openinverter forum

there are things I really like about my BMW 530e battery modules, they are like Lego blocks, they are small yet pack a big punch, however some things are left to be desired (I'm looking at your those dreadful OEM(ish) not so quick finger pincher disconnects, you guys know what I'm talking about

well I am big on repurposing OEM stuff like cables, Safety Boxes, brackets, etc. so this project started with me wanting to figure out a way to connect the BMW Safety box directly to an Inverter (the Lexus GS450 heitch in my case, but it does not really matter) I wanted cables with ring terminals like the EV gods intended not some orange plastic Ls

• I wanted the output cables from the safety box to be longer

• I wanted them to have ring terminals on the ends

• and as a bonus I wanted the ability to add another lead to the plug

So you're talking about the Safety Box cables not the battery pack cables? Hold on tiger.

The safety box sports two kinds of connector types or styles, the outside ones are different from the inside ones

What if we swapped the orange connectors from the inside wires to the outside and vice versa? Is it possible? are the guts the same? But why, so that we could use the much longer leads from the actual modules as our Safety Box new output leads, therefor eliminating the need for that external square bulky OEM connector.

let's start with the Output Positive lead

OK, now let's do the same to the longest cable in the pack, this is the negative lead from the #1 module to the Safety Box. It does not matter that it's an official OEM negative lead as we will remove the positive terminal housing. If this makes your brain hurt, then know that I could have grabbed the much shorter official Positive lean from the #6 module that runs to the Safety Box, but again I was shooting for the maximum reachability using stock cables.

This will make more sense as we move along.

Mandatory Stare & Compare

and result, we just replaced the OEM smooth single foot long cable with the webbed loom dual cable 5 foot lead, we could just lop off the other end and crimp on a 2 AWG ring terminal and call it good for this side if that's the distance we need to cover from our pack to the inverter

Couple Lessons Learned about this swap or Reconfigure method.

• the OEM output cables are round the battery pack cables since there's two of them in that webbing are sort of rectangular so some filing is required in order to fit the bit larger two cables into the housing meant for one

• though you can gently pry these orange housings apart they were really not meant to be opened up so getting your hands on brand new ones would snap them back together like they came from the factory

now let's take a look at the "Rekey" method, this method does NOT require us to remove the house, it involves a knife instead... BONUS !


this does require something called "patience" and surgical like precision
there is one additional trim/cut that I am not specifically showing, it's a tiny ridge on the back side

and there we have it a perfect fit, we now have a longer Negative Output lead (bottom of pic). I learned that all four of the Safety Box ports can accept clips on the front (like those stock OEM output stubby cables) or their back sides (like the stock OEM webbed long battery leads)

and here is a mandator stare and compare birds eye view this time of all four connections, featuring both the Reconfigured

there are pros and cons to each method

RECONFIGURE METHOD

• Pros of using the first Reconfigure Method are that it remains Idiot Proof as the Output connectors will not also plug in to the inside Input ports

• Cons of using the first Reconfigure Method are that removing the OEM connector housings mangles them a tad despite of how careful you are and requires some cutting away or filing away of material to make the new cables fit the Output connectors (crazy glue or Gorilla glue may halp keep them snapped closed)

REKEY METHOD

• Pros of the Rekey Method are that you do not have to remove any connectors

• Cons of the Rekey Method are that you could accidentally plug the new modified Output lead into the old input port, but I'm not sure what harm that would do as it would be running to an unpowered inverter and not to the battery pack, hope that makes sense

can you guys think of any Pros or Cons?

to be continued....

so here I am taking one for the team and cutting the longest cable in the BMW 530e battery pack (that of module #1) in half


and it's all over but the crying

I am still investigating if this 1/0 AWG 6mm lug is the optimal size there is actually a slight difference between it and the 1 AWG 6mm, and I just ordered some 2/1 AWG and just 2 AWG, I really wanted this to be a snug fit

so then it was time to make the cable, note how I deliberately put black heat shrink on both ends just to make sure I know that is the negative lead


I am not too in love with this hydraulic terminal crimper as it tends to leave sharp edges

and here's one longer lead connected to an inverter with a ring terminal and a proper bolt

just wanted to share what the finished Rekeyed option looks like (though I am leaning more towards the Reconfigured just so the connectors look different and won't interchange with the inside two on the box)