just purchased the xantrex power hub 1800 and solar panels.

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System
System Posts: 2,511 admin
in Solar Beginners Corner #1
So I went out and purchase a 12 volt xantrex 1800 power hub and 2 170 watt 24 volt bp solar panels from a wholesaler. He told me all I need to do is go buy the charge controler which is separate to connect them to the hub.. I assume that they would not sell me something that would not work together but maybe I was wrong.
Is it possible to use 24 volt solar panels with the xantrex 1800 that is a 12 volt system? If so what do I need? The batteries recommended is (2) 100 amp hour batteries. What size mppt charge controler do I need? 15,20,30amps? Also do these connections on the panels plug directly into the charge controler or do I need to buy some special extension cables to tie everything together.b Thanks for the replies.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    #2
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    Re: just purchased the xantrex power hub 1800 and solar panels.

    All you need is an expensive MPPT type charge controller, or you loose 1/3 of your charging capacity. Better if your panels had about a 17.4 VMP so you could use an inexpensive PWM charge controller.

    They aren't 24 volt VOC?

    You also need a deep cycle battery bank, a couple 6volt golf cart batteries would likely be cheapest alternative.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #3
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    Re: just purchased the xantrex power hub 1800 and solar panels.

    Welcome to the forum.

    Yes it's possible to use 24 Volt solar panels on a 12 Volts system. There are two ways of doing it. One is with a PWM type controller, which will basically waste half the power. The proper way to do it is with a MPPT type controller, which will down-convert the higher Voltage to greater charge current.

    I'm not familiar with the Xantrex 1800, but I presume it has built-in battery? If so, how much capacity in Amp hours?

    Your two panels should put out just under 20 amps at 14.2 Volts via a small MPPT charger such as the Rogue or Bluesky. That's good for about 360 Amp hours max.

    Rough calculations - not exact numbers or specific recommendations.
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  • System2
    System2 Posts: 6,290 admin
    #4
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    Re: just purchased the xantrex power hub 1800 and solar panels.

    This particular model recommends to use (2) 100ah batteries. total 200 amp hours batteries. what type of cables do I need to use to go from the panels to the charge controller? Each solar panel has 2 connections and I would like to have a little more length that way I can place the solar panels farther away than 3' from the hub unit.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,457 admin
    #5
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    Re: just purchased the xantrex power hub 1800 and solar panels.

    I believe this is the Xantrex system here:

    http://www.xantrex.com/power-products/backup-power/xantrex-powerhub.aspx

    I guess you did not get the external battery case with the inverter unit?

    Anyway, you will have to determine how to get the 12 VDC from your batteries to the inverter.

    The estimated current rating for the wiring / connectors would be:
    • 1,800 watts * 1/10.5 volts minimum * 1/0.85 inverter eff * 1.25 NEC safety margin= 252 amp branch circuit
    So, depending on the length of cabling, you will need to design it to carry a minimum of ~252 amps of 12 volt DC.

    You are probably looking at between 0 and 0000 gauge wire for that level of current. Again, depends on insulation type/rating and how short you can keep the cables.

    If you do have the battery carrier from Xantrex, it should make you life a lot easier.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    #6
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    Re: just purchased the xantrex power hub 1800 and solar panels.

    I have a Powerhub and sell them as an addon for supplying critical loads for my on-grid customers. If you did not get the battery box, I recommend doing so as it neatly handles the battery connections, fusing etc. It is designed for two 12V deep cycle batteries in parallel. Probably best to get AGM type or at least sealed golf cart batteries as the battery box is steel which will get wasted by regular batteries. I don't why they do not build in a charge controller to this product as it has everything else. Does give you the chance to choose the right one depending one your needs though. Get the least expensive 15A MPPT type controller you can find. Probably Morningstar or Bluesky as I think Rogue's are out of production right now.
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  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
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    Re: just purchased the xantrex power hub 1800 and solar panels.

    Not sure why you got the 24 volt panels - is that what they recommended?

    If they are the older BP 170 SX, then they are a 24 volt panel, and you will lose about 50% of your power with a standard charge controller.

    You would be better off with one panel and the small Morningstar 15 amp MPPT controller. You could use both, but the controller will current limit at 15 amps. One panel would give a max of around 14 amps.
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