NiMH Tenergy C cells protected? New: Vanson charger help!

[bigchelis]

I just purchased Tenergy 5000mAh C cells for a P7 Mag. Do I just use the Maglight untill the light goes out and then charge them?

I know the Lio-on protected cells cut off power before they reach the point where they will not charge anymore. So, do NiMH behave the same way?

I looked everywhere for this and apologize in advance if it is a dumb question.

Thank you,
bigchelis

Edit: I just got the Vanson charger and some NiMH 18650 cells, but they do not have a button top on the positve side. The charger will not turn on with or without them and the cells will not work in a P60 P7 Direct drive 3 18650 hosts. Do I have to but solder paste at the end of each positive on the cell to mimick a button top?

 

[Turbo Guy]

Re: NiMH Tenergy C cells protected?

I would assume being C size and 5000 mAh they are NiMH and that being the case I doubt they have any form of low voltage protection. It would be best not to discharge them completely flat and there is really no reason not to recharge them often. I would use a DMM in the amps. mode and check to see what the normal drain(discharge rate) is and try and limit normal useage to a range of 3 to 4 Ah. . If the brain is fairly high they not no deliver much of 3000 to 4000 any way.

P7 is listed as 1800 mA on 6V and 1000 on 12V.

 

[Benson]

Re: NiMH Tenergy C cells protected?

I just purchased Tenergy 5000mAh C cells for a P7 Mag. Do I just use the Maglight untill the light goes out and then charge them?

I know the Lio-on protected cells cut off power before they reach the point where they will not charge anymore. So, do NiMH behave the same way?

Not exactly; there's no protection, so they won't switch off.

However, NiMH are considered empty at 0.8V/cell, but stopping at 1V/cell gives somewhat increased cycle life. At 3V (I'm assuming, from other threads, this is your 3xC DD ), the P7 will only draw about 450 mA, so it'll be about 1/5 as bright as when you started at 2.8A (so it's easy to see when you should recharge) and no significant current should flow below 2.4V (so even if it gets left on, it shouldn't hurt them badly). So because of the characteristics of an LED (as opposed to an incandescent, which will eventually drain your batteries flat), you don't really have anything to worry about.

Still, charge 'em as often as you can; 2 hours of runtime isn't much use if you used an hour and a half up last time, and didn't recharge it.

 

[bigchelis]

Re: NiMH Tenergy C cells protected?

Not exactly; there's no protection, so they won't switch off.

However, NiMH are considered empty at 0.8V/cell, but stopping at 1V/cell gives somewhat increased cycle life. At 3V (I'm assuming, from other threads, this is your 3xC DD ), the P7 will only draw about 450 mA, so it'll be about 1/5 as bright as when you started at 2.8A (so it's easy to see when you should recharge) and no significant current should flow below 2.4V (so even if it gets left on, it shouldn't hurt them badly). So because of the characteristics of an LED (as opposed to an incandescent, which will eventually drain your batteries flat), you don't really have anything to worry about.

Still, charge 'em as often as you can; 2 hours of runtime isn't much use if you used an hour and a half up last time, and didn't recharge it.

Yes, this is the 3C NiMH on direct drive P7. I was thinking how to know when to charge them. when I get the P7 Mag build I willl test them after 2 hours and see if the cells still read 1volt. Here's hoping at 2.5hours the cells still read 1v.

Thank you,
bigchelis

 

[gswitter]

Re: NiMH Tenergy C cells protected?

Here's hoping at 2.5hours the cells still read 1v.

Not a chance.

2.8 A draw from a 5000 mAh cell will give you about an hour and 45 minutes.

...if the cells are a true 5000 mAh under a constant 2.8 A load (doubtful) and if the P7 draws a constant 2.8 A (nope).

If you use the lights for short bursts and don't let the LED heat up too much, 1:45 total is the theoretical limit, and I wouldn't push it much beyond 1:30. If you use the lights for long, continuous periods (as the P7 heats up, its forward voltage and current draw increase), I'd probably check it after 1:00 or 1:15 tops.

 

[bigchelis]

Re: NiMH Tenergy C cells protected?

Not a chance.

2.8 A draw from a 5000 mAh cell will give you about an hour and 45 minutes.

...if the cells are a true 5000 mAh under a constant 2.8 A load (doubtful) and if the P7 draws a constant 2.8 A (nope).

