Below,

On 02/07/2013 02:40 PM, Steve Williams wrote:
> Last August, Rocket J Squirrel wrote:
>> For charging the deep-cycle battery I use a Powerstream
>> PST-BC1212-15 DC-to-DC charger <http://www.powerstream.com/DCC.htm>,
>> an early version which is set to provide 15 amps peak charging
>> current, about perfect for my 130 A/h battery.
>
> I'd like to know more about this, if you have time.
>
> The charger you linked to is 7.5 A peak, so what's this about an
> "early version"?

The model sold now only charges at 7.5A, but the one I got has a switch
which allows it to operate at 15A,

>
> How do you have this wired into the van?  For example, how did you
> set it up so the radio runs off the house battery (downstream of the
> DC-to-DC charger) when the engine is off, but off the alternator when
> the engine is running?

The radio gets its "memory" +12 from the dash wiring -- the engine
battery. It gets its +12 operating power from the house battery. There
is a main cutoff switch which kills all loads on the house battery, I
use that to turn off all the house appliances and stuff.

>
> How do you connect the DC-to-DC charger's input and the starting
> battery to the alternator when the engine is running, but disconnect
> the charger from the starting battery when the engine is off?

The original camper wiring has a relay under the driver's seat that
pulls in when the alternator spins up and it bridges the stock house
battery to the engine battery. I've replaced that with a hefty Stancor
contactor. When the contactor pulls in, it provides +12 to a selector
switch located on the face of the rear bench seat (where the two house
batteries live). In one position of the switch, that +12 goes to the
input of the DC > DC charger, which charges the house battery at 15A max
then tapers off; in the other position that +12 powers a second
contactor which connects the alternator to the house battery.

The direct-alternator connection is good for fast bulk charging, but it
doesn't fully top off the house battery; the DC > DC charger is good for
topping them off. I do a lot of extended dry camping, often in quite hot
weather, and I need plenty of power to run the refrigerator, so I try to
hit camp with every coulomb of juice in the batteries that I can. I use
solar (6A max) for supplemental charging while in camp.

>
> I'll come clean: I have extensive electrical knowledge and an
> avionics technician certificate, but I've never bothered to decipher
> the schematics of my '84 camper's charging system or understand how
> the GoWesty aux battery kit modified it.  Sorry I'm asking this
> question without first doing my homework.
>
> Thanks!
>
> I added a couple of skeleton pages to the wiki, if you'd like to respond
> there:
>
> http://www.vanagonwiki.net/wiki/House_Battery_Articles
>
> http://www.vanagonwiki.net/wiki/Charging_House_Batteries_from_Alternator

Thanks, I'll take a look! But after the old wiki was lost, taking with
it a really long and carefully researched article I'd written about my
solar rig, I lost heart and gained disgruntlage and haven't been able to
work up much enthusiasm for the wiki.

--
Jack "Rocket j Squirrel" Elliott
1984 Westfalia, auto trans,
Bend, Ore.