Navitron Renewable Energy and Sustainability Forum

Energy/Electricity Storage and Use/Grid Connection => Off-Grid, Batteries & Inverters => Topic started by: Justme on January 18, 2010, 07:01:44 PM



Title: Can this be right?
Post by: Justme on January 18, 2010, 07:01:44 PM
I spotted this on a battery suppliers web site

Quote
Electrolyte Circulation Systems

We can supply electrolyte circulation systems for motive power batteries that are working heavy-duty multi-shift work patterns. The system operates through an air pump controlled by the charger and which is connected via a pipe to each cell. The electrolyte is agitated during the bulk charge period, which precludes the need for a "gassing time" during the charging, and therefore shortens the recycling time.

I know its done but I thought the reason was to stop stratification of the electrolyte in bats that were not moving.


Title: Re: Can this be right?
Post by: stephendv on January 18, 2010, 07:30:35 PM
I don't see the contradiction, looks like they're describing mixing the electrolyte during charging, i.e. when the batt is stationary.


Title: Re: Can this be right?
Post by: Justme on January 18, 2010, 07:38:16 PM
But it will be well mixed from the driving round & vibration so at the start of charging it wont be stratified.

That said more interested in the statement that says the charge time is reduced due to the gassing stage not needed. As the bulk phase is the quick bit that would be a large time saving.


Title: Re: Can this be right?
Post by: stephendv on January 18, 2010, 07:54:52 PM
Hmmm, wouldn't think that vibration alone could mix electrolyte enough in those tall cells - might get horizontal movement but not a lot of vertical. 

Read on another manu's site that: "... energy consumption is reduced by 20%"

Also good news for solar charging  ;D


Title: Re: Can this be right?
Post by: billi on January 18, 2010, 08:16:16 PM
did you mean this ? http://www.hoppecke.com/products/applications/industrial_trucks/trak_r_air


winter seems gone here , looking forward for longer days now

Billi


stephendv  what happened ? you seem to be a new innocent  member ,


Title: Re: Can this be right?
Post by: Outtasight on February 05, 2010, 11:49:56 AM
As well as eliminating the need to bubble the electrolyte just to stop it stratifying, the process may also speed charging as it will circulate the electrolyte.  When under fast charge, the electrolyte near the plate gets stronger with the sulphate coming out of the lead sulphate (and back into stronger sulphuric acid).  If the stronger acid is transported away from the area and mixed, it will improve the conductivity of the electrolyte as a whole and promote more current to pass, and so speed up charging.

Gel cells are slower to charge because the electrolyte is fixed and so the reaction has to migrate through the gel at a slow pace.  This limits the charge current they can accept and forcing it with higher voltage just makes gas that creates pockets in the gel that then means the electrolyte doesn't touch the plates at all so the cell is damaged.