Weird RV 12V issue. Only getting voltage from genset starter battery.

[proost]

Lengthy post but could use some assist on a weird issue that popped while we're boondocking down in Key West. It appears that my coach is not receiving any 12V voltage provided by my 10 LiFePO4 battery bank via two Orion 24/12-70 DC-DC Converters and I'm only getting it from a single 12V starter battery for my generator that was supposed to only be receiving charge voltage from my new bank. I've verified that my converters are both putting out good (14.3V) voltage but the only voltage I'm seeing across my entire system including IRD relay, Coach Disconnect, and everywhere is the starter battery's 12.5V. Not sure when the problem started but the starting battery died and we lost all power to the coach which got me troubleshooting. I have no idea how the installer wired my system but I'd love some input on what he might have done.

Here's some background info on my install and I've attached the original schematic, a pic of my battery bank FYI and a modified schematic of my 12V system not including the new battery bank.
- I have a 2007 Gulf Stream Tourmaster T-40A coach which was originally equipped with two 12V deep cycle batteries to provide 12V power to the coach near my chassis batteries in back and four 6V deep cycles (in series and parallel) up front to provide 12V to a 2000W Xantrex inverter and start the generator. Both banks were charged by the generator and shorepower via the ATS and and a Progressive Dynamics IntelliPower converter charger.
- When we installed our new Victron system, we removed those old batteries and migrated the battery location to one of my bays. The installer moved one of my old 12V batteries up front to serve as a starter battery for the generator. (Did he really need to do that if I had such a large lithium bank?)
- I can see two 2/0 wires leaving the bank (see picture and black wires in front of the batteries) but that's it.
- There are no wires in the front at the starter battery that have 14.0+ volts.
- There's a 2/0 wire similar to one of the ones leaving the bay coming into the rear battery location where the two 12V coach batteries were and it's connected to the two positive wires that were attached to those batteries. One 4AWG wire is presumably a lead coming from the now disconnected IntelliPower converter and the other 2AWG is connected to the coach IRD relay solenoid. The original drawing has it connected to the coach disconnect but they are next to each other so assume that was the manufacturer's prerogative.
- I'm assuming the coach is getting starter battery voltage via the connection via the Main IRD relay and the Coach IRD relay to the disconnect solenoid.
- EDIT: The only way the starter battery will charge is via the alternator with the engine running or by attaching a charger which is what I have to do to keep the lights on for any length of time.

So my questions are (if you're still reading lol)
1. If you were installing, how would you wire up the starter battery to take charge voltage from the Orion DC-DC converter? Is it as easy as just connecting it up? The Orion does say it's a Battery Charger as well as a converter but not sure how that affects the entire system. It has been working great for the past four years of full-time living.
2. Do I even need a starter battery for my generator? I have Lion's but Battle Born has guidance on the minimum number of batteries you'd need to provide safe starting ability for gennies.
3. How would you connect my lithium bank to the 12V distribution system? My guess is straight to the Main IRD relay for emergency connect power to the chassis system.

Thanks a lot for your input. Standing by if you have any questions for clarification.

 

[HarryN]

So if I were setting it up for my own vehicle, I would:

1) Wire each individual Li battery (+) - breaker - common bus bar - ( loads and charging )
2) Wire the battery (-) of each one to a common (-) battery bus bar - shunt - ( loads (-) bus bar.

The reason is that each battery has a built in BMS and it can trip on an individual level. The only way to re-set it is to isolate it from the others and all wired together it will be impossible to diagnose. With the breaker in place, if you "suspect" that a bms has tripped, you can just flip them off and on one at a time with zero pain level.

Each wire will have < 50 - 60 amps, so you can just use 6 awg or similar wire for each one and a similar breaker.

_____________

A Li battery bank like that is sort of a black hole for absorbing charging power, so it really needs to be charged using a real charger, not just a relay isolator off the engine alternator. A real battery to battery charger run from the starter batteries over to the house bank with real control.

Example sterling or victron or other of your choice.

If you try to charge just via an isolator, then the current will go completely out of control sometimes and might burn out your alternator.

It might make sense to just completely disconnect the starter and house batteries. Just charge the house battery pack with the generator and solar and skip trying to charge from the engine alternator if you want simplicity.
____________

The house battery bank that you have is enough to move nearly all loads over to it. The only one that is questionable are the slide actuators but it might be enough with such a large bank. Will have to think about that one.

