Date: Mon, 1 Aug 2016 09:27:10 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: testing capacity of house battery
In-Reply-To: <CABToOY+MXPQ9zVpy9oc=b1967YD0KoT9cUSrWcM0_fsp5DsGHg@mail.gmail.com>
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Small (true) deep cycle batteries are rated at both a 5 and a 20 hour rate. These rates come up with somewhat different overall amp hour ratings due the batteries resistance to deliver higher currents over time. If you are using substantial loads such as lights and heaters along with stereo / inverters or what have you the 5 hour rate is the one that is important.
The group 41 starting battery (if that is what you are using) as a starting-lighting-ignition battery also get rated for cold cranking amps, (0F), and reserve capacity. For an "SLI" battery the total amp hour rating is based on the 20 hour rate. For the group 41 battery ~60 A/H is typical. Reserve capacity is the time it can sustain a 25 amp load which is a factor when the a charging system fails or you need lighting during a break down. Again for the group 41 "SLI" battery a typical rating is 110 minutes.
So based on your results below your battery is good for the core deposit or a door stop.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Edward Maglott
Sent: Monday, August 1, 2016 8:56 AM
To: vanagon@GERRY.VANAGON.COM
Subject: testing capacity of house battery
I have a few years old non-deep-cycle automotive starting battery I've been using as my house battery in the 86 Westy. it's been acting a little flaky so I pulled it out for some testing and possible replacement. I've had some other issues/symptoms with my house battery side of the electrical system so I wanted to take a possibly failing battery out of the equation.
I last drove the van about a week ago for about 2 hours with not much load on the house battery. I hooked up the battery to one of these:
http://www.banggood.com/ZB2L3-Battery-Capacity-Tester-External-Load-Discharge-Type-Module-p-1058571.html
For the load I used a tail light bulb with both filaments burning. This put 2.55Amps load on the battery according to the display on the above device. I set the device to stop discharging at 10.5V and it came out to about 13Ah of capacity. That sounds low to me and like the battery was either not very well charged or it's toast. I've now got it on a charger and will check it again after it's recharged. comments? is discharging it to 10.5V more damaging than any info I gain from testing it?
Edward