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jason-t asked

Orion Tr Smart 12/12-30a isolated starts absorption charging too soon

On my yacht i have just fitted an Orion Smart 12/12-30 isolated B2B charger charging a new 150AH lithium battery with a built in BMS for my Domestic power. This is fed by a new 100Ah AGM start battery supplied by a regular 100 Amp alternator. The problem I have is that the Orion charger enters Absoprtion charge too soon (3-5amps) with the Lithium battery at about 55% when it should still be in bulk mode. I have ensured that the charge voltages are as per specification for the battery (14.4v charge, 13.8v float), the charger is close to the start and domestic batteries (50cm) and the cabling is oversized 6mm2 I also have a new Victron Smart Solar 20 amp charger that is connected to the same battery which is in bulk (engine off) mode while the Orion was in Absorption mode. I also have a new victron 30amp 240v mains charger which was bulk charging 20-30amps I would like the Orion to Bulk charge to at least 80%, is the smart solar confusing the Orion? can yo help?

Lithium Batteryorion-tr smartsmart solar charging behaviour
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1 Answer
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snoobler answered ·

Biggest cause of premature absorption is wiring losses/connection issues.


First, make sure the Orion firmware is up to date.


Second, use a voltmeter and check voltage AT the battery terminals and then AT the output terminals of the Orion. The Orion voltage reading in the app should be about the same as the reading at the Orion terminals.


If you MEASURE a notable voltage drop between the Orion and Battery, you have a wiring or connection issue. If you have a fuse or a breaker in that circuit, it could be failing and adding resistance.


If the Orion doesn't report the same voltage as the measurement at the Orion terminals (allow for about 0.05-0.10V error), then the Orion may be defective.


Note that having multiple concurrent chargers has other implications. Assuming all are programmed to and sense the same absorption voltage, the only time all chargers will be at max current is during the bulk phase. Once absorption is reached, it's very common for all but one charger (the one outputting the most amps) to drop to float. The strongest charger usually finishes the charge.

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jason-t avatar image jason-t commented ·

Thanks for the advice, I visited my yacht at the weekend and checked the cabling and I did find a loose terminal on an isolator switch which feeds the chargers which I addressed, however I am not certain that was the problem. I ran up the engine and the for a few minutes my NASA BMS was telling me I was charging at 31 amps although this quickly reduced (5 mins) but the battery had jumped from 59% to 99%+. One charge that I also made was that I isolated the solar panels from the Smart Solar so this was producing no power.

I am thinking that the constant supply by the smart solar maybe is upsetting the internal (Bluetooth) battery BMS, or it isn’t very good?

I have currently wired my smart solar to the domestic batteries also fed by the Orion, however would wiring it to the start battery be an alternative solution? It would then raise the voltage in the start battery and then the Orion would start charging although this may create greater losses as I am passing the same current thought 2 devices, but in the winter it would also keep the engine battery charged.

I would be interested in thoughts on the above and if this alternative arrangement may work?

Many thanks

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