Loss of Bulk Charging

[Vlenventure]

I'm having a strange problem I can't quite get my head around. 2021 Renegade Valencia 38BB w/ solar and BattleBorn Lithium packages.

With solar off, generator off, no shore power, engine off, the Victron battery management system shows 12.81V, 30% SOC. Firefly display shows 12.8V, ME-ARC (Magnum Energy Advanced Remote Control- the inverter/charger display in the stairwell) shows 12.5V. A multimeter across the batter terminals reads 12.8V. OK. If I turn on the generator and turn on the charger, I'd expect the inverter/charger to go into bulk charging, and send somewhere around 100A to the batteries.

When I turn on the generator and then the charger, instead the ME-ARC reads 15.1V and goes immediately into absorb charging at 12A. Here are the charge settings:
• Battery type: custom
• Absorb Volts: 14.6
• Float Volts: 13.6
• EQ Volts: 14.6
• EQ Done Time: 0.8 hours

This made me thing something was wrong with the inverter/charger. There were 2 fault codes: low battery voltage, and internal relay fault. I cleared the codes, did a hard reset by removing the positive input DC cable for 5 minutes. The codes have not come back, but it still jumps immediately to absorb charging. This makes me think the inverter/charger needs to be repaired. However...

I did what I think is an independent test with the solar. Generator off, charger off, engine off, solar off, no shore power. Firefly shows 12.8V, Victron app shows 12.8V, 30% SOC, solar shows 12.5V. I enabled the solar, and it too immediately jumps to absorb charging at 14.4V after showing bulk for a second or two. Any ideas?

I am working on building a wiring diagram for the rats nest in the battery compartment. I hope to have that complete today... will post when ready.

[Paul_D]

When you do your wiring diagram, include the size of the wires, especially between the batteries and inverter/charger. If you are pushing 100 amps, there could be a significant voltage drop. Not sure it would impact the battery charginglogic, but its another data point.

[twinboat]

Possible Bad connection. Turn on charging and feel them all for heat.

[Vlenventure]

Good suggestions. Checking for loose or corroded connections as I build the diagram. Nothing found yet. All of the 12V high current carrying wires are 4/0 gauge. There are some larger gauge (smaller) wires for the steps, hose reel, and cord reel, as expected.

[Vlenventure]

Additional data. Generator running, Victron reports 13.45V with +56.51A. Looks like bulk charging to me. But ME-ARC reports 14.9V +55A absorb charging. (?) Multimeter across battery terminal reads 13.2V, across inverter/charger DC input terminals reads 14.2V. I don't know why DC voltage across inverter terminals would read differently than battery terminals. I thought they were directly connected. Perhaps a bad ground somewhere?

[wolfe10]

Originally Posted by Vlenventure

I don't know why DC voltage across inverter terminals would read differently than battery terminals. I thought they were directly connected. Perhaps a bad ground somewhere?

Only explanation is poor connection or significantly undersized wire for the amp load.

[twinboat]

Check the 300 amp fuse for good connections. Not much else between the batteries and inverter, unless you have a switch.

[Vlenventure]

Aha! Found the issue. Excellent suggestions @twinboat. Thanks. The cable connecting what I call the +12V bus bar to the BlueSea systems fuse was loose. While charging, it was hot, to the point where uncomfortable to hold. When I pulled on it, I saw and heard arcing. I removed the cable, and the connector was pitted where it was loose against the fuse block. I cleaned up the connector, tightened it down, and all is well. I am now reading the same battery voltage at the inverter/charger as I do at the battery terminals themselves, and bulk charging happens normally. I am pushing about 150A into the batteries. Much better.

It was funny- I could control the RPM of the generator just by pulling on the cable. When I pulled it tight, the RPMs increased as the charging system suddenly realized it needed bulk charging. When I let go, the connection was loose, there was voltage drop across it, and the system went into absorb charging.

Here are 2 pictures the forum may find interesting. The first shows the connection in question. On closer inspection, someone was in there before. Notice how the nut all the way to the right on the BlueSea systems fuse has the red paint worn off it. There is also a plastic cover for the fuse block that I found on the floor of the compartment behind the second chassis battery. I am not sure who was in there- I am the original owner. Someone must have gone back in after initial installation at the factory and left that connection finger tight.

https://www.dropbox.com/s/gtth4jsbjo...%20PM.jpg?dl=0

The second picture is the promised wiring diagram. It's not great, but may help someone. I haven't tracked down the second connection to the 12V shunt yet. I also haven't traced the various signal and control wires. There should be one that goes to the battery kill switch in the stairwell, and the shunts have connectors with multiple wires going to the Firefly presumably and the Victron battery monitor.

https://www.dropbox.com/s/tqau9kj2p741i63/Photo Mar 12 2023%2C 7 47 07 PM.jpg?dl=0

Now if I can just find the controller for the living room slide, that would be helpful. Just in case I need it someday. I am well acquainted with the bedroom slide controller stuffed behind the drawer the the bathroom. I have an intermittent short on bedroom slide motor #2 power wire. Wire looks OK from the motor up until it goes under the floor- then I can't see it anymore. But that will be for a different thread.

Cheers.