I am looking for some advice on a 2 way DC to DC charger. Meaning I want to simply add a LifePo4 battery to my existing AGM house bank set up. They are new Victron supercycle batteries. (and multiplus, MPPT’s, Cerbo gx, and solar)
I am hoping that I can just add an additional LifePO4 battery and have a charger that will charge that battery and when needed send power back to the house bank.
Does that option exist?
Not sure about a bi direction dc to dc charger like you are asking for.
You might check out the Redarc BCDC models. They are made to charge a house bank and a starter battery. If you set it up to charge the LFP and then let your house be the “starter” battery it may work for you. There are also some trickle chargers out there that are made to charge a starting battery from a house bank. You could basically reverse it and use it to trickle charge your house from the LFP. Ablemail makes one that will charge at 5amps at 12V. There are others out there too. Not sure where you are but most of them are UK companies. I am in the US and have a hard time getting them reliably and affordably but they are great.
May I ask why not just add more AGM batteries? If they are brand new it shouldn’t be a problem. I’m a fan of simple.
Victron doesn’t have such things as bidirectional DC-DC, although the question/request has appeared before…
But if they decide to make something like this below, on their Orion range, then you can use HV batteries on their systems, closing the circle.
Thanks. I have 4 Victron AGM’s now and am limited by space. Since they are new I was wanting to continue to use them and just add some additional storage in the form of Lithium batteries.
I am in the US as well.
Thanks
I have found this one online but it comes from Europe. Not sure if anyone has any experience with this unit?
I’ve had experience with Sterling’s new “Saturn” line of DC-DC chargers (the ones shown), yes, and they’re pretty solid overall. Sterling’s reputation suffered pretty greatly over the past 5-ish years due to issues plaguing their old white-case DC-DC chargers, but this lineup is a good comeback.
Take the current ratings with a little bit of a grain of salt; Sterling has a tendency to creatively rate their chargers at voltages that aren’t practicable - as an example, the BB1212120, which is advertised as a 120A draw charger, so around 110A delivery, is a rating spec’d at 12v… but of course you’re not charging at 12v, you’re charging at around 14.4 or thereabouts, so in practice you actually see a maximum charge delivery of around 100A to 105A in standard charging; the reverse charging can be finicky, as it’ll occasionally randomly stop reverse charging for a couple seconds to a couple minutes and then start back up again. But all that being said, they still work pretty darn well as long as you’re not watching them too closely!
They’re not nearly as configurable as a Victron unit, but in many cases that’s of benefit, really, as there’s nothing to get lost in in the setup of the unit and no FW updates to worry about in the future; it pretty much just does what it does, and -again, as long as you don’t watch it too closely- does it well. Reasonably efficient, stays reasonably cool, and -at least within the past couple of years that this line has been on the market- very low failure rate. They’ll try to upsell you on their remote control, but frankly I wouldn’t bother, it’s an expensive but cheaply-made remote that doesn’t do a whole lot for you.
I advise to bypass low voltage and go straight to a Bidirectional Isolated High Efficiency Gan Solution: 12Vdc - 48Vdc ↔ 400Vdc - 800Vdc with >>95% efficiency.
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https://epc-co.com/epc/about-epc/gan-talk-blog/post/26206
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In my defense: you did say: some advice