Vamo PCB with NiMH batteries

[Relayer1974]

So I got me one of them fancy Vamo PCBs and did some rudimentary bench testing with NiMH cells. Because the Vamo was designed for either one or two lithium cells, it wants to see ~3.7 or ~7.4 volts. I still need to test the cutoff voltages, but the general consensus online is that it throws a "LO V" at 3.2V and 6.4V for one and two lithium cells, respectively. Throw four NiMH cells in there and it thinks you put a really low set of two lithiums in there. Put in three or six NiMH batteries and it acts right. My only concern is that the voltage drop under load will mean I can't get as much useful life out of one charge cycle as I like. I'll have to build a test mod and see how it goes.

At first I was kind of upset because I thought I had a bum board. It ended up reminding me that I should never assume that something is a problem. It might just be a feature of the equipment.

 

[Thrasher]

the other problem is, those are not high drain batteries and may become a safety issue when the vamo board tries to start pulling 3 amps out of them. apv batteries are usually rated at 10 amps with a 15 amp or higher momentary peak for safety. even protected batteries at least have a 6 amp limit.

the only way i can see low drain batteries working effectively is running something like 5 ohm cartos lol

 

[awsum140]

If all else fails, a car battery regulated down to either 7.4 or 3.7 volts would work out for a VERY long vape session.

 

[Relayer1974]

the other problem is, those are not high drain batteries and may become a safety issue when the vamo board tries to start pulling 3 amps out of them. apv batteries are usually rated at 10 amps with a 15 amp or higher momentary peak for safety. even protected batteries at least have a 6 amp limit.

the only way i can see low drain batteries working effectively is running something like 5 ohm cartos lol

I've never had an issue running NiMH cells at 2C. Generally speaking, there are very few safety concerns running them at even 10C. You could over-discharge them, shortening their lifespan and capacity, but that's about it. That's why I like NiMH cells so much, aside from being able to get them at the grocery store.

If all else fails, a car battery regulated down to either 7.4 or 3.7 volts would work out for a VERY long vape session.

I'm going to build a puck mod using a SEPIC buck/boost unit so I can run it with just about any battery chemistry, USB or a 12V lighter socket. I could even run the Vamo board after it if I really wanted to, but it would be more for academic purposes than practical use.

 

[awsum140]

Nah, I see an Express Wagon, two 12 volt car batteries, a 5 gallon bucket of liquid, a small pump for liquid feed and a hose/cable harness up to the mod. Serious vaping there. although dragging the wagon around the house might get to be a problem.

 

[Relayer1974]

Nah, I see an Express Wagon, two 12 volt car batteries, a 5 gallon bucket of liquid, a small pump for liquid feed and a hose/cable harness up to the mod. Serious vaping there. although dragging the wagon around the house might get to be a problem.

All with a .2 ohm coil. 720W of vaping delight! I'll get arrested for covering the town in fog before I get tired of dragging the wagon a while.

 

[Relayer1974]

I found a workaround for the Vamo issue while using 4xAA NiMH cells. I discovered that it decides how many Li-Ion cells it has when it flashes the LED three times upon completing a connection with the battery. It doesn't matter where the voltage goes from there, it'll maintain that setting until the battery is disconnected. So if it gets <4.5V starting up, it'll think it's a single Li-Ion cell configuration no matter what.

Sooo... to fool it, I added a 100 ohm resistor in series with the board until it flashed three times. The flashing lowered the resistance of the circuit to where the resistor was dropping about 1.8V across it, making the board think it had a single Li-Ion cell setup. After that, I jumpered across the resistor, effectively removing it from the circuit. No 6.4V "LO-V" from there on out. Good to go!

 

[classwife]

Moved to the Modding Forum - Battery Mods

 

[Lastlokean]

I like how half of the ECF has such misunderstanding about NiMh batteries. I have heard hundreds of times... How they won't work. Can't output power. Statements like... 'The voltage is there but the power is insufficient'. These statements make are completely unfounded and untrue. I believe them to be pouring out of vendors selling Li-Ion mods...

1xAAA NiMh have no issues up to ~6-10 amps.

The only real advantage of a lithium ion cell is increased storage capacity. Not increased instantaneous output. No magical forces. They have nearly identical internal resistance.

They come with a handful of negatives including $$$, consumer availability and safety.

Also 4xAAA in series will not have a greater capacity or current rating than three, two or one AAA by itself.

 

[dr g]

The power density of li ion is higher than NiMh, which matters for most portable electronics.

 

[ScorpioZZZ]

I found a workaround for the Vamo issue while using 4xAA NiMH cells. I discovered that it decides how many Li-Ion cells it has when it flashes the LED three times upon completing a connection with the battery. It doesn't matter where the voltage goes from there, it'll maintain that setting until the battery is disconnected. So if it gets <4.5V starting up, it'll think it's a single Li-Ion cell configuration no matter what.

Sooo... to fool it, I added a 100 ohm resistor in series with the board until it flashed three times. The flashing lowered the resistance of the circuit to where the resistor was dropping about 1.8V across it, making the board think it had a single Li-Ion cell setup. After that, I jumpered across the resistor, effectively removing it from the circuit. No 6.4V "LO-V" from there on out. Good to go!

