Battery Power for BOE BOT - BOT won't power up!
I recently assembled a BOE BOT kit, but it did not power up on the battery pack.· I have a Board of Education that I purchased earlier and used the AC supply from it and it worked fine.· The battery pack had·new/unused batteries and was putting out 6.5V but didn't bring up either board.· Reading earlier posts about using NiCd or NiMh batteries it seems like my input voltage is marginal, but spec says anything above 6V is OK.·
I got another set of fresh batteries - same results.
I was going to suggest that if it is this touchy it should be a 6 cell battery pack (even with alkaline cells) to get maximum life out of the batteries (rather than have them drop out as soon as peak voltage drops from 1.7V to 1.6V) ???· For this application minor mods would allow a 6 cell (rechargeable) battery pack that could be recharged in place from the 9V AC adapter.· By the way the AC adapter puts out about 15V DV so 9-10VDC from·a six cell·battery pack should be fine - space is the issue.· I am going to add two more cells hooked in series - on the top of the chassis, under the circuit board.· Maybe fasten it in place with a little velcro.
But then I realized that the battery pack provided had the polarity reversed - it was setup as center pin negative, sleave positive!· Note that the striped wire was connected to the sleeve of the connector and the positive side of the battery pack.· I reversed the wires (striped wire to negative terminal of battery pack) and everything worked ok.· It even worked on fresh charged NiMh batteries - but they won't last as lonk as alkaline when using just 4 cells.
I lost a couple of hours on this - so I thought I would post a heads up for those that may be seeing the same problem - check the voltage at the connector and make sure the polarity is correct!· I guess a few of these battery packs slipped through QC - maybe Parallax can send me a new one?
For those that may attempt a fix on their own - note that the plastic of the battery pack is a very low temperature plastic.· If you attempt to resolder the wires - be sure and use heat sinks (hemostats or needle nose pliers) on the tabs - and work quickly.· If you heat up the tabs even briefly to solder the wires they will melt the plastic and come loose.·
I got another set of fresh batteries - same results.
I was going to suggest that if it is this touchy it should be a 6 cell battery pack (even with alkaline cells) to get maximum life out of the batteries (rather than have them drop out as soon as peak voltage drops from 1.7V to 1.6V) ???· For this application minor mods would allow a 6 cell (rechargeable) battery pack that could be recharged in place from the 9V AC adapter.· By the way the AC adapter puts out about 15V DV so 9-10VDC from·a six cell·battery pack should be fine - space is the issue.· I am going to add two more cells hooked in series - on the top of the chassis, under the circuit board.· Maybe fasten it in place with a little velcro.
But then I realized that the battery pack provided had the polarity reversed - it was setup as center pin negative, sleave positive!· Note that the striped wire was connected to the sleeve of the connector and the positive side of the battery pack.· I reversed the wires (striped wire to negative terminal of battery pack) and everything worked ok.· It even worked on fresh charged NiMh batteries - but they won't last as lonk as alkaline when using just 4 cells.
I lost a couple of hours on this - so I thought I would post a heads up for those that may be seeing the same problem - check the voltage at the connector and make sure the polarity is correct!· I guess a few of these battery packs slipped through QC - maybe Parallax can send me a new one?
For those that may attempt a fix on their own - note that the plastic of the battery pack is a very low temperature plastic.· If you attempt to resolder the wires - be sure and use heat sinks (hemostats or needle nose pliers) on the tabs - and work quickly.· If you heat up the tabs even briefly to solder the wires they will melt the plastic and come loose.·
Comments
·· Please contact Tech Support tomorrow regarding this issue, and refer to this post.· Thanks!
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Chris Savage
Parallax Tech Support
csavage@parallax.com