Hello, I am looking for some guidance on the potential to install 2 x 24V Lithium NG battery banks in separate areas onboard a vessel. The current plan is to have 4 x 300AH 24V NG batteries in each bank, located aprox 60 ft apart. I understand the Lynx Smart product line offers this as an installation option with corresponding BMS’s & Distributors at each bank.
A few questions I have:
Can I locate loads and charging sources at each bank’s corresponding Distributor?
Is it possible to locate a 3rd Distributor roughly half way between the banks to allow for some higher current loads to be more centrally located between them, as well as some additional charging sources? I understand the traditional issue of having dissimilar cable lengths (i.e. resistance) in a single battery bank for equal charging and discharging, however is there a product within the Victron / Lynx / NG family that would allow for this type of application?
In addition, we would like to have 2 x Multiplus II located in the proximity of each bank to create a split phase 240V system. Are there any concerns with this?
See below concept drawing that illustrates the above.
Technically there is no reason why you should not have a central distributor too. With Lithium batteries, the cable lengths don’t necessarily have to be the same, however differences in cable and connection resistances will affect the distribution of current - but the charge will equalise out over time. Lithium batteries are 95% efficient for the charge/discharge cycle, compared with 60% for lead - so the charge loss in moving charge from one battery to another is relatively small. Similarly, charging can be located at both ends, or centrally.
For point 3 - This implies that there will be 2 independent 240V systems on board. Whilst this is not a problem, do be aware that they will not be phase synchronised, so the wiring for each must be completely independent other than the Earth and possibly also the neutral connection. However, if using RCCBO’s then the neutrals will need to be isolated too.
Thank you for your reply Mike. Although it is not a necessity, we were exploring the option of configuring the inverter chargers to a split phase 240V setup. I was potentially planning to network the inverter chargers in the master/slave configuration and setting them up to provide synchronized 240v split phase. Thoughts?
I’ve not personally used these inverters in 120-0-120 configuration, if this is what you are referring to as split phase operation- using 2 x 120v inverters at each location.
on a large yacht such as this must be, I would consider installing a 3 phase power system using 3 MP2 inverters. This would be more efficient. One thing you need to watch is the standby or idle current of the inverters. These inverters will spend many hours on light load, so minimising this current will reduce waste power.
