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Thread: Critique my electrical diagram please

  1. #1

    Default Critique my electrical diagram please

    I see all these diagrams doing around with 2 inverters and I'm wondering if I couldn't get away with just the one. I'm looking at the Xantrax HFS Freedom which also charges and passes through mains AC. This is what I've come up with. Real interested to hear what you guys think of something like this. I'm fresh to the community so please keep that in mind.

    I'd like to use those diodes but I can't find any for that load. At some point I may install a second alternator and run AC kitchen loads off that so it would be high. I could use a relay but I can't think of the right arrangement with the powering of the relay so I may not have any which mean I need to build in a manual switch protocol to avoid cross loading.

    Sent from my SM-N920W8 using Tapatalk
    Last edited by tmotten; 12-01-2017 at 03:03 PM.

  2. #2
    Join Date
    Feb 2009
    The photo is not working, but I am unclear why you think you would need two inverters? The only place I can see a second inverter coming into play is if you wanted to charge the house batteries from the chassis batteries while driving down the road. The first inverter powers the second inverter/charger to charge the house batteries.
    1997 Dodge Ram CTD, 5 Speed manual, BD exhaust brake, 5x12 injectors, 4k Gov. springs, Thuren coils, Fox shocks, Stable loads, 99HD steering, Carli end links, Method Race Wheels, 295/70/18 Cooper STTMaxx tires.

    2011 Northstar Adventurer

  3. #3
    Join Date
    Mar 2010
    Jämte i exil
    Nothing wrong with a single inverter. Most guys use single.
    One benefit of multiple inverters is efficiency. Closely matching a load to inverters capacity gives best efficiency.
    For example, running 1kW inverter to charge a 150W laptop is silly.
    I cant see your ’pics on this screen. But as diodes on a battery system are seldom used as individual component, I suspect your diodes scheme is not a good idea. Tomorrow I get a chance to see your ’pix, I may edit my comments.

    You might look thru the Power Systems sub forum. Lots of good info from very smart folks there.

  4. #4
    Join Date
    Mar 2013
    Usually 2 inverters means one big inverter/charger (sized to charge the battery bank), and a separate smaller inverter for nominal AC loads (like TV, laptop, phones) that don't require 3000W or whatever. If this is your situation, I wouldn't worry too much about it. Size the inverter/charger appropriately for the battery bank, and add point-of-use inverters for small loads that don't make it worth turning on the big one.

  5. #5
    Sorry. Photobucket had an issue with third party links it seems. I've fixed my post. I think it'll show up fine now. If not, this is the direct link.

    I'm not too worried about having a second inverter but just would prefer to mitigate it for cost and simplicity reasons. Just not sure if a wiring diagram like this would do that given that there are a lot of people out there smarter than me who installed two inverters. Two would indeed be to have AC and charge the battery whilst driving and on mains power with the same device.

    Using a DC to DC charger would mean I still need an inverter and an AC charger. Three devices in other words. With an arrangement like this I've got the inverter/charger charge the battery whilst driving and on mains. Pass through mains if needed and provide AC from both DC sources (engine and house battery). That would provide the flexibility to install a second alternator later too. I'm just a little nervous about that three way connection where I've got diodes shown. A: I can't source any for high amp loads and B: putting in a manual switch would increase the margins of error. Is that my I haven't seen a setup like that in blogs?

    Sent from my SM-N920W8 using Tapatalk
    Last edited by tmotten; 12-01-2017 at 03:12 PM.

  6. #6
    Join Date
    Feb 2014
    Redwood City CA
    I'd put a fuse or CB between battery and BlueSea aux. box. I believe that 12 slot BlueSea is rated to carry 100 amp. A circuit breaker also acts as a quick disconnect for all the circuits in the aux....
    1990 SAS 4runner
    2007 LX build thread:
    my 4wheelin' videos:

  7. #7
    Yeah. Good suggestion

    Sent from my iPhone using Tapatalk

  8. #8
    Join Date
    Nov 2012
    Central CT
    A couple years ago when I was shopping Charger/Inverters I was all excited about the Xantrax Freedom. Series, after lots of research it seemed like too many people had issues with them. Many of them fail immediately and are replaced under warranty. I figured mine would be the one that failed one day after the warranty expired.
    I ended up going with a small Magnum. I had to go with a modified sine wave one to keep it in my budget, but they have a much better track record.
    Just my two cents, and this could have changed in the last couple years

    Sent from my iPhone using Tapatalk Pro

  9. #9
    Join Date
    Oct 2013
    Credit for the inverter->inverter/charger system goes to Dave Orton. He explains it and has a diagram here: The vehicle powered inverter provides 120V power while driving. This is used to heat water and air and also charge his house batteries via the charger in the second inverter/charger (it's inverter is off). The second inverter is used to supply 120V when parked and to charge using shore power (rarely needed).

    Today's AGM house batteries last longer if charged using a specific voltage profile which is usually not what the vehicle alternator is delivering via a traditional combiner relay. The 2 inverter system overcomes this because the charger (in the second inverter) is running on 120V supplied by the vehicle powered inverter. This allows it's output charge voltage to be independent of the alternator voltage so the house batteries are charged according to their own voltage profile requirements.

    There are some DC to DC chargers that also provide an independent voltage profile for charging the house batteries. Sterling power, Ctek and Kisae are some that I am aware of.

    I can't see the drawing. Cable sizes and the location of fuses and/or breakers are typically what folks struggle with. Best systems will have a shunt and battery monitor that counts amp-hours to determine state of charge (SOC).

  10. #10
    Join Date
    Nov 2010
    Middle of Nowhere, Outer Skin of Space Ship Earth, 1 A.U. from Sol, Outskirts of Milky Way.
    Screw Photobucket. The issue is that they no longer allow linking to pics (3rd party linking) on non-paid accounts. Fine that's up to them, but the way they went about it was shady and underhanded.

    Clicking the link to view the pic opens it, but it's surrounded by Photobucket crapola which makes it a PITA to view on a phone.

    Just upload the pic here, so it can easily be viewed.

    Without actually seeing the pic - yes you can use an inverter to feed a battery charger. The issue that will normally be pointed out as a deal-breaker is the inefficiency of the whole AC->DC->AC->DC multi-step conversion.


    In my opinion, the inefficiency is a non-issue. Using an alternator to charge a battery isn't very efficient to begin with and doesn't do a great job of battery charging. Adding more inefficiency, but getting better battery charging, is a worthwhile tradeoff in my opinion.

    I have no idea what diodes you are referring to, and won't unless you upload the pic here, but I would guess that you are trying to use one inverter - fed by the engine battery for charging the house battery (and supplying AC while driving), and fed by the house battery while parked.

    I can think of a few ways to rig something like that, and I can think of a few possible problems as well.

    Right off the top of my head...using a single inverter/charger won't work because an inverter charger can't both suck power in via its battery connection and simultaneously push power out its battery connection. It can do the inverter thing (power in from battery) or do the charger thing (power out to battery) - but not both at the same time.

    Let's see the diagram and we can figure out how to do what you want.

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