My BII has started going dead; no battery power. Ideas?

[markinms]

Looking for advice. My 87 BII has started going dead unexpectantly. No headlights, no inside lights, no power anywhere; I mean dead. Runs and drives fine one minute then the next, nothing. I can jump start it and it'll fire right up and run great. It's a crap-shoot whether it'll start back up or not. Any suggestions on what I should start looking at? Thanks!

 

[sgtsandman]

How old is the battery? What do the battery terminals and cable connectors look like? Does it look like any of the cables might have some corrosion in the wiring? What is the voltage output to the battery when the engine is running (should be 14 volts or more but not 15 volts - ideally 14.1 - 14.2 if the battery is in decent condition)? Do the connections at the other end of the battery cables look ok and corrosion free? If all those check out, we'll throw more troubleshooting at you.

 

[markinms]

Thanks for the feedback!

Battery is approximately 1 yr old. Battery terminals and cable connectors appear to be in good condition. I did find corrosion in the negative battery cable where it fastens to the frame; I'm going to assume whole cable is corroded. I ordered a new cable on eBay this morning. Voltage output (per volt meter) to battery fluctuates from 13 - 14 volts.

I'll do a better inspection of things when the temp gets above freezing.

 

[Curious Hound]

Sounds like a loose or dirty connection. Replacing that cables fix it.

 

[RonD]

Unhook one battery cable
Test battery voltage, 12.3 to 12.8v is expected, write it down

1 year old battery 12.6v at least

Wait 3 or 4 hours and test it again, the longer the better, should be EXACTLY the same with cable unhooked
If its dropping then replace battery under warranty, it has an internal short, self draining, for sure

Above 12.3v the engine/starter motor should start easily, under 12.3v is when there are issues starting

If battery voltage is above 12.2v and engine/starter motor don't work but jumping does, then battery cable terminal is bad, positive or negative BOTH need to pass the same AMPs for a DC system to work

i.e. jumper cables are usually clamped to the outside of the battery terminal cables bypassing connection to battery, external and internal
So could be cable ends need to be cleaned/changed or internal connection inside battery is bad

After engine is started NO POWER comes from the battery, battery is not used at all when alternator is generating voltage
Max battery volts is 12.9/13.0v, brand new out of the box, lol
Alternator generates 13.5-14.8volts
So voltage flows TO the battery, to keep it charged up, so battery is off line with engine running
Battery's only purpose is to start the engine

 

[markinms]

I took the battery back to Advance Auto to have it tested. They didn't even bother; just gave me a replacement under the warranty I have. Now with a new battery and new negative cable I should be in good shape. I'll find out for sure after the cable arrives here on Wed.

Thanks for all the feedback!