Difficult to help you without knowing basic details about how your cell is built. Types of electrodes you are using, medium composition,  how you are monitoring the cell, how are the fluctuations, what do you mean by "clip de electrode"  ...

The power of algal fuel cells can be very low. Here are a couple of paragraphs from our recent review (Milledge & Heaven, 2014).

Using Chlorella as a substrate around 60 % of the chemical oxygen demand was removed, but conversion of chemical energy to electrical energy was low at between 10 - 25 % (Velasquez-Orta et al., 2009). The electrical yield from MFCs has been quoted at 2.5 kWh kg-1 of dry Chlorellabiomass (Velasquez-Orta et al., 2009), but this appears to be over stated by a factor of 10 due to the use of an incorrect conversion factor of 2.77 kWh MJ-1 rather than  0.277 kWh MJ-1(Perry & Chilton, 1973). When the data presented are corrected, however, the energy produced from dry microalgal biomass by a fuel cell is approximately a quarter of that achieved by either direct combustion or anaerobic digestion. The maximum power generation of MFCs oxidising biomass is currently only up to 1 W m-2(Howe, 2012; Thorne et al., 2011) and could only produce power equivalent to 3.8 tonnes of oil (toe) ha-1 considerable below that anticipated from growth of microalgae for the production of biodiesel (Howe, 2012).

A recent development in MFCs is a photo-microbial fuel cell or bio-photovoltaic fuel cell where photosynthetic microalgae growing at the anode generate the electrons, thereby removing the need for an organic substrate (Howe, 2012; Thorne et al., 2011). Bio-photovoltaic fuel cells currently have very low efficiency, however, and energy production is between 1 and 1.5 orders of magnitude lower than in MFCs oxidising biomass (Howe, 2012).

Photosynthetic microalgae can also act as electron acceptors at the cathode (Powell et al., 2011). A power density 0.95 mW m-2 was achieved in a coupled MFC, with Chlorella growing at the cathode and yeast growing heterotrophically on glucose as an electron donor (Powell et al., 2011): this is considerably below the best output of MFCs. In a unique design combining anaerobic digestion and a coupled MFC, bacteria growing on the waste from the anaerobic digestion of microalgae biomass act as the electron donor, with microalgae, grown as the biomass for anaerobic digestion, acting as the electron acceptor, but power output was low at an average of 12 mW m-3(De Schamphelaire & Verstraete, 2009).

The energy output of MFCs can be low and is currently many times lower when live microalgae are used either as an electron donor or acceptor. It is clear that there is a need for a considerable improvement in microalgal fuel cell efficiencies before they can be considered as a commercial option for exploiting microalgae for biofuel.

De Schamphelaire, L., Verstraete, W. 2009. Revival of the Biological Sunlight-to-Biogas Energy Conversion System. Biotechnology and Bioengineering, 103(2), 296-304.

Howe, C. 2012. Direct Electricity Generation from Microalgae using biophotovoltaics. in: Algal biotechnology; biofuels and beyond. UCL, London.

Milledge, J.J., Heaven, S. 2014. Methods of energy extraction from microalgal biomass: a review. Reviews in Environmental Science and Bio/Technology, 13(3), 301-320.

Perry, R.H., Chilton, C.H. 1973. Chemical Engineers' Handbook. Fifth ed. McGraw Hill, Tokyo.

Powell, E.E., Evitts, R.W., Hill, G.A., Bolster, J.C. 2011. A Microbial Fuel Cell with a Photosynthetic Microalgae Cathodic Half Cell Coupled to a Yeast Anodic Half Cell. Energy Sources Part a-Recovery Utilization and Environmental Effects, 33(5), 440-448.

Thorne, R., Hu, H.N., Schneider, K., Bombelli, P., Fisher, A., Peter, L.M., Dent, A., Cameron, P.J. 2011. Porous ceramic anode materials for photo-microbial fuel cells. Journal of Materials Chemistry, 21(44), 18055-18060.

Velasquez-Orta, S.B., Curtis, T.P., Logan, B.E. 2009. Energy From Algae Using Microbial Fuel Cells. Biotechnology and Bioengineering, 103(6), 1068-1076.

Dear Ramar,

It is difficult to suggest you... without sufficient information about system configuration, type of electrode material, and substrate (electrolyte) nature and conductivity, and material used to connect electrode (electrical conductive wire, Eg.  copper)... bcoz, all these parameters influence the system Ohmic resistance.....

With best regards

Dr K. Chandrasekhar

I am nearly facing the same problem, I have 2 single chamber MFC, at the beginning they both give sharp voltag readings (with no fluctuation), with slight difference between them. But after making the polarization, one of them, which have the smaller voltage, gives fluctuated voltage reading in the open circuit voltage, is the reason the ohmic losses also? but the thing is that the other cell maintain its performance as the begining?

increse the conduction of electrode