Exploded my batteries in my XB-600
What a depressing week-end! three months ago I got a 5th battery for my 1 month old XB-600 (60V system) and everything was fine until Saturday. After a 3 mile ride on a new charge, the batteries were pretty much drained! Took them down to the local battery store and found the one I had added was bad. Left it with them for further testing and went home to install the 4 original batteries, plugged the original 48V charger and went to bed.
Went out 4 hours later to a hissing noise, a really hot garage and the smell, OH BOY!
Fortunately, I did not screw down the battery cover, popped it open and the tops of the batteries had expanded, spewing the batteries sweet nectar over my carpet and down onto the garage floor and a pretty intense heat, even after 4 hours of cooling. Not sure why they exploded like that. My first guess is that I installed one of the batteries backwards and I'll confirm that later, but I am 100% sure I had them correct and I double checked them before I plugged the charger in.
Now for the good news, I get to rebuild it...STRONGER, FASTER, SMARTER! How would you rebuild a scooter that just exploded? I think my first purchase is going to be 5 Lithium batteries. What else, or what advice can you offer? :-)
I'd put in a series-parallel plug to charge the batteries with a higher-quality 12V charger. You could then charge that fifth battery along with the res of the pack.
That'll be the first thing I do to my XB600 if/when it comes...
Here are the photos of my old, dead, exploded, ugly batteries. They were REALLY hot for several hours and since they expanded sideways as well, they are wedged in there pretty good!
Still haven't found a good battery supplier :-(
Wow! Looks like a thermal cut-off would be a good thing to add to the scoot. As mod #1. It shouldn't be too hard. Anybody got a circuit?
classic thermal runaway.
basically your charger isnt temperature compensated, and it tried to charge hot batteries. pack voltage never got high enough for the charger to shut down, and they got cooked.
if you are planning on getting alot of use out of this bike, then go for lithium.
the xb-600 uses a 60v 12AH pack IIRC
id suggest getting a lithium pack at least the same capacity (so 20 cells, 10AH or more)
if you stay with lead acid, there are a few things that need to be done to get decent service life:
1) temperature compensated charging (ideally you would have a variable 1st-2nd stage change over voltage, variable 2nd-3rd stage change over current)
2) pack balancing (by using voltage clampers or individual chargers, ideally you would do this at the cell level, but convenience usually dictates doing this at the 6-cell block level)
3) decent SOC meter (a cycle analyst or any other AH counter will do)
the xb-600 uses a 60v 12AH pack IIRC
Nope. Stock pack is 48v 20ah.
i stand corrected, must have confused it with another bike.
i replaced my batteries after a year and a couple of months of service..i was amazed at the condition they where in. not as bad as the picks above but pretty close ,,now when i replaced them, i used the same sequence as they where from the dealership.my new batteries are only going half the distance that i was getting.now keep in mind i,ve only been running the for 2 weeks.so i figuared that maybe one of the batteries is bad .so i took it back apart and found that they are starting to crack and swell.i assure u that i replaced them the same way as i removed them.my quesion is should the batteries be set up parallel or in series ,ive searched and searched and i cant find a answer to this, the last thing i want to do is ruin these guys,maybe extreem has them wrong..thanks in advance.
also i tested the batteries and they are almost equal with charge.so it,s not a bad batterie as i was hoping for
They should be hooked up in series, + to -. Making sure that the last + and - are hooked into the correct wire of the connecting cable. Do you live in a Very hot climate? as very high temps could cause the batteries to vent gases at an unusual rate.
Another thing to check is the output voltage of the charger. If it is more than 54V you could be overcharging them. I had a similar problem at 60V. My charger was putting out 72V in stead of the 68V or so that it should, causing my batteries to get very hot and never completing the charge cycle. Have you done the "shunt" mod to the bike? you may be drawing too much current for the batteries to supply thus over heating them.
If none of this seems to be true or correct the problem. My last idea without more info from you would be to get a KillaWatt meter to hook up to the charger. To verify how much energy is being used.
The "correct" CV stage charge voltage and CV-stop charge current changes with pack temperature (and to a lesser extent with age).
the correct charge voltage decreases with temperature, and the terminating current increases.
The opposite is true of a decrease in temperature away from the 25 deg C ratings.
with a charger of fixed CV stage charge voltage, and fixed terminating current, the charger will *always* overcharge your batteries when they are warmer, and undercharge them when they are colder.
add a bit of battery im-balance, and you have poor service life.
I wish i could point out an affordable temperature compensated charger.
I have found its almost always cheaper (up front, aswell as in the long run) to change over to lithium, than buy a temp compensated charger and balancing setup for a lead acid pack.
I haven't analyzed the charge profile of the stock charger, but the one time I used it the pack was pretty warm. In its place, I've been pretty happy with the (probably non-temperature modulated) Vector 2-6-10 3-stage chargers (especially their digital readouts).
I wired the batteries in the pack separately to a gang Anderson PowerPole connector:
... and then charge the pack with one charger supplying all four batteries in parallel (if I had five batteries, they would work as easily). My original plan was to have four separate chargers working in parallel (see http://i200.photobucket.com/albums/aa122/mf70/Charger-story.jpg), but that substituted questions of differences in the cutoff values between chargers for the original balance questions, so I went to a single charger.:
For operation, I use a jumper plug that re-wires to pack to series (the wires in the center go off to a circuit breaker instead of the 30A fuse):
The stock charger is a 2.5A @ 48V unit, I believe. With the Vector, I can ask for roughly the same charge rate by setting it at 10A (split, remember, between four batteries), or, when it's hotter, I can reduce the maximum charge rate to 2.5A for the pack.
- I would like to add a thermal shutoff (as I said in an earlier post). Can anyone suggest a circuit, or a temperature value to use above which the charge should be terminated?
again thanks to matt n dave.tonight im using the old charger,,right now it is just humming along seems ok.i,ll charge it for 3 hrs then finish it in the mourning.hopefully that is the problem,(the new charger)and yes i live in fl ,and now i understand that the weather here (hot)isnt so god for these lead batteries .unfortionally after purchasing these new batteries,250.00 dollars,with new charger. I cant afford to upgrade to the li,s but as soon as i can i will,,i ride 8 mile,s to work then back..so the li,s seem to be in my best interest...thanks a million cause for now i know i have the batteries wired correctly..
How about putting the probe from an oven thermometer in the pack to monitor recharge temperature?
(You would want to avoid shorting anything with the SS probe jacket, of course...)
You could even set it to alarm at a particular point...