If you use the lights for short bursts and don't let the LED heat up too much, 1:45 total is the theoretical limit, and I wouldn't push it much beyond 1:30. If you use the lights for long, continuous periods (as the P7 heats up, its forward voltage and current draw increase), I'd probably check it after 1:00 or 1:15 tops.

Great,
very helpfull info. So, I will check at 1 hour, and then every 15 minutes. They also make the 6000mAh capacity NiMH C cells too.. Maybe those make closer to an actual 5000mAh.

Thank you,
bigchelis

 

[Kestrel]

Re: NiMH Tenergy C cells protected?

In case you're interested, you can get low-self-discharge C NiMH cells from Thomas Dist:
http://thomasdistributing.com/shop/...P_id=&osCsid=fd5dda71a85ffe25e930f8d3a8899d81
A test evaluation thread (total of 10 units) on those is here:
http://www.candlepowerforums.com/vb/showthread.php?t=187271
They push close to 5000 mAh, pretty good for LSD

 

[gswitter]

Re: NiMH Tenergy C cells protected?

In case you're interested, you can get low-self-discharge C NiMH cells from Thomas Dist:
http://thomasdistributing.com/shop/...P_id=&osCsid=fd5dda71a85ffe25e930f8d3a8899d81

That's what I use in my P7 builds.

 

[bigchelis]

Re: NiMH Tenergy C cells protected?

I just got the 18650 NiMH cells, but they have no button top on the positive end. I was going to use 3 of these in a P60 P7 on direct drive by Nailbender. The host is a Solarforce 6P with 2 18650 extentions. I put them in a Vanson Speedy Box charger and the light will not turn on to indicate it is on or even charging. Did I get a good Charger or is mine a lemon.

 

[VidPro]

most of these chargers dont allow for a flat (er) top, because generally flat tops are not intended for them, they are intended for packs, or they are not ni-mh and are instead li-ion.
so if your sure its ni-mh and not a li-ion (i assumed you checked the voltage before shoving it in something) then you will have to make a modification.
but really where did you get a tenergy 18650 in a ni-mh? when usually they are li-ion, i mean they DO make them in that size, but are you SURE that is what you got?

 

[gswitter]

I assume those are the 4/3 A cells you were asking about recently?

Does the charger work with any other cells?

I think I have the same charger under a different brand, and it looks like you might need magnets at the contact points. On mine there appears to be extra, small contact points on the positive side, and I suspect they're used to identify cell size (and maybe control the charge rate?), so you might have to experiment with it.

 

[bigchelis]

I assume those are the 4/3 A cells you were asking about recently?

Does the charger work with any other cells?

I think I have the same charger under a different brand, and it looks like you might need magnets at the contact points. On mine there appears to be extra, small contact points on the positive side, and I suspect they're used to identify cell size (and maybe control the charge rate?), so you might have to experiment with it.

Yes, These are the 4/3 A cells NiMH 4500mAh (same size as my 18650's).

I have 6 "C" size Tenergy's on the way to test them in the charger. I should have them by Saturday.

I guess I have to solder some paste at the positive end to be able to use them both in the charger and in the host.

If the paste works I would use 3 NiMH 18650 size cells in a Solarforce 18650 hosts with 2 18650 extentions. The P7 P60 drop-in pulls 2.6amps with a single 18650 at the tail end. I am just looking for ways to maximize runtime, although technically I do not need it: it is just good to know the runtime is there.

Thank you,
bigchelis

 

[VidPro]

there is another reason they resess the nipple and shoulder up the sides, i saw it one other time (in a D), it was to stop the top of a cell from crushing into the bottom of the next one. it was a heavy cell, then it was packed with capacity which means the electrolyte roll was closer to the base of the bottom of the cells.
so when it was stacked in a series stack it made connection but didnt POKE the next cell. they had actually put a cardboard shoulder (like a washer) up around the nipple to prevent that. it was a high capacity cell for the times, lighter metal can case, but heavy cell, tightly packed internals.

with that we prefered to modify the charger instead of the cell, at any rate its something to think about if you go to raise the top, like making a nice nipple that doesnt poke out to much, or if you can some chargers you can just take off the shoulder on them that prevents charger Polarity reversals, then just make sure you stuff things in the charger right.
looking at it, it might just be that same design, that the nipple is there, just buffered down by the shoulder.