Detect cyrillic encoding and convert to utf-8

Encoding.php

<?php

class Encoding
{
    private $chars = [
        'й', 'ц', 'у', 'к', 'е', 'н', 'г', 'ш', 'щ', 'з', 'х', 'ъ', 'ф', 'ы', 'в', 'а', 'п', 'р', 'о', 'л', 'д',
        'ж', 'э', 'я', 'ч', 'с', 'м', 'и', 'т', 'ь', 'б', 'ю',
        'Й', 'Ц', 'У', 'К', 'Е', 'Н', 'Г', 'Ш', 'Щ', 'З', 'Х', 'Ъ', 'Ф', 'Ы', 'В', 'А', 'П', 'Р', 'О', 'Л', 'Д',
        'Ж', 'Э', 'Я', 'Ч', 'С', 'М', 'И', 'Т', 'Ь', 'Б', 'Ю'
    ];

    private $cp1251chars = [];

    public function __construct()
    {
        foreach ($this->chars as $char) {
            $this->cp1251chars[] = iconv('utf-8', 'cp1251', $char);
        }
    }

    public function detectEncoding($s)
    {
        $utf8count = 0;
        $cp1251count = 0;

        foreach ($this->chars as $char) {
            if (strpos($s, $char) !== false) {
                $utf8count++;
            }
        }
        foreach ($this->cp1251chars as $char) {
            if (strpos($s, $char) !== false) {
                $cp1251count++;
            }
        }

        if ($cp1251count > $utf8count) {
            return 'cp1251';
        }

        return 'utf-8';
    }

    public function toUtf8($s)
    {
        $encoding = $this->detectEncoding($s);
        if ($encoding == 'utf-8') {
            return $s;
        }

        return iconv($encoding, 'utf-8//IGNORE', $s);
    }
}