____________

I would be tempted to set up a small solar solar panel ( 200 watts or so) and a simple solar charger controller that just feeds your starter battery to keep it charged up when you are not driving much. That way you don't have to really worry about it having enough power to start or going dead on you unless things go really sideways.

 

[HarryN]

Sorry, missed that your coach is dead and you are trying to diagnose.

So your house bank is 24 volt? Are you reading 24 volt there at the battery pack?

 

[chrisski]

The installer moved one of my old 12V batteries up front to serve as a starter battery for the generator. (Did he really need to do that if I had such a large lithium bank?)

Probably. The 2 X Orion 70 amp converters may not have the surge capacity to run the generator. The motor could take a bit of amps to start. I have a 23 watt motor that won’t run with a 250 watt inverter because of surge.

via two Orion 24/12-70 DC-DC Converters and I'm only getting it from a single 12V starter battery for my generator that was supposed to only be receiving charge voltage from my new bank

Sounds as if a fuse after the Orion Converters has blown.

On my single Orion 24/12 volt 70 amp converter, I have an ANL fuse at 80 amps on the 12 volt side and 50 amps on the 24 volt side.. The installer should have put some the of overcurrent protection on each side of the converter.


Since you’re getting power out of the converter, I suspect the fuse is blown on the 12 volt side.

If the generator battery were dead, and you tried to start the converter, there is a chance that without the battery to cover the surge capacity, the fuse blew.

 

[proost]

Sorry, missed that your coach is dead and you are trying to diagnose.

So your house bank is 24 volt? Are you reading 24 volt there at the battery pack?

Hi Harry,

I am and have no issues with the bank since I run my Multiplus and 110v full-time. I have good consistent voltage on the output side of my converters (14.3v) but somewhere, the connection is broken downstream.

As another alluded, it may be a blown fuse somewhere but there is no visible fuse connection in any of my 12 V bays or cabinets. I'm moving to a full hook up site tomorrow that won't be covered in fire ants so I will get under the coach and see if I can see something else.

 

[proost]

Probably. The 2 X Orion 70 amp converters may not have the surge capacity to run the generator. The motor could take a bit of amps to start. I have a 23 watt motor that won’t run with a 250 watt inverter because of surge.

Sounds as if a fuse after the Orion Converters has blown.

On my single Orion 24/12 volt 70 amp converter, I have an ANL fuse at 80 amps on the 12 volt side and 50 amps on the 24 volt side.. The installer should have put some the of overcurrent protection on each side of the converter.


Since you’re getting power out of the converter, I suspect the fuse is blown on the 12 volt side.

If the generator battery were dead, and you tried to start the converter, there is a chance that without the battery to cover the surge capacity, the fuse blew.

Thanks a lot for the input. I didn't think about a limiter on starting the genset being the converters since I run a 24 V system and that's probably why I have the starter battery. The two outputs do come together at the common positive bus bar but then there's those 2/0 wires that head into the coach. It just seems odd that I would blow a fuse that would affect everything since there are two separate wires leaving the bay.

 

[HarryN]

I guess that I am having some difficulty interpreting your wiring diagram, but maybe it is just me.

Are you saying that basically the only 24 volt part of your system are the house batteries, and even the inverter is 12 volt?

 

[Rocketman]

Quick question- you have several of the “chassis disconnects” - does your coach have a “Salesman Switch” and is it by chance flipping off. That was an issue in my rig - could bump that switch without realizing it (then I changed out the relays).

 

[proost]

I guess that I am having some difficulty interpreting your wiring diagram, but maybe it is just me.

Are you saying that basically the only 24 volt part of your system are the house batteries, and even the inverter is 12 volt?

My new house battery set up is configured in 24V and my inverter is a Victron multi 24/3000/70.

I'll have to go back and look at the drawing I posted but the old system used a 12 V inverter charger with a 12 V configuration but because I went with solar as well, I needed to shift over to 24 V to make it easier.

I did find out though that it doesn't appear that my Victron Orion non-isolated 24/12/70A converters are putting out anything. Today, I disconnected everything to make sure I wasn't reading voltage coming from my generator start battery and I was. I'm getting nothing on the output side of those converters.

