I bought a 220 amp smart battery protect recently as apart of a project in my motorhome. My motorhome has a battery to battery 50amp, 30 amp mains charger, 30 amp solar charger, 1600 watt pure sine inverter, 280 watt solar and 330 amp batteries. Its all from Sterling Power and works very very well. I had the idea that when the batteries were full on solar I could then use the excess energy to hear the water. The water heater is a Truma 10lt boiler that can be used on gas or mains electric. The element is only 450 watt so doesn't take a long time to hear up and switch off via a thermostat. Anyway the idea was that I would use the smart battery protect to switch the inverter off if there wasn't enough power in the sun to keep the batteries afloat, cut off if they got to low and start up when the batteries were good to go again.
What I didnt fully appreciate is that you cannot directly connect the inverter to the SBP without frying it as the capacitors draw a huge sudden current draw on re-connection. Had a think about this and I came up with the idea of using the SBP to monitor the battery voltage and switch a 3 amp AC relay that is 12v controlled to disconnect the boiler element. The 220 amp SBP is a bit over the top then but I will keep it anyway incase I use it for another project.
Does this seam like the best route or is there another way. I also thought that this would be a better way of doing this as it would allow other devices to remain connected e.g. small laptop charger.
Regards
Grant Kay