Nice find on the flashing lights!!!
Also planning to make a NiMH mod from one of my VAMOS when my Li-Ion's crap out.
So far I made a 4 AA NiMh mod and run a RSST on it with 4 wrap 28g (about 1 ohm) and fish wick ceramic coil and so far (about 3 months) my go to mod. The batts do not get hot. I know they have a V drop but it doesn't matter this match vapes well. The nice thing is it lasts about 2 days (only got 1 day from my 18650's) and when the vape drops out slightly the NiMh still have about 1.1v so no need for a low V indicator on the mod.

Looking forward to see what you do with that VAMO PCB
Suscribed!

 

[awsum140]

For those interested, I checked current draw on a Vamo using a single 18650 and a stack of 18350s at both seven and ten watts. At no time did current draw exceed four amps, and, with the stack, was only just over an amp. Another friend ran some "real world" tests with a battery analyzer using a five second load followed by a 25 second rest on both 18650 and a stack of 18350s. Full results are in the "Vamo Battery" thread. It may be helpful for those of your working with NiMH/NiCD.

 

[ScorpioZZZ]

For those interested, I checked current draw on a Vamo using a single 18650 and a stack of 18350s at both seven and ten watts. At no time did current draw exceed four amps, and, with the stack, was only just over an amp. Another friend ran some "real world" tests with a battery analyzer using a five second load followed by a 25 second rest on both 18650 and a stack of 18350s. Full results are in the "Vamo Battery" thread. It may be helpful for those of your working with NiMH/NiCD.

Cool thx!
Is the thread in the mod section???

 

[awsum140]

The discussion more or less starts here - http://www.e-cigarette-forum.com/forum/vamo/355592-vamo-battery-thread-58.html and runs about four, ten post per page, pages. The current draws are what might be of value for this discussion in terms of relative drain on other battery types.

 

[Relayer1974]

For those interested, I checked current draw on a Vamo using a single 18650 and a stack of 18350s at both seven and ten watts. At no time did current draw exceed four amps, and, with the stack, was only just over an amp. Another friend ran some "real world" tests with a battery analyzer using a five second load followed by a 25 second rest on both 18650 and a stack of 18350s. Full results are in the "Vamo Battery" thread. It may be helpful for those of your working with NiMH/NiCD.

Thanks for the info. I did a max amp test on the VV Gripper board, which is essentially the same tech without VW and RMS. It capped at 3A. It's great to see that the Vamo board also has a higher current limit.

 

[Relayer1974]

I've been doing a battery drain test on my initial Vamo NiMH build and it seems to be performing as well as the VV Gripper, which is to say it's doing well. The batteries are down to 4.7V at rest and the board isn't throwing a Lo V even at 15W (or whatever its actual output is, if it's hitting its amp limit). I still haven't tested it with a USB port, but I expect it to perform well. More to come.

 

[Relayer1974]

Here's my completed Vamo Puck. It works fine with the NiMH batteries and on a USB port. It hits its amp limit before 15W because of the voltage being supplied, but it still works really well.

 

[ThePuck]

Here's my completed Vamo Puck. It works fine with the NiMH batteries and on a USB port. It hits its amp limit before 15W because of the voltage being supplied, but it still works really well.

Great Job! And you've provided some really good research for the VAMO. Way to stick with it and get it going!

And for those who still, to this day, deny that Nimhs work fantastic for ecig applications, do me a favor. Forget the bogus science and electronics theory. Been there, done that. Just try them. See for yourself. Nimhs were designed to be the work horse of the battery industry (in high drain applications). They wouldn't sell them in every grocery store if there was ever a chance of them blowing up due to a full discharge (and I have fully discharged them hundreds if not thousands of times under full load). They are the safest rechargeable batteries you can buy.

I'm glad to see someone carry on the interest in Nimh batteries and see their value and usefulness. Cudos to you Relayer1974 for your work and research (yeah, I know it was all fun ).

 

[Relayer1974]

I almost forgot to post the good stuff for those interested...

I build this into a 4xAAA box and wired the 100-ohm resistor into the box's switch. It's a SPDT switch, so I have the resistor in series with the battery pack until the board's display flashes three times. Then I switch it straight to the battery pack and turn it on.

The board is a little tall for the box with the buttons I used. I cut a hole in the back cover to make room. I'll make a cover for the hole when I get around to it.

 

[WarHawk-AVG]

NICE!!!

Very nice...is it the V2 PCB??

Oh and question, if you could shoehorn in an IC regulator rated at 1.5A and stack em to get 3A and and output of 3.6vdc would it fix the 100Ω resistor issue...as long as the NiMH batteries remained above 4.75vdc it would continue to push 3.6vdc to the PCB, its a little low, but it might be a work around

hope this helps and subscribed!
http://www.e-cigarette-forum.com/fo...8-variable-voltage-question.html#post10470964

Oh and is that a USB charge port you put on there??