Another Lithium Battery Upgrade - Check My Work?

[Scalf77]

For more clarity the BMS max discharge rate is 600 Amp for 4 seconds, they don't really list a nominal discharge current, but do list 200 amps as the max charge current. It would generally be safe to say the same value could be used for discharge current. Acopower's website is limited on specifications. If you ask for more it will just shutdown, not limit current as @1der says.

The BMS should be looked at as a safety device much like fuses and breakers, your goal is to design your system to not shut down the BMS in normal operation.

For the solar panel fusing, the critical specification aren't provided (ISC) or short circuit current and maximum series fusing rating. I would suspect that no fusing would be needed in a parallel or series setup. The 20 amp dual breaker is acting as a disconnect switch, as we should never really see 20 amps on that circuit.

 

[geoffff]

Thanks for the clarification of the BMS and current limiting.

I guess I will just give it (an emergency start) a try and see what happens. I'll report back.

 

[1der]

As @DRobinson posted, seriously hard not to have one if these for emergency starts of my vehicles and other's cars. This one I got is good to 10 liter diesel size engines for under $100

Amazon.com

 

[geoffff]

Oh, I have one of those mini emergency starters, too! They are great.

But if I'm building this van electrical system, why not also wire up this option, too? I used emergency start a few times on my original Sportsmobile.

 

[1der]

I understand the desire. The difficulty comes w the switch to Lithium batteries and the constraint on discharge.

When the BMS disconnects the battery then you are likely to use the jumper to reset the BMS.

I have had the breaker on a 15 amp shore power feed trip because the 120v heater and water heater were going. Used the Microwave at the same time and poof, breaker tripped, inverter immediately transferred to batteries, and the 2000w inverter current exceeded the BMS discharge. BMS shut off the batteries, inverter was off, every single 12v house battery based load was off.

Easy to fix, right? Just turn off a load and reset the breaker on the pedestal and all should be good. Nope. Inverter did not sense a 12v battery because the battery was in protect and below the low voltage threshold to charge. Even though the inverter was supplied with 120v, it was not able to go into charge mode thus unable to reset the BMS.

I had to jump the lith batteries w a jumper to wake up the BMS. Then everything was back to normal. It was an interesting lesson and taught me how to recover and that the BMS shut offs typically are not self resetting. Does not take much current to reset but it does take at least 12.5 volts or so.

So, try the emergency start but be prepared to reset the BMS if needed.

 

[geoffff]

Yeah, I wouldn't want be out there in the boondocks dealing with trying to wake my battery with a 12v source when my starter battery is dead.

Acopower is pretty bad with providing documentation, but at least for this battery it says the battery should come back after a few seconds:

High Current Discharge Surges
The BMS will not allow a current that exceeds 100 /200 (+/- 5%) Amps for more than 30s, or anything larger for 0.5s. After a high current disconnection, the battery will automatically reconnect after 5 seconds.

 

[geoffff]

I've started wiring things up! This is the main bus area under the passenger side of the rear seat.

The chargers (solar & DC-DC) and battery will also go under the rear seat, but on the driver side.

 

[geoffff]

And this is the second electrical component area, tucked in tight in the gap next to the battery, under the rear seat, on the driver side of the van.

 

[geoffff]

After some misadventures, it finally works!

Solar not actually connected yet. And I still need to reconnect the 12V wires to the fusebox and wire up the 120V stuff.

 

[Twoxentrix]

Geoffff, this really is a great thread for those like me looking to go down the same path… extremely useful too are all the contributions from the others with directions & opinions (especially their explanations of ‘why’ as they are critiquing your process).
Glad I’ve been following from the bleachers.

 

[Scalf77]

Nice work, I would have some concerns over the lack of airflow. Very little room for airflow. Although the the Orion XS 50 doesn't run as hot as their previous models they still generate heat. You have the Cerbo GX pretty much blocking airflow of the Orion and being preheated by it.

