ZX40S Batteries popping like popcorn!
 

Hello All,

I recently got my 'new' 2007 Miles ZX40S, and after driving it 3 miles a battery blew. I stuck Walmart's finest battery in as a replacement (to get the car home), and after driving it about 4 more miles two more batteries blew. These are the huge Chinese batteries that come with the car. I don't know if the batteries are bad or something is causing them to blow. I am working with Miles, who said before they shipped the car that the batteries put in were new, but it is very painful to get them to do anything. Anyone have any suggestions on what to troubleshoot?

Thanks!

Are the cases warped?

Are the terminals good?

Did you drive the car before charging?

That is indeed a very strange occurance, however if those glass mats were dried I do know that they fail by having cells blow apart.

Good Luck

The cases were not warped, nor do the terminals appear to be bad. When I got the car I did drive it about 1/2 mile before charging, and everything seemed fine. I charged it for 6 hours or so, and drove it 2 more times (1-2 miles each), when the first battery blew. I think it 'gassed' (not sure), as each time the the pack voltage dropped by 12-13 volts and the battery whistled like a tea pot. I could smell the vapor in the air.

The dealer said it could be a bad charger, but I don't have enough experience with this to understand how. I don't know if I just had 3 bad batteries or something systemically wrong. Any other suggestions?

Those batteries are normally not very picky about charging, but I do know you need to avoid overcharging, especially if the batteries sit a long period.

When those batteries sit you need to draw them down to roughly 10.5 volts before you charge them then continue to do so and the capacity increases (at least thats how it worked with mine)

If the batteries gas while charging it can be problematic since they are sealed AGMs.

I would definately use the warranty but if your stuck you should check to see what the batteries did.

Good Luck

It probably shorted out, it is possible that you had a bad charger, many times Miles used cheap chinese chargers which are only semi automatic.

Is the charger in this car a 'smart charger'? I don't think I overcharged, nor did I know it was possible with the the charger it comes with! I thought this came with a 2 or 3 phase charger that wouldn't overcharge. I read the manual that came with the car, and I don't remember any over charge warnings, not that it isn't a risk. Anyway, I am trying to get Miles to replace the batteries, as they prepped the car and certified it road ready. However, they don't seem as eager to send me the batteries as they were to take my money when I bought the car. I hope I can get this resolve quickly, but I am not optimistic at this point.

If I can't get Miles to replace these, I thought about replacing all of the batteries with 9 8-volt, 165 AH golf cart batteries. These are wet batteries, not AGM or gel. I don't need much range, 20 miles or so, but I don't know how these batteries would affect performance, which I am concerned about. Do you have any experience with batteries that aren't $350 each? I am sick of spending money on a car I haven't been able to drive yet!

In my car it isn't very smart, although it will shut off after running a specific period on float. The miles chinese chargers are prone to failure so make sure they test the thing.

Also the batteries listed in my manual are $250 each but that shouldn't matter they should be under warranty, let them look it over, let em baulk but if they died in short order there was something wrong out the door.

If you get different batteries the miles charger brings them up to about 15v (on a 12v battery) Which some batteries don't like.

Also those big 150ahr batteries have a LOT of capacity, smaller 8v batteries will likely provide less range than properly working Miles AGM "150ahr" batteries, reason is 150ahr seems to be under load and not a 20hr rate.

Good Luck

Unfortunately I live in South Carolina, about as far away from Miles as I could be in the Continental US! Even the closest service center is ~700 miles away according to their dealer map. So Miles can't troubleshoot this themselves. The dealer I bought it from is trying to help, and suggested I check the charging side of the charger to make sure it isn't pushing more then 72 volts and frying the batteries. I will do that today. Thanks again for the replies, I will update the thread as I get more information.

You are about as far away as I am, in any event you need workable batteries of some sort in the car to test the charger, the charger (if your car is a 72v car) should charge the batteries up to between 84-90 volts NOT 72 volts which is your nominal, Those miles batteries when new sit around 13.3 volts without the charger running when fully charged. Anyway the charge should climb up to 84-90v depending on the temperature then sit there a long time then drop down to the float mode then the charger shuts off, Miles has used different types of chargers so it may vary a bit but not by much

Something else you should check is ARE all the batteries at the same voltage before you charge?

If one is way low and the others are way high you can blow out batteries since the charger will drive them up over 18 volts ea if you have one that isn't coming up correct, so take care.

Good Luck
Ryan

Thanks for all the info, Ryan. I do have a question. If the charger was causing the battery problems, wouldn't they blow on a charge? So far all 3 have blown when driving the car. Once they get hot and blow, the vehicle doesn't run (well maybe 4-5 MPH top speed). I would think I wouldn't get it out of the driveway if the charge was blowing them, unless they cool down and don't have problems until they heat up again.

I checked the charging side of the charger and it is pushing about 80-81 volts. I also checked each battery, and they vary from 12.3-13.3 after 2 hours of charging. The exception is one of the temp batteries I put in, a deep cycle from Wal-Mart that is at 15.5 volts. Should I be worried about this battery? BTW the bad batteries that I pulled out are also showing a 12.5 or so volt reading. I will forward this info to the deal to see what he says.