DC converter – Orion

[Michael.Hall]

QUESTION: Does the Orion DC-DC converter pass enough power both ways to satisfy my needs?

I’m doing my first solar install for an RV. While this forum has been very helpful, I do have a question about DC-DC converters. In a discussion with a solar vendor, they stressed that my understanding of the Victron Orion converter was erroneous – to the effect that one would have to conclude that Orion converters don’t do anything (i.e., unable to pass power either way). So, I’m turning to help from those who have done an actual installation. *grin*

I’m designing my upgrade of my RV solar system from a 12V to a 48V system (target date: Nov 2024). Most of this upgrade process has been easy, but I have one specific need, converting from/to the RV’s 12V chassis system and the house’s 48V system. My understanding is that four Orion converters could handle this process, allowing power to flow from the chassis 12V alternator to charge the house’s 48V batteries, and from the 48V system to run the RV’s 12V systems (listed below). Please correct me if I’m wrong. Any advice would be appreciated.

48V draws:
12V lighting, etc. (mandatory) (low power needs)
12V slide-out system (mandatory) (low power needs)
12V generator start (mandatory) – 12V 105A for 10 seconds. (power hungry system)
12V booster (optional) – boost the RV’s chassis, if/when the RV battery would be low (I have never needed this in 5 yrs).

12V draw:
Charge the 48V batteries from the RV's alternator (12V 70A). I needed this once, in 5 yrs, when I drew down the house batteries while under trees. So, the RV could not move until the slides were in but lacked the voltage to retract the slides (Battery Protect shutdown). So, I charged the house batteries from the alternator for about 15 minutes, and was able to retract the slides. (mandatory)

Future System:
10 * 220W bifacial solar panels (Lumera)
1 * Victron MPPT 150/45
1 * Victron Quattro 48V/5000W
2 * 48V/100A batteries (either EG4 LP4 48V or MidNite Solar MNPowerFlo5)
4 * Victron Orion 48-12V 30A (total: 120A, w/surge to 160A)
All the wiring is slightly oversized (i.e., inverter cables are #2/0, although only 105A could flow through the system), fusing follows this forum’s recommendations (2 * 125A Blue Seas Class-T between batteries and Lynx Distributor, 48V Mega fuses in Distributor, etc.).

Current System:
3 * 370W monofacial solar panels (Rec Solar)
1 * Victron MPPT 150/85 (clips power to 1020W)
1 * Victron Quattro 12V/5000W (Not properly programmed: i.e., UPS, PowerControl, & PowerAssist not activated)
6 * 12V/100A Battle Born batteries
Wiring was subpar (350A switch on 416A system, initial system had 4*BB12/100 batteries (lacked reserve to power fridge thru the night), Multiplus 12/3000 (could not run both A/C, even when on Shore power), etc.). Hence, my decision to DIY this time around!!

Main RV draws:
2 * 13.5 BTU A/Cs (1600W/each)
1 * Residential refrigerator (1500W max)
1 * washer (1000W max)
1 * dryer (1500W max)
1 * water heater (1000W max)

RV: 2019 motorhome (50A system)

Note: I have maxed out the solar panels and batteries within the carrying capacity of my RV, so I cannot increase either (I'm already slightly overweight). I've entertained the idea of using two 12V batteries to power my 12V needs, but do not want to carry the extra weight. I'm more focused on weight, rather than cost. I know the Orions will cost more, but they will also weigh less and take up less space. I'm looking for "best-practice" solutions.

Thanks, in advance, for any help or suggestions!!

 

[chrisski]

My guess is a 48 volt to 12 volt 30 amp Orion converter is enough, but if I’m wrong, a second one can be added.

Before I got my converter, I measured my max amp draw, 50 amps for the leveling jacks. That was more than my max expected dc usage of 25 amps. (10 amps for heater blower motor+5 amps for lights + 5 amps for accessories + 5 amp safety factor.)

So I bought the Victron Orion 25 volt to 70 amp converter to support the leveling jacks.

I expect your slide out is 16 amps.

Without hard data, you’ll have to be happy paralleling something if it does not work.

 

[Michael.Hall]

My guess is a 48 volt to 12 volt 30 amp Orion converter is enough, but if I’m wrong, a second one can be added.

Before I got my converter, I measured my max amp draw, 50 amps for the leveling jacks. That was more than my max expected dc usage of 25 amps. (10 amps for heater blower motor+5 amps for lights + 5 amps for accessories + 5 amp safety factor.)

So I bought the Victron Orion 25 volt to 70 amp converter to support the leveling jacks.

I expect your slide out is 16 amps.

Without hard data, you’ll have to be happy paralleling something if it does not work.

I've got the hard data. My slide outs should be about 16 amps, as they have a 20 amp fuse (each). However, the major draw would be starting the generator (105 amps), so I've sourced the DC-DC converters to handle this load (i.e., 4 * 30A = 120A). But, do the Orions allow for safe charging of the 48V batteries (i.e., house batteries)?

