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jimf909
Samba Member
Joined: April 03, 2014
Posts: 8117
Location: WA/ID
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 Posted: Thu Feb 13, 2025 11:02 am Post subject: Re: Cleaning Up Auxiliary Battery Install |
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| Quote: |
| Interesting that the last ferries I have been on did not allow anyone to stay in their vehicles or even access the vehicles during travel. |
WA state ferries allow passengers to stay in the vehicles. Plus, there's sometimes a long wait in line before getting on the ferry. The Vanagon is the ultimate ferry car. Take a nap, make a ham sandwich, warm up some soup while other folks are stuffed into their suv.
Longer run BC ferries do not allow passengers to stay in the car. People have died when they couldn't evacuate the auto deck.
_________________
- Jim
| Butcher wrote: |
| This is the main fault with DIY'ers, they get together on these forums and pat themselves on their backs spreading bad information. |
Guilty as charged.
Current: 1990 Westy Camper - Bostig RG4, 2wd, manual trans w/Peloquin, NAHT high-top, 280 ah LFP battery, 160 watts solar, Flash Silver, seam rust, bondo, etc., etc.
Past: 1985 Westy Camper - 1.9 wbx, 2wd, manual trans, Merian Brown, (sold after 17 years to Northwesty who converted it to a Syncro). |
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tuanis
Samba Member
Joined: March 20, 2019
Posts: 37
Location: Seattle
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| Posted: Fri Feb 14, 2025 10:14 am Post subject: Re: Cleaning Up Auxiliary Battery Install |
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| jimf909 wrote: |
| WA state ferries allow passengers to stay in the vehicles. Plus, there's sometimes a long wait in line before getting on the ferry. The Vanagon is the ultimate ferry car. Take a nap, make a ham sandwich, warm up some soup while other folks are stuffed into their suv. |
Exactly, it is so much nicer hanging out in the van than stuck in a car when waiting in a long ferry line.
| jimf909 wrote: |
If you can return the Blue Sea ACR you bought the additional $60 (?) for the DC-DC charger will offer configurable charging rates for your marine battery (see article above) and provide scalability for future possibilities.
Keep asking questions!
Edit: What vanagon he said. |
Luckily I got the Blue Seas ACR at a garage sale for relatively cheap, so I'm not super concerned if I end up going a different direction. It's sounding like the DC-DC charger is likely what I'll end up doing. I'll start doing a little research into the various amperage options.
| tuanis wrote: |
| The run from the aux battery to where it splices under the dash is maybe 10 or 12 feet. It runs the radio, and powers the cigarette lighter (which I’m planning on replacing with a USB outlet), interior lights and the clock. I’m not positive how to figure out the amperage the stereo is drawing in order to do the math on the required wire size. |
Anyone have thoughts on this so I can size this wire run properly?
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1989 Westfalia - 2.5L Subie
1988 VW Westfalia - Stolen  |
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boxer74
Samba Member
Joined: July 03, 2011
Posts: 844
Location: Ontario, Canada
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| Posted: Fri Feb 14, 2025 11:42 am Post subject: Re: Cleaning Up Auxiliary Battery Install |
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| tuanis wrote: |
| It's sounding like the DC-DC charger is likely what I'll end up doing. I'll start doing a little research into the various amperage options. |
I've been quite happy with the 25A Redarc BCDC1225D. It's compact, built well and handles solar charging as well. I do also like Victron gear and have their shunt and AC charger, but their DC-DC Orion that was available when I was getting into this had a reputation for running quite hot. I think they've corrected this with their new Orion XS model. Might be worth a look.
