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Hi all,
This isn't something I've seen discussed. What stops me using a 12/24 Orion Tr as the 'solar' input on a smart solar? This would effectively create a DC-DC Victron charger in my mind that could also take a real solar input with a change over relay.
The Orion-Tr 12/24-10 seems the perfect size for a Smartsolar 100/20
Any issues doing this?
Hi. There may well be no issues doing this. But there may be no point doing it either.
Please explain where you're heading here. A 'better mousetrap' may already exist..?
It's a fair question. Application is a vehicle.
Current setup exists of a Smartsolar 100/20 and a 2 x '12v' panels in series to feed a house battery, these panels are portable and aren't out when the vehicle is moving. I also have a second MPPT reg on a smaller panel that keeps the starting batteries (2 of them) in float charge when parked.
I would like to charge the house battery from the alternator when the engine is running. I believe a Cyrix would assist here, however I would prefer if both the front and rear batteries were isolated AND to obtain a proper charge on both banks as they have slightly different recommend charger / absorption voltages and are installed in places of fairly different temperatures.
The price difference between the Cyrix and Orion-Tr in Australia isn't much.
Traditionally, for an application such as this, most 4wd vehicles here would run a DC-DC charger.
All that said I am open for better ideas and/or suggestions.
Ok, you seem pretty well up on it all. I'd be tempted to just use the alternator directly to both batts, All you'd miss then is the mppt charge algorithm, but it depends how much that means to you.. it wouldn't to me, but I'm not you.
You've covered it already, but essential you separate the two batt systems when the engine is off.
Should be a fun project, and if you go with the Orion/mppt I'd love to hear how it goes.
You need to make sure that the DC/DC converter does not draw from your starter battery when the engine is off, that means you should connect it to a circuit that is powered only with the engine running.
Check the fuse size of that circuit, and possible other consumers on that circuit. If necessary you can reduce the maximum output amps of the MPPT to adapt to the available supply current.
Or use a relay to connect the Orion to you starter battery when the engine is running, then you don´t have a current limit.
With 20A MPPT charge current to the battery you might overload the Orion with 10A output when you consider some losses in the MPPT. You could try reducing the MPPT output to 18A. Another option is to increase the Orion output voltage (adjustable).
You could add a diode between the Orion and the MPPT so you can leave them permanently connected. Otherwise you should better disconnect the Orion when you connect your two PV panels in series, to avoid a high PV voltage getting to the Orion output.
Thanks very much. All the points you raise I have considered. The wattage of the 12/24-10 is lower than the max wattage of the 100/20 so dropping the max charge current is a good idea (or going a more powerful DC converter, but this then goes away from being a budget fix)
I have dedicated wiring in the rear that's easily able to handle a constant 20a from the start battery, and I will connect a ignition switched circuit to the trigger on the Orion (50mm2 cable with a max constant draw of 100a not including the additional Orion)
I was also thinking of a manual connect for solar and orion. Unplug Orion to plug in solar, this would prevent any accidental connections. Although a change over relay could work here, I just see it as unnecessary complexity.
Not OP, but I can confirm this works. I have an Orion TR 12/24-10 which feeds power to a 75/15 MPPT, works great. As mentioned previously, a couple details to pay attention to: The remove on/off of the Orion TR is connected to switched power in my vehicle. The MPPT input is never connected to the Orion TR or solar panels at the same time.... I switch inputs. Solar suitcase when parked or Orion TR when driving and I wish to use alternator based charging.
