power source battery charger power supply model pc40 making loud buzzing noise

[89 allegro]

i have a 89 allegro class A  motorhome  3 total batteries and today when i plugged it into power after a couple hours my battery charger/power supply started making a sizzling sound inside of it ,i got a air hose and blew it out and it kept making the same noise, i checked it as good as i could and did not see any sparks are anything and i checked battery voltage and they were 14.4 volts,i unplugged the charger and the volts dropped slowly then leveled out, so i know its charging . it is called a  ",power source battery charger power supply model pc40 "  ,was what was written on it .after about a half hour, the noise just stopped ,so my question is do i need to replace it because its going bad and if so what do i replace it with that's a simple swap out and my next question is , whats considered to high of volts while plugged in to electric and its charging ,14.4 seems really high to me after about 4 hours of being plugged in.i do know about 2 years ago i had a cooked battery while plugged in at campsite ,but nothing since.and consider this is a 1989 so as far as i know, this is just the charger /power supply ,it has a inverter in another spot so as far as i know, its just a charger, ..please help with any suggestions.

 

[Gary RV_Wizard]

That vintage of charger technology was prone to that sort of thing and it is typically triggered by some combination of external factors. It is conceivable it may be failing, but I would not leap to that conclusion.

However, that device is really poor at its job by modern standards. Newer designs and cheap electronics yield much more efficient battery management that will charge faster using less power and extend battery life substantially.  I would consider replacing it for that reason alone. A Progressive Dynamics 9245 would be a great replacement, but even a less expensive unit such as the Powermax ought to do nicely.

 

[89 allegro]

i found a power max PM3-45 that they said is a direct replacement for my pc 40 for $96 ,so i will be getting it soon,.what should be the highest volts this charger should be putting out if you know. thanks for your help

 

[Gary RV_Wizard]

Probably around 14.4v, but smart 3-stage chargers can take some liberties if closely monitoring amps and volts the battery is accepting. Without getting too much of a headache, you can learn a bit about how 3-stage charging works at one of these sites:

https://www.batterystuff.com/blog/3-stages-of-smart-chargers.html

http://www.chargingchargers.com/tutorials/charging.html

http://all-about-lead-acid-batteries.capnfatz.com/all-about-lead-acid-batteries/lead-acid-battery-charging/three-stage-battery-charging/

 

[89 allegro]

thank you sir , i will check them out.thanks for your help.