Troubleshooting Voltage Regulator (1 Viewer)

[Bloomer]

The last thing I want is an electrical fire so coming to the IH8MUD brain trust for thoughts.

There has been a few times after driving the battery seemed too low to efficiently engage (original) starter. I’ve kept a battery tender on the battery so it’s fully charged when needed. I recently checked the charging system and saw inconsistent readings when at idle. Replaced (what I think is the original) voltage regulator with Denso Reman for Toyota 27700-55040-84 and started up. Saw some light wisps of smoke come off the voltage regulator. Did a quick touch test and didn’t feel any heat but did shut it down and disconnected the voltage regulator pretty quickly.

Did some searching on the internet and found comments ranging from the smoke is normal for a new regulator (burning off oils from manufacturing) to an issue with the alternator overcharging.

A few troubleshooting steps performed:
Checked the battery and get 12.9 volts with engine off.
Reconnected voltage regulator and started engine and get around 13.8 volts at idle with minimal deviation.
Increased RPM and voltage jumps to around 14.5 with minimal deviation.
After running for a few minutes I did start to see some wisps of smoke again, but did take longer for it to happen than the first time. Did not notice the voltage jumping around on the meter and no appreciable heat from the regulator. No electrical smell from either occurrence.

Any thoughts?

 

[charliemeyer007]

Trickle chargers/battery maintainers will fry your battery if left on a lot. Yes I run them on a switch, and only like over night every once in a while. I don't care who makes them or what that cost - they will fry a battery sooner or later.

Electro-mechanical systems have built in slop because that's how it is. I'm going to do a one wire 120A alternator and just add a digital volt meter with big usb charger's for less than $150.

Not a purest approach.

Magic smoke? - if it still works then it was oil flashing off the contacts etc. not the real magic smoke that is required to actually work

 

[Bloomer]

Interesting. Thanks for the input @charliemeyer007 This is the only vehicle I use a battery tender on regularly when not driving, others I do what you mentioned (overnight or no more than a couple days as they are driven often).

 

[73FJ40]

It depends upon the technology. The older buzz box trickle chargers may overcharge a battery.

The high tech float chargers don't. I have a NOCO Genius 10 and it has actually saved a battery on my snow-throwing tractor. The Genius 10 has a repair mode that brought it back to life (after sitting uncharged for 7 months)

I left it hooked up all winter in my garage to the FJ40 and the four year old battery still tests like new.

 

[45Dougal]

Sounds like a bit of oil burning off the contacts. Voltage looks good, doing its job. I wouldn't be worrying but I'd keep an eye on it for a few days - personally I'd prefer the silicon solution any day though, and can't believe they're still making this.

 

[Bloomer]

@45Dougal Appreciate it. Let it run for over an hour yesterday and all seemed to do fine. Still regulating voltage like I would expect and haven’t seen smoke again. Think I’m driving it today.