question

chapelier avatar image
chapelier asked

Charging a 44.4v battery from a 67v battery with Orion DC-DC

Hi

I have a 2kwh 67v lithium battery which I want to use as an emergency backup to charge the main 44v battery that will run my pod drive.

At first glance it seems I could use

Orion-Tr DC-DC converters isolated

but then I noticed on the data sheet the following

Adjustable output voltage
Not intended for battery charging.

Please consider using an Orion-Tr Smart for battery charging.


There doesn’t seem to be an option that would cover that voltage in the Orion-Tr Smart range.

It seems that I can set the output outage to a suitable setting and even the nominal output voltage of 48.2 is perfect so is there any reason this is a bad idea or wouldn’t work for me ?

Again I stress it’s an emergency backup for a bit of extra range, I have several of these batteries I have no use for and I can fit 2 of them in a place on my small boat which is free and I have no further space for another 44v battery which is a much larger format.


Any advice appreciated.


Edit: I’ve since come across this page

PDF of dc-dc converter

Which seems to be the same product and states the following so no I’m really confused 


Adjustable output voltage: can also be used as a battery charger
Orion DC-DC Converters not smart
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JohnC avatar image
JohnC answered ·

Hi @Chapelier

Yes, you can use a 48/48 Orion as a charger. But they're not Smart and can only deliver a set output V. That's adjustable with a tiny screwdriver (& multimeter). Max power model is 8A, so only like 350W. Has remote terminals though, so can be brought on as required automatically if you have something to switch it.

Given your 67V to 44V requirement, you could also consider using a 48V mppt (smart or not). The smallest of these is 20A, and of course has the full charge algorithms. Bear in mind that this wouldn't work without at least a 5V difference between the input & output V's. You have that, so should work fine.

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chapelier avatar image chapelier commented ·
Thanks for that information. I never thought to use a MPPT. That’s a great idea. If I understand you correctly I’d simply connect the 67v battery to the pv in and the 44v battery to the battery output ? And then configure in VictronConnect?
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JohnC avatar image JohnC ♦ chapelier commented ·
Yes.
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