Twelvoltification

Our three week trip to Kinver and back has provided the first test in the wild of the changes we've made to Erin Mae's electrics. The purpose of these has been to minimise our use of the Victron inverter / charger (Phoenix MultiPlus 3000), since that seemed to be the chief culprit in draining the batteries. I would find they were well down every morning, sometimes damagingly so, necessitating running the engine at 8 a.m. to charge them. So:

• We installed a 12 volt fridge in place of the old 230v model
• We installed a 12 volt TV in place of the old 230v model
• We installed some 12 volt sockets for running / charging various devices
• We bought 12 or USB-voltage chargers for devices that didn't have them
• We bought an expensive electric toothbrush that will charge from USB
• We re-wired the batteries to match SmileyPete's scheme
• Not part of this activity round, but a year ago, we installed a 330W BenQ solar panel

The result: during this trip we have not had to run the engine at all for charging batteries, in spite of having some days just moored up and the weather often being cloudy. The only point at which the batteries dropped to anywhere near 50% SOC (state-of-charge) was one evening when I forgot to turn off the inverter after using the grill. By the time we went to bed the SmartGauge was reading 51%, which was when I realised what I'd done and turned the inverter off. In the morning the SmartGauge showed 50%, but the solar panel was already doing its job. On every cruising day, the SOC has been up near 100% after cruising, and still well up in the 90s by 11 p.m. The SmartGauge people are very clear that the reading is only a guesstimate while the batteries are charging, but gets more accurate during discharge. Typically, it is showing upper 80s by the morning.

We've watched a fair bit more TV than usual during this period, what with the tennis, the football, the referendum, some good dramas and one or two other things. The combined drain from the fridge, the TV-on-standby and the Zoom mobile broadband / local wifi gizmo, which are on all the time, seems ridiculously small compared to when all of them needed the inverter to run.

The 12 volt charger for my MacBook is doing very well. 12 volt to USB converter plugs are now commonplace and cheap, and are successfully powering my best beloved's iPhone and iPad, and an AA / AAA battery charger. That charger is the most disappointing device, since it doesn't seem to pump up the AA batteries for my Garmin as much as the mains charger did. My own cheap phone needs mains to charge, but I hardly ever use it and have no intention of replacing it. I'll have to get used to plugging it in when we run the washing machine (while we are cruising). I think the grill and the oven need the mains supply to work safely, but will go on experimenting with that.

The Philips toothbrush sounds and feels like a wasp in the mouth. It's taking a bit of getting used to, though it's doing an excellent cleaning job. Amazingly, after three weeks it's still going strong on its initial USB charge.

Overall, I am delighted with the outcome. I check the SOC regularly, but have completely stopped worrying about it.