T-Pain Is On A Boat: Re: [Electric Boats] 18650 cells for propulsion bank?

Friday, August 7, 2015

Re: [Electric Boats] 18650 cells for propulsion bank?

I am of the opinion that lithium chemistries do not need intelligent chargers. The intelligence is in the battery management system and as long as the BMS can shut off the charger, any CC/CV power source will do. There is also the added bonus of the power source being available run the boat propulsion from a generator whereas an "intelligent" charger may think that the battery has an error condition if being asked to output full power for too long -- ProMariner Quad series, for example.

It is still early days for fully integrated hybrid propulsion and energy management systems in pleasure craft. There is much to be discovered/identified/determined. It may be best to keep the intelligence of individual components rather limited and to have a single, centralized governor that manages the various sources and loads.

/Jason

On Aug 7, 2015, at 05:01, Hannu Venermo gcode.fi@gmail.com [electricboats] <electricboats@yahoogroups.com> wrote:

To everyone, please:

If at all possible, try to put the power of the battery, and the
technology used, in the power quoted.
Ah is not power.

Power is measured over time, and its in kWh or Wh.

Ah =/= Ah. Means its not.

Example.
100 Ah @ 12 V => 1200 Wh.
With lead acid (forklift, gold cart), == usable 30%, => 400 Wh usable power.

100 Ah @ 12 V => 1200 Wh.
With AGM (marine batt, wheelchair) == usable 60%, => 720 Wh usable power.

100 Ah @ 12 V => 1200 Wh.
With lion (18650 et al) == usable 90%, => 1080 Wh usable power.

When of if you compare *real usable power*, you will find that;
Lion is about the same cost as anything else for usable power.
At 1/4 the mass.
It can also be drawn out much faster, and recharged much faster.
But needs an intelligent charger.

Heavier is always better, and heavier lasts longer pretty much by ratio
of mass.

--
-hanermo (cnc designs)