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Old 07-03-2020, 01:26 PM   #19
sbman
Guru
 
City: San Diego, CA
Vessel Name: Second Chance
Vessel Model: 42' Uniflite Double Cabin
Join Date: Jul 2017
Posts: 828
Quote:
Originally Posted by jungpeter View Post
High Wire-I put my IR temp gun directly on my house battery posts after being underway for several hours. None exceeded 72 deg F. My battery bank is located between my main engines, as low as possible in the bilge of my Tolly 48. Don't forget-here in the PNW, we operate in roughly 50 deg F water 24/7. So the entire underbody of my boat's bathed in a relatively cool thermal sink. Yup, the temp at the ceiling of my engine room is higher. But the batteries are pretty cool 24/7.

And as stated in my original posting, the chargers (the main engine alternators while underway) are temperature compensated via temperature sensors on the house batteries.

Baker-Again, with all due respect, perhaps we should agree to disagree. You continue to admonish me to "...get (significantly) better charging capacity." Due to the inherent design of the 3208 CATs (my main engines), and the resulting cramped installation in a Tolly 48 engine room, there simply isn't physical space to accommodate higher output alternators, or the attendant drive belt requirements. And the as-installed 105A Delco-Remys are WAY more capable than the 78-vintage 65A internally-regulated OEM CAT alternators. Those went away years ago under previous ownership.

If you're referring to my puny Blue Seas 40A shore power charger, I would LOVE to upgrade it. But given it's only used to put in the last residual charge deficit remaining upon plugging into shore power whenever possible, I think it'll do. It may take a while, but it gets the job done, usually within 24 hours.
And it is programmed to deliver a similar charge profile (14.7V bulk/14.7V absorb/ 13.6V float) as the Delcos.

And finally to answer your question regarding manually controlling the field of my alternators underway, the answer is yes. A published "fix" for this situation is to run a lead from the voltage regulators' temperature sensor port to a on/off switch at the dashboard. One can then artificially trip the sensor, signalling the alternator that an over-temperature state exists on the alternators, which immediately reduces the output to something like 50%. But given I'm already at way-less than full-field (SOC is 100%) upon leaving the dock at the beginning of a trip, and the combined output of the alternators is only sufficient to compensate for the running DC loads, the result is ???

And I guess if that's my only option, I guess I may post a full-on rant to Balmar, and those that promote it's virtues and programmability so highly, that (in my case) an approximately $1000 regulator/centerfielder combo requires manual operator intervention to operate "properly". Say it isn't so!!!

Regards,

Pete
If I understand correctly, you are wanting to have the alternator regulators go immediately into 'float' charge if the battery is already full from the shore power charging when you start a journey since the are already full from shore power. Is that correct?

The Full River documentation states that the maximum absorption phase of charge is 8 hours @ 14.7 volts followed by float charge @ 13.65 for a minimum of 8 hours, so doing that absorb phase again for a long period of time after it has already been completed by the shore power charger would seem to violate that part of the specified charge regimen.

Given that, the MC-614 is pretty smart. You can set the bulk and absorption times pretty short (6 minutes) and then let it perform the calc-bulk and calc-absorb so it will back off if the batteries are already full, and go with the manufacturer's recommended voltages for those phases. If you pull the shore power plug as the first thing you do when you arrive to use the boat you can deplete the batteries a little bit and the 614's should do a good job of topping them back off and not overcharging getting to float pretty quickly.

The documentation also says that 20 hours is the maximum total charge cycle time, so your 40 amp shore power charger, if used to replenish the batteries from a 50% charge state would be unlikely to be able to meet that requirement. You didn't ask about that, but it is the case. On a 48' boat, I'm surprised it can handle dock-side 12V power needs alone if you use the boat at the dock at all.
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