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skilargo avatar image
skilargo asked

Orion Smart Tr sizing and related questions

Similar to a few other posts, I want to add an Orion Smart Tr to my boat for running a LiFePO4 house battery in parallel with a Lead Acid starting battery. The LiFePO4 is replacing a Lead Acid that has a common ground with the two other starting batteries. My engines are Yamaha F200s that have charging systems with 50 amp max output. Through other research I've read recommendations to conservatively subtract 10 amps for engine needs (40 amps left), subtract 25% of my paralleled lead acid battery capacity for its amp draw (25% of 80 amp-hours is 20 amps). End result - 20 amps left for DC-DC charger and LiFePO4.

1. So it seems like getting the 12/12-30 would result in too much potential current draw on the Yamahas charging system, and I should purchase the 12/12-18 instead (and with little margin). Does this make sense?

2. Currently the lead acid house battery is charged through the aux connection of one of the Yamaha charging systems. Since the house will now be paralleled off the starter battery, I would connect this aux line to the same battery switch port as the the main connection from the same battery (similar to when the switch is currently in combined mode). Don't think this would help or hurt, just didn't want to leave it floating. Make sense?

3. Since there is only a 12/12-18 "isolated" model, I would do what others have done and share a common ground with both sides of the DC-DC charger. Also wondering if this is going to eliminate my desire to use a SmartShunt to capture current draw, etc of the LiFePO4 (a secondary concern). Thoughts?

I also have installed a NOCO Genius 3-Bank battery charger that has a configurable lithium profile I will occasionally use, but liked the configurability of the Smart Tr to be able to selectively turn on when I'm out in the water once the Lithium is down to a lower SoC, limiting the number of recharges. Seems like this will prolong battery life.

Thanks in advance.

battery chargingSmartShuntorion-tr smart
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dc4me avatar image
dc4me answered ·

Something that people don't realize is just because your charging system on the Yamaha says max 50a output, this doesn't mean it will put out 50 amps continuous and that output is rated at a certain rpm. Alternators have an output rating but after heavy loads heat will diminish their rated output. This is true with most if not all alternators. That being said you would be asking a lot out of your alternator which will in turn shorten life. Another thought is what if you don't operate your motor at the rpm needed to acquire max output whatever that may be. You might have problems with the Orion working as it is designed.

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skilargo avatar image skilargo commented ·

Thank you for the quick response! Since the current lead acid house battery is connected to a single engine aux cable, wouldn‘t the lead acid pull those same 20 amps when it was low? (Which is frequent when out at islands).

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kevgermany answered ·

If you use the boat regularly/frequently, the load from the starter batteries can be ignored in your calculations. There's a setting in the Orions that delays the start of charging, which you can increase. This allows the alternator to charge the starter battery fully before the Orion starts charging the house battery. Default is 2 minutes, and I was able to increase it to 1 hour.

Assuming you wish to keep starter batteries independent, I suggest you consider an isolated Orion on each motor, connected in parallel on the output side to the new house battery. Two 12/12-18 models would give up to 36A into the house, keeping load per engine under 20A. Input positive to the Orion's could be the alternator aux, or from the starter batteries, whichever is easier. If you have a single starter battery, use the aux connections.

Common ground for all batteries/orions is correct. But the house battery grounds on the load side of the shunt, not direct. Smart shunt will then work correctly on the new house battery. Similarly the NOCO Genius neg must be connected to the load side of the shunt.

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skilargo avatar image skilargo commented ·

Thank you for the quick response! I did think about using one on each engine, was hoping I would not need to. I am curious, since the current lead acid house battery is connected to a single engine aux cable, wouldn‘t the lead acid pull those same 20 amps when it was low? (Which is frequent when out at islands). I also noticed the output voltage on the Aux was slightly less than the main cable (~13.5V vs ~14.5V if I’m remembering correctly), not sure if that matters. And if I use the Aux line, is it still in parallel with the house battery? (I have read it is only energized after the main battery is fully charged. Also was told as batteries age they do not fully charge, resulting in the aux line not energizing.) Worried about the issues mentioned if the BMS shuts off the LiFePO4 with no other battery In parallel. This is my original thought:

lifepo4-configuration-using-one-l-a.png

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lifepo4-configuration-using-one-l-a.png (804.8 KiB)
skilargo avatar image skilargo skilargo commented ·

Another thought…since I am trying to limit output amperage from the engines, and my LiFePO4 can accept up to 100 input amps, wouldn’t using a separate Smart Tr 12/12-18 on each engine still potentially draw 18 amps from each engine? Could I instead use one Smart Tr 12/12-18 with its input connected to both starting batteries/engines? That way they would share the current load, maxing it out at 18 amps for both. But maybe not a good idea since it would parallel the two starting batteries in combined mode all the time. This is what I'm referring to:

lifepo4-configuration.png

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kevgermany avatar image kevgermany ♦♦ skilargo commented ·
Lead acid has higher internal resistance than lithium. But will draw a substantial current when low.

