HANDYBOARD POWER MANAGEMENT INFORMATION

1. The Handy Board (HB) alone draws about 50mA of current when the power switch is on. (It draws about 0.6 mA from the battery to maintain memory even when the power switch is off). Even a fully charged battery draws at least 15mA maintenance level (losses, heat). So, the electrical current load is (50+15)= 65mA for just the Handy Board with nothing hookup up to it, and with only the power LED lit, and with a fully charged battery to start with.

2. Each additional HB LED that turns on is another 5mA.

3. The charging circuit in ‘NORMAL’ mode supplies at most 100mA but that is only at the very beginning of charging a very low battery. The last 50% of charging is at 60mA or less. (NOTE: The HB needs 65mA just to be running! The ‘extra’ comes from the battery and varies depending on actual situation.) That means, if the HB is ON, and the charger is hooked up and in ‘NORMAL’ mode, a FULLY CHARGED battery will be gradually DISCHARGED to 80%-85% of capacity. Therefore, you may use charger ‘ZAP’ mode WHEN THE HB IS ON. Otherwise, only use ‘ZAP’ if the battery is known to be needing charge and the HB is MONITORED by someone. NEVER USE ‘ZAP’ FOR MORE THAN 1 HOUR WHEN THE HB IS OFF and DEFINITELY DO NOT USE ‘ZAP’ IF THE HB IS OFF AND THE BATTERY IS NEARLY FULLY CHARGED. YOU WILL BE RESPONSIBLE FOR ANY DAMAGE REPAIR COSTS!

4. If the HB battery is ever found to be essentially ‘dead’ (HB display won’t show or HB does not reset and run), then make sure the HB power switch is OFF, use the charger ‘ZAP’ mode for 30 minutes, and then set it to ‘NORMAL’ for the rest of the charging cycle (14 hours).

5. Even though the book says it is ok, when the HB is OFF, DO NOT leave the HB on ‘NORMAL’ charge for more than 20 hours.

6. NEVER PLUG THE POWER MODULE DIRECTLY TO THE HB. YOU WILL BE RESPONSIBLE FOR ANY DAMAGE REPAIR COSTS!

7. More consumption numbers:

a. Hacked servo motor with 5.3 volt regulator board…120mA no load and 800 to 1000mA stalled.

b. Improperly hacked servo motor… 450mA no load and >1000mA stalled. Probably asymmetric in drive directions.

c. Twin tank motor with 2.5 volt regulator (each)… 340mA no load and 1600mA stalled.

d. Acroname motor directly from HB… 210mA no load and 1200mA stalled.

e. Each shaft encoder with suggested components… 15mA.

f. Each optosensor with suggested components… 30mA.

g. Bump switch… negligible, <1mA when activated.

h. IR detector… 3mA minimum (regardless of software).

It is suggested to draw 600mA or less from the HB battery.