andrewmcleod
Well-known member
I put a lithium non-rechargeable AA in my backup headtorch (old Fenix E12) on the grounds that they last (almost) forever if you don't use them. I also carry a spare (as I have used it a bit occasionally).
Battery Capacity...?
- Thread starter JAshley73
- Start date
Tritim230
Well-known member
At least you probably don't get the grief from a non caving partner who would rather you be helping at home and complains when you bring back and deposit mud everywhere!Not sure who their UK distributor is, but I would write/call them, and ask for a replacement. Their USA distributor has been excellent. They covered (2) lights that failed at the same time, under warranty, then let me select a different/cheaper/better model, and then gave me promo-codes for the negative-balance, all without much fuss. I was very pleased by them.
I have 4** of the HM23's, and I've been rather happy with them. I use Energizer NH15-2000? I think rechargable batteries, without issue. They (supposedly) don't offer the same capacity as regular alkaline batteries, but that's no worry for me, as I just carry some backups with me in the cave & swap as need. My youngest still uses one as his "primary" light. As mentioned earlier, I wear mine as a "backup" like a necklace.
**The crummy thing about caving with a family of 4, is that it requires 4x the kit to buy.Most of the time they have an OK time though, and when only 1-2 of us caves, we have lots of "backups" to equip ourselves with.
I'll also have plenty of kit too, if ever my friends & family accept a bloody invitation to try caving with us...
JAshley73
Active member
Realistically, I get semi-grief from a less-than-enthusiastic-but-begrudgingly-goes-anyway caving partner.
aricooperdavis
Moderator
You have to be a bit cautious about using lithium AAs (although I'm sure you know this already) because:
- they often have a voltage above 1.5V out of the box
- their voltage is very stable as they discharge, so their capacity is hard to estimate, which can mess with output regulation
PeteHall
Moderator
I regularly use my backup light looking into small places, or passing tight squeezes, where I need to take my helmet off (or where it is more comfortable to do so), so my bsckup gets regular, but short duration use. Over a number of trips, I wouldn't like to guess how far gone the battery would be, so I like to charge it between trips.
A Petzl Pixa fits the bill for me, while the Fenix is relegated to household duties.
PeteHall
Moderator
Useful info, thanks. I might try some.
Reading the above about rechargeables and otherwise reminded me of a significant point about capacity. In my Custom Duo I was disappointed with the life of top level Duracells, and on researching discovered that rechargeables might be better. Eneloops have indeed given longer life, despite lower nominal capacity, because of the shape of the discharge curve. While the Duracells have capacity, the second half is at a lower voltage than necessary to power the LEDs, but the Eneloops have a flatter curve and provide sufficient voltage for longer.
Cantclimbtom
Well-known member
Or ditch them and the AA battery holder and use 3 x 18650 wired in parallel, shrink wrapped to a slight curve and with a battery protection doohdah (just be better at soldering than me!). You should get approaching double the run time of AA batteries for a Custom Duo. This is probably a different thread though
I adapted a Duo to a 2-18650 cell setup and I have to say I'd not be convinced of the waterproofing with the way the lid has to be forced on.Fulk I believe went with a 3 cell design using 18490s
Ooops sorry it was Fjell and 18500s and you already know all about it
ukcaving.com
Ooops sorry it was Fjell and 18500s and you already know all about it
Duo conversion using 18500
I imagine this has been done before, but in our lockdown interlude I was inspired by various posts to have a go at a Duo conversion with an old one I had. We were already using several Duo inserts on Explorer helmets, but I am very reluctant to mess with them, so are using AA?s. Unless you...
ukcaving.com
Stuart France
Active member
First of all, paying USD20 just for one 18650 Li-ion battery seems way over the top to me. Tonight I see ten tagged Sanyo NCR18650GA 3500mAH costs £33 (USD43) post free from Hong Kong. Similar for untagged. I use four of these in series, untagged and in a 4x18650 holder, for my bicycle which powers white front and red rear from a single pack, nominal 16 volts. I ordered ten, so I still have six in stock, there being no issues with the four that are in use.
I use two of these batteries wired in series for the exchangeable packs in my main caving light, so nominal 8 volts. My bike and caving LED lights are home made and all incorporate an analog knob to adjust the light level smoothly and instantly to anything I want between off and the max. None of the batteries have protection circuitry at the single cell level. Instead I have just put a thermal resettable fuse into the battery pack and use a bombproof charger. Old-school Oldham batteries also incorporated a fuse, though not resettable as those didn't exist in the day.
I've also got a couple of top-end Fenix lights with Fenix own-brand batteries inside, used for cave photography, and I have the four-cell Fenix universal charger, all of which I'm happy with other than the colour balance which is blue-ish.
As a general comment: take the supplier's AH capacity claim with a big pinch of salt and do you own tests that reflect the actual conditions of use. Only at that point you can do a proper value for money calculation and predict when your lights will go out during your type of activity.
