Haven't found the size mismatch - yet, but haven't you made a copy-paste mistake here :
Accu 10 { 
    type = "accumulator", 
    name = "accumulator-10 ", 
    icon = "__HTO__/graphics/accumulators/icons/accumulator-10.png", 
    flags = {"placeable-neutral", "player-creation"}, 
    minable = {hardness = 0.2, mining_time = 0.5, result = "accumulator-10"}, 
    max_health = 350, 
    corpse = "medium-remnants", 
    collision_box = {{-0.9, -0.9}, {0.9, 0.9}}, 
    selection_box = {{-1, -1}, {1, 1}}, 
	fast_replaceable_group = "accumulator", 
    energy_source = 
    { 
      type = "electric", 
      buffer_capacity = "50MJ", 
      usage_priority = "terciary", 
      input_flow_limit = "3000kW", 
      output_flow_limit = "3000kW" 
    }, 
    picture = 
    { 
      filename = "__HTO__/graphics/accumulators/accumulator-9.png ", 
      priority = "extra-high", 
      width = 124, 
      height = 103, 
      shift = {0.7, -0.2} 
    }, 
    charge_animation = 
    { 
      filename = "__HTO__/graphics/accumulators/accumulator-9-charge.png ", 
      width = 138, 
      height = 135, 
      line_length = 8, 
      frame_count = 24, 
      shift = {0.482, -0.638}, 
      animation_speed = 0.5 
    }, 
    charge_cooldown = 30, 
    charge_light = {intensity = 0.3, size = 7}, 
    discharge_animation = 
    { 
      filename = "__HTO__/graphics/accumulators/accumulator-9-discharge.png ", 
      width = 147, 
      height = 128, 
      line_length = 8, 
      frame_count = 24, 
      shift = {0.395, -0.525}, 
      animation_speed = 0.5 
    }, 
    discharge_cooldown = 60, 
    discharge_light = {intensity = 0.7, size = 7}, 
    working_sound = 
    { 
      sound = 
      { 
        filename = "__base__/sound/accumulator-working.ogg", 
        volume = 1 
      }, 
      idle_sound = { 
        filename = "__base__/sound/accumulator-idle.ogg", 
        volume = 0.4 
      }, 
      max_sounds_per_type = 5 
    }, 
	},