Older MD4 body and 18650 compatibility

[NutSAK]

I have an old MD4 body that I'm having trouble finding compatible 18650 cells for. Evidently the internal bore is smaller than current production, as my more recent MD4 bodies have not shown this issue. I've thought about using a cylinder hone on it to enlarge the bore, but I hesitate to do that since it will remove the anti-corrosion coating.

Any thoughts or suggestions? Should I contact Gene?

Thanks.

 

[TomK85]

Don't have a straight answer but I would always contact Gene. Always ready to help and think about possible solutions.

 

[thermal guy]

I'd leave it as is and use 2X16650's. They have 80 percent capacity of 18650's. Runtimes will still be good. Just my opinion.

 

[mckeand13]

I have an old MD4 body that I'm having trouble finding compatible 18650 cells for. Evidently the internal bore is smaller than current production, as my more recent MD4 bodies have not shown this issue. I've thought about using a cylinder hone on it to enlarge the bore, but I hesitate to do that since it will remove the anti-corrosion coating.

Any thoughts or suggestions? Should I contact Gene?

Thanks.

Call Gene. See what he says. Maybe you can send it back to him for boring?

 

[NutSAK]

Don't have a straight answer but I would always contact Gene. Always ready to help and think about possible solutions.

Done, and Gene has already offered to replace it with one with a larger bore. More of the typical "above and beyond" CS from Malkoff! :twothumbs

I'd leave it as is and use 2X16650's. They have 80 percent capacity of 18650's. Runtimes will still be good. Just my opinion.

That's not a bad idea, but it has taken years for me to standardize my cells to 14500 and 18650, and I just don't want to break from that. The more recent 18650 cells are delivering a true 3500mAh, so the gap is spreading and 16650 are now more like 70% of their capacity. Some of the lower-capacity 18650's I have (2900-3100mAh) fit the body OK--tight but doable--so that is still a better option than 16650 for me.

 

[tuelleric]

Done, and Gene has already offered to replace it with one with a larger bore. More of the typical "above and beyond" CS from Malkoff! :twothumbs

That is really outstanding service! I bored my older MD3 myself as it also had this "issue". This was a 2 minutes job and could be done by every workshop that has a lathe. Just a thought for someone outside the US, where shipping back and fourth to Gene would not make sense.

 

[NotRegulated]

I had the same problem with two of my older gen1 MD4's, an MD3 and an MD2.

I ordered new KeepPower 18650's and 18500's from his site and found they would not fit in my older Malkoff tubes. I contacted Gene about the issue. He took care of the issue right away.

In all fairness, when the MD tubes were purchased, 18650's were considerably thinner and lower in capacity. At the time, the batteries fit in the tubes just fine. Over the years the diameter and capacity of the batteries have grown. His customer service is indeed outstanding.

 

[RCRVRP]

Done, and Gene has already offered to replace it with one with a larger bore. More of the typical "above and beyond" CS from Malkoff! :twothumbs



That's not a bad idea, but it has taken years for me to standardize my cells to 14500 and 18650, and I just don't want to break from that. The more recent 18650 cells are delivering a true 3500mAh, so the gap is spreading and 16650 are now more like 70% of their capacity. Some of the lower-capacity 18650's I have (2900-3100mAh) fit the body OK--tight but doable--so that is still a better option than 16650 for me.

May I ask which 18650s you use and where you buy them? I need to get a few and there are so many bad ones out there, I'd prefer to buy some based on a users recommendation. Thanks!

 

[NutSAK]

In all fairness, when the MD tubes were purchased, 18650's were considerably thinner and lower in capacity. At the time, the batteries fit in the tubes just fine. Over the years the diameter and capacity of the batteries have grown. His customer service is indeed outstanding.

My thoughts exactly, and well above service I would expect from any vendor or manufacturer. I've had no problems with this body in the past, and 18650's have grown beyond spec, especially in protected form.

May I ask which 18650s you use and where you buy them? I need to get a few and there are so many bad ones out there, I'd prefer to buy some based on a users recommendation. Thanks!

The current ones I'm using are KeepPower/Panasonic NCR18650G from Illumn. They are excellent, but any of the Panasonics from that family (rated 3400, 3500, 3600mAh) test very well. I've also had very good service from Orbtronic 18650 built on Sanyo/Panasonic cells.

