Directly replacing NiMh cells with Li-Ion cells - bad idea ?

[eccerr0r]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

Well, the charger does properly cut off when charging at 0.1C ... battery is full and never gets warm during charge.

Now I never checked temperatures during discharge, now that's a different story...

[sam_sam_sam]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

No it just that most items that are worth a shit
come with a very shite charge I find this a lot
and most of the time the battery or batteries are real shit

Here is an example of what I am talking about

https://www.tractorsupply.com/tsc/pr...t&cm_vc=-10005

This is very good flashlight and good quality batteries but the charging board over current the batteries and causes them to become very warm

I will not use the charger base because of this and this is with good quality batteries

[eccerr0r]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

The question is why was my vacuum designed with such a slow charge? Does it benefit the battery to have a slow charge after a fast discharge when it's being used. Current setup is like 0.1C charge, 8C discharge...

I suppose this is not any worse than the original NiCd system that also charges probably at 0.1C.

[sam_sam_sam]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

This is the type of charge I use for a one cell 18650 battery they work very well But I check to make sure that it cut the voltage at level it suppose to

https://www.ebay.com/itm/Free-Shippi....c100005.m1851

I am sorry but I just bought the last two that they had

But I will still leave here so you can see what type of battery charger I use

One note I do recap them before I use them

[Dannyx]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

Talk about coincidence: this just popped up in my subscriptions NOW

[sam_sam_sam]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

the second is really good - 9/10.
i would say 10/10 if it had usb and a charge controller in it.

https://www.aliexpress.com/item/LED-...867214598.html

I just bought two kits so I have the power supply cord to charge it

Now I will have to buy some more Panasonic batteries that have protection boards on them

Thanks for sharing this

[eccerr0r]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

I should make my vacuum USB charged, screw these special wall warts

[stj]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

the first one with the teeth is 5/10, the led is so-so for a T6 or clone.
still good output, but others are better.
i was thinking of changing the led before i even got it - maybe to InfraRed.

the second is really good - 9/10.
i would say 10/10 if it had usb and a charge controller in it.

the thing about those lights with the tubular socket, they are very solid construction - real nice.
just let down by the charge cable - i made a new cable that terminates into one of these.
https://www.aliexpress.com/item/10pc...948825580.html

i think i'll get one of these next - infact i know i will - just waiting for the price to drop a touch.
https://www.aliexpress.com/wholesale...pocketman+1315



ah yes, your questions.
the controller on the first one is the usual 3pin + parallel resistors - i replaced it.
the second i didnt try to strip.

they all generally drive the main led at around 1A so calculate runtime yourself.
i dont know if i metered the current for the cob-ring on the second.

[sam_sam_sam]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

and this is even better:
https://www.aliexpress.com/item/LED-...867214598.html

now here's the catch.
the charge-port goes directly to the battery contacts,
and the only thing in the car charger is a fucking resistor!!!
( real SHIT I seen this so many times )

(well 2 if you include the one for the led) ( O really how are they doing the brightness control )
btw, *never* buy these with the battery - it's a slavage job with no protection circuit - even if the label says otherwise. ( are trying hurt someone with this crap)

First of all

Are these worth buying meaning are LED modules any good and do they last

What is the quality of these LED module on a scale of One to Ten one meaning shit and ten meaning very good quality

Second of all

With a good quality battery what is the run time

Third of all

I would not use a shite battery in the first place not using it every day
I would also not use the charging controller that comes with it I have good quality charging controller for this I would just use the connectors on it

[stj]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

never bodge something that either comes into contact with the user, or gets used in a bathroom!!

[Dannyx]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

Suspecting the wall wart is a CC PSU versus a CV/CC PSU most Li-ion chargers are. Very weird indeed.

I think I encountered this setup with a Braun epilator a while back: someone brought it in for repair and the wall-wart was dead. It was sealed VERY tightly - not only was the case virtually impossible to crack without destroying it, but the insides were also completely sealed in hard wax, so there was no way any sane human being would service that at component level, made most sense to replace it entirely. I thought, no problem, I'll just dig through my box of wall warts and find one with identical voltage and maybe higher current for the nice lady.

