Battery terminal thread size?

Post by **MrAl** » 09 Sep 2017, 17:35

Hi there,

Anyone happen to know the thread size of this 'bolt'? [see pic]
It is the hollow 'bolt' pointed to just above that green arrow.
It looks like some kind of service bolt maybe for when the battery is switched or something, but if i can find out the thread size and diameter then i can buy two nuts and connect my own wire to the battery for monitoring and/or charging purposes.

I considered measuring it, but it is hard to get the thread size right and so i'd have to buy a bunch of nuts to try, so i was hoping someone here might know.
If not then maybe the other bolt with the nut on it.

Thanks.

Post by **wizechatmgr** » 09 Sep 2017, 18:47

That post is used on the '99 (on the positive side) for the Main fuse block wire.

I'll try to pull my nut off and figure it out for you at the hardware store - unfortunately Tuesday is the earliest I can do this.

Post by **jreed** » 10 Sep 2017, 06:23

I happened to have a spare negative battery cable (Volvo p/n 94561616) in the workshop, for a '97 855 GLT. On my cable, the nut you show in your picture is a M6 with 1.0mm thread pitch.

Post by **MrAl** » 10 Sep 2017, 11:08

Hi,

Wow thanks guys, you dont know how much trouble this saves me. Last time i had to guess a thread size for mounting the SAS air pump i had to buy several bolts and try each one and hope i bought one that fits. That came about because when i bought the car the pump was removed along with the bracket so there were no bolts there, just the nut inserts that could not be removed easily.

By eye it does appear to be around the M6 size so i'll try that. I have to get to the hardware store soon anyway for some other hardware.

So thanks again...

Post by **wizechatmgr** » 12 Sep 2017, 20:49

Confirmed the M6 x 1.0 today. Suggest stainless nut if you can get it - may last longer.

Post by **MrAl** » 13 Sep 2017, 15:27

wizechatmgr wrote: ↑12 Sep 2017, 20:49 Confirmed the M6 x 1.0 today. Suggest stainless nut if you can get it - may last longer.

Hello again,

Oh ok thanks for checking that. This allows me to be more confident when buying the pasts, and i only have to go to the store and buy them once. last time i had to do this for something else i had to buy several single pieces, then go out to the car and try them, then go back in and buy the ones that worked.

Coincidentally, i had another totally different application for M6 hardware that had nothing to do with the car but i did not get around to going to the hardware store for that yet, so i'll be able to get parts for both applications at the same time

The store is somewhat farther than i usually have to go so i like to make each trip count.

Thanks again, this helps a lot. I'll be able to install a new 12v line right to the battery.

Post by **wizechatmgr** » 13 Sep 2017, 21:41

Just make sure to fuse whatever is going to be run off that terminal. =)

Post by **MrAl** » 14 Sep 2017, 00:51

wizechatmgr wrote: ↑13 Sep 2017, 21:41 Just make sure to fuse whatever is going to be run off that terminal. =)

Hi,

Yes, thanks for mentioning that. I ordered some weather proof inline fuse holders with fuses. The wire gauge is decent too, number 12 AWG. Eventually i'll have a separate 12v cigar lighter socket on the inside end too.

Post by **MrAl** » 21 Sep 2017, 17:04

Hello again,

I was able to pick up the M6 hardware early this morning at Home Depot. I was lucky they had just enough although i had to get two difference size bolts to get the total quantity i needed for something else not related to the car.

As for the nuts, i tried them in the parking lot and sure enough, they fit very nicely. I can see though that i will have to clean the bolt stems they will be screwed onto as they are quite dirty. Nice fit though so i am on my way to finally getting this thing installed. This will enable constant monitoring of the battery voltage, adding a heavy duty 12v cigar socket, and experiment a little with a solar battery charger/maintainer later.

So thanks again for the thread/nut sizes as that enabled me to walk into the store, pick out the items, then check out all within maybe 15 minutes, rather than have to buy a bunch of different sizes and try them all.

Post by **wizechatmgr** » 22 Sep 2017, 01:33

Once you install your wires, I'd suggest using either a lock washer or a second nut (jamb nut) in order to make sure you don't run into the issues I had.

In order to use a nut as a jamb nut you basically hold onto the first nut (already installed) with a wrench while tightening the 2nd/newest nut towards it. This allows torque between them and makes it just short of impossible for them to both back out on their own.

Or, you can always use blue or green lock-tite. It'll do the same job.