Connecting Victron 12-12/30 DC-DC converter in a Travel Supreme MH

[jaysigel]

I have a 2006 Travel Supreme 38' DP MH. It has two 100 AH Battleborns. (I realize that there is a separate Travel Supreme forum, but this question will likely be applicable to other vehicles.) I purchased the Victron Orion Tr 12-12/30 DC-DC converter (hereafter referred by just "DC-DC") to protect the alternator when charging the lithiums. The issue is powering the DC-DC with respect to the separation of engine and house batteries.


The related equipment are the original alternator, Magnum Energy inverter/charger ME2012 with ME-ARC50 controller, which works fine (a newer MS2012 failed under warranty, waiting for an RMA for it) and a subcompartment under the Magnum with 2 large relays. I also have the Victron SmartBMV with the shunt, etc. Per advice from Battleborn (Firefly Energy), I have installed a 60 amp fuse to the DC-DC and bus bars for all of the connections (positive and negative, of course).



The original connections to the + terminal of the lithiums (in addition to the jumpers connecting the lithiums in parallel) are 2 red, fat, 2-3 gauge cables, the thin, red wire to the shunt and a communication-type cable (looks like a telephone cable) that probably goes to the ME-ARC50 controller. One of the fat, red cables is from the Magnum. That was easy to identify. The other, I presumed, was "from the alternator" (in quotes here because it's probably not). With the engine ignition off and the "alternator" wire disconnected from the battery, it reads zero volts. Disconnecting the "alternator" wire from the lithiums and routing it to the 60 amp fuse and then to the input of the DC-DC with the green switch plugged in on the DC-DC, the DC-DC is not powered on and there is no output from it. Connecting the DC-DC output to the lithiums therefore does nothing. At the same time, inside the coach, the electric step and automatic entry lights, which are normally triggered by opening the door (independent of ignition status), do not work. When connecting that so-called "alternator" cable back to the + lithium terminal (it's original connection), everything inside the coach then works fine. However, that means that the DC-DC does nothing to protect the alternator.


Under the Magnum in the same compartment (I uploaded 2 pictures including one with a close-up of the fuse on the bottom) are 2 relays and a large terminal post that connects 3 fat, red cables. There is also a small bus bar and 120 amp fuse. The pictured White Rogers relay failed several years ago and I replaced it with the current one. Its purpose is to interconnect the house and engine batteries for emergency engine starting when the engine batteries fail (a procedure NOT recommended for lithiums). I don't know what the other, smaller relay does.


I understand that the alternator normally charges both engine and house batteries when it is running. When the ignition is off, the alternator obviously does nothing and the 2 battery systems are isolated. The Magnum charges the house batteries (lithiums here) and not the engine batteries when the ignition is off. If the engine is running and the Magnum is also getting AC power, the Magnum would therefore be charging both battery systems. The 2 battery systems need to be isolated until the engine starts. After the engine starts, in order to protect the alternator for use with lithium house batteries, the alternator output to the engine batteries must be isolated from the alternator output to the lithiums with the alternator output that would have gone to the lithiums now redirected to the DC-DC with its powered output then going to the lithiums.


I believe the key to what needs to be connected/disconnected/rerouted is in the subcompartment with the 2 relays. Does anyone know what I should do to properly connect the DC-DC to the lithiums?

[jaysigel]

Here's an addendum: I measured the voltages from the bus bar (ground) to all of the terminals in the relay subcompartment. With the ignition key off, everything reads positive including the activator terminals on the left relay, except for the red activator terminal on the larger right relay, the White Rogers, that red lead being open (the white is grounded to the bus bar). The White Rogers is a normally open (NO) relay, so without power to the activator terminals, it should read positive on both load terminals. With the ignition key on, the red activator lead on the White Rogers is now positive with no other change within the compartment. I ordered replacements for both relays (Amazon) and they're scheduled to arrive in 2 days.

[windsorbill]

The DC to DC connection is pretty straight forward.




BUT you need to disable the device that connects your 2 banks when engine is running. I don't know how TS did that in 2006.

