Lithium Upgrade Questions

[Stormy98]

I'm preparing to upgrade from Lead-Acid to LiFePo. I'm going with Victron components:

Multiplus 12/3000/120 Inverter/Charger
Lynx Distributor
Orion 12/12 30 DC-DC Charger

And I have a few questions:

Regarding grounding the Multiplus chassis, should I connect it directly to the frame? That's how the current Trace Inverter/Charger is wired, but I have seen videos that ground the Multiplus to the Lynx and then ground the Lynx to the frame. Is that ok or is it better to ground the Multiplus and the Lynx to the frame separately?

I'm using 4/0 cable to connect the batteries to the Lynx. The Trace unit currently has smaller gauge cable for the ground connections, but shouldn't I also use 4/0 cable for the new system?

Regarding shore power, the current Trace unit has a 30A "pass through breaker". Since the Multiplus doesn't have that built in, I should add a 30A breaker between the shore power connection and the Multiplus AC in, right?

[1der]

First, 3000 watt inverter is overkill unless you have some unusual energy demands. 2000w more than covers a Microwave and induction (if your set on that - I do not recommend them). What are you planning on powering off the batteries?

30 Amp DC to DC - How often and how long are you driving vs your draw downs for multi day stays / over night?
What is your alternator capacity?

What size Lith bank ?

Breaker- yes, shorepower inlet should have a 30A breaker.

[Scalf77]

The 3000 is probably a better choice, Victron is big on the temperature derating game. Plus if you get a larger charger if your battery bank an handle it. I have a multiplus II and it has configurable input breaker, I am pretty sure the multiplus does also.

A standalone input breaker is generally recommended based on the distance between receptacle to input. I use a Power Watchdog surge protector instead of a breaker. It adds some surge protection and monitors incoming AC before it connects. Maybe nice if you use enough. I just plug in and wait to hear the breaker close.

One main ground connection, that should probably 4/0. The equipment (safety grounds) don't have to be 4/0, you can go to the frame, it shouldn't cause a ground loop, there is no harm going back to your ground bus bar.

I would go with the Victron Orion XS 50 amp. It is a far betty unit, and can be configured lower if your alternator won't have enough power.

I am neutral on the lynx distributer , as I have never installed one myself.

[Stormy98]

Thanks for the info. Haven't been able to get to all the testing I want to do but here's some prelim responses.

I got a deal on the Multplus and the Orion 30 so that's why I went with them. I hear the Orion generates a lot of heat and I did like the features of the 50 amp unit though.

Main reason for the upgrade is to switch to LiFePo. I don't have a ton of AC loads, although I do want to try running a resistive heater. I also want to be able to start the Starcool with a Honda 2200 generator. I also want to see if it's possible to start and run the Starcool on inverter power only, as some others have been able to do. Some occasional microwave use (the microwave currently won't work on battery power only, and I still need to diagnose that). I was running my fridge on AC because the DC wasn't working, but that's a non-issue now. (I will reply to my other thread to close the loop on that saga.)

Currently have 3 100Ah LiFePo batteries. Alternator is rated for 140 amps. I still need to put the clamp meter on and test the draw when everything is running to see how much amperage is left to send to the batteries, but the SMB-installed 50 amp breaker is still there so no more than 50 amps will make it to the batteries.

Thanks for the info about the grounds. I will ground the Lynx with 4/0 and use the smaller existing wire to ground the chassis of the Multiplus. The Lynx takes up a bit of space but definitely less than the individual components would, and it's a good deal for what you get. Only minor downside I see so far is it dictates where the wires need to run.

First thing I will do is replace the current Trace inverter with the Multiplus and get into the programming. Then I'll replace the batteries and wire up the Orion.

[Scalf77]

So i suspect that you will be starving your batteries while running starcool in the summer. When running Starcool is using significant 12 volt power while running (blower, fans , etc.). This is all powered via the house side of the electrical system, so they will all be behind your Orion 30 amp. So everything it uses (plus any other always on stuff) will reduce what is going to the battery.

The multiplus has a boost function so you should be able to get it to power up the starcool with generator. Again you problem will be the need to both run the starcool and charge the battery (again there is a 12 volt power draw)

I have a 550 Ah battery and can power my rooftop AC overnight, depending on other usages it can get down. But I have 150 amp charging capability when driving.

So I would measure the 12 volt current starcool uses, to get a idea on what you need to overcome. I don't have that rig anymore and can't locate any real time run data I had.

[Stormy98]

Thanks, I'll check the AC and DC current draw of the Starcool. When you say "starve the batteries", do you mean while driving with Starcool operating? I assume so because that's when the current to the batteries will be limited by the Orion 30. If that's the case and the draw exceeds 30a then yes, the 50a Orion would be a much better way to go.

[Scalf77]

I don't expect it to draw 30 amps, but if it takes 15 that is 50% of your available charging power. Considering the temperature derating even more.

[1der]

suggestion similar to what I have and you already have an Orion 30 - keep the 30 as your baseline charger and add a 50. The nice part of the XS 50 is you can select the output via your phone. Idling ? then turn the 50 down. Driving for a few hours? Turn the 50 up to what your alternator can manage at speed.

Whatever you do you will find you need an input well above 30 amps/hr to have a viable house bank.

[arctictraveller]

Originally Posted by Scalf77

own. But I have 150 amp charging capability when driving.

Does the battery allow charging at 150 amp?

[Scalf77]

Originally Posted by arctictraveller

Does the battery allow charging at 150 amp?

Yes, it does. Actually it has a charge limit of 350 amps.