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Impression of the battery charger in our 1719 Mercedes truck. It can deal with a fair amount of electrical abuse and messy AC mains grids – far away from stable electricity grids in the western world.
Battery charger motorhome, RV and campervan
When traveling long and far – forget about a stable unlimited electricity supply from a AC mains wall outlet. Chances are you have to live with interrupted, messy and weak Power Grid just as locals do. When staying in one place for a few weeks chances are your motorhome battery charger simply has to cope with all that instability.
Here’s what’s in our 1719 Mercedes Benz; The Mastervolt Mass combi;
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| Mastervolt Mass Combi - hidden in the sink cupboard with splash screen and forced cooling |
Apart from the obvious functions found in vehicle battery chargers, this is what we selected this battery charger for;
- - Adjustable AC power intake from 4 to 25 Amps AC
- - Power supply function – electricity with disconnected batteries
- - Power support to compensate weak AC mains boosted by the internal inverter
- - Starter battery charge function
- - Remote status panels
Here’s why these functions matter to us on long distance overland journeys.
Battery charging on a messy and weak AC mains / power grid
Long distance overland travel isn’t always about continuous driving – it’s also about living in different places for weeks in a row. Although solar power is a good power source, it’s not always enough to get through cloudy days or in a place in the shade in hot climates. A local AC mains grid can bridge the energy gap - that is - if you got the right equipment - specially in developing countries.
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| Mastervolt Mass Combi - battery charger and inverter in one |
Connecting a battery charger to a weak power grid can turn the lights off in the area. A drained 200 Amp - 24V battery bank with matched charger (ie: 20 - 40 Amps DC) can easily cause a huge load (ie: 1.5 Kw) on an already weak non-fused AC mains grid. The voltage drops or the local fuse trips because the power grid is stretched to the max already.
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| Parked in Bardia National Parc in Nepal with our 1017 truck - the power grid is very weak. |
Your battery remains empty if you can’t reduce the AC mains power intake. Above all local residents want their fridges and lights on. It’s an instant show stopper only to be resolved by a fossil fueled generator. Either by driving or starting a noisy portable generator.
The Mastervolt Combi has 2 ways to supply power in our house in this ‘weak power grid’ situation. 1) Adjust power intake to a maximum of 4 Amps, 2) switch to direct power supply mode, disconnecting drained batteries. Either way, lights stay on without burning fossil fuels and batteries get charged, though on a slower rate.
This is just one situation most battery chargers can’t deal with – bulk charge can’t be limited. It’s either full throttle or nothing.
See the documentary "The Generator Man" to what's its like to live in world with messy, weak power grids.
AC Power support mode
The Combi Mass Power support mode delivers more power in-house than outside AC mains / Power grid can supply. A drill, winch, grinder or small welding equipment is powered by both external AC mains and battery power through the inverter.
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| AC power support mode - when AC mains is too weak for a winch, battery power is added |
The Mastervolt Mass can go as far in supporting external AC mains, acting as a power source on the grid. Compared with a separate inverter / charger – the Combi Mass delivers more power by adding AC power from the batteries to external AC mains.
This saves your batteries compared to a single inverter alone.
Starter battery charger and remote panels
The secondary output on the Mastervolt Combi mass charges the starter battery when there’s AC Mains. It’s an optional output which follows the charge curve of the main batteries. The function is essential to keep starter batteries alive for a long time – specially when parked for several weeks or longer.
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| Remote control panels for Mastervolt Mass Combi battery charger / inverter |
Remote panels indicate power intake, DC load, state of charge and AC voltage – including an On/Off switch and power intake setting. It provides instant feedback about what’s going on – something we highly value in countries with stretched out AC power grids.
Bulk battery charging
In countries / area’s where load shedding (rolling black outs) is the norm, your nifty 4 state battery charger is reduced to a 1 state bulk charger. Before absorption / float charge mode is reached, AC mains is gone again. Sorry for all the work, but a simple car battery charger will function just the same.
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| Battery charger - 1 state bulk charging in India where load shedding is common |
Besides this, bulk charging causes excess heat in charger and batteries, so plenty of ventilation is a must. Best is to mount a charger on a wall not exposed to sun light to avoid excessive heating. When ambient temperature starts at 40 degrees, most battery chargers reach their max spec at +55 C degrees (131 F). The Mass Combi can cope with an ambient temp up to +80 C degrees. (176 F.)
Battery charger information
Mastervolt remote control panels
Load shedding / Rolling blackouts
The Generator Man - Living with load shedding, blackouts and generators
