kramttocs Posted September 5, 2019 Share Posted September 5, 2019 I looked and couldn’t find it. But I can measure mine. However, it won’t be until later tomorrow or maybe Saturday. That would be great. Thanks! Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 5, 2019 Author Share Posted September 5, 2019 That would be great. Thanks! Had a few minutes today, so did the test. My 200a unit pulls .67a at 12.8 volts to hold the relay in. I have an original Battery Tender on those two batteries and it handled that load fine. But I have smaller HF ones on the boat, and one of them wasn't up to the task. Perhaps that particular 85a unit takes a bit more to hold in? Link to comment Share on other sites More sharing options...
kramttocs Posted September 5, 2019 Share Posted September 5, 2019 Had a few minutes today, so did the test. My 200a unit pulls .67a at 12.8 volts to hold the relay in. I have an original Battery Tender on those two batteries and it handled that load fine. But I have smaller HF ones on the boat, and one of them wasn't up to the task. Perhaps that particular 85a unit takes a bit more to hold in? Thanks for testing that. Good info to have. Link to comment Share on other sites More sharing options...
FrazerJames Posted December 27, 2021 Share Posted December 27, 2021 I'm going to use a Cole Hersee 48530 Smart Isolator on Big Blue, but I have its little brother, the 48525, on our boat. The bigger one is rated at 200a and the little one at 85a continuous, which fits the output capability of the two alternators. The documentation is here, but my favorite features are: Automatic Parallel: The two batteries are paralleled when either battery's voltage is above 13.2V for 2 minutes. So you can pull the auxiliary battery down to zero and it won't connect that one in parallel to the starting battery during starting - like the factory relay does. Automatic Disconnect: The two batteries are isolated when both battery voltages are below 12.7V for 1 minute. So if your aux battery dies and it starts taking everything the alternator can put out and still the voltage goes south it'll drop it out of the circuit. However, it doesn't work if the main battery goes south. I know that for sure. Forced Parallel: One little switch can force it to parallel the two batteries, like if the main has gone south and the aux is up. LED: There's an output that tells you when the batteries are in parallel. I check that on the boat frequently. Gary, I think I’m going to get your recommended isolator (been reading all the threads). Quick question: I have a 3g alt which connects to a mega fuse then to the main battery. I assume I should connect the isolator after the fuse. Any other places you think I’ll need a mega fuse? I’ll be putting an aux fuse box on the aux battery. I suppose it wouldn’t hurt to put a mega fuse between the battery and fuse box there… Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 27, 2021 Author Share Posted December 27, 2021 Gary, I think I’m going to get your recommended isolator (been reading all the threads). Quick question: I have a 3g alt which connects to a mega fuse then to the main battery. I assume I should connect the isolator after the fuse. Any other places you think I’ll need a mega fuse? I’ll be putting an aux fuse box on the aux battery. I suppose it wouldn’t hurt to put a mega fuse between the battery and fuse box there… Yes, I’d connect the isolator after the fuse. And I’d put a megafuse between the aux battery and the aux fuse box. Link to comment Share on other sites More sharing options...
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