In most cases, the useless come lead plates, which eventually wear out and erased. To assemble one working battery, take a few good plates and weld them into one body.
This will clean the top surface of the housing of the batteryand cut out the center square hole and separate the contact bridge. Then move the plate, connect the contact line by means of the spikes and seal the battery. In this situation it is important to achieve full containment.
Of course, it is better to use heat welding, in which the heated parts of the housing are pressed to each other and hold in this position for 2-5 minutes. This closes even big gaps. If this is the situation, use an additional strip that can be cut from another non-working battery. Before carrying out this operation, drain the electrolyte and dry the device. The most careful attention to the place of soldering. At the end of the work machine is drained of electrolyte of the double charge-discharge, which normalizes the performance of banks.
If you don't want to delve into this complexity, just purchase in a special shop adhesive that securely bonds the plastic and is suitable for devices operating in aggressive environments (into this category of substances include the electrolyte). In particular, use of epoxy glue, which is also called cold welding. With it, you will prevent corrosion of the casing of the batteryand acid.
To achieve high quality bonding, clean the housing of the batteryand from all the dirt and dust, apply a degreaser, let dry and sand. So the glue will stick tight. After gluing, wait a few hours after which pour the electrolyte and start using the battery.