Battery Question

JusDreaming · 28-01-2009, 05:29

I need a new battery for the gen set. It is totally isolated from house banks, and is charged by an echo charger. So my question is why should I not use a maintenance free auto battery rather than an AGM marine starter battery? It needs to be maintenance free do to access!!!

westsail42 · 28-01-2009, 07:08

The "purists" would say "dont mix different chemistries". But in your case, you would be fine with a standard automotive battery for a starter on the genset.

The reason is...

The EchoCharge. It only "echos" when the main bank is topped up, then it "trickle charges" the second battery (genset starter). Since your genset starter battery is only used for "starting" it will nearly always be at "full charge" under normal use. The charging voltage for both gels and flooded at near full capacity is not very different (if at all), so concern for "charge profile" is not warranted (the primary reason why you dont mix chemistries: different charge profiles).

Now, if you were using your genset starter battery for other regular uses, to cause deeper discharges, it would be a different story.

My opinion of course. I am sure there is someone here that will disagree.

btrayfors · 28-01-2009, 07:15

Right on!

Same question asked and answered (in like manner) on SSCA Board.

B.

28-01-2009, 05:29	#1
JusDreaming Registered User Join Date: Jul 2004 Location: Stuart, FL & Bahamas Cruising Boat: Lagoon 37 Posts: 446 Images: 13	Battery Question I need a new battery for the gen set. It is totally isolated from house banks, and is charged by an echo charger. So my question is why should I not use a maintenance free auto battery rather than an AGM marine starter battery? It needs to be maintenance free do to access!!! __________________ Denny and Diane Formerly "NCDD" S/V JusDreaming Lagoon 37 www.svjusdreaming.com http://www.sailblogs.com/member/svjusdreaming/ "The only way to get a good crew is to marry one." -Eric Hiscock

28-01-2009, 07:08	#2
westsail42 Registered User Join Date: Oct 2008 Posts: 57	The "purists" would say "dont mix different chemistries". But in your case, you would be fine with a standard automotive battery for a starter on the genset. The reason is... The EchoCharge. It only "echos" when the main bank is topped up, then it "trickle charges" the second battery (genset starter). Since your genset starter battery is only used for "starting" it will nearly always be at "full charge" under normal use. The charging voltage for both gels and flooded at near full capacity is not very different (if at all), so concern for "charge profile" is not warranted (the primary reason why you dont mix chemistries: different charge profiles). Now, if you were using your genset starter battery for other regular uses, to cause deeper discharges, it would be a different story. My opinion of course. I am sure there is someone here that will disagree. __________________ Building out a Westsail 42 http://www.westsail42.com

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28-01-2009, 07:15	#3
btrayfors Senior Cruiser Join Date: Jul 2006 Location: Chesapeake Region Boat: 42' Bob Perry sloop, "Born Free" Posts: 1,428 Images: 3	Right on! Same question asked and answered (in like manner) on SSCA Board. B.