DIY harness for DIY charger/discharger

Inspired by @Abarnabe's thread showing his MeanWell LED driver as grid charger and a set of 230V bulbs as a discharger I'm going to show how I built my own harness to balance charge without removing any covers.

First, I used two terminal rings that fit the modules screws. One for the positive end and other for the negative one. Wiring was made with household electric wires (1,5mm) but since they should not carry more than 2A could be thinner.



I added a 15A fuse in the middle of the longest wire (positive in this case). Again, 15A is a lot more than what is expected to carry, but it was what at hand and, in case of short, it will break instantly.



This is how the other end looks when the black covers are on:


To make a safe connection to the charger I used a Schuko female marked + and - signs at each side. Later I thought I could have used the ground pins as negative and the main holes as positive, maybe next time...


Next, to power the fan while balancing (very very important to prevent overheating) I used the pinout schema posted somewhere in PriusChat. I just inserted rigid wires in the female fan connector (fan side) like this:


Purple and red end in a DC female jack that gets connected to a 12V power supply after a long enough wire. Purple and blue meet in a switch that can also be used to force ventilation when the car is on.



That's all. I also zip-tied the battery charging wires to the fan power wires so the stay together while hidden in the tray that sits under the trunk floor, so now I only have to take them out of there and plug the LED driver (or the bulb array) and the 12V power source.

Hope you find it useful. And if I made any foolish mistake, please, comment!

 

It is a regular ATO blade fuse. No voltage specs on it, though they are used in cars low voltage circuits. Since I was concerned about arcing at high voltage, I made a test with a broken one and I saw no arc nor spark so I guessed it was good to go. Anyway, I'm not 100% sure if harmful arcing always appears visible. Would feel better if someone could confirm that

Not a bad option either, though C14 posts seem too exposed if not covered with a cap. I liked the Schuko because the female is well protected while moving around the trunk.

I already had a few eyelets of different sizes and picked the ones that fit better, I guess something around 5mm or 6mm can do the job. Maybe someone in the forum knows the exact diameter of the posts if you are looking for the narrowest option.

BTW, here you have two pics of how it looks in the trunk:

 

So to be sure it is a safe choice I should try to put an unblown fuse, blow it by shorting the circuit and see if arcing occurs while keeping the circuit shorted, right?

 

Wow! Then I’ll look for a high DC voltage rated fuse ASAP. Thank you for saving my eyebrows, Chapman!

 

I've been looking for DC fuses in Spanish shops and most of them sell fuses designed and certified for photovoltaic systems (usually tagged as gPV). In the specs of the ones I'm about to buy the breaking capacity is rated at 30kA and hold up to 1000V DC. I also seen in some general purpose fuses (gG) that specs show they can hold up to 250V DC with a breaking capacity of 15kA. Would those fuses be suitable for the harness or may still be dangerous? Does anyone know the specs of the fuse that comes with Prolong's system?

 

That’s good to hear, @waldox.
I’m currently waiting for the fuses and holders I ordered. But instead of soldering I think a fuse holder is more convenient. The one I ordered looks like this.
It was listed as “car audio fuse box”, but it is supposed to fit 10x38mm fuses so I guess it will be fine. I finally decided to go with a fuse per wire (positive and negative) for extra safety in any short circuit scenario.

Let us know if you put that harness to work!

 

In my case, living in Europe, buying the Prolong charger, discharger and harness from USA means paying an expensive shipping and kind of abusive customs taxes. So adding that extra to the products price would cost me up to 1000€.
The money I spent in the DIY version is no more than 100€. Of course, apart from money, you also have to take into account the hours (happily) spent learning how to make it safely, finding where to buy the right LED driver and fuses, and a morning assembling stuff up.
Of course, Prolong devices are more complete, better constructed, look nicer and feel safer than DIY. But that, from my perspective, is not worth 900€ more.
I also have to say that the intelligent discharger they sell seems really convenient and it’s something I would be willing to invest in if it wouldn’t require their harness and was shipped from Europe.