Originally Posted by briang9480

I modified another currie Ezip to raise voltage to 36V. If one opens up the lid on the electronics box in the rack, one will find a connector that goes between the battery switch-over/on-off switch to the controller. The connector can be separated and by letting the negative side stay connected and wiring the extra 12v battery in series with the 24V battery one can increase the voltage to 36V. The switch is still functional as well as the 40A fuse in the battery boxes. The fuse protects the new battery as well. The negative battery connection is connected to the switch (red) wire and the positive side to the controller controller wire (red). In this particular situation there were two battery packs on each side of the rack. The new battery was placed on top of the rack. The wires from the new battery were fed into the hole at the rear of the box under the seat.

In the future we are going to increase the battery to a 12v 20aH from the 12V 10aH, so that if we switch battery packs from A to B, the addtional 12V battery can still be functional to allow 36V operation on either of the battery packs. The extra speed with a 185lb person was about 7mph. The torque is the greatest benefit as it was impossible to climb the hills around the area without 36V. The motor gets hot. At this stage don't want to start drilling holes in the motor casing to dissipate heat. May look at adding heat sinking and improving airflow. The casing is not that bad a heat conductor so this might be an alternative. Noticed that switching battery pack after climbing a hill benefited the battery because it was allowed to cool down. The battery status light typically stays in the green/amber. Under load it drops to red but not as often as with 24v operation.

Lifeop4 batteries are still expensive. Pricing is expected to drop by 25% in the next 12 months so batteries can be replaced when the SLAs start to underperform. SLA batteries perform better if they are charged with a 3 step charger. The currie charger should not be left on for more than 3 hours after the green light on the charger comes on. Battery should be allowed to sit for a couple of hours after recharging is completed to allow the battery chemistry to equalize the charge. Float chargers are ok because they help to equalize the charge as they are operating at a lower voltage than the charging voltage.