Possible rework of DC system

[HMT2]

OK, I’ve been trying to avoid this but I am thinking of reworking my dc system. I have a 37 watt solar panel that keeps my batts well topped off, but there is no controller. I rarely use my charger here are two pics. Can anyone tell me what the block is at the bottom?

 

[JimInPB]

Could be a rectifier. Could be a regulator. Could be a regulator-rectifier...

Does it have any numbers or other info on it?

 

[capta]

It is a splitter. One charging source charges two banks w/o a connection (diode separation) between the banks. Old tech and there is voltage loss involved, but I don't remember how much. I took mine off the boat because I want the alternator to charge only the house bank.

 

[NYSail]

Called an isolator.....

 

[JimInPB]

The voltage drop across a diode is normally 0.7vdc

 

[dlochner]

Diode based isolator. It will slowly kill your batteries. Because of the diodes there is a voltage drop, the batteries never get fully charged or charged properly. That ancient charger isn't helping either. And even small solar panels need a controller, on a bright sunny day some small panels put out 17+ volts at a very low amperage, better for the battery to see less voltage and more amperage.

So, you're right, a modern charging system is in order.