I have two 12 12 30 isolated orion smart tr’s connected to two 206 ah lifepo4 batteries. They are sourced from two 200 amp alternators and a pair of new lead acid batteries. The two chargers shae settings and they do not stay in similar charging profiles. Is there a setting that isn’t correct since they do not stay in bulk very long before going into absorption. SOK New Zealand states 14.6v for absortipn and 13.8 for float. They are 4 years old without much use but i did have an issue with faulty CB’s and now determined they aren’t performing as well as they should.
How far away are the chargers from the batteries and what size wire is used?
Do you have a shunt or anything to determine the SOC on the batteries? Have you verified the actual battery voltage compared to the voltage showing on the charger?
If you have a poor connection or undersized wiring the charger will see a higher voltage than the actual voltage at the battery, which would result in it dropping out of bulk mode prematurely and going into absorption
The chargers are maybe 2’ from the starter battery of the truck. The cables used were 6awg with two 60 amp blue sea CB’s. The voltage going to the batteries after a couple minutes of engine running is about 14.2. SOK uses bluetooth additionally there is a victron shunt in the camper which shows batteries at around 60%. I have pulled the chargers and verified the torque on all eight terminals of the chargers.
How far are the chargers from the lifepo4 batteries? That’s what really matters here.
Either it’s a pretty long run or you have some resistance issues with the cable/ends/breakers. As you can well see from your picture there’s almost a full 1v drop from your chargers to the shunt. As I suspected, the chargers are seeing a “false” high voltage and dropping out of bulk prematurely
Thanks Dave for your input, the chargers are connected via 6awg @ 2 foot run to a junction post where 1/0 cable runs along the frame rail of the truck to an anderson connector used to connect to the truck camper. I will have to check those connections on the output side of the chargers.
Definitely ohm your cables and hopefully you’ll find out what the issue is
In my personal opionion and this is how I install these chargers, the charger should be as close as possible to the battery it is charging. The charger can make up the voltage drop on the input side, but excess wiring/connections and crimps can easily add up to a system that does exactly what you’re describing
If you’ve got the charger under the hood, I’ll go out on a limb and say you’ve got at least 15ft of wire and the Anderson plug between your charger and the batteries in the camper. A similar setup I’ve done in my service truck is closer to 20ft of wire from the engine bay to the rear of the service body where my charger and batteries are, it works flawlessly
Hi Dave, I checked resistance to the point just after the bus bars and total resistance is .1ohm and .2ohm for neg and pos respectively. I’m thinking of connecting the batteries and doing a proper voltage drop test on connections I can access.
Wouldn’t hurt to double check with a dmm, but if your chargers are showing 14.6v and the other accessories are showing the batteries at 13.8v, well the writing is on the wall
Without an external voltage sense input to the charger (which would be a real nice addition) the configuration you have is really no better than just hooking up a wire directly between the coach and starting batteries. It wouldn’t be ideal but you could increase the charge voltages to compensate for the voltage drop, float voltage would be a grey area and best left alone.
Good morning Dave, I’d like to thank you again for your input with my issue. Unfortunately moving the chargers is not ideal since space in the truck camper is limited and I also pull a fifth wheel trailer with a battery bank that needs charging. I have lokked at the many screen shots I took and noted the input voltage differences as you pointed out and I found that the differences ranged anywhere from 1 volt to .1 volt. I’m guessing the Andersons but i will squeeze into the tight spots and do proper voltage drop testing to try to determine the cause of the variability between the voltage inputs.
There’s no real magic bullet for an improper install, if you’re stuck on the way it is installed your only real option is to bump up the charger voltage to make up for the drop
Only issue here is trying to find the happy balance where you can get the batteries to fully (or near) charge without overcharging them depending on conditions. I personally wouldn’t be comfortable running the charger at ~15.6v, but unfortunately that’s what you’re going to have to do here short of trying to find a charger that has a v-sens connection to properly regulate voltage over such a long distance (I don’t believe any of the victron lineup offers this)
Keep checking wiring though. If you’ve got 1ohm that seems pretty high but the Anderson connector could be the culprit. Doesn’t take much of a oxidized/dirty layer on the contacts to really jack up the resistance
The specs specs for the 12 12 30 give wire size for 10 metres which I’m well under. Just going out to look for the cause now.
Yes, 10m between the charger and the battery it’s getting its power supply from is perfectly fine but you want the charger as close as reasonably possible to the battery it is trying to charge (I believe the manual states this also)
The setup you’ve got is the exact reason you can’t charge a camper/trailer battery properly by just hooking it up to the tow vehicles battery. The voltage drop is too great, and there is no compensation for it in the system. Having your chargers mounted as far away from the battery you’re charging like this, is just an expensive way of achieving the same thing as hooking it directly to the tow vehicles battery and hoping the alternator will charge it
Just had a brain wave here, you’re using tr smart chargers, and you have a battery sense. Did you happen to connect them on the smart network? (if they are able to connect to each other over the distance)
I believe if a smart shunt or battery sense is connected to a smart charger it can compensate for the voltage drop. I don’t know if you’d get them to connect though, I can’t even connect to the smart charger in the back of my truck while sitting in the cab
Looking at upping the game to the xs
I’ve got .35 vd to inside of camper so not too bad it’s just cable even though it’s 1/0
Shunt is still reading 55amps
The xs although a lot more bells and whistles overall, doesn’t offer you anything above and beyond the smart tr chargers you already have in the respect of dealing with voltage drop over the distance (ability to use smart networking)
You will still achieve the rated amperage (or close to it) regardless of this voltage drop, that part isn’t an issue. It’s being able to achieve a full charge especially with a lifepo4 battery, you still need to achieve the desired voltage AT the battery to have it fully charge
Now, if you’re not concerned about squeezing every amp hour out of the batteries, that’s not so much of a concern.
I was looking into specs drom alldata and .2 for cable and .3 for switch os whats rated so im close The Tr’s are on the way out and the aren’t able to connect to the network. Getting 55amp from two 30amp Tr’s isnt bad but to charge my 400ah bank from 25% would take 7hrs and i dont know how charged they would get in absorb mode. The voltage loss seems variable as seen in this screen shot from today.
Ah yes, a pair of xs’s would definitely help speed things up
It’s normal for that voltage loss to fluctuate depending on battery soc and any loads on that side of the system. Exactly why I wouldn’t recommend jacking up the voltage as it would be too easy to end up in a situation that puts the battery in an overvoltage state. That differential in voltage is not constant
Only one q&d solution : run a set of thin (0.75 sqmm) wires from the battery back from the trailer to somewhere near the tr’s, and connect a victron bt battery monitor.
Put up a smart network and connect the tr’s to the network, this will serve as a dependable sense line.
Don’t forget the 5a fuse on the plus wire !