question

@Joos

The only difference (besides battery) would likely have been set up. Amps are amps.

In the install part of the manual minimum requirements are set. They include, space for cooling, ventilation and wire gauge (strand specs) and length.

The gauge cable (and length run on the gauge see 5.2.1. C) do have a bearing on heat. So does lug crimping and terminal torque.

Is your charger connected to more than one battery? multiple outputs are not regulated separately so ideally those should be the same length.

As for them being the same length for positive and negative, technically on DC it shouldn't matter, but they are likely to be fairly close since it is connecting to the battery.

At the end of the day what is laid out as a requirement should be adhered to to keep the warranty.

Hi @Alexandra, thanks for your answer.

I did read and comply with the installation and cabling requirements. Any resistance in the circuit generates a voltage drop and thus generates heat. I did check the cables and connections during the charging and did not find any hot spots (not hot to the touch). Next step will be to verify that with an infrared camera.

My charger is not connected to more than one battery. I understand that if you start putting components in parallel (batteries or chargers) you need to pay attention to cable lengths because of the difference in voltage and thus in different loads on the different components. However, that is not the case here. One battery, one charger, all in series.

To keep the plus and minus cables of the same length, or, to be more exact, the same resistance, is virtually impossible in the real world. In the plus cable is usually a fuse (in my case 2, a charger fuse and a main fuse), and in the minus side is a busbar, a (smart) shunt and a BMS. All adding to the resistance of the connection. The difference of cable runs between plus and minus is maybe 15 or 20 cm. All this is exactly how Victron draws it on their system sample drawings, by the way.

The total voltage drop of the charge loop stays well within the 3% that Victron states as a maximum.

The questions in my first post both stand open:

1. Does Victron require same cable lengths for plus and minus on a single charger, single battery system? I cannot find any hint to that on the website.

2. Is there a possibility that cabling is in any way related to the noise and the heat? Not only length, but thickness as well?

Regards,

Joos

edit:

PS: fun fact: the supplier did not change the settings before charging an AGM battery, so they charged a battery with the wrong settings.

Hello all,

As a follow-up on my previous post, here some IR camera images of the charger while doing a full (almost full) charge of my Lithium battery. I have IR pictures of all the steps, but included only some, because the post would get very long if I did. I also have pictures of the plus cable with the fuse for every step.

I started the test at 10:24, the ambiant temp was around 11 degrees Celsius.

• At 10:47 (23 mins into the test) the charger was at 30,5°C

• At 11:15 (51 mins into the test) the charger was 40°C. I stopped the test here to replace the plus cable (from 10 mmsq to 16 mmsq), because I noticed that that cable runs quite hot as well around the charge fuse. The charger had some time to cool down.
• At 11:46 I started the charging again: the charger had cooled down to 33.8°C.
• At 12:39 (53 mins since restart) the charger was already 57°C. The upgraded plus cable was already hotter than it had been using the 10 mmsq cable. This is caused by the fuse itself, which is, of course, a resistance. The minus cable (still a 10 mmsq) did not heat up nearly as much as the plus cable did around the fuse.
• At 13:15 (01:29 since restart) the charger was 64.8°C
• At 14:07 (02:21 since restart) the charger was 69.5°C
• At 14:31 (02:45 since restart) the charger was at 69.3°C
• At 14:57 (03:11 since restart) the charger was at 66.3°C
• At 16:00 (04:14 since restart) I stopped the charging. The charger was at 67.2°C

It is good to notice that the charger is installed inside my battery box, which was open all the time during the test. When the charger became very hot (around 70°C) I created some additional airflow through the boat by opening some hatches. the temps did react a little as you can see, but not much.

Throughout this test the charger delivered the rated 50 amps at all times. It did not trottle back or made a thermal break. I checked this using the smartshunt and some checks using an ampere clamp meter.

The charger produced a humming noise during charging. It grew louder and louder as the charger grew hotter.

Does anybody have any idea if these temps and noises are normal for this charger? If so, I intend to return it and find a different solution. This is not suitable for usage on a boat. The noise is unbearable and if fitted inside a battery compartment (which is the most convinient, also for cable lengths), this will heat up the batteries itself, deteriorating them rapidly. My BMS will cut of the battery if the temps get above 60°C. This was during spring, in 10°C outside temp. What will happen if it is 35°C (or above)?

For the moment, I am a bit dissapointed by this product. Not what I was expecting from Victron.