From instructions: What happens if I didn't remove it?

Lynxmotion Rovers, Sumo, and Tracked
1

(2) 3.7VLiPobatterychargingcircuit.Importantnote:jumpershouldonlybeinplacewhenusingaLiPo
battery connected to (38), otherwise remove. Do NOT use jumper if you are using the 4xAA pack

I only saw this now, and have been using the rover with a battery pack and the jumper in place.

What does the jumper do?

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The jumper connects the onboard 3.7V LiPo charger to the battery, so when you plug in a USB cable, it will charge a 3.7V battery plugged into the white JST connector. Normally you don’t want the USB cable trying to charge AA batteries.

3

Thanks! It would be good if the instructions said that! I will remove the jumper. Will I notice any change do you think?

4

No change, but no chance of trying to force charge the AA batteries. We included the LiPo charger since it’s inexpensive and rather than using AA batteries, a small 3.7V LiPo is quite inexpensive and can be reused many times:
robotshop.com/en/37v-1000mah … ttery.html
robotshop.com/en/37v-2000mah … ttery.html
The voltage for a one cell LiPo is lower than that of 4xAA batteries, so you would notice that the motors rotate less quickly.

5

Thanks. Are there instructions on how to charge the LiPo exactly using the on board charger? Will it charge through the USB? I guess so since theres no other choice. But how long would it take to charge?

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Also exactly where on the board do you plug it in and where would you put it so it stays put?

7

If you use the LiPo battery, reinstall the jumper, and the battery will be charged via the USB connector.
A USB port on a computer tends to provide around 400mA, so a 1,000mAh battery can take around 2.5 hours to charge.
Normally people just charge the battery in the background.
The LiPo battery fits snugly between the bottom of the Tamiya Twin Motor Gearbox and the lower axle.
If it’s a bit of a loose fit, add some tape to give it additional thickness.