Vanagon EuroVan
Previous messageNext messagePrevious in topicNext in topicPrevious by same authorNext by same authorPrevious page (July 2007, week 4)Back to main VANAGON pageJoin or leave VANAGON (or change settings)ReplyPost a new messageSearchProportional fontNon-proportional font
Date:         Sat, 28 Jul 2007 09:52:21 -0700
Reply-To:     Michael Elliott <camping.elliott@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Michael Elliott <camping.elliott@GMAIL.COM>
Subject:      Re: CDN Tire: Two  6 volt vs One  12 volt battery question
Comments: To: Malcolm Stebbins <mwstebbins@YAHOO.COM>
In-Reply-To:  <283416.87244.qm@web43138.mail.sp1.yahoo.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

There are trade-offs.

The links your provided take me to a log-in page where my USA-style zip code is not accepted.

So I can't comment on those batteries. But I can offer these possibly useful thoughts.

1. The ampere/hour ratings of the batteries are not given at the same discharge rate. The 6V battery is rated at 6 hours discharge (golf cart usage) while the 12V battery is rated at 100 hours. Typical ratings for batteries being sold into the solar market are given at the 20-hour discharge rate. So apples to oranges, almost. One can make guesses if he knew more about the batteries, which I don't.

2. The 12V battery is an AGM. For longest life they want care when charging to avoid damage. If you plan to connect them to a wall charger and let them sit, then make sure it is designed for AGMs which want a three-stage charging cycle: bring battery up to about 14V by dumping current into it ("bulk" charge stage), choke back current as needed to hold voltage for about two hours (absorption stage), then drop voltage to manufacturer's recommend "float" voltage. This is less critical for flooded batteries, like the 12V one, which can be held at the same voltage for float as for absorption w/o damage as long as you keep an eye on the electrolyte levels and add distilled water as needed to replace any that has fizzed out. For less muss and fuss, three-stage charging can be a good idea for flooded batteries. Flooded batteries also want occasional "equalization" to make sure that all the cells in the battery are providing the same voltage. This is something that some chargers and our solar controller can be told to do. More here: http://www.bigginhill.co.uk/batteries.htm

Though. The difference between a two stage and three stage controller when using AGMs is probably not worrying about if you use your battery like we use our non-AGM battery, where the battery gets charge taken out every morning before getting charged up during the day. Daily cycling with a two-stage charger apparently isn't a problem for AGMs, although battery mfgrs may differ; this mainly because they are thinking about wall chargers that will keep the battery at 14V 24 hours a day, and will damage an AGM.

More tradeoffs. Your alternator + 1315 probably won't take the battery up to its full absorption voltage, so it won't get baked, but it won't get quite as fully charged as a good solar controller or two- or three-stage charger can take it. In my application I see that we run about 10Ah short of fully charged when I use the alternator to charge the battery when compared to a good charge from the solar controller.

For me, if I was choosing between the two, and since you are contemplating using your alternator for charge (at first) and want a few days of use between charges, I'd go with two golf cart batteries if they are of good quality. My opinion only, and one that is not as informed as others, but better than many.

-- Mike "Rocket J Squirrel" Elliott 71 Type 2: the Wonderbus 84 Westfalia: Mellow Yellow ("The Electrical Banana") 74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano KG6RCR

Malcolm Stebbins typed: > Having read the post regarding Canadian Tire's battery sale, CDN Tire has 2 batteries that seem to > be what I want/need: > > http://www.canadiantire.ca/browse/product_detail.jsp?FOLDER%3C%3Efolder_id=1408474396673605&bmUID=1185573901792&PRODUCT%3C%3Eprd_id=845524443277145&assortment=primary&fromSearch=true > and > http://www.canadiantire.ca/browse/product_detail.jsp?FOLDER%3C%3Efolder_id=1408474396673605&PRODUCT%3C%3Eprd_id=845524443290779&bmUID=1185574219890&assortment=primary&fromSearch=true > > If your browser breaks up those URLs, The specs are: > > 6 volt: $85 CDN - Features > > * Deep-cycle 6 V battery can be used with solar panels as a source for stored energy when used > > in conjunction with inverters > * 390 minutes of reserve capacity (at 25 amps) > * 150 Amp Hours (at 6 hours) > * Also fits golf cart applications > * 6-month manufacturer's warranty > * 6-month free replacement > > 12 Volt:; $213 CDN Features > > * Renewable energy deep cycle battery > * 12V sealed AGM (Absorbed Glass Mat) deep cycle lead acid battery > * Designed to be used with Xantrex PowerHub 1800 (11-1877) or as part of any battery bank for > a > renewable energy system > * 100 ah at 100 hour rate > > > I know VERY little about electricity. but I do know that 2, 6 volts can = 12 volts. > > So which is "better"? My intended application/use is: > > Battery under rear seat (so no space limitations), to power all stock interior lights and my > lap-top through an inverter, but NOT the Dometic fridge; I have a top loading Waeco compressor > type fridge that draws, on average (at 70 Deg F) 1 amp per hour. I figure that 3 to 4 days of NOT > running the van (to charge the batteries) will be about all I'll need. > > I also plan to maybe add a solar panel to the top of my van, maybe a 2 or 3 amp panel. > > I also have a SurePower 1315 and I called them and they said their unit would not care if it sees > One 12 volt or Two 6-volt batteries. > Cost is really NOT a factor, (but 2x$85 = $170, or $213) I want the best, more reliable, and > longest running set-up. > > So which is "better".................... I fear the answer will be "There are trade-offs...." > > Malcolm (who barely understands watts = amps x volts, AC vs DC etc.) > > > > > ____________________________________________________________________________________ > Need a vacation? Get great deals > to amazing places on Yahoo! Travel. > http://travel.yahoo.com/ >


Back to: Top of message | Previous page | Main VANAGON page

Please note - During the past 17 years of operation, several gigabytes of Vanagon mail messages have been archived. Searching the entire collection will take up to five minutes to complete. Please be patient!


Return to the archives @ gerry.vanagon.com


The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.

Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.