 

[INFRNL]

May I ask which 18650s you use and where you buy them? I need to get a few and there are so many bad ones out there, I'd prefer to buy some based on a users recommendation. Thanks!

Which part of the country are you in?
Illumn (Cali) is where I get most of my cells too. Sometimes fleabay has reputable sellers, lions wholesale (i think they are) is another good place out east. Lastly, rtd vapor us3d to be a good place too. I'm sure there are more places, but these are where i go

 

[RCRVRP]

Which part of the country are you in?
Illumn (Cali) is where I get most of my cells too. Sometimes fleabay has reputable sellers, lions wholesale (i think they are) is another good place out east. Lastly, rtd vapor us3d to be a good place too. I'm sure there are more places, but these are where i go

I'm in the midwest. Thank you for the info, I'll check it out.

 

[INFRNL]

The Sanyo 18650ga protected is what I usually use but lg make just as good of cells. I also have lg cells. LG are INR which might be safer than NCR but i haven't had issues. INR might also be better from over-discharge, idk

Don't buy the rebranded cells unless you find them at a really good price. I try to buy the basic Sanyo cells as they are the cheapest and are what others rewrap. I have a few keeppower 18650, these can be found at good prices too.

Not sure if you are looking for protected or unprotected

Don't get the 3600mah cells either, their amp rating is lower iirc
Get the 3500mah cells... nothing more... nothing less

If you need higher amperage cells, something like the sony 3100 vtc. I can't remember what gen i i have but they are killer cells (sony)

Edit, doesn't look like illumn carries the protected version of the sanyo or lg anymore. Keeppower are more expensive than I thought but usually cheaper than the other rewraps.

 

[RCRVRP]

The Sanyo 18650ga protected is what I usually use but lg make just as good of cells. I also have lg cells. LG are INR which might be safer than NCR but i haven't had issues. INR might also be better from over-discharge, idk

Don't buy the rebranded cells unless you find them at a really good price. I try to buy the basic Sanyo cells as they are the cheapest and are what others rewrap. I have a few keeppower 18650, these can be found at good prices too.

Not sure if you are looking for protected or unprotected

Don't get the 3600mah cells either, their amp rating is lower iirc
Get the 3500mah cells... nothing more... nothing less

If you need higher amperage cells, something like the sony 3100 vtc. I can't remember what gen i i have but they are killer cells (sony)

Edit, doesn't look like illumn carries the protected version of the sanyo or lg anymore. Keeppower are more expensive than I thought but usually cheaper than the other rewraps.

Please tell me the pros and cons of protected vs unprotected cells. These will only be used in flashlights. Specificly at present a Malkoff Hounddog.

 

[thermal guy]

Unprotected cells need constant Monitoring. If they get to low they could be ruined and won't be able to recharge.If your on top of your game with them you might get a little extra runtime but not much.There also is a small possibility of them draining to low and causing damage to the battery or the light.With protected cells you put them in and the protected circuit kicks in and shuts off saving the battery and light from damage. Others will chime in with more details and I'm sure dire warnings of what can go wrong with each but that's the abridged version. I'd go protected. Much easier to deal with.

 

[INFRNL]

One thing to note for differences.
When using 2 li-ion cells: protected cells usually run flat(near full output) then completely dies once one of the cells reaches it's cutoff pt.
Unprotected cells usually run for a bit then have a constant decline in output. Or start off with a steady decline (depends on module)

If you need reliability, many run unprotected cells. I haven't had a protected cell fail but I'm sure one will one day. If one does, I'll grab another. Others have had issues with protected cells and won't use them. One thing that can be done if a protected cell fails...cut off the protection circuit disc and rewrap it. Then you have an unprotected cell.

unprotected cells can be more dangerous. You have to keep an eye on them and continually monitor them as Thermal said. Many people use unprotected cells without issue. I don't use unprotected in my runtime tests because I let them run overnight sometimes. I could use them while actually using my lights but I haven't I have a zebralight that can only run unprotected cells but it has low voltage protection built into the light. If a light accidentally gets left on it could impose some serious risks.