 

[proost]

Quick question- you have several of the “chassis disconnects” - does your coach have a “Salesman Switch” and is it by chance flipping off. That was an issue in my rig - could bump that switch without realizing it (then I changed out the relays).

I went through the whole 12 V system and double check that all of my relays are operational.

Just above, I think I have determined that my Orien converters are not putting out 12V. These don't have internal fuses that I can see but when I measured help put voltage with them disconnected except for the 24 V positive side and the ground, I got nothing. I think that's my main issue now.

 

[proost]

Update: Hey y'all, thanks for taking a look at this thread. I believe my root issue is that neither of my converters are putting out necessary voltage. I have two Victron Orion non-isolated 24/12 70A converters and when I disconnected the outputs, I was getting 0V where I should be reading 12 to 14V. Ground is good as is the input 24V. I took one down and opened it up thinking that it might have an internal fuse like some other lower amperage versions and didn't see anything.

In the manual for these converters you either have the option to connect a remote on/off switch or just leave the little bridge installed and then activates on "high current". Does anyone have any expertise on these converters because it seems like they are just off-line? TIA

 

[proost]

Probably. The 2 X Orion 70 amp converters may not have the surge capacity to run the generator. The motor could take a bit of amps to start. I have a 23 watt motor that won’t run with a 250 watt inverter because of surge.

Sounds as if a fuse after the Orion Converters has blown.

On my single Orion 24/12 volt 70 amp converter, I have an ANL fuse at 80 amps on the 12 volt side and 50 amps on the 24 volt side.. The installer should have put some the of overcurrent protection on each side of the converter.


Since you’re getting power out of the converter, I suspect the fuse is blown on the 12 volt side.

If the generator battery were dead, and you tried to start the converter, there is a chance that without the battery to cover the surge capacity, the fuse blew.

Neither of my converters are putting out any voltage. I verified good ground and also good input voltage but zero voltage on the output side. I don't have any in-line fuses on either side of these but should they just activate with positive input voltage? I'm seeing nothing and I think this may be my problem. The voltage I was reading on the output side was coming from my generator battery so I disconnected the output side to test accurately this morning.

I did notice this problem after I threw my battery disconnect switch and rearranged my batteries but nothing I did would have caused any overcurrent on the input or the discharge side. I know other models of Victor converters have internal fuses but when I opened one of them up this morning, I saw nothing.

 

[Rocketman]

Are those smart ones?

With my Victron Dc-Dc charger - it has an engine detect (voltage up to 14v), so it doesn’t drain the starter battery. Can you change the settings on it?

 

[chrisski]

Are those smart ones?

The Orion 24 volt to 12 volt 70 mp DC converter is a constant voltage DC to DC converter with nothing smart about it. No Blue tooth. Voltage can be adjusted vi a rheostat, fancy name for a screwdriver resistor.

Neither of my converters are putting out any voltage.

A couple things to do to fix this.

1) Check ground from the one negative on the converter to the frame.

This converter needs both the 12 volt and the 24 volt ground into that wire or it won’t work.

2) Check the jumper. This is the remote one switch. Mine works and the remote off switch needs to be jumpered for it to be turned on

This photo shows the way the green connector on the left came from the factory with a black jumper to keep it on all the time.

This is not a great pick, but the ground wire in the middle on the bottom has two black groin cables going into it; a 24 volt one and a 12 volt one. The top left red wire is labeled at 24 volts. The top right Red wire is not labeled at 12 votls.

 

[eXodus]

The installer moved one of my old 12V batteries up front to serve as a starter battery for the generator. (Did he really need to do that if I had such a large lithium bank?)

Depends on the Generator size - I have a single 12V 100AH LFP starting a 5500W Gas generator - it has no problem doing that.

Hey y'all, thanks for taking a look at this thread. I believe my root issue is that neither of my converters are putting out necessary voltage

do you have a regular 120V - 12V charger/converter? Maybe the old one from the powercenter? Those you should be able to get anywhere. Just charge your 12V system through the 120V (which comes from the 24V) it's inefficient but at least gets you going

 

[HRTKD]

In my travel trailer I isolated the generator starter battery from the rest of the LiFePO4 system. The generator starter battery is charged by a separate converter that only charges that battery. That way, should my LiFePO4 battery bank be completely drained I can still start the generator.

As Chrisski pointed out, the Orion you're using produces constant voltage. I would not use it to keep a battery charged. You need something smarter for that.