April 14, 2022 – Finally on the road, we are putting our ideas back in order. After our visit to Gulliver’s Camper, we took stock of the processes that concern our Falkor. Unfortunately, the pandemic period has lengthened the expected time a lot, but it now seems that our “little one” can go under the beautician’s knife without further delay. However, the wait did not go in vain, and so we identified some other gems that will improve the equipment of the van.
Particularly interesting, for us who mount a single LiFEPO4 Teleco TLI Extra lithium battery (we talked about it here), is the monitoring system developed by ERA Electronics. In fact, our solution has neither an external panel nor a Bluetooth connection capable of communicating with the internal Battery Management System to find out the status of the battery (something that Teleco offers instead with the products of the TLI Extra Pro range). Thus, to find out the charge level of the accumulator we must turn to other systems.
When we had, as in most cases, lead-acid batteries, we could rely on the voltage measurement with some peace of mind. An AGM or Gel accumulator, in fact, shows a fairly constant voltage drop curve and when it drops below the nominal 12V there is still a good supply in terms of ampere/hour (Ah) available. With lithium batteries, on the other hand, it is complicated to rely on the voltage measurement to understand how much energy we still have available, because the voltage remains constant until the last: only when the residual Ah are now few does this value suddenly drop, thus giving little warning to the user.
Everything is measured through a shunt
Thanks to the BM35021 system of the Italian startup it is instead possible to accurately measure the energy entering and leaving the battery. By setting the system parameters correctly, you can accurately know the residual autonomy. To achieve this, the ERA system uses a shunt, supplied, which must be connected to the accumulator. The data measured by this small device is transferred to a color, touch-sensitive, 3.5-inch control panel. And here the magic happens!
An interface designed to make the most of all the available space offers at a glance all the most important parameters, from the power delivered to the Ah count, from the residual capacity in percentage to the estimated time for recharging or discharging, from the voltage of the engine battery (which obviously remains lead-acid) up to the amperes coming from the photovoltaic system. In addition, a series of graphs allows you to view and evaluate even the historical data of the last month.
We chose the BM35021 because it is perfect for vehicles with only one service battery, such as ours. But the ERA system can still be used even if you have a pair of accumulators, only you need to connect them in parallel, and in this case the device will see them as if they were a single battery. It should also be remembered that, even if we will use it with a lithium battery, this solution is also perfect for all lead batteries, improving the accuracy of energy estimates.
More can be done
There are two other cool things about this product, although we probably won’t be using them. The first one is that it has two outputs capable of controlling as many relays that can be programmed to switch specific loads on and off. For example, if we want to activate a device at a particular time, just connect it to one of these lines. The second peculiarity, which however requires the adoption of an optional module, is that Wi-Fi and Bluetooth connectivity can be added. In this way, the whole system can also be controlled remotely.
For our needs, the display + shunt combination is enough, allowing us to have valuable information on the state of charge of our battery, thus allowing us to better manage our daily life.
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