# Miles ZX40S barely moves, how to test batteries & charger?



## heatherton (Sep 19, 2010)

I don't use this 2007 Miles too much and I last charged it a few days ago and today after about 5 miles out I get a funny smell inside the car, I guess kind of like acid. Also remember hearing one or two popping sounds I thought came from driving over a pebble but could be a battery exploding? Anyway, after about 10 miles I'm almost home but the car can't make it up a steep 1000 foot long section on my street. I just left it there for tonight. The voltage in the display read 69 volts, and when I went back to try again it was 73 volts but still wouldn't go. Just moves and foot and thats it. Are the batteries fried even when it shows 73 volts? How do I test them? Do I have to disconnect them from each other to test? I have an electronic car battery tester will that work? What CCA setting should I test? Thanks for any ideas.


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## ngrimm (Oct 19, 2007)

Sorry I don't know much about your vehicle and there are others with more expertize but it seems like the problem could just as easily be the controller or the motor. Maybe even a bad connection. Does the voltage drop a lot while you are trying to move? I imagine the controller has a low battery voltage cut off but I don't know what the cut off is. Did it come with an operators manual?


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## heatherton (Sep 19, 2010)

I towed it the rest of the way up the hill with my Prius and a rope early in the morning so nobody could see me. Once on the flat road it made it all the way home under it's own power. I'm keeping it plugged in all day. It came with an owners manual but not a repair manual.


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## vpoppv (Jul 27, 2009)

Doesn't seem like a good idea to charge it if you are having a problem, but hey, to each his own. You need to put a voltmeter to each battery at the very least. When I popped a battery it smelled like eggs.


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## Tesseract (Sep 27, 2008)

heatherton, I am 99% sure that you blew up a battery. Do not charge or drive the car until you've identified and replaced it. The Miles ZX40S is supposed to use 150Ah AGM batteries - it should be possible to get a replacement from a golf cart supply store.


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## heatherton (Sep 19, 2010)

Had it plugged in yesterday for about 6 hours. Let it rest overnight and tested the batteries today. They range from 12.95 to 13.10 volts. I have an electronic car battery load tester and with that set at 1000CCA four batteries tested between 750-850 CCA, one at 670 CCA and one at 440 CCA. What do you make of that?


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## EVfun (Mar 14, 2010)

One is dying fast and another if following it into a death spiral. As a battery looses capacity each drive represents a deeper discharge for that battery compared to the rest of the pack. This works the battery harder than the others, further shortening its lifespan.

My guess is you ran the littlest one flat and it went very high resistance as a result. AGM batteries are acid starved by nature so at zero state of charge the internal resistance should be very high.


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## heatherton (Sep 19, 2010)

So what would the specs be on a healthy battery? The car is under warranty so should I expect to get just one new battery or all 6? Since they are pro-rated I'll still have to pay about $130 each plus shipping unless I can pick it up in person.


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## rmay635703 (Oct 23, 2008)

Arg, don't use the cars onboard charger and DON"T drive the car!!!

If you ever hear a pop in a Miles car its the sound of the batteries active material blowing away from the separators.

The only way to fix this is the slowly discharge each battery individually with a 12v lightbulb down to about 11.5 volts then slowly recharge each battery individually with a trickle charger.

You do the above about 10 times.

When you do drive the car after this procedure, accelerate very slowly avoiding hills keep speed low and drive a couple miles then test each battery with a DVM (voltmeter) Batteries should never be more than .2 volts apart.

If any drop down low during that test you need to charge every battery individually again and repeat.

The batteries usually come back if you perform the above, but if you have a warranty, I recommend using it because after you actually pop batteries you usually have already destroyed them from overcharging and general lack of maintenance.

Cheers
Ryan


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