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74 Super
84 Westy |
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jimf909
Samba Member
Joined: April 03, 2014
Posts: 8117
Location: WA/ID
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| Posted: Fri Feb 14, 2025 1:35 pm Post subject: Re: Cleaning Up Auxiliary Battery Install |
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| tuanis wrote: |
It's sounding like the DC-DC charger is likely what I'll end up doing. I'll start doing a little research into the various amperage options. |
Considerations for the max charge current from the DC-DC charger:
- What is the max charge rate (C-Rate) for your battery. This is best gotten from the mfr's specs but your 97(?)ah Die Hard battery should tolerate a C-Rate of 50% - 80% (C-Rate = .5C - .8C). This means you could comfortably charge at 50 amps so that won't be a limiting factor (likewise for anything but the smallest, say 50ah, LiFePO4 batteries). Always look to mfr. specs for charge rates - the rates above are generalizations and actual specs do vary.
- The next factor is alternator capacity and this is where you can get into trouble w/out some caution. Running a 30 amp charger from a 70-90 amp alternator could overload the alternator when running headlights, the rad fan at high, the heater or AC blowers at high. You've got a 2.5 so you'll want to check the capacity of your alternator. I run a 30 amp DC-DC charger with my 110 amp Zetec alternator comfortably. Others are more conservative and limit the charge rate to 20 amps.
Alternators were not meant to operate at max current continuously. They have a duty-cycle (similar to an air compressor) which calls for a break from high current loads to cool off. DC-DC chargers have no regard for duty-cycle and will take every last amp available which is why they are a risk to the system without good design and oversight.
Using the on/off switch on the DC-DC charger is very useful. Got a drained battery but you're running the A/C on high with the headlights and the rad fan is running (each a heavy load)? Turn off the charger to give the alternator a break until other loads can be reduced.
If you just won the lottery the $325 Victron Orion XS is their newest and allows charging up to 50 amps AND it offers a user configurable charge rate. That is a big win. Maybe other brands are also offering this feature now.
| tuanis wrote: |
I’m not positive how to figure out the amperage the stereo is drawing in order to do the math on the required wire size.
Anyone have thoughts on this so I can size this wire run properly?
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The best way to know this is to check the owners manual for the spec of the inline fuse leading to the head unit. It may also be listed on the back of the head unit or at the fuse holder. Less reliable is checking the installed fuse because someone may have put the wrong one in there. Regardless, if there's a 10 amp fuse inline the amp won't draw more than 10 amps.
Many typical head units have 10 amp inline fuses but will draw less than that. Add that into your math to see the max current you'll be running through that wire.
By the way, Battery University is a terrific resource:
https://batteryuniversity.com/articles
_________________
- Jim
| Butcher wrote: |
| This is the main fault with DIY'ers, they get together on these forums and pat themselves on their backs spreading bad information. |
Guilty as charged.
Current: 1990 Westy Camper - Bostig RG4, 2wd, manual trans w/Peloquin, NAHT high-top, 280 ah LFP battery, 160 watts solar, Flash Silver, seam rust, bondo, etc., etc.
Past: 1985 Westy Camper - 1.9 wbx, 2wd, manual trans, Merian Brown, (sold after 17 years to Northwesty who converted it to a Syncro). |
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tuanis
Samba Member
Joined: March 20, 2019
Posts: 37
Location: Seattle
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| Posted: Wed Feb 26, 2025 9:06 am Post subject: Re: Cleaning Up Auxiliary Battery Install |
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Ok I did some reworking of the current diagram and wanted to get thoughts before I dive in:
A few notes:
- I'm planning on removing the circuit with the radio, lights, etc. entirely from the stock fuse box. I'll cut that wire, and connect directly to the aux fuse box to remove the janky quick splice the PO had.
- The only fuse size I still need to work out is from the solar panel to the MPPT. The PO didn't have any fuse there, but the MPPT wiring manual recommends one. As I don't know the wattage of the panel (it's hard mounted to the roof and there's no model # or anything visible) I'm planning on moving the van into the sunlight and measuring the amperage input to figure that out. Unless there's a better way?
- Previously everything was 14 gauge wire (with the exception of the battery to battery wire). I've resized a lot of the wiring based on blue seas wire calc tool.
- I'm considering doing a common ground bus under the seat, as the grounds are starting to get a little cluttered. Any reason not to?