[jaysigel]

I think that I have figured it out:


First in the pictures: Both relays are fried in the closed position. The White Rogers relay on the R, I believe, interconnects battery banks when the ignition key is turned on (I will use its activation wire later on here). That doesn't seem to be a very good idea, but it does result in both battery banks normally being charged by the alternator. Obviously, we want to limit the amps going to the lithiums, so that arrangement needs to be changed. I found a replacement White Rogers relay that I had stored as a backup. I connected both load leads to it and the activation wire but not the ground wire, so it's not being powered. The smaller relay on the L disconnects the house 12V systems with the switch by the entry door. If the leads are not connected, then there's no 12V power to the house side (ceiling lights, water pump, etc.). The activation wire to that relay reads positive even with the ignition off. A replacement relay for that arrives tomorrow.



I ran an extension from that ignition wire on the White Rogers relay to the Victron converter's green connector switch. I disconnected the loop on it, connected the ignition wire to the H terminal, which is on the R side of it (the other side is the L terminal and attaching the ignition wire there doesn't work). The input power to the converter comes from the engine batteries (via a 60 amp fuse). The output from the converter goes to a bus bar. Connected to the bus bar are the large cables to the inverter/charger, a cable to the positive lithium posts, a communication cable that, I believe, goes to the inverter/charger controller, and red wire for the SmartBMV shunt. If the ignition key is turned to the on position without starting the engine, the bluetooth for the converter says that the engine hasn't been started. After actually starting the engine, the converter detects that and goes into bulk charge mode using its lithium default settings. It is very clever how it detects an engine start.



When I did this, I left the L relay disconnected. That resulted in no power to the house 12V systems. Since the relay was cooked in the closed position, I placed the leads back on the relay and the ceiling lights came on. The inverter/charger fan also came on, charging started in bulk mode, the lithium voltage increased to 14.3V from 13.0.


To test the system (it's too late at night to do so now), I will start up the engine and make sure that the voltages of the engine and house batteries are different. If they are the same, then the battery systems are interconnected and something else has been done wrong.

[twinboat]

The house battery disconnect relay ( solenoid ) is a latching relay. They latch in position after a shot of 12 volts.

It's probably not cooked, just latched to ON.
Some take a 12 volt pulse to operate and some take a reverse polarity pulse to latch or unlatch.

Look at the switch inside to see how it's wired.

The DC to DC charger turns on by sensing charging voltage above 13 volts.


The large relay is cabled between the house and chassis battery positive posts. There will be power to both sides, one being house voltage and the other being chassis voltage.

It is normally open and closes when charging voltage is sensed. If its a bi-directional system, it will also close if it senses house battery charging. That's so it maintains the chassis battery while on shore power.

You have disabled that feature, as you must because of the lithiums, but now there is no chassis battery charging.
The fix is an Amp L Start for Lithium device.

[jaysigel]

Twinboat, you are absolutely correct. I put the original back. An internet search for "24200 solenoid" resulted in my finding it to be a "Cole Hersee 24200 latching solenoid," not a relay. I bench-tested the original and when applying momentary power to the coil, it switches from open to closed to open. The relay I had replaced it with got super hot (must have been defective) and while it did connect the 12V system, it did so only while the coil was powered. That relay will get returned. I purchased a backup latching solenoid from AllBatterySalesAndService.com for $39 plus shipping ($52 total). Other places sell it for over double that price.



The White Rogers relay was stuck in the closed position. I replaced it, but left it ungrounded (nonfunctional) because when the positive ignition wire powers it, it will interconnect the engine and house batteries, which means that the alternator would be charging both. Keeping them isolated allows the alternator to only charge the engine batteries and the Victron DC-DC converter to charge only the lithium house batteries. The ignition wire goes to the H terminal on the Victron converter. It is not fooled by just turning the ignition key to the on position! You must actually start the engine.



The chassis batteries never got charged by the inverter/charger when on just shore power. When the RV is sitting in my garage and plugged in, I put a trickle charger on the chassis batteries. The Magnum takes care of the lithiums.


I'm going to start a new thread about Magnum Energy. I can't seem to get them to honor their warranty.