Re: [Amel Yacht Owners] Re: Does my ONAN need a new 12V charger?
Alex Ramseyer <alexramseyer@...>
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thanks for your information.
I looked at IWW in St. Georges and catalogue and couldn't see the 1000 CCA starter battery there. Not sure that I will get it here in Grenada. The other reason I bought this battery was that before the boat had the same one built in. The former owner replaced it also in the Caribbean...
The next problem with batteries here in Grenada and other parts of the Caribbean is that the height of the battery compartment wouldn' allwo to install the (higher) american dimensions. The former owner changed the starter battery space, so I can at least have a higher battery there. But when I was looking for housing batteries in the U.S. earlier this year I found nothing. So I bought new housing batteries in St. Martin (Duracel AGM 12V 85A). They worked fine so far.
Yesterday I let the Volvo run for an hour and this morning I read 13,2V at the starter battery. Likelyhood increases that I have a problem with the 12V alternator on the ONAN.
A friend of mine will pass by with a battery load tester device tomorrow. Will know more by then..
Best regards, Alex
NO STRESS, AMEL54#15
On Monday, November 20, 2017, 5:49:52 PM GMT-4, 'Bill & Judy Rouse' yahoogroups@... [amelyachtowners] wrote:
batteryis undersized. Why did you buy a Grp27? Your 54 came with a Grp31
The Grp27 battery you bought is 840CCA. Deka makes a Grp 31 1000CCA battery.
Did you replace your other batteries?
Do you have the 4 cylinder Onan, or 3?
If you are reading battery voltage in the cockpit, you must be reading it on a Volvo output panel, which means that you have the entire suite of Volvo electronics, 2 computers and various sensors powered-up as well as the 12VDC exhaust fans running. I am guessing 6-10 amps at 12VDC draw on your starting battery. This is NOT a way to test resting voltage, nor is it the thing to do before starting the generator.
In my opinion, you undersized the starting battery. This is especially significant when we are talking about the generator. The length of 12VDC wire from the starting battery to the starter is almost 7 meters from battery to starting motor. If everything is perfect, the wire that Amel uses for this is adequate, but, with an undersized battery, I suspect NOT.
Continue testing the "resting voltage," but at the battery. Continue to look for resting voltage of less than 12.8 volts, then see if you can determine why. Turning ON your Volvo systems and energizing the fans will drop the voltage and drain the battery. You did not say whether you "prime" the Onan when starting. This is pressing and holding down before starting. This should not be necessary for you unless the Onan has not started in a while. If you do this before starting, you will drain the battery.
Hopefully, you will learn why the resting voltage got as low as 12.4 volts (basically discharged), and hopefully your battery is OK. However, I think you need to plan on replacing that Group 27 starting battery with the correct size. BTW, if after running the Onan only for 1-2 hours the resting voltage on the starting battery after turning OFF the Onan should be 12.8-12.9 VDC at the battery...if it is not, the little alternator on the Onan needs attention.
I have forgotten the output of that little alternator, but see to remember something like only 10 amps.
On Mon, Nov 20, 2017 at 3:01 PM, Alex Ramseyer alexramseyer@... [amelyachtowners] <amelyachtowners@...> wrote: