2019 Ford Transit Connect Self built camper Some mechanical knowledge

Under the computer, in the engine compartment, I connected an AGM house battery to the 80 amp bolt in fuse. AT some point I did something to pop the fuse. Luckily there was a a second open auxiliary 80 amp fuse. It charges the battery just fine.

I am considering changing to lithium for weight and space reasons. The internet recommends a 40-50 amp DC to DC charger.

  1. Would a DC to DC charger be any different than hooking up to the bolt in aux fuse?

  2. If I change it to 50 Amp, will the car automatically know to limit the current to 50 amps? is there anyway to tell it?

  3. Is swapping the broken fuse something a DIYer can do?

Thanks in advance.

1 Answer 1


Here is what I have proven to myself:

  1. Compared to the aux fuse, a DC to DC charger as additional features has added protection against overcharge. A mostly redundant feature since most lithium batteries already have the feature. The real value is in limiting the current draw on the alternator, thus prolonging its life (which I dont care about), and most importantly: it converts the voltage to 14+ to ensure optimal charging.

  2. A 50 amp fuse is most likely a MIDI fuse which is current limiting. The fuse itself would prevent current over 50 amps from flowing.

  3. You would have to remove the battery, cut a few zip ties and unbolt a few things. Yes a DIYer could do it.

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