Charger not working

you can try to reset your charger and get it working again:

Check the battery voltage: Use a voltmeter to check the voltage of your battery. If it's below 3 volts, it may be too low for the charger to detect. In this case, you may need to use a different charger or replace the battery.

Check the connections: Make sure that the battery terminals are clean and securely connected to the charger. Loose connections can cause voltage drops and prevent the charger from detecting the battery.

Check the fuse: If your charger has a fuse, check if it's blown. A blown fuse can prevent the charger from working properly.

Reset the charger: Unplug your charger from the power source and remove any connected batteries. Wait for 10 seconds and then plug it back in. This should reset your charger and clear any error codes.

If none of these steps work, you may need to contact customer support

a lead acid will not charge with the polarity reversed
What happens is that in dead shorts and can destroy the battery
it can blow up the battery , blow the charger fuses and destroy the charger
Depending on the damage to the battery cell plates it may be recoverable

check that you have the red lead of the charger on the positive terminal of the battery and the black lead on the negative terminal of the battery. Next check the voltage to be charged is selected correctly 6 volt or 12 volt. next check the rating of the fuse used as 3.15 amp may be too low for the charger. I would not go greater than 5 amp at best. Lastly have the charger checked by an accredited electrician for internal shorts.

is this a built in charger ??? if not check the resistance between the two outside holes not the middle one, that's the inhibit hole... is there a short ? i never experienced batteries blowing up a charger normally the issue is with the wiring to the batteries....

Regards

check the input and spray compressed air to clean.. do not blow into it cause moisture is expelled when blowing. turn of device and remove battery. spray again. wait 15 minutes. place battery back in power on

If the fuse is blowing before the battery is installed to charge, the problem lies on the circuit board. Since it is most likely a switch mode supply, you might try replacing the electrolytic capacitors first. Then check what should be a MOSFET, although some may have a regular bipolar transistor as well.

If the charger blows the fuse when the battery is installed for charging, the battery has some shorted cells that overloading the charger, or the contacts are distorted and being shorted by the battery

There are several solutions to this problem which I have seen twice in my technical career.
You indicated that the power light on the charger comes on which indicates it is plugged into a working AC wall outlet. Check to make sure the power switch of the charger is turned on. Make sure that the round charger plug is plugged all the way into the battery charger receptacle on the battery box.
Next, check the on-board fuse AND the circuit breaker. I have had this little 5 Amp automotive style fuse burn out on several go go's and the charger does not work. Pull back the cover over the charger port and look for the fuse in its center slot. With a good set of fingernails it can be pulled straight out and inspected. Use fine needle nose pliers if necessary. I am assuming the go go runs and the push-button for the 15 Amp circuit breaker is pushed in. If it is out and the go go is not running reset the breaker by pushing the white button in. There is a clear rubber boot over the button. In my experience, the 5 amp auto fuse is your most likely problem. By holding it up to the light you can see if the fuse wire inside is burnt causing an open circuit. Most auto and hardware stores have this fuse in stock. Bring the old one to the store for comparison. It is a 5 Amp ATO fuse.
The question my clients often ask is what caused the charger circuit to overheat and the fuse to blow? The simple answer is that the two 12 Amp hour batteries in the go go are probably old and weak. This causes the charger to work too hard and the circuit to overheat and the fuse to blow. These small batteries have a short life span of between 6 months and 1 year depending on type. I recommend the AGM (advanced glass mat) batteries for longevity. Also make sure the charger being used on the chair is the 2 Amp small charger that came with the chair (There is a label on the charger to verify this). A larger charger will burn the batteries(shortening their life) and burn out the 5 Amp on-board fuse. Hope this helps.

The batteries will discharge below the reference voltage required for the charger to "see" the batteries if left uncharged for more than a month or more. You have to carefully bring the batteries back up to about 12 volts each for the charger to see them. The easiest way is take them to a qualified battery shop that has a step charger for sealed batteries. If you attempt to use a car charger on sealed batteries, you will ruin the batteries or even blow them up as the cases are sealed and the gas from charging has no way to escape. Some people have used a standard car battery charger on low only, applying a charge to one battery for about 15 minutes, then the other for 15, etc. until the batteries are back up to 12 volts, but again, using a car charger is dangerous and could cause the battery to explode.

What happens when you replace the fuse, plug in the charger without plugging the charger into the 660? Does it blow then? If not, the 660 is damaged internally and causing the fuse to blow. If it still blows, then there is a problem in the charger.


http://www.sharc.net/gps_charger_repair.htm

- Jim

My charger has a fuse located on the circuit board inside the unit....when mine stopped working, it was the fuse...replaced it and it is working fine for one battery, the other blows the fuse every time....bad battery.