12v Battery Butler Chargers don't work

[JJZ109]

I recently bought four Battery Butler 12v battery long-term storage float chargers, all of them don't work afaik. They have a red 'Power' LED and a green 'Charging' LED. The red Power LEDs come on, but the green charging LEDs on all four won't come on, even on a known partially discharged 12v automotive battery. One of my older Battery Butlers still works and the red and green LEDs comes on when hooked up to the same battery. The battery voltage does not come up even a little when I hook the new BBs to it. I'm a newbie to electronics in general, but have done some reading and studying so can speak a little intelligently about it.

Please find attached pictures of one of the chargers. The four major ICs are: a DB107 Rectifier, an EL817 Photocoupler, a Viper12A Pulse Width Controller with high power MOSFET, and a LM358P Dual Op Amp. The rectifier is working and sends 160VDC to the 'input' side of the large 'transformer'? There are four pins soldered to the circuit board on the 'input' side, and only two pins soldered to the board on the 'output' side of the transformer. That's as far as I have been able to go with this circuit, because I don't get why 160VDC goes to a transformer. Maybe it's a choke? Not sure.

Ideally, I'm hoping someone has a schematic of the Battery Butler float charger, or can explain to me what signals I should be seeing coming in or out of what components to troubleshoot it?

Thanks for any help,
Wil

 

[tcmtech]

Unfortunately what you have there are typical SMPS (switch mode power supply)units which unless you are fairly knowledgeable in electronics and switching power supply design troubleshooting one and actually repairing it is highly unlikely.

 

[JJZ109]

I've been learning about SMPSs, didn't realize this was one. That will help. Does anyone know of a schematic for these or other similar chargers?

 

[ronsimpson]

Hope this helps.

 

[JJZ109]

Thanks, I have the data sheets for the four IC chip components. I'm hoping for a schematic of the entire charger. It's probably proprietary information, but maybe there's similar circuits out there somewhere.

 

[debe]

Highly unlikely to get a circuit This circuit is from application notes & should be close to what you have in principal on the mains side. To see if that is working ok I would measure the filter capacitor on the secondary side for voltage. If that's ok then the problem is in regulator circuit that feeds the battery.

 

[JJZ109]

Thanks, that application note has given me something to get my teeth into. What does the recurring term 'offline' or 'standby' refer to?