For our Quattro, the Victron specs recommend more stringent cabling and overcurrent protection than ISO. For example, Victron recommends 2x120 mm2 for both positve and negative battery cables. Yet, I read ISO as allowing 50 mm2: 4kW (continuous output power) ÷ 12v ÷ 2 = 167A maximum continuous amperage per cable. 50 mm2 conforms if the cable insulation is rated at 70°C or higher. Our installation meets ISO but not Victron.
Is there any general provision in ISO that states more stringent manufacturer recommendations preempt less stringent ISO standards? I have ISO 13297 for boat electrical installations, which appears to be silent on this point.
OGPS
(Ed @ Off-Grid Power Systems - offgridps.com)
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Victron’s recommendations take into account more than just ampacity. Under high load the inverter can introduce DC ripple (a consequence of rapid switching to build the AC sinusoidal waveform) and the inverters will quickly de-rate if much ripple is detected. Yes, you can use smaller cables so long as you aren’t running under continuous high loads or high peak loads. Keep an eye on ripple as reported by VEconfigure (and maybe VictronConnect….I don’t remember) and if the Quattro complains about too much DC ripple then upsize the DC cables.
I must not be clear. This is a separate post not related to grounding the Quattro case. This post is whether the battery cables between the batteries and the Quattro are large enough. These are the cables that charge the batteries or power the inverter depending on the mode of the Quattro. Victron says they should be one size, ISO allows a smaller size. This is not about the proper size of the case grounding cable. I want to know if ISO can be overruled by a stricter manufacturer specification. The boat manufacturer claims the cables conform to ISO 13297. I claim the cables do not conform to Victron’s specs. We are both be right. but which governs? Does ISO require the installation to conform to Victron’s specs if those specs are stricter than the ISO standard?
This is useful and helps me understand. However, my question is not so much about what will work or why. The question is whether there is a general ISO provision that defers to device manufacturer specs if those specs are more stringent than the ISO standard. This boat is for sale. A buyer’s survey may cite the cables as a deficiency since they are not up to Victron specs. I want to know if I can fall back on conformity to the ISO basic standard or does ISO require conformity to a more stringent device manufacturer standard, which is a Victron spec in this case.
Not difficult at all. However, somewhat time consuming. I’m in Colorado and the boat’s in Annapolis. I need to hire the work if it is to be done. My electrician estimates $2k for materials and labor. So, the questions are: 1) must it be done and 2) if so, who pays? Both are answered by whether ISO trumps Victron or vice versa. If ISO prevails, the status quo is meets standards. If Victron prevails, there is work to do.
I would stick to what the manufacturer recommends as usually that’s how they guarantee a stable system. If you read the manual it actual states those are minimum recommended sizes. So where it should start.
I can confirm smaller cables cause premature faliures on units. Smaller cables run hotter and that is also not good.
Thanks for this. I agree the cables should be what Victron recommends. The boat manufacturer, however, represents it is bound only by ISO. If ISO explicitly defers to device manufacturer specs, not only must the upgrade be made, but the boat manufacturer must pay because the boat does not conform to ISO.