Heat generation from Victron DC to DC Charger

[smokey73]

How much heat does the Victron DC to DC Converter charger create using it to charge the LiFePo from the start battery?
I would assume it depends on whether it is charging the LiFePo House Battery at a high current or is in an absorption or float status.

I'm deciding where to put Victron DC to DC charger . Shortest wiring distance would be in the salon under the galley sink (where the LiFePo house battery will be). It is only about 3 feet from the Lithium House Battery to the FLA Start Battery. To get it out of the salon would take about 16 feet one way.

Fire away with comments.

 

[Project_Mayhem]

Have you checked the spec sheet for BTU ratings?

 

[Johann]

The old Orion TR DC-DC charger get pretty hot at max output. Upwards of 165°F for the 12/12V 30A model. They are about 80% efficient. The new Orion XS is around 98% efficient, so it’s much cooler, but I don’t know the exact temp.

 

[dlochner]

Depends on the charger, the larger the current the higher the temp. Look at the efficiency rating for the model you have, higher efficiency units will run cooler than lower efficiency units.

The most important factors are ambient temperature and ventilation. The small engine rooms we have are a usually a poor place for electronics because of the high ambient temperature. While the charger will get warm, it will not produce a lot of BTUs so it can be in a fairly small space, like under the sink and be OK. Make sure there is ample room around the charger for natural ventilation, i.e., don't stick it up in a corner where there is little to no air floor. If the sink area abuts the engine room, mount it as far from the adjoining bulkhead as possible.

Without having been on your boat, it's difficult to make a firm recommendation for locating the charger, however, I would lean towards mounting it closer to the batteries than further away.

 

[jssailem]

The Orion XS complies with ingress protection rating IP65; this means the product is dust-tight and protected against heavy rain.

• Mount vertically on a non-flammable surface, with the power terminals facing downwards.
• For optimum performance, a minimum of 10cm space should be kept free around the product for cooling. With limited cooling, e.g. due to insufficient ventilation, the charging current will be reduced sooner than at the specified maximum ambient temperature. With improved airflow (e.g. forced airflow), the performance will greatly improve.
• With limited cooling or extreme ambient temperature, the charger can become hot (especially the bottom plate). Due to internal temperature control, the heat sink will never get warmer than 90 °C; this is no problem for the charger. Make sure that the mounting surface can withstand this temperature.
• Mount close to the battery but never directly above the battery (to prevent damage from gassing of the battery).

Here is what Victron recommends (XS Orion Manual).
Will the undersink location meet these criteria?

You can always add a fan to the space to improve airflow around the unit if needed.

 

[Davidasailor26]

The old Orion TR DC-DC charger get pretty hot at max output. Upwards of 165°F for the 12/12V 30A model. They are about 80% efficient. The new Orion XS is around 98% efficient, so it’s much cooler, but I don’t know the exact temp.

98% efficient would be about 12 watts of heat dissipation at maximum output. That’s a pretty manageable amount - like a really dim incandescent bulb or a really big LED.

 

[CrispyCringle]

I have dual 30 amp Orion Tr DC to DC chargers. Yesterday they were running full blast as I was making water and motoring. They get hot. very hot. They need to be well ventilated. Mine are mounted on a panel at the edge of the quarter berth. So not in an enclosed space. The newer, and more efficient 50 amp version came out after I had installed the older model. I wish I could have gotten the newer. I guess I still can, but, you know...

 

[Johann]

I wish I could have gotten the newer. I guess I still can, but, you know...

I installed three 40mm fans above the Orion pulling air up through the heat sink. The power is taken from the ignition feed that enables the Orion. Before this I saw a high of 176°F with output dropping to 22A. After adding the fans, the max temperature was 155°F and output was up to 32A.

 

[CrispyCringle]

I installed three 40mm fans above the Orion pulling air up through the heat sink. The power is taken from the ignition feed that enables the Orion. Before this I saw a high of 176°F with output dropping to 22A. After adding the fans, the max temperature was 155°F and output was up to 32A.

Thats a great idea. I completely forgot about the output drop off due to heat. I have mine controlled by the ignition feed as well.

 

[shemandr]

I don't know very much about battery systems but I read with some interest threads about battery issues and systems. And I struggle to understand the in and outs of these systems. Time to ask a stupid question about this thread:
Does anyone think it's sorta bassackwards to charge a LiFePo4 battery with a FLA battery via a DC-DC charger? Wouldn't you want to charge the FLA battery, on occasion, with the LiFePo4 battery with the DC-DC charger? I assume the alternator output would go to the house LiFePo4 battery in that set up. The other way seems like bringing a knife to a gunfight.

 

[Johann]

Does anyone think it's sorta bassackwards to charge a LiFePo4 battery with a FLA battery via a DC-DC charger? Wouldn't you want to charge the FLA battery, on occasion, with the LiFePo4 battery with the DC-DC charger? I assume the alternator output would go to the house LiFePo4 battery in that set up. The other way seems like bringing a knife to a gunfight.

If you have an internally regulated alternator, you wouldn’t want to charge the LFP house with it for a few reasons. First, the alternator may overheat due to how slowly the voltage rises on the LFP during charging. Second, if the LFP is has a BMS disconnect during charging, the alternator diodes may fail. Third, you may damage the LFP during extended motoring if the LFP is full and output voltage is above 13.6V.

So your choices are to replace or convert the alternator to external regulation, or use DC-DC charger(s) with an output around 50% of the rated output of the internally regulated alternator.

 

[dLj]

If you have an internally regulated alternator, you wouldn’t want to charge the LFP house with it for a few reasons. First, the alternator may overheat due to how slowly the voltage rises on the LFP during charging. Second, if the LFP is has a BMS disconnect during charging, the alternator diodes may fail. Third, you may damage the LFP during extended motoring if the LFP is full and output voltage is above 13.6V.

So your choices are to replace or convert the alternator to external regulation, or use DC-DC charger(s) with an output around 50% of the rated output of the internally regulated alternator.

Agreed.

However, sure seems penny wise and pound foolish to me. If upgrading to LiFePo batteries, going to externally regulated then allows you to control your alternator output to conserve your alternators and allows you to keep your lead acid batteries always fully charged via the DC to DC from house to lead acid. Keeps your lead acid batteries healthy for longer, as they are never at a partial state of charge for any appreciable time. Takes advantage of the LiFePo system, makes for easier system monitoring, easier expansion to more charging sources, lots of advantages. The only advantage seems to me not doing this is initial installation cost. I can't see any other advantage.

dj