The original was 6v at (I think) 200mA. Before that however, I wanted to make sure the device itself runs fine and the internal battery isn't shot, so I cut the dedicated plug off the original dead adapter, stripped the ends, hooked up some alligator clips to my bench supply and applied 6v: to my surprise the current shot up to the supply's maximum 1.5a capacity and entered OC protection...what gives ? Great, I thought, the thing's busted as well.

However, next I tried slowly increasing the voltage from 0v to keep the current below the supply's limit to see what happens: again, much to my surprise, it didn't behave like a dead-short would, i.e. the current didn't remain constant indefinitely, but instead begin to drop...almost....like a....battery getting.....charged...OOOOOHH I see: so the adapter is a CC supply and adjusts the voltage up/down based on the current. My supply at the time only did CV, so I had to manually increase the voltage when the current dropped. The charge LED was also on, so I let it sit for around an hour and then tried it out: it worked...my colleague and I even tried it on the hairs on our arms...you know, for testing purposes ....hurts like a Mo-fo BTW...yeah, we did a lot of stupid sh!t back at my old shop...those were the days I'd like to take a moment to thank all the ladies out there for putting themselves through pain to make themselves more attractive for us

So this meant my idea with the replacement adapter went down the drain, since they're all CV and my colleague ended up contacting the local Braun dealer and ordering an original wall-wart. Imagine getting a 3a+ supply and hooking it up to the device (like I originally planned): instant dead cell I'd say and possibly some smoke, UNLESS the device had OC protection inside of it as well. I DID find an adapter which did 5v at 200mA, so the "CC" was merely the supply's limit and not an active current sensing...it worked this way as well, but we figured the best way was to go with the original one rather than half-assing something like this.

[stj]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

there's a lot of shit sold to the public.

there are some very nice led flashlights from china worth getting but being cautious with.
they have a charging connector on them - NOT usb.
here is one - ignore the Lumens bullshit.
https://www.aliexpress.com/item/4200...818422476.html

and this is even better:
https://www.aliexpress.com/item/LED-...867214598.html

now here's the catch.
the charge-port goes directly to the battery contacts,
and the only thing in the car charger is a fucking resistor!!!
(well 2 if you include the one for the led)
btw, *never* buy these with the battery - it's a slavage job with no protection circuit - even if the label says otherwise.

[eccerr0r]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

Well, looks like that circuit board is indeed a charge protection board and will cut off power when the battery is fully charged.

The weird thing is that the original wall wart for the li-ion cell appears to be 15V @ 150mA. I have a suspicion that the original wall wart which didn't come with the vacuum has a fairly high impedance for a power supply, else the charger would dissipate way too much power while charging the extremely low impedance of the battery.

Suspecting the wall wart is a CC PSU versus a CV/CC PSU most Li-ion chargers are. Very weird indeed.

[eccerr0r]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

The thing I wonder is if I can use the old charger... after all, what is this circuit board for if it doesn't appear to have overdischarge cutoff (since it appears to hook the + and - directly to the output/motor)?

Must be some charge controller?

If so, then the old NiCd charger should work

I should test this outside my house somewhere away flammables...

NOPE. Forgot, the charger is AC. This won't work :\

[eccerr0r]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

It's an old Hoover, and yes 10A...though only at 3.6V = 36 watts.
Only good for small spills but sometimes that's what you need. Anything bigger I need to use the shop vac.

[Dannyx]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

Must admit I haven't seen a BATTERY operated wet/dry vac...what brand might this be ? Sounds pretty "power hungry", at least by directly comparing it with a mains-unit - a Karcher - I use at home which is 3000w

[eccerr0r]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

Well, not exactly. I transplanted the power system from a seemingly working vacuum that theoretically was designed properly to the old one.

I wanted the wet/dry system of the older vacuum, hence sacrificing the newer one.

[Dannyx]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

Interesting, so you did what my super skilled buddy tried to do here for *ahem* research purposes Do not try this at home kids

[eccerr0r]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

Eh no... I'm saving my _old_ vacuum cleaner that came with NiCd cells...
Now my _old_ vacuum has a single Li-ion cell and it sucks once again!

[Dannyx]

Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

At least yours was intended to run on LiIon from the factory Vac still hasn't returned...guess he got lucky this time or the cells were of better quality and resisted the abuse better