Date: Thu, 20 Sep 2012 18:14:22 -0700
Reply-To: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Subject: Re: [Nearly Off-Topic] Seeking Battery Switch
In-Reply-To: <BAY152-ds1735C69E66F860E482374EA0990@phx.gbl>
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I get where you're coming from, Dennis.
But,
"Use the smart charger for your solar array since you may then have
power for enough hours for it to matter."
The solar array already has a smart charger, a Blue Sky Solar Boost
2000E
<http://www.blueskyenergyinc.com/products/details/solar_boost_2000e/>.
The solar array (two panels) is only good for about 5-1/2 A/h, which on
sunny, mild days is plenty of power to top off the battery after the
night's use with LED lighting and the refrigerator. But on hot days, or
on partially cloudy ones, the panel can't always keep up with reefer
usage and the battery goes progressively lower day after day, so knowing
that the battery is at 100% when I arrive at camp is very reassuring;
"Install a proper 110 volt charger such as one of the progressive
dynamic units for when the van is home or when shore power is available."
I don't go from home to a campsite, then back to home, then back to
another campsite; I go from campsite to campsite. Sometimes with several
hours of driving in between, sometimes with just a couple. In the latter
case I need fast bulk charging followed by topping off using the DC-DC
charger to give me a bit of extra charge for the next location.
"Do keep in mind that each time you 'top off' (80-100%) the battery you
are doing a charge cycle which is limiting factor of battery life."
Well, A) Having 20% additional charge in the battery could make a
difference between staying an extra day or having to depart early (or
running the engine*), and B) isn't that like saying keep in mind that
every time you drive your van to a campsite you're causing wear and tear
on the vehicle? What the heck else do I have the battery along for if
not to use it to make life in camp more comfortable?
==================
* I dislike leaving the van idling when camping so if I can avoid it, I
will. Nothing more irritating to me than people who run generators or
engines in a remote camping area. Such people should be condemned to
live next to a 24-hour truck stop on an interstate.
--
Jack "Rocket j Squirrel" Elliott
1984 Westfalia, auto trans,
Bend, Ore.
On 09/20/2012 05:18 PM, Dennis Haynes wrote:
> You're really just adding complexity for almost no benefit. Use the
> smart charger for your solar array since you may then have power for
> enough hours for it to matter. Install a proper 110 volt charger such
> as one of the progressive dynamic units for when the van is home or
> when shore power is available. Do keep in mind that each time you
> "top off" (80-100%) the battery you are doing a charge cycle which is
> limiting factor of battery life.
>
> Dennis
>
> -----Original Message----- From: Vanagon Mailing List
> [mailto:vanagon@gerry.vanagon.com] On Behalf Of Rocket J Squirrel
> Sent: Thursday, September 20, 2012 7:46 PM To:
> vanagon@GERRY.VANAGON.COM Subject: Re: [Nearly Off-Topic] Seeking
> Battery Switch
>
> "Oh. I thought you were talking about running down the road using
> an inverter to power a smart charger, and manually switching to it
> after current monitoring to the house battery showed that bulk charge
> from the engine alternator had diminished below the output of the
> AC-powered charger (which would then go through its own
> bulk-finish-float sequence)."
>
> Almost. I am using a smart charger but it takes 12VDC from the
> alternator as input, not 120VAC from an inverter, though that would
> work, too. See <http://www.powerstream.com/DCC.htm>
>
> -- Jack "Rocket j Squirrel" Elliott 1984 Westfalia, auto trans, Bend,
> Ore.
>
> On 09/20/2012 03:43 PM, David Beierl wrote:
>> At 05:03 PM 9/20/2012, Rocket J Squirrel wrote:
>>> I have a little "smart charger" in the van which trickles the
>>> house battery when I connect the side inlet to household AC
>>> power. But I unplug the extension cord before starting the van,
>>> and turn off the van before plugging in the extension cord.
>>
>> Oh. I thought you were talking about running down the road using
>> an inverter to power a smart charger, and manually switching to it
>> after current monitoring to the house battery showed that bulk
>> charge from the engine alternator had diminished below the output
>> of the AC-powered charger (which would then go through its own
>> bulk-finish-float
> sequence).
>>
>> If you're just concerned about paralleling the alternator and your
>> AC-powered charger when the engine starts and automagically
>> parallels your two batteries, I think you can probably stop
>> worrying. The AC charger's bulk cutoff voltage will be higher than
>> the alternator regulator setting, so it will continue charging
>> until you unplug it. If the terminal voltage of the combined
>> batteries rises above the alternator regulator setting, the
>> alternator will reduce its field current or shut off entirely.*
>>
>> * A while back I did a little bench testing of one of the
>> regulator units which indicated (to my surprise) that the regulator
>> simply switches the field current on and off rather than modulating
>> it. This keeps the regulator cool but generates a lot of hash on
>> the B+ line (and I suspect is not ideal for battery longevity
>> either).
>>
>> However, to be certain about this, ask the charger mfr. about it.
>> If the charger has already shifted into float mode then the
>> alternator might try to back-feed it, which it might or might not
>> care about.
>>
>> If it's an issue, I suggest using a fancier (spdt/dpdt) relay on
>> your paralleling arrangement. Common terminal to the house battery,
>> NC to the AC charger, NO to the starter battery. Bypass diode
>> between NC and common, in case unhooking the powered charger
>> generates a spike (many chargers specify to connect the battery
>> before plugging in the charger).
>>
>> Yrs, d
>
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