Frustrated, all I want to figure out is...How to charge two different types of batteries in the one system

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oceanwolfe asked May 9, '20

Frustrated, all I want to figure out is...How to charge two different types of batteries in the one system

...Is there a Victron setup that will allow me that control charging of my two 12V 100Ah Relion LiFePO4 house batteries and a 12V gel starting battery with a 12V charger/inverter, while also handling solar panel and wind generator charging.
Every attempt to determine how to do this (if possible) from the website info has ended up with me completely confused. I've talked to two dealers by email (from when I would buy the necessary equipment), and both have quit responding after the second email from me asking how their suggested equipment would handle one aspect or another of my setup. I guess they didn't know the answer (and I know the overall Victron system options are very large and confusing) and figured finding out the answers wasn't worth the profit.
Can anyone provide some guidance on whether my system wishes are even possible? It seems straightforward, but I guess it isn't.

system design

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Daniël Boekel (Victron Energy Staff) ♦♦ commented · May 09, 2020 at 07:57 AM

Hi @Oceanwolfe

Normally:

2 types of batteries = 2 chargers

But when your starter battery is normally charged by an alternator, and doesn't need 'shore-power charging' you can probably get away with a charging relay (Cyrix) between starter battery and lithium battery.

But...as always...there are so many variables that there is no 'one size fits all' solution, a couple possible caveats:

-alternator that can't handle the currents for lithium charging (usually small output alternators are fine)

-alternator charge voltage too high (or low) for lithium charging

-etc. etc.

That's why there are specialists, but luckily most systems aren't too difficult, and with lithium batteries with 'internal BMS' that disconnect on deep discharge and over-charge, protection is also easier.

-please check maximum continuous charge / discharge current of the batteries when selecting alternator / inverter / charger.

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Answer 1 · 2020-05-09T13:27:05Z

oceanwolfe answered · May 09, 2020 at 01:27 PM

Thanks for your reply. Much appreciated.

In previous conversations, I had come up with few workaround tactics to handle the starting battery difference. I haven't really got answer as to whether any of the various Victron charger/inverters that have separate house and starting battery charging allow for programming different charge patterns for each. It seemed like some of the 24V models might have this, but not the 12V models "yet".
The part where the dealers quit responding is when I ask about how to meld in the wind and solar charging. I know lots of people who struggle with their setups from various manufacturers because the two sources trip each other on and off and don't "play well together". I would like to avoid that and have a system where the two charging sources work together and not against each other. Can I get this with a Victron setup?

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Matthias Lange - DE ♦ commented · May 09, 2020 at 08:31 PM

Victron don't have any "wind chargers" and using a MPPT for that is official not recommended.

Charging the lithium batteries from the alternator can be done with a Orion-Tr Smart DCDC charger.
https://www.victronenergy.com/dc-dc-converters/orion-tr%20smart
OR
https://www.victronenergy.com/dc-dc-converters/orion-tr-smart-non-isolated
If you only want to charge the starter battery with shore power then the easiest way would be a simple small charger.
But if you want to charge the starter battery with surplus PV energy this is where it becomes tricky.

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oceanwolfe Matthias Lange - DE ♦ commented · May 10, 2020 at 03:10 AM

Yes, charging both sets of batteries primarily by solar and wind is the goal. We will seldom be at dock and don't want to run the engine to charge batteries unless absolutely necessary. When we tried this cruising about 15 years ago with a wind generator and no solar, we couldn't keep up with the wind generator. We think adding solar panels will allow us to avoid engine charging, but don't want to have the two systems fighting each other (which I gather is a common problem). I figured if I went entirely with one charging manufacturer we should be able to avoid most of the problems. Victron seems to have the largest and most varied array of equipment, so my thinking was they would have the parts to achieve this. It's a common setup on cruising boats, so figured it would have been "taken care of".
Maybe not...

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