USPS small flat rate box always showing up

Hello, I'm having a little trouble with the USPS shipping module for a while now.

We sell medical supplies on our site, from test tubes to wheel chairs, the issue is I want to use USPS flat rate shipping options for the smaller options, like test tubes for example. I don't want it to appear for larger items, like wheelchairs.

So for example, if a customer checks out with a wheel chair in their cart, they'll usually end up choosing the USPS flat fate small box (because it's the cheapest), which is not correct! Every product does have weights/heights but it's always showing up the USPS small flat rate box even for extremely large/heavy items. We end up eating up the cost not to annoy the customer because it's an error on our part, but for the life of me I can't figure how to hide Small/medium/large flat rate boxes for larger items. Any help would be greatly appreciated! Thank you so much.

Using opencart 1.4.9.4

The USPS shipping module is pretty basic and doesn't use the product dimensions. It assumes that all products can fit in the small, medium and large flat rate boxes regardless of size.

You may want to try the USPS Alternate module that does calculate a box size using the product dimensions. It's not perfect because it calculates boxes to the inch (it uses 1"x5"x8" for the small flat rate box for example), and it only uses the maximum product dimensions and volume to determine if a product fits, so it may think two 6x3x1 boxes can fit in that 1x5x8 box. However it will be much closer and as long as you have entered product dimensions it won't put the wheelchair in the flat rate box.

See http://www.opencart.com/index.php?route ... n_id=15602

While it's only listed as comparable for 1.5.6 and 1.5.6.1, i think it should work with your version. I just have no way to test myself. (If you do test it please let me know)

Thanks for the reply! That seems like a perfect solution, just tried it on 1.4.9 but it's getting a fatal error on line 214 at/admin/controller/shipping/usps_alt.php, so I don't think it works unfortunately for 1.4.9

We're looking to upgrade soon so hopefully this should work. Thanks again.

If you want to try separating out the flat rate box rates while you have 1.4.9, you can use my Volume-Based Shipping extension to create rates based on volume and weight -- you can see my tutorial on how to do it here:

http://forum.opencart.com/viewtopic.php?f=114&t=85148