A good quality lead/acid battery will self-discharge at the rate of 3 to 5 percent a month. So if you start with a fully charged start battery and have no load on it – like your bilge pump – you should be able to leave the boat for 5 or 6 months and still be confident about being able to start the engine.
Batteries do last longer if stored fully charged. Sulfation is a large part of the problem when batteries are at a low state of charge for an extended period. But it really doesn’t look like you are talking about an extended period. And as long as you can start the engine, you can always recharge a depleted house bank as needed. My electrical consumption, when on the boat, is pretty similar to yours; fridge, lights, radio, instruments when sailing, and recharge phones and tablet. All powered exclusively from the house bank. I figure my average consumption is about 75-80 AH per day. My 4 group 27 deep cycle batteries will give me at least 2 and usually 3 days of service without starting the engine to recharge. I would imagine your house bank would be adequate for a couple of days at anchor. And a couple of weeks – at least - of powering the bilge pump unless you have an unusually wet boat. Before I leave to go full time cruising, I do plan to install the wind generator I already have but have never installed, and to add a charge controller and maybe 300 watts of solar panels. But that will be to allow extended living on the hook while I travel – which is a whole other situation that week long coastal cruising. I actually have a third bank on Imzadi: a group 24 deep cycle under the v berth that supplies power to the windlass and the Lectra-san. Current draw in high, but only for very short periods. The house and start banks are charged from either the engine or shore power, but the group 24 is not wired in. I have a little 35 watt solar panel bought at WalMart that I use sporadically as a trickle charger for the group 24 battery. I just replaced the group 24 after 6 years. Maybe all you really need – and mostly for your own comfort and confidence – is a small solar panel you can use to trickle charge the start battery. Rick Brass Washington, NC From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Danny Haughey via CnC-List Sent: Saturday, February 27, 2016 10:23 PM To: cnc-list@cnc-list.com Cc: Danny Haughey <djhaug...@juno.com> Subject: Re: Stus-List Stus-list: portable generator on sale at harbor freight Rick, She has a house bank of 3 group 27s and a starting battery. Maybe I should just get a solar panel now. I had a small one I would hook up when leaving the boat on lolita. I also understand keeping your batteries topped up prolongs their life. We usually use the boat every weekend and do weekends on her here and there and then, we plan on doing maybe 2 one week cruises around the islands here. We do have a refer and use lights, charging tablets and phones. Just your regular convenience type usage. Danny
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