Lost electrics while driving ... failed battery?

Technical questions and answers about the Mazda Bongo

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ilmomento
Apprentice Bongonaut
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Joined: Fri Jun 18, 2021 7:24 pm

Lost electrics while driving ... failed battery?

Post by ilmomento » Thu Oct 14, 2021 4:02 pm

Hello,
While driving along today I pressed to lower the driver window and noticed the speed and rev meters dropping to zero. To check what was happening I turned on the lights and everything went off and Bongo went into a "limp mode". Luckily I got home without having to switch off the engine. When I did at home there was no power to start. Leisure battery was fine and then I found the startre battery had dropped to 9.7V despite alternator puttting out 14V. The starter battery is only two months old. When I replaced it with an old battery all is fine again. No fuse issues and all systems checked. I suspect the new battery has gone faulty and I have put it on charge and it seems to be holding 12.6V. Before I get the battery replaced I have a question, is it possible the alternator or other component is not operating correctly (current wise) or is the voltage of 14V definitive proof that it is fine?
Bob
Supreme Being
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Joined: Wed Oct 17, 2007 12:54 pm
Location: North Somerset

Re: Lost electrics while driving ... failed battery?

Post by Bob » Thu Oct 14, 2021 7:36 pm

Which engine do you have, please?

And how long does the battery retain 12.6 volts?
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g8dhe
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Location: Worthing, West Sussex.

Re: Lost electrics while driving ... failed battery?

Post by g8dhe » Fri Oct 15, 2021 8:20 am

Check out all the battery clamps and the connection to the chassis for the -ve, also the 100 Amp fuse has been known to have problems (its bolted in be aware!). Otherwise it might be an internal fault in the battery but that is pretty rare situation.
Geoff
2001 Aero V6, AFT, full side conversion.
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ilmomento
Apprentice Bongonaut
Posts: 2
Joined: Fri Jun 18, 2021 7:24 pm

Re: Lost electrics while driving ... failed battery?

Post by ilmomento » Fri Oct 15, 2021 1:27 pm

My Bongo is a 1996, 2.5 Auto diesel.
I cannot recreate the fault today but I have checked fuses and connections. I suspect I had a poor connection from the alternator. the battery is now charged and holds 12.6V although I have not stress tested yet. The alternator puts out a solid 14V. I am continuing to investigate.
Bob
Supreme Being
Posts: 14881
Joined: Wed Oct 17, 2007 12:54 pm
Location: North Somerset

Re: Lost electrics while driving ... failed battery?

Post by Bob » Fri Oct 15, 2021 4:15 pm

Fingers crossed. 8)