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allamaabroad
Samba Member
Joined: September 22, 2016
Posts: 560
Location: South Jordan, Utah
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 Posted: Mon May 10, 2021 2:28 pm Post subject: Aux Battery Charging Issues |
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Over the weekend I installed a second battery into my 1970 bus. I did my own wiring with a standard Bosch relay, I thought I had a relatively good idea on how the circuit would work, but it has failed to behave properly so far.
As it sits now, I have:
Battery power to #30
Aux battery to #87
Alternator excite wire (D+ ??) split off to #85
Ground to #86
Whenever I have the alternator excite wire plugged into the relay, the alternator doesn’t charge (voltage stays at ~12v, idiot light stays on)
Once I unplug the alternator wire, the charging circuit behaves normally, but isn’t engaging the relay so the secondary battery isn’t charging.
Any thoughts on what the issue may be?
Thanks!
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Dennis - 1973 Super Beetle ('16-'21)
Debbie- 1970 Baywindow Bus ('21 - Present)
Tin top camper/adventure bus
2180 TW: CNC Panchitos, Beehives Done Right, Web 163, Ultralight Lifters, 1.3 Rockers, CSP Python, Custom Speeduino EFI Conversion with 40mm Throttle Bodies
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I have a really hard time leaving things alone...
Innovative and affordable engine management systems and EFI conversions for your Vintage VW
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pioneer1
Samba Member
Joined: February 11, 2008
Posts: 2069
Location: Ontario Canada
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| Posted: Mon May 10, 2021 3:04 pm Post subject: Re: Aux Battery Charging Issues |
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Sooo close... 30 battery
87 aux. Battery
86 alternator exciter blue wire split from voltage regulator
85 ground
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"Always waiting for tomorrow ruined everything"
'85 Porsche 911 Targa
'76 Westfalia project |
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allamaabroad
Samba Member
Joined: September 22, 2016
Posts: 560
Location: South Jordan, Utah
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| Posted: Mon May 10, 2021 4:16 pm Post subject: Re: Aux Battery Charging Issues |
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I will double check that, though I’m pretty positive that’s how I had it at least once. Hopefully it’s that simple
_________________
Dennis - 1973 Super Beetle ('16-'21)
Debbie- 1970 Baywindow Bus ('21 - Present)
Tin top camper/adventure bus
2180 TW: CNC Panchitos, Beehives Done Right, Web 163, Ultralight Lifters, 1.3 Rockers, CSP Python, Custom Speeduino EFI Conversion with 40mm Throttle Bodies
Distributors are lame
I have a really hard time leaving things alone...
Innovative and affordable engine management systems and EFI conversions for your Vintage VW
Visit https://debbiesaircooled.com/ |
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bsairhead
Samba Member
Joined: October 08, 2008
Posts: 3580
Location: viroqua wi.
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| Posted: Mon May 10, 2021 4:26 pm Post subject: Re: Aux Battery Charging Issues |
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| Unless your relay has an integrated diode 85 or 86 can be + or - the coil doesn't care. But if it does and you hooked backwards you may have destroyed it. |
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WhirledTraveller
Samba Member
Joined: January 09, 2008
Posts: 1399
Location: Cambridge, MA
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| Posted: Tue May 11, 2021 7:25 am Post subject: Re: Aux Battery Charging Issues |
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Just hard wire them together and carry a lithium jump pack.
The idea of a start and house battery is outdated IMHO. With the batteries wired together you get better starts, longer camping, better charging, and the batteries last longer.
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1977 Westy, Automatic. Big Valve heads, CS Cam. |
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danfromsyr
Samba Member
Joined: March 01, 2004
Posts: 15144
Location: Syracuse, NY
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| Posted: Tue May 11, 2021 7:48 am Post subject: Re: Aux Battery Charging Issues |
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that's how I have and have had mine wired for ~15years..
though with a onboard fridge & furnace I use 2 deep cycle aux batteries.
all married together.
| WhirledTraveller wrote: |
Just hard wire them together and carry a lithium jump pack.
The idea of a start and house battery is outdated IMHO. With the batteries wired together you get better starts, longer camping, better charging, and the batteries last longer. |
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ImAddicted
Samba Member
Joined: April 24, 2012
Posts: 1195
Location: Unorganized Territory, Maine
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| Posted: Tue May 11, 2021 1:09 pm Post subject: Re: Aux Battery Charging Issues |
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I wired mine to be able to be combined if needed and for charging, otherwise they are isolated.
1) My vehicle circuit doesn't have any parasitic draws, the house side does.
2) I have two different capacity batteries currently.
3) I can completely disconnect my house battery for any reason and not worry about what I do with that side's cables.
4) I also have kill switches on both, just for safety.
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1979 Transporter (sold)
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WhirledTraveller
Samba Member
Joined: January 09, 2008
Posts: 1399
Location: Cambridge, MA
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| Posted: Tue May 11, 2021 1:27 pm Post subject: Re: Aux Battery Charging Issues |
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| ImAddicted wrote: |
I wired mine to be able to be combined if needed and for charging, otherwise they are isolated.
1) My vehicle circuit doesn't have any parasitic draws, the house side does.
2) I have two different capacity batteries currently.
3) I can completely disconnect my house battery for any reason and not worry about what I do with that side's cables.
4) I also have kill switches on both, just for safety. |
When I said hardwired together, that is a good option, although I actually have mine running through an old fashioned marine switch (1, 2, All, Off)
But it stays on All pretty much 100% of the time. The other options are basically in case one battery fails or I want to work on the bus. Which you could just pull wires off posts if you didn't have the switch. Disconnect the negative and no big worries about where it goes so long as it doesn't touch the positive.
I don't have any parasitic draws. Over the winter it lives on a battery tender anyway.
Two different capacity batteries are not a big deal. Assuming they are similar chemistry, they will discharge and charge proportionally. Totally fine to do. Shouldn't really mix AGM and Flooded though.
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1977 Westy, Automatic. Big Valve heads, CS Cam. |
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