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1989 Westfalia - 2.5L Subie
1988 VW Westfalia - Stolen |
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jimf909
Samba Member
Joined: April 03, 2014
Posts: 8117
Location: WA/ID
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| Posted: Wed Feb 26, 2025 3:42 pm Post subject: Re: Cleaning Up Auxiliary Battery Install |
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| tuanis wrote: |
Ok I did some reworking of the current diagram and wanted to get thoughts before I dive in:
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A few notes:
- You're showing a 2 amp fuse for the Propex. I thought this was supposed to be 5 amps. There's a smaller fuse inside the unit but double check your Propex manual for the inline fuse size.
- Where will the DC-DC charger be located? If it's under the rear bench it may be shorter and easier to connect the positive to the positive terminal on the alternator.
| Quote: |
- I'm planning on removing the circuit with the radio, lights, etc. entirely from the stock fuse box. I'll cut that wire, and connect directly to the aux fuse box to remove the janky quick splice the PO had.
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I can't say that I'm a big fan of cutting a stock wire to the fuse box. I like T-taps (see link) to preserve stock wiring while tapping into it. I've had them work trouble-free for many years. I've also added a blown fuse in the #3 spot with a label on it explaining what's happening to the circuit to make troubleshooting years later easy on my feeble memory.
https://www.amazon.com/dp/B0BW4MCPWN?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
| Quote: |
| The only fuse size I still need to work out is from the solar panel to the MPPT. The PO didn't have any fuse there, but the MPPT wiring manual recommends one. As I don't know the wattage of the panel (it's hard mounted to the roof and there's no model # or anything visible) I'm planning on moving the van into the sunlight and measuring the amperage input to figure that out. Unless there's a better way? |
If it's a single panel you won't need a fuse. If there is more than one panel you may need to fuse it.
Fuse size should be listed listed on the specs label on the back of the panel. Is there anyway that you can get under it to see that label? Alternatively, do you know the model of the panel so you can check the mgr's specs? It's important to know those specs in order to work with them safely.
| Quote: |
I'm considering doing a common ground bus under the seat, as the grounds are starting to get a little cluttered. Any reason not to? |
A bus bar is a good idea to simplify the connections at the battery terminal. It will also provide an easy ground for future additions or even to connect a meter.
_________________
- Jim
| Butcher wrote: |
| This is the main fault with DIY'ers, they get together on these forums and pat themselves on their backs spreading bad information. |
Guilty as charged.
Current: 1990 Westy Camper - Bostig RG4, 2wd, manual trans w/Peloquin, NAHT high-top, 280 ah LFP battery, 160 watts solar, Flash Silver, seam rust, bondo, etc., etc.
Past: 1985 Westy Camper - 1.9 wbx, 2wd, manual trans, Merian Brown, (sold after 17 years to Northwesty who converted it to a Syncro). |
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tuanis
Samba Member
Joined: March 20, 2019
Posts: 37
Location: Seattle
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| Posted: Wed Feb 26, 2025 5:23 pm Post subject: Re: Cleaning Up Auxiliary Battery Install |
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| jimf909 wrote: |
| - You're showing a 2 amp fuse for the Propex. I thought this was supposed to be 5 amps. There's a smaller fuse inside the unit but double check your Propex manual for the inline fuse size. |
I thought I had read 2A somewhere, but I'll definitely double check the Propex manual. Thanks for pointing that out.
| jimf909 wrote: |
- Where will the DC-DC charger be located? If it's under the rear bench it may be shorter and easier to connect the positive to the positive terminal on the alternator. |
That is an awesome idea, thanks for that. I was trying to figure out how to fit an inline fuse in the stock battery compartment, but if I go straight from the alt that makes things a lot easier.
| jimf909 wrote: |
I can't say that I'm a big fan of cutting a stock wire to the fuse box. I like T-taps (see link) to preserve stock wiring while tapping into it. I've had them work trouble-free for many years. I've also added a blown fuse in the #3 spot with a label on it explaining what's happening to the circuit to make troubleshooting years later easy on my feeble memory.