I use two of these batteries wired in series for the exchangeable packs in my main caving light, so nominal 8 volts. My bike and caving LED lights are home made and all incorporate an analog knob to adjust the light level smoothly and instantly to anything I want between off and the max. None of the batteries have protection circuitry at the single cell level. Instead I have just put a thermal resettable fuse into the battery pack and use a bombproof charger. Old-school Oldham batteries also incorporated a fuse, though not resettable as those didn't exist in the day.
I've also got a couple of top-end Fenix lights with Fenix own-brand batteries inside, used for cave photography, and I have the four-cell Fenix universal charger, all of which I'm happy with other than the colour balance which is blue-ish.
As a general comment: take the supplier's AH capacity claim with a big pinch of salt and do you own tests that reflect the actual conditions of use. Only at that point you can do a proper value for money calculation and predict when your lights will go out during your type of activity.
aricooperdavis
Moderator
The best choice of colours I've found is in the Emisar DW4 (right angle if you want to helmet mount). You can choose from a huge range of different LEDs:
- Cool White - SST20, 6500K
- Neutral White - SST20 5000K
- Neutral White - SST-20 4000K 95CRI
- Warm White - SST20 2700K 95CRI
- E21A, R9080 Neutral White 4500K
- E21A, R9080 Warm White, 3500K
- E21A, R9080 Warm White, 2700K
- E21A, R9050 Warm White, 2000K
- SST-20 Deep Red, 660nm
- 219BT-V1, R9080 Neutral White, 4500K
- 8*3W UV 365nm mule with ZWB2 filter
- 8*5W UV 365nm mule with ZWB2 filter
- W2 6000K (CSLPM1.TG)
- W1 Amber
- E17A Azure
- E17A 1850K
- 519A 5700K with dome
- 519A 5700K dedome
- 519A 5000K with dome
- 519A 5000K dedome
- 519A 4500K with dome
- 519A 4500K dedome
- 519A 4000K with dome
- 519A 4000K dedome
- 519A 3500K with dome
- 519A 3500K dedome
- 519A 2700K with dome
- 519A 2700K dedome
royfellows
Well-known member
Been away so late on this one.
Most quality 3500mAh cells are Sanyo NCR18650GA cells. These are OEM (Original Equipment Manufacturer) and as such come bare, that is without any protection circuitry. Retail manufacturers fit a round PCB protection circuit to the base and then cover them with their own wrapper and obviously sell them at a mark up.
These cells are rated at a max of 10 amps discharge, cells that are rated at a higher discharge capability such as the Samsung INR 18650 30Q 3000mAh will have a lower capacity.but higher safe maximum discharge, these are rated at 20 amps. There is also the issue of the practical possible discharge, for example I use the Sanyo on my Scorpion X and X12 models, but the Samsung in the X16 as only these or similar will support that very powerful lamps max power.
So you can see that the capacity of the cell can relate to its application in respect of the required discharge capability.
The preceeding characters, eg "NCR" relate to the chemistry of the cell. And the chemistry of the cell is important to consider in its application as early chemistriy have a higher max safe discharge, typically 3V, than the later NCR chemistry. This could be a caution regarding old cells in modern lights, you would have to check the specification. Obviously there is room for error here with DIY projects using obsolete chemistry cells with a current protection circuit that allows a lower voltage max dischage. Over discharging a LiIon cells carries safety issues as recharging an over depleated cell could cause it to ignite. Water will not normally do this as the cell is sealed. The vent in the top that you can see is an anti explosion valve and will only open under internal pressure. The bottom line here is that modern cells with modern chemisty are a lot inherently safer.
I wrote a paper a while back on LiIon cells, what cavers need to know. Its on my lamps website somewhere for download.
Finally, I can recommended UK supplier, I deal with these people
www.fogstar.co.uk
I hope that this is helpful
Most quality 3500mAh cells are Sanyo NCR18650GA cells. These are OEM (Original Equipment Manufacturer) and as such come bare, that is without any protection circuitry. Retail manufacturers fit a round PCB protection circuit to the base and then cover them with their own wrapper and obviously sell them at a mark up.
These cells are rated at a max of 10 amps discharge, cells that are rated at a higher discharge capability such as the Samsung INR 18650 30Q 3000mAh will have a lower capacity.but higher safe maximum discharge, these are rated at 20 amps. There is also the issue of the practical possible discharge, for example I use the Sanyo on my Scorpion X and X12 models, but the Samsung in the X16 as only these or similar will support that very powerful lamps max power.
So you can see that the capacity of the cell can relate to its application in respect of the required discharge capability.
The preceeding characters, eg "NCR" relate to the chemistry of the cell. And the chemistry of the cell is important to consider in its application as early chemistriy have a higher max safe discharge, typically 3V, than the later NCR chemistry. This could be a caution regarding old cells in modern lights, you would have to check the specification. Obviously there is room for error here with DIY projects using obsolete chemistry cells with a current protection circuit that allows a lower voltage max dischage. Over discharging a LiIon cells carries safety issues as recharging an over depleated cell could cause it to ignite. Water will not normally do this as the cell is sealed. The vent in the top that you can see is an anti explosion valve and will only open under internal pressure. The bottom line here is that modern cells with modern chemisty are a lot inherently safer.
