Try something like this.
Check out the query in your phpmyadmin

$result = Model::with('relations')->whereIn('id', function($query){
$query->select('models.id')->from('models')
->join('relations', 'models.id', '=', 'relations.model_id')
->whereRaw('models.total > SUM(relations.total)')
->groupBy('models.id');
})->get();

#1111 - Invalid use of group function 

Thanks, I will try to play with it.

the error comes because of model.total. SQL doesn't know every unique models.id has a unique models.total.
I thought this would happen. I think I found a solution. Group by both, models.total and models.id.

->groupBy('models.id', 'models.total')

I hope this works. :)

Still no luck :(

select * from `models` where `id` in (select `models`.`id` from `models` inner join `relations` on `models`.`id` = `relations`.`model_id` where model .total > SUM(relations.total) group by `models`.`id`, `models`.`total`) )

#1111 - Invalid use of group function 

Bingo! You are the Man! I owe you a Beer :) There are still things to learn. Thank you very much.

Laravel way for audience:

$result = Model::with('relations')->whereIn('id', function($query){
			$query->select('models.id')->from('models')
			->join('relations', 'models.id', '=', 'relations.model_id')
			->groupBy('model.id','model.total')
			->havingRaw('model.total > SUM(relations.total)');
		})->get();