Introducing the OLPC Multi-Battery Charger.

Richard A. Smith richard at
Tue Mar 24 16:20:34 EDT 2009

Welcome to mbc at  The mailing list for OLPC's 
Multi-Battery Charger.  Rather than try to send a bunch of duplicate 
e-mails to people or make a big cc: list I decided to create a mailing 
list so that its really easy to share info among everyone interested.

You are on this list and receiving this mail because you are:

1) A developer or manufacturer of the Multi-Battery Charger,
2) Have previously indicated interest in the multi-battery charger,
3) Were selected by my as a site that may find the Multi-Battery
charger useful.
4) Involved in OLPC deployments.

5) On one of mail lists I cross-posted the announcement to. :)
(Sorry if you get this multiple times)

If you wish to be removed you may do so via the web-interface or let me know and I'll remove you.

If you know of other people who you think would like to receive this
info please forward it on or let me know and I'll send it to them.

If you are receiving this message via another channel like a forward or 
a cross-post from another list and you want to join the 
mbc at list then you can subscribe here:

What is the Multi-Battery Charger?

The Multi-Battery Charger (MBC) is a product designed by OLPC to assist
deployments with the task of bulk charging XO laptop batteries.  In a
nutshell it will:

Charge 15 batteries running on AC input 300 Watts
Charge  7 batteries running on DC input 150 Watts
Charge ~5 batteries on 2 60W solar blankets at full sun *[1]

The charge time is approx 2 hours (depending on the input source)

It will run on either AC or DC.

AC input is 120/220V 50 or 60 Hz.
DC input 9-28 VDC 150W max output.

What is currently available?

19 Pre-production test units.  A few more if you just want AC only

These are fully functional units but have NOT gone through Safety and
Regulatory approval.

These units also have minor cosmetic damage from some issues with the
original shipping packaging.

How can I get a test unit?

Reply-to-all this email with responses to the questions below, a contact
person and a shipping method (see note *[2]).

Please answer the questions below with as much info as you have.  If you
  don't know answer to a question thats fine but the more information I
can get the better to make the product as useful as possible.  Some of
the questions may be better answered once you have had a chance to use a
test unit.

OLPC will have test unit(s) shipped to you for evaluation. In return you
promise to provide prompt feedback information from your test site on
how you use the device and how many you would be interested in purchasing.

The info I need to know is:

How many XO's do you have in your current deployment/pilot?
Where is your deployment/pilot?
What power source would you be using? AC or DC?
What power source (AC or DC) do you see as most useful for your
Would you purchase extra batteries for use with the MBC?
What time frame you would roll out MBC units.
How many MBC units do you think your deployment would need in the short
and long term?

And of course firmware bugs/problems/improvements or any other info you
want to feedback to OLPC about the MBC.

How much will production units cost?

Everybody's favorite question.  The goal has been to keep the cost as
low as possible while still make the product robust enough to withstand
the large variability of deployment environments.  Its very
dependent on the quantity of the order I can place with the 
manufacturer.  In smaller quantities of < 500 it will between $450 - 
$600 USD and a 12 week lead time. With higher quantities OLPC can get 
better pricing.

Thanks for taking the time to respond and I look forward to everyones

*[1] Based on test measurements and the rated output of the solar
blankets at sunlight of 1000W/m^2 .  Solar conditions are highly
variable and will affect the charge time considerably.  The firmware
attempts to optimize the charging based on the available power.  The
wide DC input voltage range allows the use of other more powerful panels.

*[2] In the past international customs has been a source of extended
delays when shipping various items to pilots.  If you know of any
special instructions that will help with the delivery please indicate them.

Richard Smith  <richard at>
One Laptop Per Child

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