voltage after start 12.5v, 30s later 13.7v

[bankshk]

It normally happens on the first start of the day, it takes a while before the voltage shows 13.7v and i live in warm climate. The alternator is about a month old. I do have a blue sea setup with 2 batteries, is it going through some testing before isolating?

Any ideas?

Thanks

Edited September 20, 2014 by bankshk

[shawndoggy]

Is it possible that you have set up the switch and relay "backwards" so that your starting battery and alternator cable are on opposite sides of the switch?

[REW]

Did this start reciently? Like with the new altenator? Next cold start, have a buddy read the voltage off the altenator during and after start with a multimeter, make sure the meter and dash make the change tom13.7 at the same time. Imhave never heard of a BIT on an altenator, it is either making power or not, the dash shows system voltage,what ever makes the most power wins.

hope this helps......fun problem

[bankshk]

yes it started with the new alternator. i was hoping it might the belt getting tired and doesnt spin up the alternator till warmed up properly?

i have it wired as per the blue sea add a battery instructions, so starter battery + to bottom of 2 (on the switch) , and alternator out of the top of 2 (on the switch) is that correct?

[shawndoggy]

and then what about the wire to the helm? Is it also on the #2 side?

[formulaben]

I'm betting your new alternator has a "soft start" feature in the voltage regulator. It waits 30 seconds before fully charging. I upgraded mine this spring and have the exact same deal. Luckily the technician warned me about it after the install.

[Pistol Pete]

If it makes this change dead-nuts after 30s every time then, I'd agree with formulaben.

[formulaben]

This Balmar ad refers to it. Can't find much else but according to the tech who installed my new alternator the newer "smart" alternators all do it.

[bankshk]

i hope its the soft start feature the new alternator looks identical to the old one. i will investigate further tomorrow when i take the boat. thanks for the help so far

[wakeparadise]

I'm almost certain this is a normal thing when using the battery isolator. I have the exact same setup and it does the exact same thing.