You'd have to check aux cutting in after starter full. Might be not while cranking.

If you use a single Orion across both starter batteries, check cable sizes. Potentially high current between batteries if one low.


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dc4me answered ·

I personally like your latest diagram. I combine both my starter batteries on my outboard and have had no issues. The only difference is I have a 1-2-both-off switch incase I needed to isolate starter batteries. I have a separate volt meter for both starter batteries to be able to monitor when isolated. I found that useful recently when one of the batteries wasn't performing like it should. With both combined a meter would not of informed me one of the batteries was not up to par.

With your two outboards sharing the load you should not have any problems with the 12/12/18 even at lower rpms. IMO running the charger on one outboard risk the chance of too much work on the alternator. If you go with the Orion I think you will really like it. I have one on a different application with LiFePO4 and really like it. Good luck and hope all works well.

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skilargo avatar image skilargo commented ·

Thanks again for your comments @DC4me.

"I combine both my starter batteries on my outboard and have had no issues. The only difference is I have a 1-2-both-off switch incase I needed to isolate starter batteries." I do too, that's what the engine switch in the first drawings does. "On" is isolated starters, "Combined" is combined. But are you running two separate starter batteries into the input of a Smart Tr?

I still don't understand if or why the first configuration with Smart Tr on one Lead-Acid Starter battery would allow the LiFePO4 Home battery to draw any more amps from my alternator than the original lead-acid 80ah Home battery when the Lead-Acid Home is not charged. Seems like an equivalent current-draw wise. (except I use the Aux line today for home battery, so unclear since it may not energize until the starter battery is charged). Anyone have thoughts on this? In fact, thinking if I switch the engine switch to combined on the first drawing, I in effect have the second drawing connection, all three batteries in parallel.

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dc4me answered ·

Not being familiar with the Aux lines on the Yamaha, if your outboard has a closed circuit to the lead acid batteries and BMS shuts down the voltage spike will be absorbed with the lead acid batteries. Your Orion should have no problem with the BMS shutting down on your LiFePO4 battery. I have experienced a single cell over voltage several times on my LiFePO4 BMS shutting down with the Orion charging it.

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skilargo avatar image skilargo commented ·
Hoping it will. What happened with you single cell over voltage? Did you have a lead-acid in parallel?
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dc4me avatar image dc4me skilargo commented ·

I use my Orion TR-18 to charge a aux LiFePO4 for refrigerator/freezer and small 12v needs in a jeep. So if and when BMS shuts down there is no chance for alternator damage because the main battery is still in line for any voltage spike. I have since adjusted settings in Orion and found a happy medium where that won't happen.

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skilargo avatar image
skilargo answered ·

In case someone still looks at this thread for ideas, after installation following the last configuration diagram posted (except I bought a Smart-Tr 12/12-30 non-isolated), I found that my SmartShunt would no longer provide current data. The Smart-Tr output was not allowing current to flow back from the LiFePO4 (as one would expect). I've modified the configuration to connect the LiFePO4 through the switch to the house electronics directly, and the two Yamaha Aux lines directly through the Smart-Tr to the LiFePO4. This means I can't use the switch to disconnect the Smart-Tr-LiFePO4 setup from the Yamahas, but that's fine because turning the engines off does that anyway. There is also a positive line from two batteries to the SmartShunt I wasn't depicting, one to power the bluetooth module and complete the circuit for the LiFePO4, the other to collect voltage data on another (starter) battery. I'm running these lines to the switches instead of directly to the batteries so I can disconnect the SmartShunt from the batteries when not in use. Below is an updated configuration diagram. Maybe it will help somebody.

lifepo4-configuration2-using-2-aux-isolators.png



lifepo4-configuration2-using-2-aux-isolators.png (875.5 KiB)
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