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choddino avatar image
choddino asked

Why am i getting 68v 0amps in full sun with smartsolar charger

Looking for some advice. I just installed a Victron Energy SmartSolar 150/60 PV charger on my boat. My battery bank is 6 x 100AH 12v LiFePO4 batteries in parallel (12v system). I have 6 x 100watt topsolar flexible solar panels on the hardtop of my boat. I have them installed in two parallel strings of 3 panels in series (68v per string, ~6 amps per string). So i theoretically should see 68v, 12Amp and 600watt maximum at the solar charger input. My Victron SmartSolar charger reads 68v but 0 amps and 4 watts output. I am only getting 3-5 watts in full sun with the batteries at 50% discharge. I have the Smart Solar charger set for 12v LiFePO battery setting. Set the bulk charge rate to 14.4v per the battery manufacturer settings. Could this be a solar charger settings issue? What can i do to troubleshoot this?

smart solar set-up help
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The 14,4V Absorption voltage should be fine.

Set the Float voltage to 13,4V.

Disable equalization in the MPPT settings.

Did you charge all six batteries individually before connecting them in parallel?


the batteries at 50% discharge

Which device is indicating the battery SOC?

What was the battery voltage at that time?


If you disconnect the PV array, the MPPT is still powered?


Any change if you put a load on your battery/solar?


In the MPPT settings check the "charger enabled" toggle if it is ON.

Also there, check the maximum charge current value.

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4 Answers
choddino avatar image
choddino answered ·

I measure 13.5 volts at the battery input terminals on the charger, so that isnt it, but thanks. Worried i have a bad unit.

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Is this voltage on the MPPT's battery terminals measured with the PV disconnected (or during the night)?
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Well i feel like a dope, your diagnostic was revealing. I found with the PV off, i got 0 volts on the battery side. Turns out i have an isolated inverter battery bank that is not connected to my starter batteries. I knew that. But when i connected the Smart Solar mppt to the battery ground, i connected it to the wrong (starter) ground! Dope! Anyway, thanks so much for the advice. System was running last night at7pm putting out almost 60W at sunset! Cant wait to see if i approach 600W (theoretical system limit) today in the bright sun.
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choddino avatar image
choddino answered ·

Absorbtion is set to 14.4, float was 13.5, i changed to 13.4 as you suggested. Equalization is disabled, yes charged all individually before connecting. Then fully charged with a Xantrex inverter charger on shore power. Ran off batteries for 2 days so iknow the batteries were discharged sufficiently to need power. Ended up running the generator for 3 hours to recharge them. SOC was indicated on both the solar mppt and the Xantrex inverter and the matched surprisingly closely on percentage. Battery voltage was 13.1v. There was a load on the batteries from a full size home refrigerator. If i shut off the pv array, the MPPT shuts off. Charger is enabled and the mac current is set to 60amps.

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If i shut off the pv array, the MPPT shuts off.

Check the connection between the MPPT and the battery bank.

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kevgermany avatar image
kevgermany answered ·

What voltage does the charge control show for the batteries?

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johnsmith avatar image
johnsmith answered ·

Did you draw a load from the MPPT side with battery disconnected? The MPPT has a busmann internal fuse that could have popped. Connect pv panel to the MPPT and then battery to MPPT, check voltage on PV in on MPPT is PV voltage, check battery voltage is at mppt is battery voltage.


If all that is ok then reset your MPPT and use standard settings just to see if it charges. If not then you an internal blown fuse or a faulty unit.


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No i never had the unit configured without the battery connected. Battery and pv voltages on the mppt terminals match the mppt display and are what they should be per system specs. I'll try resetting later today.
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Does the Voltage measured at the MPPT terminals match the Voltage of the battery terminals? If the MPPT is reading 14.4V at its terminals, does the battery measure 14.4V at its terminals too? If not, then the MPPT is not connected to the battery. This could be due to a bad connection or an open fuse / circuit breaker.
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@Choddino

I second this. If the pv is switched off as you mentioned in one answer, and the mppt is then powered off, then there is no connection to the battery. So no charging.

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