.

Thanks everyone for laying out my options with the pros and cons of each. I think for cost and simplicity that I'll be going back with the SLA and look into that magicshine light for $50 if I find further need. It looks like I can pick up one of those batteries pretty cheap.

I don't really know what the run-time on the old light was as I never exhausted it. Probably only rode at most 1 hour on the lights at a time; but as I recall I usually rocked both bulbs for peak output. They were mostly used for night and morning commutes to work so they didn't have to run that long. Now that I'm starting to attend group rides where lights are coming into play as our fall daylight wanes, I've found a reason to try them again as I no longer work in town or commute by bike.

Guess, I'll head out to batteries plus and see if they've got something like this.

 

[SeaHag]

Thanks again to all those who helped me with the pros and cons here. I did find an appropriate battery quite easily at batteries plus for $19.99+tax that even had the spade adaptors on top so it was literally plug and play to get my lights operational again. First night ride planned for this Tuesday.

 

[DoctorRad]

I have a set of these which I 'rewired' to a nominally 12v system using high-efficiency halogen spots of 16W and 28W. The battery is a 4-cell LiPo from Hong Kong which gives 16.8v freshly charged, and 14.8v nominal. That's fairly serious overvolting for 12v spots, but I've not had a failure issue yet.