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Old 04-02-2018, 05:15 AM   #21
HarryN
 
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Default Re: 2017 4x4 Build Out - Grey Escape

There are a lot of ways to approach auxiliary power system in a van conversion. The approach that we use in our product offering is to keep the van's built-in electrical system as isolated as possible from the secondary system. 100% isolation is used when possible.

For applications where pulling power from the alternator is desired, we only use approaches that prevent back feed of power back into the van's electrical system. Examples of this are battery to battery chargers, inverter to charger approach or similar.

The few $100s that it costs to implement this is small compared to the cost that could happen if somehow your auxiliary system starts messing with the van's electrical system.

I realize that this is a risk / reward / problem avoidance strategy vs my being 100% sure that it is required, but then again it helps me sleep better knowing that I am not messing up a customer's van.

Personally I am not a fan of using calculations of AGM internal resistance as a charge control method, because the AGMs that we use can absorb 300 amps in bulk mode if the system can supply it.
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Old 04-02-2018, 02:56 PM   #22
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Default Re: 2017 4x4 Build Out - Grey Escape

I agree with HarryN, I would totally isolate the house side by placing the ARC between the + bus bar on the engine battery and the house battery with a mega fuse after the ARC. I'm in the process of installing a single house battery and will run the + cable from the main battery thru a Blue Sea auto/manual ARC keeping the house battery isolated.
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Old 04-02-2018, 04:42 PM   #23
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Default Re: 2017 4x4 Build Out - Grey Escape

Quote:
Originally Posted by RVCuisineScene View Post
I agree with HarryN, I would totally isolate the house side by placing the ARC between the + bus bar on the engine battery and the house battery with a mega fuse after the ARC. I'm in the process of installing a single house battery and will run the + cable from the main battery thru a Blue Sea auto/manual ARC keeping the house battery isolated.
What you are doing is good and useful, but we still would not consider that to be adequate isolation and control of the power flow between the van's electrical system and the auxiliary electrical system.

If there is not an active charge control device, such as a DC-DC charger or the Orton approach (inverter feeding an ac charger) then there is no "control" of the actual power flow.

I am not trying to criticize, just pointing out that there are various approaches and levels of control possible.
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Old 04-02-2018, 08:49 PM   #24
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Default Re: 2017 4x4 Build Out - Grey Escape

Quote:
Originally Posted by HarryN View Post

If there is not an active charge control device, such as a DC-DC charger or the Orton approach (inverter feeding an ac charger) then there is no "control" of the actual power flow.
Yes, this is the conclusion I have reached. I need some type of charger to control the flow. It also seems that in this scenario the ability to charge off of the alternator is nice, but it won't be a quick process. I am understanding the benefit of solar. Even for the Pacific NW.
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Old 04-02-2018, 08:59 PM   #25
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Default Re: 2017 4x4 Build Out - Grey Escape

Take a look at the Victron BMS 12/200. You can change the "fuze" which acts as a shunt to manage the amperage which is allowed to flow from the aux battery or alternator to the house battery pack. It will also manage the charge of Victron Lithium batteries, but can function separately as a stand alone device for limiting the power draw on the alternator. It's reasonable at around $250.

Jack

Note: I am still in my planning phases and have not implemented this yet.

Last edited by JIB; 04-02-2018 at 09:05 PM.
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Old 04-03-2018, 06:51 AM   #26
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Default Re: 2017 4x4 Build Out - Grey Escape

+1 on the Victron equipment. Flash update-able firmware in the field, open communications protocols, good integration, and excellent technical support. However, I didn't really see a suitable DC to DC charger in their lineup, so you will probably have to look to Sterling for that. If you're planning a large LiFePo4 bank, then a second alternator and regulator (like Nations/Balmar) might make better sense if it's in the budget.
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Old 05-02-2018, 08:28 PM   #27
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Default Re: 2017 4x4 Build Out - Grey Escape

So the last few weeks have mainly been installing insulation and doing some planning. This past weekend I installed the MaxxFan. I had prepped most of the pieces a few weeks back so it was time to commit to cutting. I followed all of the advice out there but will point out a few specific things I did along with some lessons learned for those undertaking this themselves.

