New battery to g12

Information relating to the Matchless G12 or AJS Model 31 650cc twin
Locked
Hillboy55
Posts: 2
Joined: Sat Jun 27, 2020 2:28 pm
Location: Worcs

New battery to g12

Post by Hillboy55 »

Hi all

I just purchased a Lucas gel battery for my G12 (1962 mag model, 6 volt), being fed up of the corrosion from the lead/acid standard. Now, I've always understood that the bike is wired positive earth. However, I connected the gel battery like this and disconnected it sharpish as the wires began to get rather hot! Connected with negative earth it seems fine. I haven't run it yet as I'm a bit concerned that something might go Badly Wrong, so to speak!
Any advice would be most appreciated!
Andy51
Member
Posts: 741
Joined: Thu Mar 31, 2005 1:00 am
Location: BERKS UK

Re: New battery to g12

Post by Andy51 »

How long have you owned the bike and how many previous owners?! I bought my current '54 G80 some 15 years ago, and the battery was not charging (it turned out to be a very poor earth but that's another story). I took it off, cleaned the terminals and connections, and fitted it back in accordance with the manual (+ve earth). The charging problem got worse! On further investigation I found the PO had put it together with -ve earth so I was pumping the electrons the wrong way. It says a lot for the battery that it continued to function when I put the whole system back to +ve earth by 'flashing' the dynamo. The moral of this story is check, check and check again, and never take anything a PO has done for granted. Oh, and by the way, he had used the wrong wiring colours, so his polarity change was not obvious. Mind you, that was nothing compared to my 1st G80 back in the early 70s, which had been completely rewired using the same colour throughout! Andy
User avatar
1608
Member
Posts: 2493
Joined: Mon Oct 05, 2009 1:00 am
Location: ESSEX UK

Re: New battery to g12

Post by 1608 »

I bought a new battery which had the + - marked back to front. This caused some head scratching until I tested with a simple volt meter which
showed the problem.
Hillboy55
Posts: 2
Joined: Sat Jun 27, 2020 2:28 pm
Location: Worcs

Re: New battery to g12

Post by Hillboy55 »

Well that could be the cause of the gassing and poor lights!
I'll try it as-is as soon as I get it checked out for polarity. Thanks all!
56G80S
Member
Posts: 3353
Joined: Wed Oct 12, 2005 10:45 pm
Location: N YORKS UK

Re: New battery to g12

Post by 56G80S »

"hich had been completely rewired using the same colour throughout! Andy"

I was guilty of doing that once in order to get to an event, so lang ago I can't remember what!

But now have a tidy correct colours and extra earth leads Colin Farrington loom - Catmando as per Jampot ad.

Johnny B
Locked