Power supply connection issue - Page 1
Forum section: electronics / projects

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: July 01, 2019, 10:19:16 pm
content: I have a CC power supply I use to constantly charge my supercapacitor bank while I weld battery tabs and I'm having difficulty finding the best way to connect the power supply to the supercapacitors.There are 4 negative and 4 positive screw terminals (M3 or M4 screw) so connecting the 8 AWG cable terminated in a female XT90 plug would not work since I cannot crimp a connector small enough to screw on.The only option I see is to either connect 4 x 14 AWG cables (equivalent to 8 AWG cable) and create a buss bar where I could then connect the large 6 mm lug and the other 4 cables to.Problem with that is it will be bulky and I wont be able to heatshrink the entire buss bar and all the connections as it will be too wide and twisting 4 x 14 AWG cables together to then solder those to an XT90 connector would be hellishly difficult.Does anyone have a better idea? Are there special isolated junctions for such tasks?

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: July 02, 2019, 08:18:36 pm
content: BUMP!

author: langwadt
author_rank: Super Contributor
timestamp: July 02, 2019, 08:28:40 pm
content: picture?

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: July 02, 2019, 08:59:17 pm
content: Quote from: langwadt on July 02, 2019, 08:28:40 pmHere you go. I'm ready to cut the lugs off since they have been crimped the wrong side anyway.Insulation is paramount as I don't want 50 A of current flowing through the case of some other metal object.

author: ajb
author_rank: Super Contributor
timestamp: July 02, 2019, 09:25:33 pm
content: Why not get some ~2mm copper sheet, form it into buss bars that hang off of the terminals with a suitable hole for an 8AWG lug, and then use one of those rubber coating products (plastidip or similar) to insulate the exposed part of the plate? Or, if you shape the plates right, you may be able to just use some large heatshrink over the whole deal.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: July 02, 2019, 09:32:12 pm
content: Quote from: ajb on July 02, 2019, 09:25:33 pmInsulating the buss bars, screws and connectors would be impossible with heatshrink and plastic dip would be hard to apply on such a 3D network of connections.

author: langwadt
author_rank: Super Contributor
timestamp: July 02, 2019, 09:42:48 pm
content: Quote from: drummerdimitri on July 02, 2019, 08:59:17 pm4 x 14 AWG cables crimped together with 1 x 8 AWG with something like this,https://media.rs-online.com/t_large/F8092385-01.jpg

author: ajb
author_rank: Super Contributor
timestamp: July 02, 2019, 09:54:35 pm
content: Quote from: drummerdimitri on July 02, 2019, 09:32:12 pmLooking at the terminals used on most Meanwell supplies, four terminals is ~36mm wide. Some 25mm ID heatshrink will go right over that and right over an 8AWG lug, too, if you taper the width of the copper tab coming off of the terminals. It won't shrink down over the 8AWG tail, but you can layer another smaller diameter heatshrink over it to taper the whole thing down, or just use a zip tie to cinch it down around the wire. Also, you can get plastic coating products in brush- and spray-on formats, so you're not limited to what can simply be dipped.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: July 02, 2019, 10:00:34 pm
content: Quote from: langwadt on July 02, 2019, 09:42:48 pmI have similar connectors that have a yellow sleeve but those will not accept anything over 12 AWG.Not sure where I could source those locally but that would be the best and most elegant solution by far!

author: langwadt
author_rank: Super Contributor
timestamp: July 02, 2019, 10:19:31 pm
content: Quote from: drummerdimitri on July 02, 2019, 10:00:34 pmyou could also just divide the core of the 8awg in four, heat shrink each of the four tails and bigger heat shrink where they meet

author: MarkF
author_rank: Super Contributor
timestamp: July 02, 2019, 10:56:48 pm
content: Maybe two of these mounted to the top of the power supply with short jumpers to the power supply terminals:https://jaydeeautocables.com.au/products/neutral-bar-brassORhttps://shop.pkys.com/BEP-Pro-Installer-Z-Bus-Bar--10-Way--200A_p_5786.html

author: MarkF
author_rank: Super Contributor
timestamp: July 02, 2019, 11:25:20 pm
content: Searching for marine power distribution bus bars will give you a lot of options.Or you could drill and tap two copper bars to achieve the same thing.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: July 03, 2019, 12:01:34 am
content: I like the bus bar idea and have already crimped and connected the 8 wires to the power supply.Will attempt to solder each of the 4 pairs to a piece of copper salvaged from household power board bus bars , drill a hole in it and screw on the 8 AWG lug and heat-shrink the whole thing. should be fine I guess as I doubt I will ever find a butt connector capable of accommodating the cables where I live.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: July 04, 2019, 04:20:42 pm
content: Jobs done thanks guys!