I made a locating jig out of plywood and drilled 7/8" holes in the corners. The picture shows the specifics of the approach I took. I 3D printed a drill jig with a bushing to place 1/4" starting holes. This was moved successively to each corner for drilling. After those were drilled I used a 7/8" max step drill to enlarge them to the tangent points. Then a jig saw to cut out the panel. A jig saw with a good metal blade cuts through like butter. I used aluminum flat bar to reinforce above the flange (great tip from Dave Orton) and a plywood flange for below. 10-32SS fasteners with Nylocks to hold it all together.

What would I do differently?
1. I only put one strip of butyl rubber inside of the bolt circle. I should have covered the underside of the flange inside and outside of the bolt circle. I started to pull it up, but it was down good. So I ultimately went with it.
2. I would use VHB tape to adhere the aluminum to the plastic mounting flange to eliminate that potential leak path.
3. I would consider rubber grommets under the fastener heads instead of using the Dicor self-leveling sealing. It made a mess. I think I would avoid the self-leveling variety in the future. Others may disagree and are welcome to provide opposing viewpoints. The pictures show the install before applying it. It is nice and clean. After not so much, but more worried about leakage than appearance.

The installation seems solid so I am calling it finished (except wiring and interior treatment). If anyone in the Seattle area is installing a MaxxFan let me know if you would like to use the jig. You are welcome to it.
Attached Images
File Type: jpg Flange_Jig.jpg (225.1 KB, 714 views)
File Type: jpg Flange_Installed.jpg (142.1 KB, 698 views)
File Type: jpg Fan_Installed.jpg (163.5 KB, 700 views)
File Type: jpg Fan_from_Below.jpg (312.6 KB, 692 views)

Last edited by ChadBuilds; 05-02-2018 at 08:40 PM. Reason: Offered up jig for others to use.
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Old 05-02-2018, 08:38 PM   #28
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Default Re: 2017 4x4 Build Out - Grey Escape

The other thing I have been working on the side is a vacuum drill jig for the upcoming installation of plusnuts. I settled on using the 1/4-20 variety. I was hoping to use some of the existing holes, but most would only work with a 10-32 size plusnut. This would be fine for paneling, but questionable for mounting structure.

I designed and 3D printed a jig that accepts a 3/8" ID drill bushing. I may enlarge it to the recommended 0.386" for the 1/4-20 plusnut hole size. I also printed a rubber pad for it. The jig has magnets embedded in it so it will stick nicely to the van wall for drilling. This attaches to a vacuum hose adapted up to 2-1/2" to mate with a shop vacuum. It should also serve as a nice drill stop assuming I can get a drill bit setup properly.

I plan to test its effectiveness this weekend. I will try to shoot a video for anyone interested.
Attached Images
File Type: jpg Drill_Jig_Internal.jpg (114.2 KB, 680 views)
File Type: jpg Drill_Jig_Magnets.jpg (203.6 KB, 652 views)
File Type: jpg Drill_Jig_Pad.jpg (124.9 KB, 638 views)
File Type: jpg Drill_Jig_w_Hose.jpg (200.0 KB, 654 views)
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Old 05-02-2018, 09:18 PM   #29
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Default Re: 2017 4x4 Build Out - Grey Escape

Chad,

Nice work on the vacuum attachment, what you need now is an optical centre to locate your jig accurately. Something like the perspex rod in this gauge...

https://www.axminster.co.uk/axminste...e-punch-100244

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Old 05-03-2018, 01:32 AM   #30
ChadBuilds
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Default Re: 2017 4x4 Build Out - Grey Escape

Quote:
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Chad,

Nice work on the vacuum attachment, what you need now is an optical centre to locate your jig accurately. Something like the perspex rod in this gauge...

https://www.axminster.co.uk/axminste...e-punch-100244

Keith.
That would be sweet! I am planning to use a punch to set the hole location and then use center to place the jig over it. I expect the drill point should be able to center the jig by causing it to slide a little until if it is a bit off. I will try to test that theory when I do some test drilling this weekend.

My primary goal this weekend is installing the CR Laurence sliding windows and hopefully most of the insulation.
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