NAO Robot from Aldebaran Robotics - now SoftBank Robotics and Battery pack issue - Page 1
Forum section: electronics / repair

author: Ago
author_rank: Newbie
timestamp: July 16, 2022, 08:21:04 am
content: Hello all and please go easy on me, as i am noob in the forum. I hope that i put this topic in the right place. It might belong to dodgy products too.Its about a robot named NAO which many schools and universities and other educational or medical organisations invest 15K to buy but it suffers from its battery pack which:The robot is not bad when it works the issue is that they use a battery pack which is using some kind of Battery Management System (BMS) that consumes battery even when NAO is powered off.And NAO is powered off for long periods in school as for example during summer/christmas holidays.A long period of no recharge can activate a "Deep Discharge state" safety on the BMS board.This means the battery charge is considered to be too low.This safety will lock the battery, making it impossible to recharge again. (from here: From <https://support.unitedrobotics.group/support/solutions/articles/80000952173-nao-how-to-preserve-the-battery-life-cycle-is-it-out-of-order->)Also because of the pandemic, many NAO's was off for long period of time and now people want to power them up and they discover that this is impossible, as the battery pack now is in the above state and not charging.Read here:https://www.linkedin.com/pulse/nao-battery-shortage-advice-li-ion-batteries-Even when battery pack was new, it doesn't need to be in the charger and at 100% for long period of time OR less than 30% or not between 70%-80% else again it will age faster.How much more hard it can be?So a perfect in condition robot that cost 15K is not working because of the battery pack.Now if we consider that the robot for safety is not working/operating moving etc. when is on the charger but requires the battery as source of power to be autonomous and have freedom in movements, we have all the case.There are people with the knowledge and the skills which open the battery pack, figure out what's inside, and how to replace the batteries which they do not cost that much and they solve the problem that way.Also people popped up in various locations around the globe, which offer their services to fix the battery pack, as long as they send it to them.For example:https://www.bartneck.de/2021/02/03/repair-of-broken-nao-robot-battery-pack/Now i send an email to Dave, which i thank one more time for his quick reply and for all the beautiful videos and work he has done, asking about it and he point me here.Can someone with the skills and time, do something about in here in Australia?Service and replacement of the batteries in the pack or reset of the BMS to allow the existing batteries to charge if it is possible would be the ideal i think.Else a new battery pack that will work with the electronics in the robot and it will have a decent life span and it want cost an arm and a leg, that would be wonderful too.When there was available battery packs, they cost over $1200 which is big cost for schools and for batteries.

author: m k
author_rank: Super Contributor
timestamp: July 19, 2022, 01:52:16 pm
content: You can always try precharging single cells with dumb charger.How those cells are connected?My prediction is below.Code:black────┐- cell +red─────────────┤+ cell -green────┤- cell +blue────────────┤+ cell -white────┤- cell +yellow──────────┤+ cell -red──────┘

author: Ago
author_rank: Newbie
timestamp: July 20, 2022, 02:37:53 am
content: The battery back seems to consist of six Sony US18650NC1 2900mAh batteries. They are connected with seven wires to a PCB board. The power supply connects with two cables to the PCB board. In addition, the case has two contacts next the charger plug that could be used for detecting if the battery cover is closed. Five contacts connect the battery pack to the robot of which the first two bigger ones seem to carry the power. The four smaller contacts are probably to communicate with between the robot and the battery PCB board.From here:https://www.bartneck.de/2021/02/03/repair-of-broken-nao-robot-battery-pack/

author: m k
author_rank: Super Contributor
timestamp: July 20, 2022, 03:51:42 pm
content: Charging a single cell will obviously mean that the case must be opened and all wires disconnected.There are 2 cell reds, one after lowest(next from black) cell.Maybe that is a standby something, so it will eventually take the pack out of balance.Light of the first picture is coming from the right side so there are shadows, seems that there are only 2 wires.Outer connection can be something general and all contacts are not necessary connected.One can be battery pack present and one temperature too high, if both are independent that's 4 contacts.E,light.