Chassis Trickle Chargers
Trickle chargers/chargers/maintainers – we get asked about ways to charge the chassis battery a lot by all Revel owners.
When adding a chassis battery charger, it's essential to ensure it integrates well with your system. The right choice depends on your usage, charging priorities, and electrical setup.
In all cases, if your chassis battery is unable to maintain an adequate charge to start the engine while your van is parked/locked for 10-14 days, you have a parasitic drain and/or damaged chassis battery, which should be investigated.
Before you choose a charger, make sure you understand the impact that trickle charging the chassis battery can have on your DC-DC charging of the house batteries. We’ve outlined some important considerations below:
How to stop unintended DC-DC charging in RoamRig power systems
Choosing a Charger
- There are numerous charging options. Each has different requirements and it is up to you and your installer to choose what will work best for your needs.
- Some use 12V power from the house battery system
- Others use power from a 120V outlet
- There are also charges that use a small solar panel to charge the chassis battery.
- Any 12V powered device should have a way to prevent completely draining the house batteries while maintaining the chassis battery. Configurable voltage parameters are the easiest way to accomplish this. Generally, if you only charge the chassis from the house when the house battery is above 13.2V, you will not fully drain the house battery while charging the chassis.
- Victron offers a full line of 120V and 12V powered devices that are fully configurable with settings that control both input voltage lockouts and output voltage levels. We don’t provide specific Victron product recommendations, as every use case is different.
If you’d like to add a trickle charger and your system has a DC-DC charger, then you must keep the following in mind.
DC-DC Charger Considerations
- Many camper van power systems use DC-DC chargers to charge the house batteries via the chassis battery/alternator when the engine is on.
- DC-DC chargers typically use chassis battery voltage— which is higher when the engine is running— to detect whether the vehicle is on. When the engine is running, they draw power from the chassis battery to charge the house batteries.
- If the charger mistakenly detects the engine as running due to a higher chassis battery voltage, it may continue charging for extended periods while the engine is off, potentially draining the chassis battery.
- Full RoamRig power systems include a Kisae DMT1250 DC-DC converter, which typically won’t charge the house batteries from the chassis battery if the chassis voltage stays below 12.7V. However, if the chassis battery remains above 12.7V, the converter may continue drawing power, mistakenly assuming the engine is running, potentially draining the chassis battery after you have turned the engine off.
How to stop unintended DC-DC charging in RoamRig power systems
- Turn off DC-DC charger via the RoamRig supplied breaker, labeled “Solar and Alternator”). In 1st Generation Revels, the breaker is on the front of the bench seat. In 2nd and 3rd Generation Revels, the breaker is in the garage above the batteries. This will also disable solar charging because the Kisae DMT1250 doubles as a solar controller.
- Add a physical disconnect device between the DC-DC charger and chassis battery that is open when the engine is off, such as a high-power solenoid, contactor, or relay. When the Kisae DMT1250 breaker is on, but it is physically disconnected from the chassis battery, solar charging of the house batteries via the Kisae solar controller will still work.
- Use a trickle charger with a configurable voltage output. Generally, if trickle charge voltage is set below 12.7V, the Kisae DC-DC charger will not inadvertently begin charging the house batteries via the chassis battery when the engine is off.
Additional Guidance
RoamRig cannot offer guidance beyond the general information provided above. This includes configuration instructions, wiring details, or troubleshooting if a chosen solution does not perform as expected. It is the responsibility of the van owner and/or installer to ensure that the selected solution is properly and safely installed, and functions as intended.