Charging Lithium batteries through DC-DC / Starter / Battery charger to 220v

Question

question

vishnuh asked Sep 27, '23

Charging Lithium batteries through DC-DC / Starter / Battery charger to 220v

Hi,

My setup, on my sailboat is as this:

Alternator (60A) -> Starter Battery (75ah, lead acid) -> DC-DC (Orion Tr Smart 12 / 12-30) > Lilead 105Ah (LiFePo4).

I suspect my lithium battery to have not really reached fully charged for a longtime.

I have a battery charger at my disposal, Victron Blue Smart IP65 battery charger 12/4. I have been advised to not plug it directly into my lithium battery.

Now I am wondering if I could plug it to the starter and through the DC-DC charge the lithium.

Battery charger (Victron Blue Smart IP65, 12/4) -> Starter Battery (75ah, lead acid) -> DC-DC (Orion Tr Smart 12 / 12-30) > Lilead 105Ah (LiFePo4).

What are your thought ?

Thanks for your help !

battery charging Lithium Battery orion dc-dc starter battery

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Alexandra answered · Sep 27, 2023 at 09:28 AM

@Vishnuh

Is there a particular reason that was stated as to why you can't connect directly? That is how it is designed to be used.

You connect it with correct polarity switch it on, program it and leave it to 3 stage charge.

It even comes with an accessory that allows you to leave connections permanently (the eyelets cable) installed and that's the way to remove the charger for next time. Or a temporary connection (clips).

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Modifications Space

Node Red Space

Answer 1 · 2023-09-27T09:31:40Z

vishnuh answered · Sep 27, 2023 at 09:31 AM

Thank you for your answer.

It is not my battery charger but a friend's and that is what they have been told. They do not know why it has been adviced not to.

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Answer 2 · 2023-09-27T10:06:40Z

Sarah answered · Sep 27, 2023 at 10:06 AM

Hi @Vishnuh I suspect they may be referring to the fact that the charger does not have an internal BMS. If you have an internal BMS in the battery you can connect the charger directly. If not you need to connect the charger to the BMS and then the battery.

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Answer 3 · 2023-09-27T10:09:54Z

vishnuh answered · Sep 27, 2023 at 10:09 AM

I do have an internal BMS that I cannot access on my LiFePo4 battery.

Now I imagine I would need to change the settings on the battery charger so it is for lithium instead of lead acid (as they use it)

Let's imagine that my friend would not want me to change any settings on his device. Do you think i could plug it on my starter and therefore charge the Lithium :

Battery charger (Victron Blue Smart IP65, 12/4) -> Starter Battery (75ah, lead acid) -> DC-DC (Orion Tr Smart 12 / 12-30) > Lilead 105Ah (LiFePo4).

What could happen ? Could I damage any device ? Will it work ?

Thanks again for your answers and time !

1

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

matthias-nagel commented · Sep 27, 2023 at 10:49 AM

I do have an internal BMS that I cannot access on my LiFePo4 battery.

That's fine. You don't need to access the BMS. It only must be there.

Now I imagine I would need to change the settings on the battery charger so it is for lithium instead of lead acid (as they use it) Let's imagine that my friend would not want me to change any settings on his device.

Yes, you must change the settings from lead-acid to lithium so that your friend's charger knows the correct voltage/current settings. Otherwise the 3-stage charging won't proceed as expected.

In theory, you should not be able to damage any device. If the your friend's charger provides the wrong voltage or current, the internal BMS of the battery should switch off as a safety measure. That's one of the many purposes of a BMS. However, you won't be able to charge the battery either.

Do you think I could plug it on my starter and therefore charge the Lithium : Battery charger (Victron Blue Smart IP65, 12/4) -> Starter Battery (75ah, lead acid) -> DC-DC (Orion Tr Smart 12 / 12-30) > Lilead 105Ah (LiFePo4). What could happen ? Could I damage any device? Will it work?

No it won't work. At least not without changing the settings of your's friend charger. The Orion Tr converter is NOT an lead-acid battery, hence your friend's charger would try to do a three-stage charging with the Orion as the "battery", but the Orion does not behave like a battery on its input side.

You do not "charge a charger" as you put it. A charger requires a power supply on in its input. Most chargers provide a operational mode in which they behave as a power supply. However, that would require to set your friend's charger into "power-suppy mode", which means to change its settings. But you don't want that and if you would do, you could just change your friend's charger to Lithium charging mode and connect it directly to the Lithium battery.

Again, in theory no damage should occur as all devices have internal protection circuits, which will shut down if anything "odd" happens. But I wouldn't rely on it. And it won't help you to charge the battery.

I don't really understand the problem: If your friend trusts you with his charger, why shouldn't he want you to change any settings?

[moderator's note: removed unsupported suggestion]

1 ·

Answer 4 · 2023-09-29T14:34:17Z

vishnuh answered · Sep 29, 2023 at 02:34 PM

Thanks everyone for your answer I will actually make a more general post of a problem I am facing with my electrical system.

These answers are already providing me with great clues and insight.

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

question