Loading different battery's with a mppt 75-10 solar charger

DIY
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1

Hello,

i’m a beginner with Victron products and not very good with electrics.

I hope somebody can help me here because the shops where is buy the parts can’t help me..

Components in my setup on the boat:

lead/acid startbattery 12v

lifepo household battery 12v

Orion-Tr 12/12-18A (220W) Isolated DC-DC converter

smartsolar mppt 75-10

2 Solar Panel 30W-12V Poly

System in my little boat from engine to battery’s:

Outboard engine to startbattery

Startbattery (lead acid) to Orion-Tr 12/12-18A (220W) Isolated DC-DC converter

Orion-Tr 12/12-18A (220W) Isolated DC-DC converter to lifepo household battery

2 solarpanels (30w each) to smartsolar mppt 75-10

smartsolar mppt 75-10 to startbattery.

My idea was to have both batterys always full when the boat is in the harbor and the solarpanels are connected.

Problem what i find is: the solar panels charge first the lead/acid start battery, if he is full the orion opens to the lifepo household battery. The voltage from the lead acid battery drops because the lifepo battery can handle a lot of electric energy from the start battery.

Voltage drop battery in a few seconds to low so the orion shut the conection between the 2 battery’s down. and the process starts again and again………

New idea to connect:

A solar charger works the best on lifepo battery’s. Is it an idea to connect the mppt 75-10 direct to the lifepo battery and connect the lead/acid start battery to the “load”output from the mppt 75-10.

If the voltage in the lifepo is high enough than he opens the load output to the startbattery?

And if it getting to low het shut the connection off.

Or is that wrong/impossible? And have somebody a better idea?

Gr Jelle
2

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You can do it as shown in the diagram.

MPPT:

  • Charges LiFePo [ Absorption: 14.2V, Float 13.5V]
  • Load is for Household and Orion „IN“

Orion:

  • Charge Starter battery
  • Start charging when Input is > 13.3V (LiFePo ist at ~80%)
  • Stop charging when Input is < 12.5V (LiFePo is at ~15%)

With this setup, the household battery is not charged while driving. How big (Ah) are these two batteries?

What are the charger settings for the starter battery?

Important to note!

  • Never connect a battery directly to the load terminal of the MPPT (the output has no current/voltage regulation).
  • I also don’t know if the MPPT appreciates having a voltage source (battery) connected to the load connection. It’s not intended to connect a battery there. The electronics on the Orion and the MPPT’s battery connection are designed to block reverse voltages.
3

What settings do you have on the Orion for engine shutdown protection and lock out voltage. Post screenshots from VictronConnect. The Orion should self limit the charge current, but it may be that as you have a much smaller solar charging current than the capacity of the Orion that the minimum current of the Orion is too high or the Orion does not work quickly enough.

4

Thank you very much Domi93!

For a newbie like me a lot to learn i see already!

But a question about this:

From my outboard engine coming only a + and - cable.

These 2 cables connect directly to the starter battery for starting the engine but also to charge te starter battery when the engine is running.

What i did was:

From the starter battery and mppt output to the input of the orion

output of orion to household (lifepo) battery.

So if the starter battery was completely full the orion opens to the household lifepo battery.

What i see here is:

From start battery to orion input still the same (except the connection from the mppt)

But than…. from the output of the orion the load connections of the mppt AND to household. What is household?

My lifepo IS the household battery.

In youre drawing there is a lifepo AND a household. Sorry but i don’t get it….

My starter battery is a 55ah lead/acid

My lifepo is now 65ah and build a new 100ah lifepo soon.

The solar panels are only connected when the boat is sitting still in the harbor where he is the whole summer.

If i take the boat i disconnect the solar panels because they are a part of my boatcover

Gr Jelle

5

Hi pwfarnell,

Thank you for your answer!

Problem now is that i disconnect the whole system because i moved the starter battery closer to the engine….

But maybe youre right!. I can set limits how to charge the household lifepo battery in stead off the standard settings like bulk loading etc.

But in my opinion the best way to charge with solar panels first the lifepo household and when he’s full make a connection to the lead/acid starter battery.

