Installation of a higher voltage pack in a boat (16,8V Li-Ion)

Q&A and troubleshooting
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1

Hi!

So, I’ve searched and searched and failed just as many times. I find my self to be a technical guy but this is a little bit of a new world to me.

I’ve just built myself a few 4S packs, with Daly BMSes, peaking at 16,8V.

I want to add this to my boat. The boat today has an old marine diesel with a 90-100A alternator.

I have a start battery and a battery bank for the fun stuff, separated by one of those relays that cuts off the start battery once the engine is off.

My plan was to swap the battery bank with an Orion XS fronting my 16,8V packs. So far so good, and I thought I could use that as a power supply once the engine is off, but then I learnt that the XS acts charger OR converter.

So, if I do what I just described, and charge my pack using the fine features of the XS, how do I get power back to my “comsumer circuit” so to say? Do I need a second XS acting as power supply, or a cheaper TR? If so, would that result in power to my stuff from the unit once the engine is off? Also, is there a problem with that config when the engine actually is running?

So, what I want to achieve, is to have 12V out of my Li-Ion pack, at all times pretty much, while it’s also being charged when the engine is running.

Solar panels shouldn’t be an issue since I can just add an SmartSolar MPPT directly to the batteriets I guess?

Thanks all, for whatever light this community night shed on me :slight_smile:

2

Yes, if you want steady 12V you would need another Orion.

You could use a non-Smart Orion, which is only a power supply, but theres nothing to adjust apart from the output voltage, no adjustable low voltage shutdown or similar

You can also use an Orion Smart and then set it to power supply mode, this will give you almost the same settings as with the Orion XS

The MPPT you can connect directly to the Li-Ion pack, however ive never tried myself how high you can actually set the absorption voltage on them. In theory they are capable of both 12V and 24V so setting 16.8V should be possible, but maybe thats locked for some reason. On the demo device i can set up to 17.39V while on the 12V preset. I have a 100/20 that i can test this if you want, to see if theres a difference between a demo and a physical device

3

Ah, like the Victron Energy Orion-Tr Smart 12/12-18A Iso?

That would save me bunch of money! The only concern I have then is what happens if the circuit closes to the start battery? Or, perhaps this is just super beneficial in that perspective, since it might just charge the start battery if I set the “power-supply-Orion” to 12,6-12,8V? Perhaps this design simply helps me keeping the start battery fully charged at all times…

I also need to figure our what happens if I try to start the engine with an Orion feeding the same circuit that the engine is conecte to, from the Li-Ion bank. I mean, the engine is really close to the start battery so I guess it shouldn’t be a problem due to wire dimensions etc. The best would probably be for the supplying Orion to shut down on engine start, since all power will come from the alternator anyway.

Thanks for the quick response! No need to test the MPPT but thank you very much for asking :slightly_smiling_face:

4

Then i misunderstood something i guess.

I thought you wanted to supply some 12V loads from the Li-Ion only. But instead those loads are also powered by the starter battery? That complicates things. And personally i think unnecessarily. Just keep the loads supplied by the Li-Ion, and charge the Li-Ion through its Orion XS from the starter battery/alternator.

Nothing much, the Orion will simply deliver its max current.

5

Misunderstanding or not, I think you provided some really good insights to myself here.

It actually makes way more sense to me to move the loads away from that circuit/system entirely, while it provides a higher level of separation of concerns.

To add some other factors to the equation I also have a bow thruster. This will probably end up in a superior configuration compared to today. I could do what I planned all along, and add a “bow battery” to the bow thruster, put that in parallell with the start battery. That way I will get rid of todays voltage drops when using the bow, while having all (the non-propulsion) loads separated, just by using an XS for charging and a TR (or second XS) to supply power to the loads.

I will draw a schema in case someone else has the same questions.

Thanks for the help!