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Martin Keogh avatar image
Martin Keogh asked

Why would a Smart Solar 100/30 and a Orion-TR 24/20 wired to the same battery not output 50Amps??

I have a van with >800W fixed solar panels in series charging a 200ah lithium battery via the Victron SmartSolar MPPT 100/30 charger. I also have an Orion-TR Smart 24/12-20A both wired in parallel to the same 200ah 12 Volt lithium battery.
The Vehicle has a 24Volt battery starting system and the House Battery is 12 Volt system.
I assumed that the max current I could achieve would be 50Amps?
But, after testing I can only ever get a max of 30Amps!
Both have been tested independently of each other and they output their correct respective currents i.e. SmartSolar MPPT 100/30 (30Amps) and the Orion-TR Smart 24/12-20A (20Amps).

Am I missing a software setting here?
(please note I have set the SmartSolar MPPT 100/30 charging limit to 30Amps and no it won't allow me to increase it past the point!)


Thanks for everyone's effort here.

MPPT SmartSolarorion-tr smartcharge current limit
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klim8skeptic avatar image klim8skeptic ♦ commented ·
What are you measuring the current with?

And is the orion an non-isolated version?

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Martin Keogh avatar image Martin Keogh klim8skeptic ♦ commented ·
I use a DC current meter.

The Orion is an isolated version.


Thanks klim8skeptic

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4 Answers
snoobler avatar image
snoobler answered ·

You're very over-paneled.


800W/12V = 67A. Your MPPT can only do 30.


Depending on your array configuration, you may exceed the PV input current limits on the controller.


Contributing factors:

  1. Battery SoC - at high SoC in absorption phase, you're voltage limited, so it doesn't matter how much current is available, it will only accept as much as will maintain the absorption voltage.
  2. Wiring losses. Long wires and high currents and/or poor connections means the 24/12 charger may "see" a voltage higher than actual and put out little to no current as a result.
  3. Connection method - depending on how you've connected the sources, one may be bypassing your current measurement device, e.g., you have one source directly connected to the battery or on the wrong side of the battery monitor shunt.

When current is in question. It's always a good idea to have a clamp DC ammeter handy to measure current flow.


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Martin Keogh avatar image Martin Keogh commented ·
Thanks so much for your reply.

This is not an issue around the array voltage and or potential current. The MPPT controls that part very well.

1. My test were performed at a low SoC (37%) so I don't feel this is a factor
2. Great point, thanks. As a qualified electrician (sorry, I did not mention earlier) I know all about Volt drop per metre, cable sizing etc. The 24/12 and the MTTP 100/30 are less than 200mm apart and each of their respective outputs is connected to the Bus using 16mm cables.
3. Both charger outputs are connected to the correct side of the Shunt.
I can accurately measure both changer outputs separately and together. I also tested with a Fluke DC Clamp meter.

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Martin Keogh avatar image Martin Keogh commented ·
I also forgot to mention that I have a Victron Bluetooth Battery Sense on the battery which shares the live battery voltage with both the Victron MTTP 100/30 and Victron Smart Shunt.



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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @Martin Keogh,

My first thought would be that the battery has reached the absorption voltage, and does not require any more current to maintain that.

So the chargers reduce their output current to keep that voltage constant. Try putting a large load on and seeing if that makes a difference, that should then require more current to maintain the same target voltage.

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Martin Keogh avatar image Martin Keogh commented ·

Thanks Guy, I have tested again once the SoC is below 50%, so in all my tests the battery is well below the absorption level.

To prove the point I connected a Victronm Blue Smart Charger 12/30 to the same busbar point and with this connected I get the expected 60Amps (30Amps from the MPPT 100/30 and 30Amps from the Blue Smart Charger 12/30)

If either of these devices is charging the Orion current drops and has never outputted the required and expected 20Amps.

All the three chargers are sent to the same absorption and float voltages.
The battery is capable of being charged at 100Amps.

Thanks for your help in advance


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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ Martin Keogh commented ·
Hi @Martin Keogh,

The state of charge is not used when determining charging parameters, only the voltage and the current. So first step is to no longer refer to SoC when diagnosing this issue, but the voltage, and the current.

It didn't sound like you modified your test procedure as I suggested above, but just repeated the same as before.

This time when testing monitor the battery voltages and current. When the voltage and current stabilise, then apply a large load to the system, and then see what happens to the voltage and the current (do either of them go up or down).

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Martin Keogh avatar image Martin Keogh Guy Stewart (Victron Community Manager) ♦♦ commented ·

Ok, thanks my bad.

Battery voltage is 13.5volts. Charging with just the MPPT100/30 charging current is between 24Amps and 30Amps (sunlight dependant).

If I add an 11-13Amp load the battery voltage drops to 13.45volts. The charging current is approximate 20Amps.

I then start the engine and the Orion starts charging.

Battery voltage is now 13.4volts.
MPPT100/30 charging current is approximate 20Amps (drops due to cloud cover).

Orion is between 2.1 & 3.4Amps.

If I disconnect the Solar panel the Orion jumps to is full 20Amps. Battery Voltage is still around 13.45

I hope this makes sense?

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kevgermany avatar image
kevgermany answered ·

Might also help if you let us have the battery/voltage setups in the MPPT and Orion.

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nicetrip avatar image
nicetrip answered ·

Isolated or not has nothing to say. What comes to mind is charging voltage. If the MPPT comes up with a higher voltage because the sun is out and battery nearly full, than the Orion detects that voltage and thinks 'that battery is full, I am not going to add to that'.

That can be the other way around as well. The MPPT stay back when seeing the high alternator charging voltage. Both acting and sensing independent, nothing you can do about it. Best leave both at the recommended charging voltage for your battery.

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