Hi just to pick up on a
Hi just to pick up on a couple of points you mentioned. I agree that simple cheap relays are not the best way to split charge but for people with not heavy electrical useage loads they can be a good cheap solution which negates the need to be operating isolation switches whilst driving. I am not sure on the type of vehicles either of guys are driving but most vehicles require the battery to be connected when running so when you switch you run the risk of one battery discharging into the other. Just as simple relays burn out from the same problem. There is some debate as to wether or not this can damage the batteries. But personally i wouldn’t want to risk it.
Also you mention that this is the only way to ensure your vehicle will start in the morning. I entirely disagree with this. Switches and relays are not the only way to isolate batteries from one another thus ensuring your vehicle battery is not used for leisure purposes.
The use of a blocking diode will prevent current flow from one battery to another. You just need to take into account of the voltage drop that you will get accross the diode by use of advanced voltage regulation charging rather than the standard voltage regulation that is fitted to 99% of vehicle alternators.
So i often i hear/read people suggesting that there is only one way to approach the issue of split charging. There are many, some cheap, some simple and others more expensive and more sophisticated. Most work to varying degrees but how well they perform depend on the load they will be subjected to.