To have all your eggs in one - basket or not? DCS has been designing and supplying boat and RV manufactures in Australia and overseas for many years with our lithium battery solutions. DCS has actually been involved in the product development of our industry leading 48V 5kW BMU which is an hybrid and off grid battery management unit with an isolated transformer design, with UPS transfer and other software and hardware smarts that rival that of leading european manufacturers - so yes we do know a thing or two about both hardware and software charging equipment and solar MPPT’s (Maximum Point Power Tracking).
Integrated Battery Management Systems (BMS) are a great idea for space critical installations. However with most consumer electronics when it comes to space saving options it also usually means a compromise on the selection of internal electronic components, overall performance and long term reliability. Also with this all eggs in one basket centralised design approach should one component fail you’ll need to part with the entire unit for repair or replacement.
Some integrated lithium 30Amp battery management systems, can cost upwards of $2,000 AUD and can’t even recover lithium batteries, even though they state they are designed to manage lithium ion batteries. It’s important that lithium profile based chargers have the capabilities to recover lithium batteries, so that in the event the batteries internal BMS shuts the battery down to protect it from under voltage conditions the charger must be able to wake up and resume charging the batteries as soon as possible to avoid permanent damage being sustained by the cells.
What does a typical 30Amp BMS do?
- 12V DC-DC in vehicle charging
- 240V AC mains charging
- MPPT solar regulator charging (1 tracker)
- Dual battery isolator
- Load disconnect
A combined maximum of only 30Amps of charging current can be utilised from all 3 power inputs (vehicle, mains & solar). These chargers do not provide maintenance charging to the engine cranking battery, so for long term 240V mains connections there is no maintenance charge of engine batteries. Most of these chargers also feature a low MPPT voltage range, which also limits solar panel selection.
So what do we like to supply and install for our customers RV’s and boats at DCS? 3 carefully selected and proven components for each of the 3 charging sources (vehicle, mains & solar) a decentralised approach;
- Enerdrive DC2DC 40Amp for in vehicle charging and automatic battery isolation from engine battery
- Votronic 31.5Amp MPPT solar regulator (high efficiency 98%) with remote LCD display screen
- DCS-LFP-1260 240V mains charger 60Amps (correct recovery capabilities of lithium ion batteries)
- 60Amp low voltage disconnect (VSR) load disconnect
Total costs $1,443 AUD.
Let’s take a closer look at the overall battery management system design and performance. Unlike the all integrated BMS the DCS solution is able to push all combined charging currents simultaneously to the batteries for a much faster recharge time. For example if there is a need to fire up a genset you can push 60Amps + 40Amps from the vehicle that’s a combined current of 100Amps. Or if your running the engine 40Amps and sufficient sun power is available 40Amps + 30Amps = 70Amps. Or if you really needed to top up the batteries fast you can run the genset (60A) + vehicle (40A) + solar (30A) = maximum combined charging current of 130Amps.
“Isn’t 130Amps way too much charging current, won’t that damage the batteries?” Not at all, the latest generation of 12V DCS batteries are able to be recharged at up to 150Amps continuously without hurting the battery cells. For example running 2 x DCS-12V-100Ah batteries, totals 12V @ 200Ah. Charging at 130Amps is only a 0.65C charge rate which is fine for our batteries. Remember these are absolute maximum’s in perfect conditions, which is very rare.
What else does the system do? The German made and manufactured Votronic MPPT solar regulator also features a dedicated charger output circuit for the engine/cranking battery. So it will maintenance charge and keep it topped up, increasing the batteries lifespan and ensuring it’s ready for cranking. Automatic compensation of voltage losses on the charging cables. It also features automatic AES (Automatic Energy Selector) mode which triggers Electrolux & Dometic brands of fridges to switch from LPG operation to 12V operation should the batteries be fully charged and excess solar power available (saving LPG). As well as a very neat slim line remote LCD display screen that provides accurate battery voltage and solar charging current.
What is our choice of solar panels for marine/boat applications you might be wondering? We'll it's the LG NEON-2 360W panels, which are a 1700mm x 1000mm 60 cell module. Featuring unbelievably high 20.8% module efficiency, 25 year warranty, robust dual channel frame for superior rigidity and cyclone wind load resistance (5400 pascals) with a thick black powder coated frame that has far superior corrosion resistance compared with regular aluminium frames. The panels are of course monocrystalline with an excellent temperature coefficient, so they keep powering on even during extremely high temperature and humidity conditions.
The DCS-LFP-1260 240V mains charger is a high performance charger with 60Amps steady charging current output and auto resume charging to keep the DCS lithium batteries at optimum levels when connected to mains for prolonged periods of time. The charger can also correctly recover DCS batteries by applying a low current should they accidentally be fully emptied and will resume full power charging once the batteries voltages are restored to normal levels. Backed by a 3 year replacement warranty. Also available in a 24V model the DCS-LFP-2445.
Dual MPPT trackers, the Enerdrive DC2DC also features a 600W MPPT PV input so if you needed to run any additional portable solar panels when free camping you can easily plug additional solar panels in via an anderson plug connection.
When failure is not an option use only DCS 12V lithium ion batteries.