 

[geoffff]

Nice work, I would have some concerns over the lack of airflow. Very little room for airflow. Although the the Orion XS 50 doesn't run as hot as their previous models they still generate heat. You have the Cerbo GX pretty much blocking airflow of the Orion and being preheated by it.

It's true. I will see how it goes, and moving the Cerbo GX elsewhere if needed won't be too difficult, as it doesn't have any heavy power cables going to it.

And, yes, I know I'm pushing it with the limited cooling space for these Victron devices. May not turn out to be a good idea, but I will see.

The layout I ended up with is the result of lots of tetris-ing, with the goal to make everything fit in that space. I avoided layouts where those two chargers were positioned vertically in a tower. The Cerbo GX seemed the least likely to get too hot, and the Orion XS 2nd place, so they are stacked together. I tried to give that MPPT charger as much room as possible.

The new Victron XS DC-DC charger is supposed to be 98% efficient, so that's only 7 watts of waste heat when charging at a 30 Amp rate, which is what I plan to do. The old Victron Tr-Smart DC-DC charger I was originally planning on using is only 87% efficient, so that would have been 47W of waste heat to dissipate!

The solar charger, Victron SmartSolar MPPT, is estimated to be about 96% efficient, so that's 8 watts of waste heat at 200W solar input (my single panel).

The Cerbo GX burns 5 watts when powering the display, so that's 5 watts of waste heat.

These numbers don't sound too scary to me.

 

[geoffff]

Geoffff, this really is a great thread for those like me looking to go down the same path… extremely useful too are all the contributions from the others with directions & opinions (especially their explanations of ‘why’ as they are critiquing your process).
Glad I’ve been following from the bleachers.

I will try to write up all the details later of what I have learned.

 

[geoffff]

One of my learning experiences involved replacing the Victron VE.Direct cables with generic JST PH2mm 4-pin female-connector cables because the official Victron ones have strangely huge plug bodies that jut out taking up a lot of precious space, and also those large dangling plug bodies easily wiggle around, preventing the white plug-ends from staying securely plugged in place.

I then learned the hard way (disassembly required) that my custom cables didn't work until I rewired them to have the Transmit and Receive lines swapped in the cables.

 

[geoffff]

Here is a summary of the parts I ended up using:

• Victron Orion XS 12/12-50A DC-DC (engine battery charger) ORI121217040 (amazon)
• Victron SmartSolar MPPT 150V/35A (solar charger) SCC115035210 (amazon)
• Victron MultiPlus Compact 2000VA (inverter & shore power charger) CMP122200102 (amazon)
• ACOPOWER 200W Mono (solar panel) HY200-12MB-1 (acopower)
• ACOPOWER 230Ah (LiFePO4 battery) (acopower)

Display Panel / Controller

• Victron CerboGX MK2 (system monitor/control) BPP900451100 (amazon)
• Victron GX Touch 50 (control panel) (amazon)
• Victron SmartShunt (battery current monitor) (amazon)

 

[geoffff]

 

[1der]

geoff - did you use the Cerbo GX to "program" / change parameters on the MultiPlus ?

 

[leblanc-SMB]

Geoffff: did you install your heater ducts and are there any issues with venting/air flow with the inverter unit with the heater ducts installed?

 

[geoffff]

geoff - did you use the Cerbo GX to "program" / change parameters on the MultiPlus ?

No, while the Cerbo GX can adjust some of the settings of the MultiPlus, the way to get to all the MultiPlus settings is to use their Victron "VEConfigure" Windows application with the "MK3-USB" adapter Amazon.com

The other Victron components (chargers, SmartShunt) can be configured using your phone with Bluetooth.

 

[geoffff]

Geoffff: did you install your heater ducts and are there any issues with venting/air flow with the inverter unit with the heater ducts installed?

Not yet. I am moving slowly here reassembling everything, and I haven't gone out on a camping trip yet. I'll report back later