Victron NG Battery terminals

DIY
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1

I am about to install some Victron NG batteries.
The supplied terminal screws come with captive spring washer and flat washer however here is also a second loose flat washer. I am wondering about the purpose of the second washer.

The NG has aluminium battery terminals & I understand that there could be galvanic corrosion issues between a zinc plated cable lug and the aluminium terminals. Is this the reason that second washer is supplied; to go between the lug & the terminal?

This would go against the normal recommendation to place cable lug directly onto battery terminal to minimise resistance so I am conflicted.

I can’t find any victron recommendation for this. Any advice?

2

Normally there shouldn’t be a 2nd washer.
Maybe it was added by accident in the factory?

3

Depending on how thick your cable lugs are and how many cable lugs you connect to a battery terminal , you may need additional washers to secure the cable lugs, or longer screws if they no longer reach deep enough into the thread.

4

Interesting, I have three batteries & all six terminals have the extra washer.

5

I never had that.
Maybe a new employee in the factory. :grinning_face_with_smiling_eyes:

6

So, is it normal practice to place cable lug directly on the aluminium battery terminal?

7

I see now that the supplied bolts bottom out in the battery terminal holes without the second washer. They must be put in as tempory packers during assembly, so that spring washers do there job during transport.

8

As far as I know, the cable lug should sit directly on the battery terminal for the best connection. The extra washer is likely for proper clamping or spacing, not meant to go between the lug and the terminal. Putting anything between them can increase resistance. For aluminium terminals, corrosion can be a concern, but that’s usually handled with clean contact, correct tightening, and sometimes anti-oxidation paste — not by adding a washer in between. Might be worth checking Victron’s specs as well, just to be sure for that model.

9

battery pole 1
battery pole 11514×2048 294 KB

battery pole 2
battery pole 21920×2010 747 KB

I have 2 NG batteries, and they have different battery poles (same delivery). The ones with the thread insert (like a helicoil) have the extra washer. I scanned the QR code on that battery, and the manual does not mention a second washer.

The springwasher and plain washer are ‘fixed’ on the bolt. The 2nd plain washer is separate so I assume it is there because of the thread insert and goes between the battery pole and the cable lug.

I don’t like to assume things (assumption is the mother of all FUs) so is there any official info about this?

10

I wouldn’t put anything between the cable lug & terminal.

My guess it that second washer is a temporary packer to stop bolt bottoming out during transport.