Have to say that there is very much possible in the settings of victron which is nice if you know what it al means but if you are like me it’s a lot…..

Gr Jelle

6

can you send screenshots from your Orion settings (specially the Motor detection)

there you can set when the charger start and when it stops.

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do you have datasheets from your Batteries, i think that someone has doing tests with Lead acid and LiFePo parallel connection. (i dont know very much about lead acid batteries) But i think the voltages are nearly the same.

7

Hi Domi93,

Tomorrow i reconnect the orion to a battery to make screenshots from the settings an place it here.

8

Hi Domi, Here the settings of the orion.

Screenshot_20251014_103857
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Screenshot_20251014_103827
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9

Thanks for the pictures. Now I see the problem with your Orion: you can’t adjust the charging current. It charges directly at 18A, and your solar panels provide about 5A (60W 12V), which means the battery has to supply the remaining 13A. This is precisely why I recently decided on the Orion XS 12/12-50.

You can view the settings of the Orion XS in the Victron Connect app as a demo device. There it has a maximum charging current that can be set.

10

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Example for settings:

MPPT:

  • Absorption 14.2V
  • Float 13.5V
  • Current 10A (most LiFePo can charge up to 1C => 65A for a 65Ah Battery)

Orion XS:

  • [Absorption ???V (Absorptie)]

  • [Float ???V (Druppel)]

  • Current 5A (2x30W / 12V)

  • Startvoltage 13.3V (startspanning)

  • stopvoltage 12.5V (uitschakel spanning)

Orion Tr 12/12-18A:

  • Absorption 14.2V (LiFePo)
  • Float 13.5V
  • current is always max. 18A

I am not familiar with the exact voltages for lead batteries, so here is my question to the forum:

Can a lead-acid battery be floated at, say, 12.8V for an extended period? My idea for Jelle’s boat electrical system is the following: MPPT charges the “house battery”; as soon as it reaches above 13.3V, the Orion floats the starter battery to, say, 12.8V (permanently).

As soon as he drives his boat, the alternator fully charges the starter battery (at that moment the Orion TR 12/12-18A would begin charging the “house battery”). The engine shutdown detection is actually set so that charging only occurs while the engine is running. At the same time, the house battery continues to be charged via solar, and the starter battery is floated to 12.8V when the engine is off.

That’s why I made the second circuit diagram (expanded the first one), because this way both batteries are charged when the boat is driven.

11

Thank you very much again!

Reason why i buy the orion 18amp is: the xs wasn’t on the market on that moment.

But i know i need a loading device because of my outboard dynamo (stator) who deliver max 35 amps.

The way i charged the lifepo batt directly without a loading device will blow up the dynamo (Stator) of the engine . That is what mercury told me about my new 100hp outboard from 2023. So the 18amp orion was a safe choice.

And when the engine is running i want also that the lifepo household battery is charged by the engine. Thats the fastest way to charge the lifepo household battery.

I use the household lifepo for the little refrigerator who use the most. When we are on the go the engine fill up both battery’s easy

But sometimes (or most of the time) the engine runs 1 or 2 hours, anchor out and relaxing and swimming the rest of the day.

Back to the harbour in 1 or 2 hours, put the cover on with the solar panels and let fill the solar panels the both battery’s.

Have to say that the household and starting system completely isolated from each other .

12

OK, good to know.

Because I also have a SmartSolar MPPT100/10 and an Orion XS installed on my mini 12V solar off-grid system. These two devices have all negative poles connected at all times (no galvanic isolation => isolation) because I use SmartShunts as electricity meters, and they all run regardless of whether the Orion or MPPT has turned off the output.

That means in your case (according to my last drawing), both batteries would simply be connected to the negative pole.

13

Okay Domi,

Why should it helpfull to connect the household and starter batteries?

And the arrow to household, what do you mean with that?

I want to make a simple system to maintain both battery"s with the solar panels but that’s not possible without a extra xs or orion you think?

And I still don’t understand what the function is from the “load connection” on the mppt.

I read in the user’smanuel that it can feed

devices who use maximum 15 or 20amp and close when the minimum voltage setting from the battery is there.