I wrote a paper a while back on LiIon cells, what cavers need to know. Its on my lamps website somewhere for download.
Finally, I can recommended UK supplier, I deal with these people
Fogstar Batteries | The UK’s #1 Lithium Battery Retailer
18650 Battery Retailer | 12V Leisure Batteries | 48V Solar Batteries | UK Based | 5* Reviews | Fast & Free Shipping - Same Day Despatch
www.fogstar.co.uk
I hope that this is helpful
royfellows
Well-known member
Oh, better add so that you can all breath easy again, dedicated LiIon chargers wont charge an over depleated cell. The electronics in a lot of cells and battery packs will also do similar.
JAshley73
Active member
I do understand that these branded-retail batteries are more cost-inflated than the OEM cells. However, in my case, that doesn't really help, as I would need to make some kind of spacer to makeup the difference in overall length, to match the Fenix battery's length. I don't want an extra part to fumble with inside a cave, nor extra parts to keep on top of.
I have a lot of respect for you folks that make your own lights, electronics, etc. However, that's just another hobby & depth of knowledge that I can't afford to dive into at this chapter in life. (I certainly don't mind this discussion continuing on in this thread - so have at it...)
aricooperdavis
Moderator
If you check out the directory of LiIons I posted before (here: https://lygte-info.dk/info/batteryIndex.html) you can search for batteries by length, which may help you find a cheaper compatible alternative.
ChrisJC
Well-known member
The problem is that the calculations are overly simplistic. To be a fair comparison, you need to measure the capacity at the discharge current that you intend to use them at, and also check that the cutoff voltage is the same (maybe it's determined by the Fenix rather than the cell protection circuit).
So to be absolutely sure you are making the right choice, you need to do some experiments...
Chris.
So to be absolutely sure you are making the right choice, you need to do some experiments...
Chris.
Stuart France
Active member
Back on topic - which is what to do about flat-ended 18650 cells - the battery slots in my 4x18650 plastic holder (for my bike lights) are slightly too long for the cells I've inserted for them to grip. The positive end of each cell doen't have a nipple like you find on (say) an AA Duracell, it has just a flat surface flush with the top of the battery. The positive terminal of each battery slot in the battery holder is just a rivet with a hole through the middle of it. So I just inserted something like an M2 screw into this with the nut on the outside of the holder and the screw head inside the battery slot occupying some of its length. The nipple is then on the battery holder rather than on the battery.
As the battery holder is non-conductive plastic, I suppose I could have inserted a suitably modified 5p coin with nipples soldered on both faces to make it slightly convex (like a lens often is). The "5p bridge" would sit between the positive end of the cell and the positive connector in the plastic holder. A 5p coin is the same diameter as a 18650 cell. I have found coins useful as shims in other situations besides electrical ones.
As to my caving light battery packs, these have tagged cells inside, so they're soldered. But solder tags (before soldering) provide an easy means to form an "in situ" nipple. You simply bend a section of the +ve tag into a Z-concertina shape, then in effect it becomes a nipple that sits proud of the flat battery top and is welded to it. The solder tag on the bottom negative end of the battery is redundant and can just be ripped off. So buying cells with tags is one way of obtaining (in effect) untagged cells with a decent sized +ve end nipple without having to solder anything yourself.
As the battery holder is non-conductive plastic, I suppose I could have inserted a suitably modified 5p coin with nipples soldered on both faces to make it slightly convex (like a lens often is). The "5p bridge" would sit between the positive end of the cell and the positive connector in the plastic holder. A 5p coin is the same diameter as a 18650 cell. I have found coins useful as shims in other situations besides electrical ones.
As to my caving light battery packs, these have tagged cells inside, so they're soldered. But solder tags (before soldering) provide an easy means to form an "in situ" nipple. You simply bend a section of the +ve tag into a Z-concertina shape, then in effect it becomes a nipple that sits proud of the flat battery top and is welded to it. The solder tag on the bottom negative end of the battery is redundant and can just be ripped off. So buying cells with tags is one way of obtaining (in effect) untagged cells with a decent sized +ve end nipple without having to solder anything yourself.
Cantclimbtom
Well-known member
I got 3 * 18650 in mine no bother, with the battery box and all innards gutted and the 3 batteries shrink wrapped to a slight curve to match. It's "snug" but perfectly doableI adapted a Duo to a 2-18650 cell setup and I have to say I'd not be convinced of the waterproofing with the way the lid has to be forced on.Fulk I believe went with a 3 cell design using 18490s
Ooops sorry it was Fjell and 18500s and you already know all about it
Duo conversion using 18500
I imagine this has been done before, but in our lockdown interlude I was inspired by various posts to have a go at a Duo conversion with an old one I had. We were already using several Duo inserts on Explorer helmets, but I am very reluctant to mess with them, so are using AA?s. Unless you...
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