jko avatar image
jko asked

Lithium charging with Orion DC-DC charger and alternator

To summarise, my setup consists of an engine alternator (old style without any intelligence) which is connected directly to Orion DC-DC charger (isolated, 12 | 12, 30A) which in turn charges lithium battery bank (2 * 200 ah batteries). This setup was in advance verified from Victron by the local reseller/distributor.

Alternator is Bosch K1 14V, 55A 20 (original for the Volvo engine).

There is a problem where the input voltage from the alternator to the Orion fluctuates from ~9V to ~36V causing the Orion to intermittently go offline ("charge is disabled due to: Input voltage lock-out"). This happens regardless of the state of charge of the lithium batteries.

Is it possible that the fluctuating voltage is caused by insufficient resistance from the Orion DC-DC charger or is there something else that may explain such a phenomena?

Is it possible that the alternator is faulty, or is such a fluctuating voltage a common issue under some specific circumstances?

Any idea how to rectify this? Do I need to replace the alternator and/or place a led acid or AGM battery in between the alternator and the Orion (exactly the scenario I was hoping to avoid)? If an intermediate battery is required, what would be the recommended chemistry (led acid, AGM...) and size (ah)? Needless to say that I'd prefer small, lightweight and affordable solution...

If there is a way to get this working without the intermediary battery I'd be interested in those suggestions as well. I have heard about Wakespeed as an option, but unfortunately haven't found a reseller in my country/region.

battery chargingLithium Batteryorion-tr smartalternatororion
2 |3000

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2 Answers
mvas avatar image
mvas answered ·

Of course, you need a battery. The alternator is battery charger, it is not a power supply.

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kevgermany avatar image
kevgermany answered ·

The battery connected to the alternator acts to stabilise the output from the alternator. While the Orion is able to accept a wide range of input voltages, as you've found it won't handle the fluctuations you describe.

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jko avatar image jko commented ·

Thanks for the answer. I'm wondering if this fluctuation I'm witnessing is normal? The electrician and Victron reseller here were not familiar with this.

Do you have a recommendation regarding what size and battery chemistry is suitable for my situation? Would I need to arrange alternative charging to this intermediate battery for periods when engine is not use frequently? My starting assumption is that such battery would not require any other charging source.

I did ask the reseller to verify the installation from Victron prior to purchase and now I'm obviously wondering why have they said the planned setup was ok... Not that I'm expecting you to know their thoughts. :-)

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