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darrendesilva asked

Orion DC-DC to SmartSolar Configuration

Problem: My engine battery drains while camping because of all the door lights staying on when doors are open.

Solution: Use Orion-Tr to trickle charge the engine battery when SmartSolar nears complete charge on my house battery.

How to hook this up?

orion-update01-schem.jpgImage 1: Direct to Load output of MPPT. I understand this might not work due to high in-rush of Orion. I plan to de-rate the Orion to 8 amps or something small to trickle the engine battery.

orion-update02-schem.jpgImage 2: Use the Remote on/off (LH) switch ports of the Orion. Is this how it is configured? " the H terminal (right) of the two-pole connector can be switched to battery plus, or the L terminal (left) of the two pole connector can be switched to battery minus"

So, then the load output of the SmartSolar triggers the switch of the Orion.

*If it's not clear in the diagram, the L port is connected to nothing, the H port to the Load+ port of SmartSolar. Orion input + to house battery.


orion-update03-schem.jpgImage 3: The Orion isolated 12/12-18 is cheaper than the non-isolated 12/12-30, is it fine to use the isolated 12/12-18 in a non-isolated environment? I suspect it's fine. I really don't need 30 amps either, and 30 amps is the smallest non-isolated smart Orion.

Thanks for your feedback.


orion-tr smartsmart solar set-up help
orion-update01-schem.jpg (176.4 KiB)
orion-update03-schem.jpg (171.3 KiB)
orion-update02-schem.jpg (172.9 KiB)
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klim8skeptic avatar image klim8skeptic ♦ commented ·

You cannot connect the battery negative and the load negative together on the mppt.


The load output of the mppt is not rated for the current the dc2dc charger requires.

You can connect the mppt load output to the dc2dc h/l remote input.

Figure 3 is fubar.

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Sarah answered ·

@darrendesilva have you considered using a Cyrix battery combiner. This can allow for bidirectional charging which may be more versatile and less expensive than an Orion based install.

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darrendesilva avatar image darrendesilva commented ·

This solution will not work. Both batteries have different chemistries. Thanks though.

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Sarah avatar image Sarah darrendesilva commented ·
@darrendesilva yes different battery chemistries can complicate the situation. I am on a catamaran and have lithium House and AGM enginge and generator batteries and use an isolated 12/18 Orion (with a three-way arfoget isolator connecting to each of the battery banks) for the same reason.


Instead of using the remote input to control the Orion I use the engine detection feature. From from memory it is set to start charging at ~.5 volts above the float voltage and to stop at .2 volts under the float voltage.
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darrendesilva avatar image darrendesilva Sarah commented ·

Thanks. You are right I could just let the Orion switch itself based on house battery voltage. It’s more simple.


I have a lithium house, and lead acid start battery.

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kevgermany answered ·

Just a thought. Maybe starter battery charging should be prioritised over house.

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darrendesilva avatar image darrendesilva commented ·
Thanks for the input.

I prioritize cold beer over starting the engine. That’s just me.

Have a lithium jump pack when engine battery drains, but this upgrade will fix it all with excess solar, and I won’t have to redesign the system.

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