https://www.amazon.com/dp/B0BW4MCPWN?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 |
The only reason I was thinking of removing entirely was because the PO installed a quick splice that is pretty janky and I think is giving me issues. But perhaps it is better to clean that up rather than remove the connection entirely. Part of my goal is to future proof this so keeping it attached to the stock fuse box probably gives me more options in the future if I want to change anything.
| jimf909 wrote: |
Fuse size should be listed listed on the specs label on the back of the panel. Is there anyway that you can get under it to see that label? Alternatively, do you know the model of the panel so you can check the mgr's specs? It's important to know those specs in order to work with them safely. |
I don't know the model number unfortunately, but I will pull it off to figure that out. The PO drilled directly into the pop top for mounts (not how I would have liked to have do it) so I haven't wanted to mess up any waterproofing but I suppose it's better to know exactly what it is so I do it right.
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1989 Westfalia - 2.5L Subie
1988 VW Westfalia - Stolen |
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fxr
Samba Member
Joined: December 07, 2014
Posts: 2608
Location: Bay area CA
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| Posted: Wed Feb 26, 2025 6:24 pm Post subject: Re: Aux Battery Final Wiring Diagram For Review |
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You should size a fuse for the wire it is meant to be protecting. Fuses in the wiring are to stop the wires melting insulation/catching fire under unexpectedly high currents. The devices should have their own internal protection, if necessary - and solar panels are not in that group.
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Jim Crowther
1984 1.9l EJ22 Westy Wolfsburg Edition
Vespa GTS 300 |
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crazyvwvanman
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Joined: January 28, 2008
Posts: 10329
Location: Orbiting San Diego
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| Posted: Thu Feb 27, 2025 4:38 am Post subject: Re: Aux Battery Final Wiring Diagram For Review |
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One issue I see is your aux fuse panel power supply wiring.
The power for all the panel loads is provided by a single 14 gauge wire and 15 amp fuse, coming from the 15 amp Solar controller load output.
The panel has 60 amps of fuses output to various loads but only a 15 amp input power limit?
Compare that to your original diagram with an 8 gauge fuse panel power input feed and an 80 amp fuse.
Mark |
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tuanis
Samba Member
Joined: March 20, 2019
Posts: 37
Location: Seattle
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| Posted: Thu Feb 27, 2025 9:23 am Post subject: Re: Aux Battery Final Wiring Diagram For Review |
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| crazyvwvanman wrote: |
One issue I see is your aux fuse panel power supply wiring.
The power for all the panel loads is provided by a single 14 gauge wire and 15 amp fuse, coming from the 15 amp Solar controller load output.
The panel has 60 amps of fuses output to various loads but only a 15 amp input power limit?
Compare that to your original diagram with an 8 gauge fuse panel power input feed and an 80 amp fuse.
Mark |
Ah good point, I could see why that is undersized at 14 gauge. I will update that, thanks.
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1989 Westfalia - 2.5L Subie
1988 VW Westfalia - Stolen |
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crazyvwvanman
Samba Member
Joined: January 28, 2008
Posts: 10329
Location: Orbiting San Diego
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| Posted: Thu Feb 27, 2025 9:51 am Post subject: Re: Aux Battery Final Wiring Diagram For Review |
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It isn't just the wire and fuse size.
The question is also whether the 15 amp Max Load of the solar outputs is enough to supply all of the combined loads on the fuse panel?
Mark
| tuanis wrote: |
| crazyvwvanman wrote: |
One issue I see is your aux fuse panel power supply wiring.
The power for all the panel loads is provided by a single 14 gauge wire and 15 amp fuse, coming from the 15 amp Solar controller load output.
The panel has 60 amps of fuses output to various loads but only a 15 amp input power limit?
Compare that to your original diagram with an 8 gauge fuse panel power input feed and an 80 amp fuse.
