Hi
Finally I took the step over to lithium in my boat. I have bought 2pcs of 12,8V 200Ah NG batteries and a small BMS NG.
In my system I’ve got 3 smart solar regulators (different solar panels) and a orion XS for charging (from start-battery/alternator).
Thanks!
The first thing you need to do is read the manual. Link at the bottom. The small BMS has the least features. You can only turn chargers and loads on and off via the ATC and ATD contacts on the BMS connected to the remote on/off inputs of the chargers. You will need a Battery Protect to disconnect your loads to prevent discharging the batteries too much. Note, the Battery Protect can not be used to disconnect inverters.
Everything needs to be wired, Bluetooth doesn’t not do this type of control. If your MPPTs do not have remote on/off then you need the Victron VE Direct non inverting cables. Example wiring in the manual.
Thanks, I’ve read the manuals several times, but I think they are not so clear for an amateur…
Do I really need to shut down mppt’s if I set absorbtion voltage to 14,2V (float 13,5V) in them? It seems like just a final safety!?
The BMS MUST shut down the chargers, this is a critical component of lithium battery safety. The BMS not.only shuts down on high or low battery voltage, but also on high or low cell voltage or high or low cell temperature. You could have one cell dangerously high at 3.9V, but if the others were at 3.4V, the pack would be at 14.1V so the MPPT would still be charging. The same with temperature.
Please do not build a lithium battery set up without a properly configured BMS.
Got it, will order 3 ve.direct non inverting cables and put a wire to the orion xs.
I guess it isn’t a problem to connect 3 ve.direct non inverting cables + the additional one to the charging port at charger port on BMS!? I don’t find any limitations for that in BMS manual (except that I need to combine them outside BMS due to limited size of connecting plint).
Thanks for your clarification!
The ATC connection can source 0.5A which will be enough to control the on/off of the 4 devices.
Do not forget that those 200Ah NG batteries have a lot of energy in them and you will need some appropriate fusing. Mega fuses are not suitable for this type of lithium battery which can deliver many thousands of amps in a short circuit. You need to look at Class T, NH, Blue Sea MRBF, Adler EF3 or equivalent that can work with short circuit currents of 10,000A or more.
If you want a check over your set up before installation add a sketch here and I am sure someone will have a look at it.
Have a look at Victron’s publication, Wiring Unlimited below.
Thanks for your support! I had fuses on every connection towards battery (mppt´s, orion, and load) so I´m not concerned about that. All fuses are set to a close value for the max current in that connection. Also used oversized cables where ever it was possible to minimize voltage drop.
The cables for mppt´s are ordered and until I get them I’ve set the output to “off” so no charging from them. The orion uses the charge-control from BMS. I will test that is functional in a few days. Thanks again.