Charging Voltage from alternator

[boatboy]

Temp sensor

Yes, I got the Max Charge regulator, but no I did not get the temp sensors. I will make a pont of adding them in the next round of upgrades. Right now I am just very happy about not needing to worry about the overcharging issue on our cruise -- which starts this coming Saturday.

 

[Loren Beach]

AGM / Alternator trivia

On the part of this thread about voltage output from a stock (Motorola) alternator....
I just replaced my "emergency/starting" battery yesterday. The former one died last week after four years. I have been using an AGM battery tucked under the aft berth in a custom box. This was done because the location precludes adding water if it were a flooded battery.
I next fired up the 23 hp Universal (easily, I might add (!)...) with the new battery and my digtal volt meter reads 14.13 to 14.15 charging volts at RPM's from idle to 2000 RPM, measured at the battery.

I note that the printed intormation that is enclosed with the new Optima (blue top) states that it should be charged with: "Alternator: 13.8 to 15.9 volts, Battery charger: 13.8 to 15.0 volts, 10 amps, Float Charge: 13.2 volts to 13.8 volts, 1 amp maximum current."
Then it states that a "Rapid Recharge" = "Maximum voltage 15.0 volts and no current limit as long as battery temperature remians below 125 degrees F."
I am still using the stock 50 amp (might be rated 55, but I forget) Motorola alternator.
Hope this additional info helps the discussion along.
Loren in PDX
Olson 34 #8

 

[Geoff Johnson]

I don't think it matters so long as you have a way of disonnnecting the Optima (which I also have) from the alternator so that it is not being continually charged at 14.13 volts which is outside the recommended range for trickle charging AGM's. FYI, the Balmar regulator, when set for AGM batteries, will drop the continuous charging voltage back to 13.2 volts. I have my Optima connected through a manual swich and almost always leave it off since the self-discharge rate is about 1% per month. I start my engine from the house batteries (also AGM).

The advantage of the battery temp sensor that goes with the Balmar 612 is that it will adjust the charging voltage according to the temperature of the battery (and presumably shut it off if the battery starts to overheat).

 

[stbdtack]

E-38 electrical system....

Seems like i always get in on the discussion late....

I have 460 ahs worth of batteries on my 38. They fit into the original battery spot under the aft bunk with just a little trimmed wood to get them into place. Its really a perfect fit for the "4" 6volt deep cycles. Boat still lists a little to stbd with the Stbd water tank full. best thing is the reefer will run 5 days before needing to recharge.
I also have a Balmar 110A alternator controlled by a Balmar/Xantrex regulator. They are the same unit although there are different models.They are made for Xantrex by Balmar. I think the Xantrex are a little better because they spec a softer potting material that will be less prone to crack and damage the IC as it ages. BTW these are available on Ebay pretty cheap. Search for Xantrex regulator or Balmar regulator. Should be able to buy a new for $75-$100. I think i payed $84 for the last one i bought. I like the wet cell feature built in that charges to 14.4 volts. Much faster putting the last slow amps back.

The regulator should not blow because of a short in the rotor. The Xantrex/balmar units have a fuse in the harness that prevents this. My old Hehr Powerline regulators had the same feature.

I use a Combiner with a separate engine start battery and a link 10 to monitor the 2 house banks. Ditch your old analog meters and install Digital. Its the only way to measure accurately. There are some inexpensive Voltmeters available now. Saw some nice cheep units in the back of Cruising world I believe.

System has been pretty foolproof and worked like a charm when the old engine start battery died. I just flipped the switch that forces the combiner to close and the house batteries jumped online to fire the Universal right up.

If any of the 38 guys want to see a pic of the batteries installed drop me a line.

Greg, enjoy your trip south, maybe see you on the trip to Drakes Bay!

Ben

 

[Geoff Johnson]

I believe the regulators on eBay for that price are the ARS-4, not the 612, which means they don't support battery temperature sensing.

 

[stbdtack]

regulator

The xantrex i just bought on Ebay has batt temp, alt temp sensor and amp output control, as well as data RX and TX. (for future use according to Xantrex)