The Losi EC5s are fine, the actual connector itself (the gold tube) is perfectly fine. They buy in some 5mm gold tube connectors, and have moulded a case for them.
There have been cases of Deans melting under the extra stress of 1/8 scale use.
Also, voltage is not what causes a connector to fail, it is current. As current increases, resistance increases which causes the temperature of the connector/wire to rise. This causes the plugs case (plastic) to melt.
The more surface area you have in contact, the less resistance, and Deans just don't really have enough of a contact patch.
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