Victron DC-DC charger, and feedback before purchase?

[fitzfarseer]

Sorry to hijack this post, but I'm a bit confused by the isolation of the Victron.
My starter battery is ground to the van (transit mk7) chassis in the front, whereas my leisure battery in the back will be ground to a bolt on the van floor, along with an inverter. From what I understand, this would mean they are both ground to the chassis, however I'm unsure whether that difference in grounding position, albeit 3 or 4 metres, is going to make a difference as to what charger I get, isolated or non-isolated. Any thoughts?

 

[DJSmiley]

Since the ground is shared (both are grounded to the chassis) there is no reason to get the isolated one.

You can use both. If installing the isolated one, it just acts/works as a non-isolated one in this situation. Only at a higher cost.
Unless you can get the isolated one cheaper, just stick with the non-isolated one.

For a RV / campervan / motorhome there is generally no reason to use the isolated one. It does make sense in some marine applications where you might have to deal with galvanic corrosion, but that doesn't appl for your application

 

[fitzfarseer]

Excellent thanks, I had almost come to that conclusion, I was just unsure whether having multiple grounding points around the van would be an issue. Seems like it wont be a problem, so the non-isolated version it is!
(although I am also considering a Sterling charger instead, so the decision goes on!)

 

[DJSmiley]

Sterlings are 60A afaik. I don't have experience with them, since they mainly sold in the UK (and i'm in NL)

Before deciding to go for 30 or 60 amp, check your alternator's rating. On a smaller alternator I won't recommend pushing 60A continously, and it might be better to go for a 30A.

Since the MK7 isn't too old, I expect it to have a decent alternator, but I would only consider 60A if the alternator is 150A+ or so.
The worst-case baseload (fans, ac, lights and other stuff) pulling from the alternator, add 60A and you might reach the alternators limit. I won't go over 60% of its rated current countinously. While driving you might be good due to the airflow, but in a traffic jam things might be different and eventually overload the alternator.

 

[fitzfarseer]

Yes I remember Will Prowse talking about over taxing the alternator, so I was aiming to push for no more than 40amps. Fortunately, Sterling do a 30a B2B charger, which is very similar to the Victron aside from a few features, like a bluetooth app for instance, which is no loss to me, and the whole unit is a bit cheaper.

 

[LVLAaron]

Yes I remember Will Prowse talking about over taxing the alternator, so I was aiming to push for no more than 40amps. Fortunately, Sterling do a 30a B2B charger, which is very similar to the Victron aside from a few features, like a bluetooth app for instance, which is no loss to me, and the whole unit is a bit cheaper.

Are you going to run a new main lead from the primary battery? If not you don't need to worry about taxing it. The others were correct... I only get about 9 amps through the dainty factory wire.

 

[Cajunwolf]

The orion TR is just a DC-DC converter.

It's not a full charger (for LFP)! It can be used as a charger due to its CC limiting capabilities, but it does lack actual charging profiles!

So when set to eg 14.2V, it will provide 14.2V, any time. So eventually it will overcharge a LFP inless you manually shut it off once the battery is full.

LFP should never be left at high voltages for long periods. Once full, charge should stop or go to (low enough) float.
For lead-acid? No problem. It just fixes the smart-alternator issues if you have them. Lead acid doesn't mind (actually likes) to be as high SOC as possible continously.

The Orion TR Smart has bluetooth, but not only that: It's a fully functional charger. you can set the appropiate charging curves as you would for LFP.

So unless you're using it as an occasional charger, which you disconnect once the battery is full, I won't recommend the non-smart (unless you have lead-acid)

Glad I read this one; I'm looking at a DC to DC for my RV.