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marrott01 avatar image
marrott01 asked

Noob here. Low voltage alarm 12/3000/120-50

Just finished my inverter install and am testing capacity with some disappointment.. I'm trying to run microwave even for a few seconds before I get a low voltage alarm and shutdown. My battery bank (2-6v 255Ah LA Duracell in series) is currently a joke but am upgrading soon. My settings in the inverter are to shutdown at 12.50v which it hits almost instantly after starting the microwave even with 100% battery SOC,.. (can I set these limits lower?) I realize this is discharging the batteries at almost 1C and perhaps the batteries cannot take it but I didn't see a discharge limit in the charge specs Deka sent me so am not sure. All cables are to the inverter are 4/0 and returning to battery (shunt first) are 4/0 and are about 6' long, my main chassis ground is only 2guage though but would this play a factor if to/from inverter goes straight to battery? Ive attached the battery specs below. And should say I have 565 watts on the roof which don't seem to be offsetting much when trying the microwave.


Any thoughts are greatly appreciated.


screenshot-20200803-110802-adobe-acrobat.jpg

MultiPlus Quattro Inverter Charger
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marrott01 avatar image marrott01 commented ·

Image of install20210402-141404.jpg

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2 Answers
Paul B avatar image
Paul B answered ·

Hi there a Nice neat looking install there.


A 12.5 volt shut down voltage is way to HIGH change this to around 9 to 10 volts for a LA battery, Reason is that on a hi current load the voltage on a LA will drop quickly but once the hi load is removed it will bounce back,

yes the bank is a bit small so the voltage may even drop more , try to avoid that for your batteries sake

or just use the Standard settings that the inverter came with

1617420575247.png


1617420575247.png (38.0 KiB)
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marrott01 avatar image marrott01 commented ·

Thank you Paul. I'll try this out. If it buys me a few months before I go lithium I'll be happy.

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Paul B avatar image
Paul B answered ·

Be careful with the Lithium's you buy (dont get me wrong I BY far prefer the Lithium Phosphate options)

However some of the cheaper ones with INBUILT BMS units have a MAX current limit that cant be changed, so if that current is exceeded then the battery TURNS OFF.

so make sure they can take the amps you require at MAX load of your inverter before you buy.

ALSO the surge current (this occurs when the inverter is first turned on as it charges its capacitors) some smaller ones also drop out on that surge)


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