Topic: Question regarding making my own Battery packs

over the last 9 years i use a self cleaning flux and basic solder
just a tiny dab of flux and tin all joints to be soldered clean joints of any flux left then solder the battery packs together use clear heat shrink as above so you are able to see the solder joints  at least 2 packs are 4-5 years old and still look good
Ron

over the last 9 years i use a self cleaning flux and basic solder
just a tiny dab of flux and tin all joints to be soldered clean joints of any flux left then solder the battery packs together use clear heat shrink as above so you are able to see the solder joints  at least 2 packs are 4-5 years old and still look good
Ron

Why would you use a flux and basic solder, when there are so many proprietary pre-fluxed solder wires available?

Totally agree 
I also use wire with flux in it already, make life much more easier.
Use to use lead and external flux to do my packs a long time ago, and discovered pre flux wire... Never went back since then ! 

I'm no pro on that sort of things, but sometimes, the flux reaction I had on some batteries was a bit worrying (black colour on the lead etc etc), even if that was holding strong... 

Why would you use a flux and basic solder, when there are so many proprietary pre-fluxed solder wires available?

because the flux i use i do not have to apply to much heat its quick and easy i use alot of pre fluxed wire on circuit boards etc none are as good as the  flux i use and when i say a dab i use a pin to apply it very small amount
Ron  

Cheers for all the comments gents.

It seems that soldering packs is not an exact science and there are many ways to do the job well. As i've got this pen thingy, i will briefly wipe it over the battery and then just solder the damn thing 

The Duracell that i got do have the white end! 

I tend not to cycle packs much, i just fly and slow charge overnight, but I could learn to use my lipo charger that apparently does it all....

slow charge! argh. you don't know how much is going in to your battery. well not unless you know exactly how much came out last time you flew it (including self-discharge).

nimhs should be charged with a peak detect charger.

I would definately use a peak detecting charger, never a trickle charger (to the extent I'm doing that for my bike lights too) on modern AA and AAA NiMH's.

Nige

slow charge! argh. you don't know how much is going in to your battery. well not unless you know exactly how much came out last time you flew it (including self-discharge).

nimhs should be charged with a peak detect charger.

Tom - yer right and yer wrong - overnight slow charging tells you nothing BUT NiMH's do have a nasty habit of false peaking - this can lead to the mistaken belief that you're topped up when you're nowhere near it - ALWAYS press 'charge' or 'start' again on any peak detect charger when NiMH's are in the frame - you'll be amazed at how much more charge goes in before the peak detect trips again!

surely that is due to the way peak detect works. I.e there needs to be a detectable peak and voltage drop.

I cycle my packs from time to time to check capacity.

Tom - yer right and yer wrong - overnight slow charging tells you nothing BUT NiMH's do have a nasty habit of false peaking - this can lead to the mistaken belief that you're topped up when you're nowhere near it - ALWAYS press 'charge' or 'start' again on any peak detect charger when NiMH's are in the frame - you'll be amazed at how much more charge goes in before the peak detect trips again!

I think this a lot depends on the actual cells and the charger being used.
From experience though the higher capacity cells are far more likely to false peak than lower ones. Typically the Instants (2100mAh) charge far more reliably than their higher capacity (2600mAh) cousins. I tried making a pack from 2900's once and they were terrible at false peaking. This is part fo the reason why the manufacturers don't use such high capacity cells for our use.

There is also a very simple way of knowing how well charged a pack is and that is to just feel how warm it is.

An overnight slow charge is also the easiest way to balance a set of Nimhs. Don't knock it - it's got it's place.

Z

Sure - overnight charging is fine - I do it but I ALWAYS top up with the peak detect before I go flying - I like to know that the stupid thing has actually been charging and not just sitting there overnight 'pretending' it has 

The false peak connundrum seems to be NiMH specific and will usually trip quite early - the old Ripmax Super Nova Pro Peak charger was a swine for it but I've found plenty of other chargers do it too - now I just prod the 'go' button again just to be sure before I unhook things.

Cycling - seldom do it these days - battery capacity is so good that there's always plenty anyway.