Note: My leveling jacks run off the chassis battery, not the house batteries.

 

[Dave in AZ]

1. A converter just does a 100% straight voltage conversion. NOT FOR CHARGING LFPs!
2. For charging, you need a charger that has a few voltages programmed to optimize battery charge and life.
3. Victron makes both converters and chargers. Be sure you are using correct one for your application.

This is the only 12 >>48 victron converter I could find, for use feeding my powerstation, not charging a battery. So I don't think you have any need for this actually.
Victron Orion-TR 12/48-8A (380W) Isolated DC-DC Converter

Victron Orion-TR 12/48-8A (380W) Isolated DC-DC Converter

12 / 48 Volt

baymarinesupply.com

 

[MakeMePower]

I would keep a single 12v agm/lifep04 in the system, and use a dc to dc charger from the 48v bank to the 12v agm to keep it charged. I would buy a portable li ion jump starter to deal with a dead generator battery, or if your talking the coach battery, then a simple solenoid override or a ACR relay. If a single AGM battery puts you too far over weight, you are already vastly overweight.

 

[MattMan119]

For taking the 48v battery and running 12v devices, I had to install 2 Victron Orion 30amp for a total of 60a .. as one did the job but it struggles on slides and was really having issues with auto leveling.. But with 2 … I have 60 amps, and the converter that was in the RV was 55a …

Now that said, I did not want to have a 12v battery system.. I could have installed a small 12v battery with a small charger and Been done with it,, I did not want to maintain 48v and 12v batteries.

I read and reread your post, and I wonder if you attempting to charge your 48v with 12v alternator? if this is the case, I know little about 12v—->48v … only take 48v—->12v … I do know that you need the “smart” version for charging,.,

Victron Orion-Tr Smart DC-DC Charger Isolated

The Victron Orion-Tr Smart 24/12, 24/24 is a powerful DC-DC adaptive 3-stage charger with robust built-in Bluetooth technology. It works perfectly in dual battery systems in vehicles or boats, automatically detecting engine running and allowing remote control with a switch.

bluemarine.com

 

[MakeMePower]

For taking the 48v battery and running 12v devices, I had to install 2 Victron Orion 30amp for a total of 60a .. as one did the job but it struggles on slides and was really having issues with auto leveling.. But with 2 … I have 60 amps, and the converter that was in the RV was 55a …

Now that said, I did not want to have a 12v battery system.. I could have installed a small 12v battery with a small charger and Been done with it,, I did not want to maintain 48v and 12v batteries.

I read and reread your post, and I wonder if you attempting to charge your 48v with 12v alternator? if this is the case, I know little about 12v—->48v … only take 48v—->12v …

he has a generator that needs over 100a to start. a single agm/ Lifep04 on a dc-dc charger is incredibly simple will prolly last 10 years and much cheaper in the long run.

 

[chrisski]

120A). But, do the Orions allow for safe charging of the 48V batteries (i.e., house batteries)

No converters don’t charge.

With a 48 volt build, accessories like a 12 volt to 48 volt charger are at best hard to find and few choices or non existent. Another reason I went to 24 volt.

I've got the hard data. My slide outs should be about 16 amps, as they have a 20 amp fuse (each). However, the major draw would be starting the generator (105 amps), so I've sourced the DC-DC converters to handle this load (i.e., 4 * 30A = 120A).

With the startup of the generator, I’d say a converter is pushing it because of start up surge. You’ll have to try it to find out but 4 converters totaling 120 amps might be good. A generator is a good reason to keep a battery. If you don’t get a good answer from experience here, than you might want to contact Victron. Probably not many people have tried to start your exact generator off a 48 volt to 12 volt system with the exact same Victron converter.
=====
If you want to see what it takes to run a single 15k BTU for at least 8 hours a day and charge batteries, take a look at my build part 2. I fill up the roof with panels and put just as many on the ground. You’re talking a second AC, so twice that number of panels.

If you can live with a single AC, THEN 24 volts is good; if 2 ACS are needed hen 48 volts.

 

[justinm001]

You want a battery for the generator. If anything happens with the system you want that battery so you can start it up, charge things and get all online. You can get a small lfp battery that has high discharge and weighs a couple pounds.

You can use an Orion and set the voltage so it'll keep the battery topped off but not charge it fully. This is fine. Then just get a 120v simple battery charger and use that sometimes to top off. You can even get a larger 120v to 12v power converter/charger and have that power the slides or keep the battery topped off. I do this and find it's nice to have multiple sources to charge and redundancies just incase.

On my system I have 200w solar dedicated to my 12v battery system and the rest on 48v. Have big lfp 12v batteries so it's just enough, but have a 120v charger setup as backup and use a wifi switch to turn it on if low. Don't use any 48/12 converters.

I have a separate generator battery on its own system with a 120v charger setup on that and leave it always on. In the winter I draw most of my tank heaters off this battery so it's a nice emergency backup.