Why can’t I feed my starter battery with that connection? You can’t overfill a lead/acid battery. A dynamo from the engine try also feed a battery even if it’s already full

Sorry for the many questions and ver much thanks for your help!

I try to learn from this!

Gr Jelle

14

what is the Voltage for the fully charged Lead/acid Battery? i Think there is something like a higher peak (14.4V) to remove crystalls from the elektrodes (only for a specified time after this it goes to 13.6V)

Do you have a datasheet for the starter Vattery? i only know things about LiFePo but not very much about Lead/Acid.

a Lifepo Maximum is 14.6V

You can put there your boat „household“ to switch it off when the battery is low.

The problem ist that the Solarpanels have less current than the Orion will use to charge the Household battery. then it is doing discharge and charge of the starter Battery all the time.

15

Hi Domi,

I can’t find specific data of the battery. It’s a wilco royal w55054. Nothing special.

These type off battery’s you can load them with a maximum of 14.7/8volts to get him 100%full. This is what i read about these types battery’s from wilco

  • Voltage: 12 Volts

  • Capacity: 52 Ah (Ampere-hours)

  • Cold Cranking Amps (CCA): 470 EN

  • Technology: Calcium (lead-calcium)

But next problem with the Load port from the mppt on the starter battery is that i connect 2 battery’s together?

The orion was isolated or is that not the problem?

Gr Jelle

16

Other possibility, if i throw the mppt charger away and replace it for a Bluesolar pwm duo ( BlueSolar PWM Charge Controller (DUO) LCD & USB | Victron Energy ) than i solved the problem or not?

I keep the orion the same as i do now so from starter battery to lifepo household.

And seperate from that the victron bluesolar pwm duo with the solar panels to charge the household and starter battery’s.

Or is this to simple?

They are not expensive.

Gr Jelle

17

Yes you can to this, but I would rather try to sell it on eBay or other portals (maybe someone here in the forum would be interested).

This would actually be the simplest solution for your boat, but I have recorded the other suggestion below.

BoatPower
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I hope this diagram helps you understand.

This would be the solution with the additional Orion XS 12/12-50.
You can see the suggested settings on the respective devices. The idea is that the Orion XS only floats the starter battery to 13.5V (maintenance charge), while the alternator charges the starter battery to 14.7V. As soon as the voltage is higher than 14.3V, the Orion TR begins charging the LiFePo battery. As long as the engine is running, the Orion XS will no longer charge because the starter battery voltage is > 13.5V. As soon as the engine is turned off, the voltage drops and the LiFePo charge is stopped. The “household” boat is supplied with power via the MPPT’s load output. When the boat is in port, the LiFePo battery is charged using solar energy. As soon as it reaches > 13.35V (approximately 80% charge level), the Orion XS begins charging the starter battery and ensures that its voltage cannot drop below 13.5V, thus recharging at 5A (which you can then adjust to match the solar power). In the summer, both batteries will soon be fully charged, depending on whether you have anything on the boat that’s always on and how much power it requires.

The negative terminals of both batteries must be connected here (the Orion XS only has one GND connection), but this would only be a one connection. And of course, fuses and the appropriate conductor cross-sections would also need to be installed.

Someone from Victron would have to say whether this is a problem for isolated Orions when both negative poles are connected.

Voltage to State of Charge (SOC) LiFePo:

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18

Domi,

thank you very much for your help but to keep it simple and less expensive it’s better to choose for the blue solar duo charge controller i think?

I don’t trow the mppt charger away! Or i sell it or keep it for another project!

As i can understand, the bluesolar is also completely isolated

But when i connect it like this:

bluesolar bat1 to lifepo battery

Bluesolar bat2 to starter battery

Orion xs 18a starter battery in

Orion xs 18a lithium battery out

So when he is in the harbour the battery’s fill by solar thru the blue solar and when i’m out they fill by the orion.

19

Okay Domi,

offcourse it was to beautiful to be true…..

The bluesolar can only load 2 of the same battery’s so not 2 different type of battery’s………

20

I don’t want to spend a extra 300 euro for a very tiny solarsystem.

The most easy thing to do is to connect the mppt only to the lifepo battery. It’s not a big problem but i wish it was possible on a easy way.