Mark |
Ah good point, I could see why that is undersized at 14 gauge. I will update that, thanks. |
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tuanis
Samba Member
Joined: March 20, 2019
Posts: 37
Location: Seattle
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| Posted: Thu Feb 27, 2025 10:10 am Post subject: Re: Aux Battery Final Wiring Diagram For Review |
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| crazyvwvanman wrote: |
It isn't just the wire and fuse size.
The question is also whether the 15 amp Max Load of the solar outputs is enough to supply all of the combined loads on the fuse panel?
Mark
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For some reason I was thinking that the 15A was only a limit on what could be supplied to the battery from the MPPT. I just reread the manual and found this paragraph:
| Quote: |
| The current rating of the load output is 15A or 20A (depending on the MPPT model) and is short-circuit proof. |
That confirms to me that as you said, the way I've got it drawn right now won't work due to the amount of power being drawn from the aux fuse panel. I'll go back to the original plan of connecting the aux fuse panel directly to the battery (with an inline fuse).
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1988 VW Westfalia - Stolen |
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shagginwagon83 
Samba Member
Joined: February 07, 2016
Posts: 4285
Location: SWVA
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| Posted: Thu Feb 27, 2025 10:13 am Post subject: Re: Aux Battery Final Wiring Diagram For Review |
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Yeah I would personally have a large fuse between your aux panel and starting battery. Then you can wire your output of your solar controller straight to the fuse position on the fuse panel.
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"Jo Ann" - '83.5 Westfalia EJ22e w/Peloquin
Instagram: @joannthevan
Last edited by shagginwagon83 on Thu Feb 27, 2025 7:29 pm; edited 1 time in total |
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vanagonjr
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Joined: October 07, 2010
Posts: 3602
Location: Dartmouth, Mass.
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| Posted: Thu Feb 27, 2025 7:21 pm Post subject: Re: Aux Battery Final Wiring Diagram For Review |
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| tuanis wrote: |
That confirms to me that as you said, the way I've got it drawn right now won't work due to the amount of power being drawn from the aux fuse panel. I'll go back to the original plan of connecting the aux fuse panel directly to the battery (with an inline fuse). |
Trying to follow along and learn. But I think feeding from the aux battery to the aux fuse panel makes logical sense to me.
For example I have Victron DC-DC and MPPT units and that’s how I am wired.
Sometimes I do not even run the solar panel at all.
My thought process is you should be able to remove those units and have the system still work from the aux battery feed.
Then, adding those components can feed the battery as they are able to do such (DC-DC with engine running and starter battery filled, MPPT with solar connected and the sun shining.)
Anyways, looking forward to final revision on your diagram and then I’m stealing it-ha!
Here’s a similar setup
https://www.wiredcampers.co.uk/es/products/victron...er-van-kit
_________________
John - 86 Wolfsburg Westfalia "Weekender"
Flint reversed 1.8T W/Passat 5-Speed
LiMBO (late model bus club) www.limbobus.org
LiMBO is on Facebook too! https://www.facebook.com/groups/
FAQ thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=525798 |
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jimf909
Samba Member
Joined: April 03, 2014
Posts: 8117
Location: WA/ID
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| Posted: Thu Feb 27, 2025 8:36 pm Post subject: Re: Aux Battery Final Wiring Diagram For Review |
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| vanagonjr wrote: |
| tuanis wrote: |
That confirms to me that as you said, the way I've got it drawn right now won't work due to the amount of power being drawn from the aux fuse panel. I'll go back to the original plan of connecting the aux fuse panel directly to the battery (with an inline fuse). |
Trying to follow along and learn. But I think feeding from the aux battery to the aux fuse panel makes logical sense to me.
For example I have Victron DC-DC and MPPT units and that’s how I am wired.
Sometimes I do not even run the solar panel at all.
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This is one of those things where there isn't one answer so the user can make a choice. The benefits of running the loads through the Victron MPPT:
1 - It provides a low voltage disconnect to protect the battery from an excessive discharge. This is handy for the OP's lead-acid battery w/out a BMS but can be mitigated with diligence or a separate battery disconnect device.
