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under the hood #2: water + batteries > combine at your own risk!

i’ve had problems charging the TWIKE recently. after driving in wet conditions, charging led to FI failures.

i was, however, always able to charge using the two external onboard chargers i added to TW560 for fast charging. charging on normal fuses was no problem and since i normally charge the TWIKE during the night on a 6A non-FI secured line, it took some time to discover the problem… the problem had to be with the internal charger and internal electronics.

thomas from moeckli elektrofahrzeuge agreed to have a look and this blog entry documents what we found…

TW560 ready for fault analysis

TW560 ready for fault analysis

TW560 was one of the first TWIKEs to receive dreifels’ battery packs. one of the most important learnings with this battery was that the space was too tight for the cables and battery packs, but i didn’t upgrade to more space because i liked the space left inside the vehicle after my nicd upgrade.

thomas having a look at TW560's innards

thomas having a look at TW560’s innards

very cramped cabling

very cramped cabling

tw560’s situation means that it is really difficult to solve problems because everything needs to be dismantled (as during WAVE2011 in india) before any analysis can begin.

finally, after getting all the cables out of the way, we finally can get the battery blocks out of the vehicle.

TW560's 20Ah blocks

TW560’s 20Ah blocks

here, we can see evidence of what indian roads do to swiss technology… my battery blocks look battered and are sometimes completely open to water… which is the culprit we are assuming is creating the problem.

open battery bays

open battery bays

and after looking at the blocks we not only find traces of water but also salt – which is used generously on swiss roads during winter.

evidence of water / salt

evidence of water / salt

the problem is found quickly – indian roads and the battering taken by the battery bay have left many cracks in the surrounding plastic and metal. this allowed water and salt enter the battery bay and as we all know: salt and water is a very good conductive material – during the charge water/salt allowed a DC current to jump as far as the AC grid connector and there the FI fuse was rightly protecting the TWIKE and the grid from this transient current.

thomas cleaned the battery bay, sealed it up and since then i’m back to charging with TW560’s internal charger.

looking forward to charging without needing to worry if i can charge at all!