Solar Van with micro inverters

[Sunking]

One option is to pony up for a Lithium battery, but this complicates design and as far as I can tell the technology is still evolving.

Lithium is doable technically, but if you cannot afford to do it right with lead acid, there is no way you can afford lithium. To use Lithium requires a great deal of knowledge and cash to operate, and judging from your questions and statements you do not have the knowledge or cash.

[Sunking]

You cannot use Micro Inverters on battery systems. End of story. Micro Inverters are used in Grid Tied Systems, not battery. You charge batteries with DC, Inverters make AC.

[Brad Taylor]

more on microinverters

Hi WWW:
Thanks for the quick reply. I'm limited for now by battery cost, weight and area. So I may have to get by with the largest battery I can afford, which still fits in the Eurovan battery compartment. This means I will need to look at 80% discharge. I understand that discharging to 80% will reduce battery life, but I may not have any other options. Of course we can always reduce our usage to match our available power. One option is to pony up for a Lithium battery, but this complicates design and as far as I can tell the technology is still evolving.

I spent the better part of the day evaluating microinverters. I Found a good link here describing the issues for residential systems. It sounds like you can make it work, but its not turnkey. The primary advantage is using micro inverters is that during the day, any used AC power just goes through one conversion (PV->AC) , rather than 2 stages (PV->DC -> AC) improving efficiency. The primary disadvantage is that the microinverters are current sources which don't have a shutdown mode. Therefore if the sun is shining, the batteries are full and house power is not used, the microinverters either need to be disconnected, or the excess power needs to be dumped into a dummy load. This is harder to do than it sounds.

http://solarprofessional.com/articles/products-equipment/inverters/ac-coupling-in-utility-interactive-and-stand-alone

[Wy_White_Wolf]

Hi - I'm putting together a solar system for my new 1995 VW camper van (well- new to me I'd appreciate any comments on the sizing and components below. Any links to existing posts, kits and suggested vendors/models would be great. Since Eurovan camper already has a RV electric system, I'm also interested in how to add solar using the existing camper infrastructure.

Usage
o Plan to vacation in my new 1995 VW camper van to store about 1 kWh
o expect to use about 50 W for lighting and computers 4 hours / night (200 Wh/day)
o wish to use 750W microwave up to 30 min/day (375 Wh/day)
o electric teapot 1000W up to 15 min/day (250 Wh/day)
o electric fridge 30W * 24 H * 30% on = (300 wH/day)
o hope to size solar for cloudy days (1.2 kWh/day = 400 W * 3 h/day)

System sizing
o 4 x Solar Panels (400W?) Not enough. Since your panels will be mounted flat instead of aimed at the sun. Also with 3hrs that doesn't figure in system ineffeciencies. Look at the off grid stickes or plan on running the engine daily to makeup the difference.
o Solar battery charger (20A? MPPT) 400W/12V=33.3A. 20A is not big enough
o Land line battery charger (20A?)
o Charger/switch from auto generator (?) Called a battery isolator
o Inverter (1800W?) on the large side for array and battery
o Meter/Display/Master controller
o Battery (1X 12V 130 AH? AGM?) Way to small for 1200WH daily. You should never use more than 20% daily. 1200WH/12V*5 = 500AH
o 14L"x6.5W"x10H" compartment available

Ideally I'd like to find a single electronics component to manage all charging sources and and the inverter. I was also considering using micro inverters on the panels with and AC charger and UPS, but that may be impractical. Micro inverters do noy work in off-grid situations.

Thanks, Brad

see above

WWW

[Brad Taylor]

Hi - I'm putting together a solar system for my new 1995 VW camper van (well- new to me I'd appreciate any comments on the sizing and components below. Any links to existing posts, kits and suggested vendors/models would be great. Since Eurovan camper already has a RV electric system, I'm also interested in how to add solar using the existing camper infrastructure.

Usage
o Plan to vacation in my new 1995 VW camper van to store about 1 kWh
o expect to use about 50 W for lighting and computers 4 hours / night (200 Wh/day)
o wish to use 750W microwave up to 30 min/day (375 Wh/day)
o electric teapot 1000W up to 15 min/day (250 Wh/day)
o electric fridge 30W * 24 H * 30% on = (300 wH/day)
o hope to size solar for cloudy days (1.2 kWh/day = 400 W * 3 h/day)

System sizing
o 4 x Solar Panels (400W?)
o Solar battery charger (20A? MPPT)
o Land line battery charger (20A?)
o Charger/switch from auto generator (?)
o Inverter (1800W?)
o Meter/Display/Master controller
o Battery (1X 12V 130 AH? AGM?)
o 14L"x6.5W"x10H" compartment available

Ideally I'd like to find a single electronics component to manage all charging sources and and the inverter. I was also considering using micro inverters on the panels with and AC charger and UPS, but that may be impractical.

Thanks, Brad