[Oeva-list] Looking to improve a 48V machine

[Jeff Kim]

You can usually add additional batteries to increase the voltage without too
much risk.  The main reason for this is that the motor does not generally
see full pack voltage.  Among other reasons, there is voltage drop during
load, particularly as your batteries are depleted.  I know of people that
have run more than 50% higher battery voltage than the motor rating, but
don't take my word for it.

Jeff Kim

On Sun, Oct 18, 2009 at 12:09 PM, Ken Potter <ken at fivestarguitars.com>wrote:

> Looking for advice:
>
> My project is on the road and doing fairly well:  48V Motorcycle using 4
> AGM batteries @ 50 AH each, and an identical 5th battery for the 12V needs
> (the two systems are separate except for the 12V contactor).  The controller
> is an Alltrax AXE, set to 70% maximum power.  The motor is a Mars ME0708
> Brush-Type, Permanent Magnet DC motor, also known as the Etek-R.
>
> *Here are the issues*:  As usual, extending the range a few more miles is
> a priority.  At the same time, just a little more power would be welcome for
> climbing hills at moderate speeds.
>
> *Here are some options:*  I have one more identical battery, and I'm
> tempted to go up to 60V, adding 50 AH at the same time (but exceeding the
> rating of the motor).  Another possibility is just reprogramming the
> controller to 80% of max and switching to larger batteries (groan).  A
> third, and less expensive option, is to add a small DC-DC converter,
> eliminate the accessory battery, and save about 30 lbs.  By law, the
> headlight must remain on at all times.  A good LED headlight would improve
> matters, so the search is on.
>
> Any thoughts?
> Ken Potter
>
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