Victron Orion 12-30 Non-isolated DC-DC charger - not holding steady charge

[concretejungle]

Need some help with this puzzling situation. Here is the short question, when I start my truck, the DC-DC charger starts charging pretty quickly up to around 10amps (I'm seeing this through the victron battery monitor). As long as my truck is at idle, it will charge. As soon as I begin to drive the truck, the charger drops down to zero amps. If I look at the battery monitor you can watch it fall from 10 amps, to 7 amps, 3 amps and then zero. No matter how long, so for instance if I leave camp at 50% battery and hit the highway, when I get home I may be at 50% battery. But when I stop and park the alternator will start to charge again.

Settings: I have the battery set as smart lithium. I have the alternator setting as regular alternator. That's all I have messed with in the settings.

Wiring: Main starting battery - 50 amp breaker switch - wire to Dc-Dc charger - out to bus bar where lithium house battery is located. Starting battery is grounded to the frame and the house lithium battery is grounded to the frame.

Is this a setting in the DC-DC charger I have wrong. or maybe this is a sign that my alternator is going bad? I'm running a sequoia alternator.

 

[sdnative]

Is the alternator somehow connected to the lithium battery? With the DC-DC charger disconnected, can you measure terminal voltage on the lithium battery with the engine at idle and at a higher RPM?

 

[concretejungle]

It's not connected to the lithium battery except through he DC-DC charger.

I'm going to test voltage drop at the unit. I have a hunch that's the problem. But.... I used the largest gauge wire the unit would accept and a marine grade. There's about a 8-9 foot run from the fuse at the battery before it get's to the DC-DC charger. So I want to measure voltage at the breaker and then at the unit.

 

[Shoredreamer]

When you say the start battery and lithium battery are both grounded to the frame, I’m assuming you added a specific cable from start negative to the frame? Because Toyota only grounds to engine block and sheet metal, both of which are isolated from the frame. Where does the Victron ground go to?

 

[concretejungle]

When you say the start battery and lithium battery are both grounded to the frame, I’m assuming you added a specific cable from start negative to the frame? Because Toyota only grounds to engine block and sheet metal, both of which are isolated from the frame. Where does the Victron ground go to?

Great question!

I have the starter battery grounded to the frame. I have a bus bar for the house Lithium battery and it is also grounded to the frame.

So the Victron ground goes to the negative bus bar which is grounded to the frame.

 

[concretejungle]

the more I've been thinking about this maybe my ground is the problem? Can you ground a battery to two different locations? If I have the negative going to the body and another going to the frame, is that truly grounding it?

 

[Shoredreamer]

Your setup sounds similar to my power setup. My lithium and dc to dc charger are in the cargo area. My neg bus on the rear 1/4 panel is grounded at two locations on the body as well as a 4awg to the frame. Start battery has a 4awg to frame in addition to the factory block and body ground directly off the battery -. I have never had any charging issues in the 6 years Ive had my lithium setup.

You have the 12-30 Orion, but you are only seeing 10 amps charging? I think your may want to go thru the settings again to make sure voltage limits are correct. It’s possible your Sequoia alt could be slowly going out. Does you monitor have start battery voltage to view while at idle vs when driving? I had one Sequoia alt fail on me already. Is there something that may be offsetting the input amps when you drive?

 

[sdnative]

the more I've been thinking about this maybe my ground is the problem? Can you ground a battery to two different locations? If I have the negative going to the body and another going to the frame, is that truly grounding it?

Ultimately in any circuit you need a low impedance path for current to flow from the battery positive terminal to loads and from loads back to battery negative terminal. If you have a weak or undersized connection anywhere in that circuit, it will cause a voltage drop affecting current flow.

 

[george_tlc]

the more I've been thinking about this maybe my ground is the problem? Can you ground a battery to two different locations? If I have the negative going to the body and another going to the frame, is that truly grounding it?

The frame/chassis should not be your ground point. Ensuring GOOD electrical contact is problematic. Toyota doesn't do it, neither Nissan on the 4wds and it's probably common with other body on frame 4wds.

The body is your better choice and you need to use locations that the bolt into the body is making GOOD electrical contact. i.e. paint etc on the body area will be an issue. Look at where Toyota has grounded to the body near the main battery and duplicate that for your aux.

cheers,
george.

 

[NeverFinis]

I think you maybe reaching the limit of the alternator or your battery setting is incorrect.

10 amps is not a lot of current flow for a DC-DC charger. My LiTime 40 Amp DC-DC does 30 Amps consistently with a 105 Amp alternator.

Also, DC-DC charger won't charge until a minimum voltage threshold has been met. Driving might cause a voltage sag from a higher electrical load.

Question, if you deplete your house battery to 30%, and then start driving, does the battery remain at 30% or does it charge to 50%?

 

[concretejungle]

I think you maybe reaching the limit of the alternator or your battery setting is incorrect.

10 amps is not a lot of current flow for a DC-DC charger. My LiTime 40 Amp DC-DC does 30 Amps consistently with a 105 Amp alternator.

Also, DC-DC charger won't charge until a minimum voltage threshold has been met. Driving might cause a voltage sag from a higher electrical load.

Question, if you deplete your house battery to 30%, and then start driving, does the battery remain at 30% or does it charge to 50%?

I tried this and I depleted the battery down to around 30%, started the truck and noticed it was charging, but slowly, got it to 32% and started driving. Drove for about an hour and got home, battery was still at 32%.

Now, if I hook up my solar panels, which run through the same bus bar in the back of the truck, it charges like a champ.