The DC/DC and 220 volts while motoring: a problem?

[Louisesjpp]

The manufacturer of my DC/DC (NE325) has made the following note, which I'm afraid I do not understand.

Attention!!! Do check if your fusebox has the function of disabling the relay coupler of the batteries while the motorhome is running and while it is 220V supplied. If it was not, we do not recommend the installation of a lithium battery.

Can anyone decipher it? I've asked for clarification but I don't have much time to sort this out before departure.

I am intending to drive with the inverter switched on to charge the e-bike batteries. Staying off grid in northern Scotland and with much work to do on computers, and only two solar panels, I'm not sure I can charge the e-bikes any other way.

Detail: 2 100Ah lithium batteries, DC/DC NE325 (not the lithium version, mains charger NE287 (not the lithium version) and an MPPT which happily does have a lithium setting.

 

[urban_biker]

So this seems to be talking about the situation where you might run the engine while the electric hookup is still plugged in and the fact that if a relay is not incorporated then this could cause charging problems.

I don't totally understand what the consequences are and maybe someone might be along who does, but in my view its not worth worrying about. Just awlays disconnect electric hookup before you start the engine.

I'm not sure I have ever run the engine while hooked up in 10 years of motorhoming so I suspect its a non-problem.

 

[Speve]

Lenny HB will know I’m sure

 

[Lenny HB]

I think I agree with urban_biker , weird Italian logic.

 

[autorouter]

I think the 'relay coupler' is another term for a 'split charge relay'. In other words a relay that connects the starter and leisure batteries together when the engine is running, so that the alternator can charge both batteries.

Whenever a DC-DC charger is fitted (also called a charge booster or Battery-to Battery charger, ie a B2B) the split charge relay should be disabled. That is to allow the alternator to charge the starter battery directly, and charge the leisure battery only through the DC-DC charger.

The '220V supplied' I think means that when the hookup is plugged in, the mains charger should not be directly connected to both the leisure battery and the starter battery. I don't know of any motorhomes that will do this anyway, usually they only charge the leisure battery, or have a switch that can select which of the two batteries to charge.

So to summarise, I don't think the warning is relevant for connecting an inverter to the leisure battery and charging an ebike battery, and can be safely ignored. Assuming the NE325 DC-DC is properly installed and working of course.

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