WARNING to electric carmakers and lithium ion battery manufacturers: it's suggested you stay away from taking equity stakes in each other's companies. Practicing this type of electric-vehicle keiretsu could lead to harikari.

In an Automotive News commentary, Dave Guiliford analyzed two examples of such investment alliances that haven't gone so well. In 2010, battery maker A123 Systems took a $20.5-million stake in Fisker Automotive and supplied the battery systems for the first (and thus far only) Fisker car, the Karma. In 2007, Ener1 took a 31 percent stake in Norwegian EV maker Think and signed a contract to supply lithium ion batteries for the Think City electric car. As part of that deal, Ener1 CEO Charles Gassenheimer became chairman of the Think board.

Initially, these partnerships seemed to make sense. If these types of partnerships worked well together, it could be similar to what's called keiretsu in Japan, where suppliers become an important part of the supply chain for automakers and long-term, successful partnerships are forged. On the other side of the coin, taking such investment risks can end poorly. As Guiliford wrote, "Tying a small, new-tech supplier and a small, new-tech automaker compounds the risk that each company has."

Both Ener1 and Think have entered bankruptcy following Think's disappointing sales of the City. A123 has written down its investment in Fisker by nearly half and cautioned, in its first-quarter report, that it could be at risk from lower-than-expected orders from Fisker. Fisker is struggling to bring its second plug-in hybrid, the Atlantic, to market.

The lesson? Taking equity links can sometimes be a shrewd move for automotive partners. It can also be like rearranging deck chairs on the Titanic.