I have single 3kw Quattro and 3x 200Ah 12v Victron smart lithium batts. I’d like to add a 2nd Quattro for faster charging with genset, but I don’t need additional inverting capacity. I also don’t want the standby current drain of the 2nd Quattro when using inverter. Is it possible to program the system so that one unit is used when in “invert” mode, but both when in “charge “ mode?
Yes you should be able to do that. but do not set them up in parallel operation. leave both as standalone.
connect the second unit up to the incoming power AC the same as the original unit.
also connect to the same battery bank.
do not connect the AC OUT connections of the second unit.
set the first unit to on and the second unit to charger only,
do not connect the secound unit to the VE BUS system
this way the second unit will only activate as a charger.
Its charging will be picked up by the battery monitor that you are using
downside the second unit will not be seen on the GX device. (thats if you have one)
Why you want to buy expensive Quattro and only use half of it?
Why not just buy a charger for the battery and run if of the generator?
Take your pick:
2 reasons.....
1. Redundancy, as Paul B. says, in case 1 fails.
2. I already have 1 Quattro. I don't think I can add a battery charger to a Quattro. If I could, and I could find one which would give me +/- 100A @ 12V, and can set for a lithium charge algorithm, I'd be fine with it. (That would give me the +/- 200A that I'm after). But I don't see a charger which will give me 200A in a single unit, or a 100A one which will work combined with the 100A that I'm already getting from the Quattro.
Hi @svbravo ,
Ad. 2 You would not be adding charger to the Quattro only to the battery.
If you do what Paul is suggesting it is exactly what you would be doing, adding charger part of the Quattro to the battery. The rest of the Quattro will be just dead weight.
But,
Ad. 1 is also valid argument. Only what if your first Quattro lasts for the next 20 years?
You will have 20 year old, slightly_cooked, "redundancy unit" at the time when, for sure, something technologically superior is available and for sure cheaper, if you calculate 20 years of frozen assets in the underutilized second Quattro.
I assume that you have chosen Victron stuff for its quality and reliability, so I am surprised that you, from the start, thinking of it failing to perform.
Another fact to consider.
If in the future you would decide to connect second Quatro in parallel with the first one, you would need to have units with the same "hw rev" numbers.
Therefore buying second Quattro today (assuming that your first and second will have the same hw rev number) is a good idea.
Your choice.
Good luck.
Edit.
You do not say if you have any PV system.
To faster charge your battery maybe installing PV system with couple MPPT chargers be better idea.
I've never yet seen any piece of equipment in the marine environment which can be considered infallible!!! Regardless of the brand. On this boat, designed for expedition cruising in remote places, redundancy of systems is of real importance and value. If the original Quattro lasts 20 years without failure, that's great!
Now, back to my original question...I'm trying to get 2x the charge capacity of the single Quattro (100A/12V). This would allow me to cut the genset runtime in half, and the 200A charge rate is well within the capability of the lithium batt bank to handle (.3C). Do you know of a charger which will give me 200A (+/-) of charge capacity? I haven't found one, so adding a Quattro seems the best approach, especially if I can disable the inverter standby load.
As far as Pv goes, yes we have 400W PV w/ dual Victron MPPT controllers, and a wind generator as well. But we still have to run a genset now and then, and it would be good to have the extra charger capacity, instead of adding unnecessary hours to the genset.
Thanks
Cost of the Centaur appears to be about half that of a Quatro, but you loose the inverter redundancy. That in itself might be sufficient justification for a second Quatro.
I did a test with my Multi Compact and it appears that there is no idle power when it is in charger only with no shore power. (When I switch to ON or INVERTER ONLY and no AC loads, DC power increases by 12 watts which I assume is the inverter idle power.)
I don't see why the two units wouldn't work on the same battery bank. I'm pretty sure there is no control interface to the Centaur so the two units would be operating on their own to charge the battery bank. I suspect that the Centaur would back down to absorption/float sooner than the Quatro so you may finish up the charging profile with just the Quatro. But you are probably at lease 80% of the way to full charge at that point.
If your battery bank can accept max charge from all sources simultaneously, then you may need to figure a way to limit total charging current.
I'd look for advise from others on how to set up the charging algorithms of the two chargers.
Hello SVBravo,
That works as we have recently done it. We have a Smartshunt on the battery bank so we can see the entire charge current into the house bank, and the Smartshunt is selected as the battery SOC monitor. Also, if you use a Cerbo GX device, the Mk3 VEBus to USB converter can be used to connect the second Quattro to the Cerbo GX. In that way, both Quattros appear on the MFD integration so you can see the individual contributions from each Quattro. Unfortunately the MFD integration calls those devices Batteries which seems to be a software anomaly but it is obvious what they really are. Also unfortunately, the combined AC load from both Quattros does not appear on the MFD integration, only the VEBus connected unit. Once again that seems like a software anomaly as you would have to assume the AC load of each Quattro is available to the CerboGX.
