Drain battery

1965-1971 Datsun 521 forums. All 520 and 521 topics and discussion can be found here.
Gotne494
Posts: 1
Joined: Sun Sep 21, 2014 6:50 pm
Car: 1969 521 truck

Drain battery

Postby Gotne494 » Sun Sep 21, 2014 6:56 pm

I am picking up a 1969 521. Runs good but battery drains after 30 min of driving. Any thoughts? The previous owner said he replaced the altenator


User avatar
Li'l Truckie
Posts: 558
Joined: Thu Jan 02, 2014 9:28 am
Car: 3 x '65 PL 320
1 x '64 PL 320
1 x '63 PL 320
1 x '62 PL 320 - parts :(
1 x '60 PLG-222
and many more Datsuns from 48hp to over 500hp
Location: Leavenworth, KS

Re: Drain battery

Postby Li'l Truckie » Sun Sep 21, 2014 7:38 pm

Sounds like a bad voltage regulator. When was the last time this was checked? Or if a solid state type, just changed out?

Also check - the batter cables - are they fairly new and clean, and properly tightened.

Ground connections - properly grounded, clean of dirt and grim, and a tight connection.

Main cable down to the starter solenoid - is this fairly new, end connection clean, and properly tightened nuts at the solenoid.

Also check the starter solenoid connections, threaded studs, and nuts.

Lastly, did they hook up the wire to the alternator correctly and what do the end connectors look like? Nice and clean? Dirty or a DIY wire connectors and crimp job?

Li'l Truckie

User avatar
Li'l Truckie
Posts: 558
Joined: Thu Jan 02, 2014 9:28 am
Car: 3 x '65 PL 320
1 x '64 PL 320
1 x '63 PL 320
1 x '62 PL 320 - parts :(
1 x '60 PLG-222
and many more Datsuns from 48hp to over 500hp
Location: Leavenworth, KS

Re: Drain battery

Postby Li'l Truckie » Mon Sep 22, 2014 2:02 pm

Sorry, forgot. What is the condition of the Battery?

I had a $300 Yellow Optima only last 18 months because one of the cells had a short. The local Infiniti dealer said I was good to go. Needless to say I had to call for help that weekend; not very happy and not going back!


Return to “Datsun 520 / 521”