2 - It provides what I call shunt-lite data of loads in and out of the battery. It's handy but a shunt provides more information.
3 - Victron's Intelligent Load Output (see the 4th post in this thread. Victron likes it but it's not very compelling for my needs.
Add up the pros and cons and wire it your way.
I run the loads through the 75|15 MPPT and haven't exceeded the 15 amp max with a fridge, propex, lights, etc. Exceeding that limit is another important consideration in not using the MPPT load output.
_________________
- Jim
| Butcher wrote: |
| This is the main fault with DIY'ers, they get together on these forums and pat themselves on their backs spreading bad information. |
Guilty as charged.
Current: 1990 Westy Camper - Bostig RG4, 2wd, manual trans w/Peloquin, NAHT high-top, 280 ah LFP battery, 160 watts solar, Flash Silver, seam rust, bondo, etc., etc.
Past: 1985 Westy Camper - 1.9 wbx, 2wd, manual trans, Merian Brown, (sold after 17 years to Northwesty who converted it to a Syncro). |
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tuanis
Samba Member
Joined: March 20, 2019
Posts: 37
Location: Seattle
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| Posted: Wed Mar 26, 2025 8:02 am Post subject: Re: Aux Battery Final Wiring Diagram For Review |
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Finally getting ready to actually install this. I know this questioned has been answered here, but I can't seem to find it in search: is it better to connect the input to the DC-DC charger to the alternator, or the positive post on the starter? It seems the starter is easier since it's a shorter run. If I go to the starter, do I need to change any of the existing wiring or can I drop a ring terminal on top of what's already there?
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1989 Westfalia - 2.5L Subie
1988 VW Westfalia - Stolen |
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dobryan
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Joined: March 24, 2006
Posts: 17037
Location: Brookeville, MD
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| Posted: Wed Mar 26, 2025 8:17 am Post subject: Re: Aux Battery Final Wiring Diagram For Review |
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| tuanis wrote: |
| Finally getting ready to actually install this. I know this questioned has been answered here, but I can't seem to find it in search: is it better to connect the input to the DC-DC charger to the alternator, or the positive post on the starter? It seems the starter is easier since it's a shorter run. If I go to the starter, do I need to change any of the existing wiring or can I drop a ring terminal on top of what's already there? |
Is the existing wiring from the alternator to the starter up to the additional load you are thinking of adding to it?
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Dave O
'87 Westy w/ 2010 Subaru EJ25 (Vanaru) and Peloquin TBD
"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson
MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646
Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371
The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794 |
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crazyvwvanman
Samba Member
Joined: January 28, 2008
Posts: 10329
Location: Orbiting San Diego
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| Posted: Wed Mar 26, 2025 8:57 am Post subject: Re: Aux Battery Final Wiring Diagram For Review |
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I would run a new #6 wire from the alternator, to a fuse on the firewall, then on to where the DC-DC is.
Mark
| tuanis wrote: |
| Finally getting ready to actually install this. I know this questioned has been answered here, but I can't seem to find it in search: is it better to connect the input to the DC-DC charger to the alternator, or the positive post on the starter? It seems the starter is easier since it's a shorter run. If I go to the starter, do I need to change any of the existing wiring or can I drop a ring terminal on top of what's already there? |
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tuanis
Samba Member
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Posts: 37
Location: Seattle
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| Posted: Thu May 22, 2025 9:07 am Post subject: Re: Aux Battery Final Wiring Diagram For Review |
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As often happens, life got in the way and this project got pushed to the side. I'm getting back to it, and have discovered that the lead acid battery I had in my old system is no longer good. Rather than replacing with another lead acid, I'm planning to upgrade to a LiFePO4 battery. I need to do a little more research on batteries but I'm leaning towards this Eco-Worthy 100Ah battery.
However specific battery selection is a subject for a different post. I've modified my wiring diagram a bit more and made a few changes to how things are linked together. I think that this should be a final version but any glaring issues before I move forward?
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