I have never had false peak problems or any battery failures.  Yeah you are lucky you don't get a failure, but a lot of chargers give false peaks and others don't.  

If I cycle say an eneloop and I get something like 1950+ mah going in to it on full cycle I am pretty happy that is okay. I recently cycled the instant in my tragi and after two years the capacity it takes is still something like 2050mah+, which is the same as when it was new.  

if you've flown for four hours and only 100mah goes back in to the battery then you know something is awry.

I don't follow the logic that overcharging cells will balance them out when they will surely just overcharge in the same state of imbalance as they started in.  

i have seen this false peak on different makes of cells one 2500mah battery pack would put in around 600mah battery cool  press charge again and it would put the rest in on finish battery warm
this is the same using 2 different chargers
other cells 2000mah and lower do not seem to suffer from this 
Ron

i have seen this false peak on different makes of cells one 2500mah battery pack would put in around 600mah battery cool  press charge again and it would put the rest in on finish battery warm
this is the same using 2 different chargers
other cells 2000mah and lower do not seem to suffer from this 
Ron

those high capactiy nimhs certainly don't have a good reputation. 

those high capactiy nimhs certainly don't have a good reputation. 

most are only good for telly remotes    some seem ok i like to test each cell  before i install better safe than sorry
Ron

I STILL say I would rather use factory assembled packs unless I have no other option.  I think of my self as a pretty good solderer, having done it for decades, but I still don't trust my soldering enough for this important application (or "app", as some might say )..

I STILL say I would rather use factory assembled packs unless I have no other option.  I think of my self as a pretty good solderer, having done it for decades, but I still don't trust my soldering enough for this important application (or "app", as some might say )..

Chris you used to be my hero.....

 

win some, lose some..

I'm starting to agree with you Woodstock!

I've jus finished soldering the duracells batts and I'm not 100% confident with my soldering!

It went ok and I must say that I did enjoy doing it but... I know all im gonna be thinking about now is those wires when I'm flying it!! I think sometimes its better not to know how good or bad the soldering is :-)

quick school boy question. When you solder the wire to the battery can the bare wire run across the whole face of the battery?? e.g. the bare wire running across the whole face of the negative end of the battery??

Jus think...I done GCSE electronics at school once :-) Did only get a 'D' tho -lol!

Negative end is ok, need to be careful at the positive end because the whole of the battery case is negative, If the +ve wire touches the case (by insulation wearing through) then it's goodbye battery.
When I've made up packs I've used plastic with holes in laid on top of the terminals and then soldered through the holes to connect bare wire thats had heatshrink applied to it as additional insurance against the above.

Regards - J

Cheers John think its ok

A quick related question.

Once I have my 4 AA cell square pack made up what diameter heat shrink tubing do I need? 

G

A quick related question.

Once I have my 4 AA cell square pack made up what diameter heat shrink tubing do I need? 

G

if i can find mine i will measure it its a 2.5 mm thick heat shrink very strong  not the thin gear
the battery pack fits just perfect ready for shrinking
Ron

if i can find mine i will measure it its a 2.5 mm thick heat shrink very strong  not the thin gear
the battery pack fits just perfect ready for shrinking
Ron

ok i think i got it from ebay its been a while as i bought 2m of it and still have 1m left its clear and not 2.5mm its 1mm -1.5mm laying flat 65mm i got clear so i can see all wires and soldered joints
Ron

A quick related question.

Once I have my 4 AA cell square pack made up what diameter heat shrink tubing do I need? 

G

if you cant find any send me an email and i will cut you some from mine and post it to you to try
Ron

ok i think i got it from ebay its been a while as i bought 2m of it and still have 1m left its clear and not 2.5mm its 1mm -1.5mm laying flat 65mm i got clear so i can see all wires and soldered joints
Ron

Thanks Ron and thanks for the offer to send me some tubing. If I can't find any I may take you up on your offer.
It was the laying flat dimension that was confusing me! I'm thinking something like 40mm diameter should do it. I've just spotted some 40mm clear tubing on EBay so I'll give that a try.
G

I've been caught out with the dimensions before - ordered what I thought was perfect, ended up with yards of really heavy duty stuff that wasn't wide enough!

Nige