So I bought some battery holders to contain gorups of several AA cells, I can buy these holders with either "solder tab" connections (small metal tabs with tiny holes through them on each end of the cell series, or 9V battery style clips. The physical layout of these batteries is quite special, for mechanical constraint reasons, I don't have many options for buying these batetry holders, just solder tabs or 9V style clips and both from the same manufacturer. Neither connector type seem willing to take a soldered cnnection to a wire.
I'm using NiMH cells in a high current application and have to solder on some relatively thick wires, I certainly would want to attach 9V clip attachment wires then have to solder their thin wires onto my own thicker wires, there also wouldn't mechanically be enough space for that in my final application. So I have to solder my wires to the solder tabs or to the 9V clip connectors. But the plastic of the battery holders is a resin which melts at around 150 celsius, and in the act of heating the tabs/clips the plastic melts before the metal can evr be hot enough to solder to. I'm quite experienced with soldering but have never found such a nasty problem as this, too cold and solder won't stick, any hotter and the plastic melts before I stand a chance of attaching my wires. I've tried multiple irons, various tip sizes, many different temperatures (I'm using LEAD and ROSIN containing solder so don't need the same heat as one would for unleaded), I've wasted many batetry holders to connectors which have metled off before the metal was hot enough to solder wires to. What am I to do? Is there a trick for these sort of thing? Manufacturers keep making these sort of batetry holders rather than ones with long metal pins or something which would be easy to solder to, so one assuems there must be a specific way to use them? Thanks?
I'm not specifically using the type of holder linked to below, but they all give exmapels of the type of tabs and/or 9V clips I'm talking about
You might try a higher wattage soldering iron. The thought is the high wattage will very quickly heat the metal to solder before there is time for the heat to conduct to the plastic. Get in, get out, quick. Some times acid flux is more effective in getting the metals to accept the solder than rosin.
Infraviolet:
I'm using NiMH cells in a high current application and have to solder on some relatively thick wires...
Those battery holders are not meant for high current.
The battery springs act as heating elements when too much current is drawn, and also melt the plastic.
Better use NiMh cells with tabs, or a 6-cell battery pack, and solder the wires directly to them.
Leo..
Try a trick we used years ago with transistors. Place a clip between the battery holder plastic on the tab where you are soldering. This should conduct enough heat away to keep form melting the plastic. This response is to help you get started in solving your problem, not solve it for you.
Good Luck & Have Fun!
Gil
@gilshultz - good memory - - somewhere in my old stuff I have some aluminum gripper heat sink things - I have also used needle nosed pliers, either have someone hold the pliers or hold them closed with a couple of rubber bands. Vise Grip also make some small needle nose type pliers that lock
ballscrewbob:
If I get a bad surface I use a small dab of plumbing flux which is a lot more aggressive.
Also great for that cheap Chinese oddball wire that never seems to want to take solder.
The bad thing about acid type flux is that it wicks up the wire and sooner or later the wire will corrode and break.
I once made some battery cables for my jump start battery and used acid flux solder. After a while they quit working. I removed the shrink tubing around the solder lugs and the wire was green and had completely failed.
Lesson learned.
The book says don't do it - but I have sometimes just touched the iron with a bit of solder that then flows to the offending part and helps to warm it up quicker - but just a small touch with the rest applied to the parts so the flux also wets and cleans the parts - have also used emery cloth, sandpaper or a file to rough things up - also cleaning the part with a cleaner that does not leave a residue helps
Notice that some of your battery holders state they are RoHS compliant. That means there is no lead in the product. That, in turn, means NONE of the connection points have been coated with lead based solder, as was done in years past.
You are trying to use a low melting point lead bearing solder and this is a common problem around the world. You need an aggressive flux and much more heat than you are giving it. Rosin flux just won't do the job.
I suspect the problem is a combination of poor technique and a lousy (low wattage?) soldering iron.
The thick wire pulls heat away, making it take longer to heat up the tab, so the metal spends more time above the melting temperature of the plastic.
Tin both the wire and the tab first, and while making the solder joint, first hold the iron against the wire until you see the solder on it melt, then quickly bring wire+iron into contact with the tab to complete the joint.
Be aware that if you need thick wire to carry the current, you may find that when you try to put that much current through the battery holder, the resistance of the tab and it's connection to the contacts that touch the ends of the battery may be high enough that it will generate enough heat to melt the plastic anyway; once I was using 18650 batteries and a cheap plastic battery holder for a somewhat high current application, and was terrified when I was testing it and saw a wisp of smoke coming from the batteries - it was a relief when I realized it was the battery holder smoking, not the battery itself. They were even over-current protected batteries (and not hitting their current limit); the holder was just cheap crap.
Plumbing flux has no place in an electronics workshop, and flux is not needed if you have some soldering skills. Battery holder clips/tabs are nickel-plated, and never come soldered/tinned either.
If you must use battery holders, then pre-tin the battery holder clip and pre-tin the wire (separately).
Put the battery holder in a vice, so you can hold the wire in one hand and the iron in the other.
Melt the solder on the wire, and when it's a liquid bring it in contact with the tab (iron still on the wire).
The solder on the tab should now melt/join in less than a second.
Remove the soldering iron, while holding the wire steady while the solder cools to below the melting temp of the plastic.
But as said, don't use battery holders for high currents.
Leo..
Wawa:
Plumbing flux has no place in an electronics workshop, and flux is not needed
I do beg to differ here and think we must agree to disagree.
I often salvage parts from many types of board and dont have all the fancy schmancy desoldering options available to may "pros"
The types of solder do often vary between boards so sometimes they need a little extra help to get it flowing.
Nope I dont have a megawatt iron either just a nice TCI that I use for everything but with differing tips as needed.
I also re-use a lot of wire / cable from said salvage so there are occasions when such wire also needs extra help.
If I could afford all the fancy items I needed I would probably need a bigger work area too.
Basic equipment and basic needs are the mother of invention here.
Also welded (MIG, TIG, MMA, FC, SUB ARC,AAG) for a large part of my life so saying blithely that flux is not needed sort of struck a nerve here as there are so many fluxes and so many different applications depending on the metals and surfaces and coatings etc etc.
I know we are just talking soldering but same differences on many occasions still apply.
zoomkat:
You might try a higher wattage soldering iron. The thought is the high wattage will very quickly heat the metal to solder before there is time for the heat to conduct to the plastic. Get in, get out, quick. Some times acid flux is more effective in getting the metals to accept the solder than rosin.
Acid flux should NEVER be used for any electronics application.
ballscrewbob:
If I get a bad surface I use a small dab of plumbing flux which is a lot more aggressive.
Also great for that cheap Chinese oddball wire that never seems to want to take solder.
Plumbing flux is zinc chloride. Corrosive, and should never be used for electronics work. Ever see the green corrosion on copper pipes? Now imagine that green crap all over your wires, shorting them out before they dissolve completely.
