I'm always looking for alternatives for a DC supply, as we have a constant problem with mains supply failure.
Add to this that I am a Ham operator who like to keep things up and running, even on DC power if required.
For DC supply I have the normal AC to DC switch mode supplies but the problem is with a suitable protection for my (very expensive according to me) AGM 12VDC batteries.
If you fail to constantly monitor the AGM battery output voltage or with swapping batteries accidentally (and it do happens if you are in a hurry at night) connect it reverse polarity you have a problem.
I have read many articles on battery protection especially with RPP and current flow back prevention as well as a battery low voltage cut-off so I'm starting a project that is compact and cost efficient enough to add to all my SLA's and AGM (and also all flooded cells for that matter) 12V batteries.
So my circuit is more a combination of several other circuits combining an efficient RPP without to many heat losses as well as combining it with a ATTiny ADC to read the voltage to cut off the battery at a preset low voltage, nothing very extravagant or to large or difficult to populate on a single sided PCB and fit it on the battery output.
My requirements would be to feed a radio or other load with DC at a maximum of 30A @ 13.8VDC (as required by my radio when transmitting.
The circuit area I'm not very sure of is the cut-off feed from the ATTiny45 via the 2N7000 that will cut the ground from the main P-ch MOSFET as a high side switch with a maximum current of 55A, Maximum gate voltage of 20V and a RDS(on) of 20mOhm at Vgs of -10VDC.
The second problem may be an Inrush current needed by the load which I do not totally want to limit as in certain instances my radio may require but I have to protect the MOSFET.
The other thing maybe to place a uni directional TVS at the battery poles of the circuit e.g. 1N6377 to clamp high voltage peaks etc.
Please advise me on the following circuit: (its available on PDF format here https://drive.google.com/drive/folders/1jG2ML2XMi52CiVaMMP-QXK-w0ViSZoYC?usp=sharing ) as well as the IRF4905 datasheet