Also have a 120v charger setup on my chassis battery. Use a shunt on my Gen battery and it's aux port to monitor the chassis, all logged via vrm so it'll email me if either is low.

 

[Michael.Hall]

You want a battery for the generator. If anything happens with the system you want that battery so you can start it up, charge things and get all online. You can get a small lfp battery that has high discharge and weighs a couple pounds.

You can use an Orion and set the voltage so it'll keep the battery topped off but not charge it fully. This is fine. Then just get a 120v simple battery charger and use that sometimes to top off. You can even get a larger 120v to 12v power converter/charger and have that power the slides or keep the battery topped off. I do this and find it's nice to have multiple sources to charge and redundancies just incase.

On my system I have 200w solar dedicated to my 12v battery system and the rest on 48v. Have big lfp 12v batteries so it's just enough, but have a 120v charger setup as backup and use a wifi switch to turn it on if low. Don't use any 48/12 converters.

I have a separate generator battery on its own system with a 120v charger setup on that and leave it always on. In the winter I draw most of my tank heaters off this battery so it's a nice emergency backup.

Also have a 120v charger setup on my chassis battery. Use a shunt on my Gen battery and it's aux port to monitor the chassis, all logged via vrm so it'll email me if either is low.

Agreed, which was the focus of my concerns. However, I subsequently discovered that my generator is actually started from the chassis battery. I just misunderstood the process.

FYI, my chassis battery is backed up with a battery boost from the house inverters. However, I've accepted the fact that, in the event I need to jump the battery, I'll have to use my towed and the Orions to jump start the chassis. However, I don't expect this issue to ever occur, as we are full-timers, and I am meticulous in the maintenance of the RV. We replaced the chassis battery last year, and will replace it every time it loses too much power (due to age).

 

[justinm001]

Agreed, which was the focus of my concerns. However, I subsequently discovered that my generator is actually started from the chassis battery. I just misunderstood the process.

FYI, my chassis battery is backed up with a battery boost from the house inverters. However, I've accepted the fact that, in the event I need to jump the battery, I'll have to use my towed and the Orions to jump start the chassis. However, I don't expect this issue to ever occur, as we are full-timers, and I am meticulous in the maintenance of the RV. We replaced the chassis battery last year, and will replace it every time it loses too much power (due to age).

I'd suggest putting a 120v battery charger on the chassis battery so its always topped off. likely if you need to jump/boost the battery its because something was left on as batteries should last a long long time if properly maintained.

 

[HRTKD]

I don't have slides or a leveling system that has to be powered in the 12 volt system, but I do have a generator. I'm retaining a 12 volt battery that is isolated to just the generator and the tongue jack. I'll be using an Orion XS to keep the 12 volt battery charged. Short term, this will be a lead acid battery. Long term, I'm going to try out one of the new NOCO LiFePO4 batteries that supposedly have a large amp surge capability.

The Orion Tr 48-12/30 is enough to power the rest of the RV's 12 volt system. The Orion XS, which will be limited to less than 10 amps output, is powered from the Orion Tr.

 

[DIYrich]

The Orion TR is one-way only (48v to 12v), and constant voltage. You will need to manually turn it off to avoid stressing the battery.
The Orion TR Smart is the Charger version. That has charger smarts built in. However, it only comes in 12v and 24v versions.

Since you only need it once every 5 years, a step-up boost converter would work. It would provide a constant 48v, and you would have to manually turn it off.

 

[justinm001]

I don't have slides or a leveling system that has to be powered in the 12 volt system, but I do have a generator. I'm retaining a 12 volt battery that is isolated to just the generator and the tongue jack. I'll be using an Orion XS to keep the 12 volt battery charged. Short term, this will be a lead acid battery. Long term, I'm going to try out one of the new NOCO LiFePO4 batteries that supposedly have a large amp surge capability.

The Orion Tr 48-12/30 is enough to power the rest of the RV's 12 volt system. The Orion XS, which will be limited to less than 10 amps output, is powered from the Orion Tr.

Is that because you leave your inverter off and it'll allow solar to keep everything charged? A tongue jack doesn't seem to use much power and the gens alt will recharge when its running so you're just topping off. I'd think a 120V charger would be better/cheaper than an XS but if you're not on shore and leave the inverter off for months I can see the appeal.

I went with Victron 120v battery chargers for chassis, generator and even the large LFP bank (as a backup) Hooked up to kasa smart switches and programed them to turn on using home assistant when Victron reports SoC above 70%. I think i have the generator and chassis voltage reporting to Home Assistant so need to program it to turn on when its low too. I like having this as redundancy so if any issues with the system I can at least plug it into a pedestal with an extension cord and charge those up separately. My genset has a 20a/240v extra wire I'm planning on using for 2 outlets for emergencies as well.

 

[HRTKD]

The generator has no alternator. It draws from the starter battery (or whatever it's connected to) but doesn't push any power back through the cables the starter uses to get power.

Yes, I do turn off the inverter. It's still connected to the battery but inverter switch is off.