The only con to a protected cells is the chance of the protection circuit failing. This could mean that it won't cut off (which would be risky as an unprotected cell) or you lose light and have to replace the cell(s) to continue. Both options have been successfully used but there are different characteristics of runtime between them. If you want the light to run as long as possible at/near full output; then you want unprotected. if you want maximum overall runtime with a declining output and want to make sure you have some sort of light to make it home; then go unprotected or single cell protected.

I'll let other add their thoughts, opinions, experience.

 

[NutSAK]

Don't get the 3600mah cells either, their amp rating is lower iirc
Get the 3500mah cells... nothing more... nothing less

The max current rating is the same, but internal resistance is a bit higher on the 3600mAh cells. This only becomes a factor at currents higher than 3amps, so for most applications isn't really a factor at all. For instance, they both provide 5A just fine, but you might see about a ~5% lower capacity in the 3600mAh cell at that current due to the internal resistance.

EDIT: I just reviewed the latest tests (2019) of the Keeppower 3500mAh cell and 3600mAh cell, and I see no difference whatsoever in capacity or energy between the cells, regardless of current up to and including 5A.

One thing to note for differences.
When using 2 li-ion cells: protected cells usually run flat(near full output) then completely dies once one of the cells reaches it's cutoff pt.
Unprotected cells usually run for a bit then have a constant decline in output. Or start off with a steady decline (depends on module)

Given the same module and cells (x2), I've never seen a significant difference in the runtime slopes of protected vs. unprotected. Yes, the protected cells will leave you in the dark when the voltage protection kicks in, but at that point you shouldn't continue to run the cells anyway unless you want to incur damage. I'm hoping you have an example plot of protected vs. unprotected to show that I'm missing something.

IMO, the solution to the cutoff problem with 2xLi-ion in these cases is to have a backup light (or cells, or both), rather than continue to run unprotected cells past acceptable low voltage limits. Better yet, monitor your protected cells and don't hit the cutoff in the first place if that is an option.

 

[Tachead]

One must keep in mind that most cells can be safely ran down to 2.5V which is way after you will notice the light drop out of regulation on most lights. Once you notice the drop out of regulation you still have a ton of useable light before you hit the 2.5V suggested cutoff. One just needs to carry a spare cell, swap when they notice a drop in output, and all will be well. It is also important to keep in mind that certain chemistries are more volatile then others. IMR are generally quite forgiving even when abused for instance.

Imo, while Li-ions can dangerous if precautions aren't taken and you are careless, some people take it WAY too far and treat them like they are frag grenades with the safety removed lol.

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[NutSAK]

One must keep in mind that most cells can be safely ran down to 2.5V which is way after you will notice the light drop out of regulation on most lights

That is true for single-cell Malkoffs and most other single-cell lights, but not true for the 2x cell lights such as the Hound Dog and Wildcat. They will run with completely flat, regulated output until cutoff occurs on two cells. You will never notice a drop in output until it shuts off.

It is true that you can "safely" run cells down to the cutoff, but if you do that frequently--especially at low current output--you with shorten the life of the cell.

 

[Tachead]

That is true for single-cell Malkoffs and most other single-cell lights, but not true for the 2x cell lights such as the Hound Dog and Wildcat. They will run with completely flat, regulated output until cutoff occurs on two cells. You will never notice a drop in output until it shuts off.

It is true that you can "safely" run cells down to the cutoff, but if you do that frequently--especially at low current output--you with shorten the life of the cell.

Yes, I was speaking of single cell setups(I don't run muli-cell lights except for primaries). I personally would not recommend using unprotected cells in multi cell lights for a number of reasons.

Yeah, it's not as big of a deal as people make it out to be(I used to be anal with cells but, have come to realize it just isn't necessary). Cells are generally quite cheap and very resilient. I don't baby my cells(other then storage voltage for VERY long term storage & staying above 2.5V for the most part) and they are still going strong years later(some with many, many cycles). When they get weak, recycle and upgrade to the latest cell tech. For most users, I think their cells will need to be recycled due to age, not cycles or mistreatment. Not to mention, many will upgrade to the newest tech before they will even wear them out.

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[INFRNL]

I'd like to make a correction to what Nutsak has mentioned. Wildcatv6 is the only module I think I have found that does not run flat on multiple protected cells. It behaves like it has single cell. However it will run flat using 3x protected li-ion as others do with 2 protected cells.