kosio86 answered · 4 hours ago
Hi,
I have an issue with my brand new setup today.
Setup: Lifepo4 200Ah with internal BMS and built in display>Smart Battery Sense connected directly to battery leads>35mm2 copper wires with beefy hydraulic-pressed copper lugs>150A fuse 20cm after battery on positive and Shunt on negarive>60cm 35mm2 copper wire to Smart BP100 on positive and negative to common ground with chassis, Engine battery and SmartSolar>Smart Solar 100/20 positive connected to BP100 In trough25A fuse with 30cm 10mm2 wire>1m 35mm2 wire from BP100 Out to breaker panel>Fridge connected to 25A breaker with 2m 12mm2 cable. 200w single 42v PV.
Irrelevant devices:AC Sterling power 20A charger connected to shunt out and BP100 In. BB1260 Sterling Power DC to DC charger connectes to shunt and BP100 In. Eberspacher Diesel Heater connected to BP100 In(trough 25A fuse and 12mm2 3m wire) , as it is not recommended to shut it off while it is Hot at it has cooldown cycle. Some other devices connected to Breaker panel after BP100 Out. All those were off, but connected.
State before test: Solar noon-overcast. 20C° shown by both inbuilt battery and Smart Battery Sense. Brand new 200Ah Lifepo4 battery showing 88% SOC and 13.3v on its Built-in diaplay. SmartSolar was Floating @13.3v and not charging(confirmed charging the previois day). Lifepo4 profile was selected and then set to Custom, so Absorbtion voltage was lowered consevatively to 13.95v and Float lowered to 13.3v. Smart Solar successfully connected to SmartBattery sense trough bluethoot network. No temp compensation just low temp cutoff. All loads OFF.
Test1: I turned the Fridge ON and Smart Solar started providing 3A of power(shown in BT app) . Battery was providing just 1A of the total 4A the fridge needs (shown on shunt monitor). Then I turned off the fridge using a breaker after Smart Battery Protect 100 and I got 16.5V spike reading at the Smart Solar and BP and at the Smart Battery Sense BP threw E4 for high Voltage. The spike dropped gradually down in several seconds.
Test2:I disabled charging trough SmartSolar Battery settings page and turned on the fridge. 4A drawn from battery (as shown on shunt monitor). 0A from Smart Solar as it is off. Shunt, Battery Sense, Smart Solar and BP100 show very similar voltages, so I assume no voltage drop in my connections. Then I turn off the fridge using the breaker and voltage doesn't spike.
I am expecting delivery of good Multimeter with DC current clamp soon and I could get more readings. I could take photos, too. I am scared that I am planning to use 60A-65A trough a Phoenix Invertor and turning the Invertor off would cause worse voltage spike and burn my Eberspacher, or other device, if solar is at its max 200w
