On sale (Closeout ) at Harbor Freight

[Cliffmeister2000]

This may be a good thread. Or there may already be one that I haven't found yet that is suited for this...

Anyway, Battery Isolator on closeout at HF for $20

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=93801

Cliff

[Alphacarina]

Those were pretty expensive in their day - They have fallen out of favor over the past few years

Problem is that semiconductor isolators like that don't allow you to get a full charge on either of the batteries they isolate. The semiconductor drops about 3/4ths of a volt, so when you apply the 13.8 charging voltage only about 13 of it reaches the battery and that's not enough to give you a full charge

Battery combiner relays (voltage sensing relays, or sometimes called ACR's for Automatic Combining Relays) are the new way to go. They isolate the two batteries all the time until they sense a charging voltage above 13 volts and then they combine the two batteries with a high power relay, so both get a full charge. When the charging voltage goes away, the relay opens and the batteries are isolated again


http://bluesea.com/category/2/productline/236

Don

[Cliffmeister2000]

alphacarina says:

Battery combiner relays are the new way to go. They isolate the two batteries all the time until they sense a charging voltage above 13 volts and then they combine the two batteries with a high power relay, so both get a full charge. When the charging voltage goes away, the relay opens and the batteries are isolated again

Well, there you go! It was worth the post just to get the newer information! When I was a teenager (35 years ago) I had a 1959 Cadillac Ambulance with a huge diode and two batteries in it. And enough room between the grill and the radiator to store an ice chest in!
Cliff