Electric Dirtbikes

While it may seem suspicious that both failed at the same time, coincidences do sometimes occur.

2 years of daily use is good for a lithium battery. I believe they are correct in suggesting that the old bike needs a new battery. It is good customer service that they are sending a new battery under warranty for the new bike. I'd test the new battery when it arrives and plan on buying a replacement for the old bike.

If BOTH still have charging problems, you may have had some sort of power line transient (like a nearby lightning strike) that damaged the on-board(?) chargers. IMHO this is highly unlikely, but not impossible.

Umm? Yea. I was wondering about the lightning thing. Because when I had cable hooked up, they at first weren't gunna do it because theres no grounding rod off of my electric box. Does that change the answer? I KNOW, I need to address it.

Whatever you do, when you get the rplacements DON'T try charging them together.
Because if there is a problem you won't be any better off than you were before the replacements.
Prove them individually first.
Del

The smaller bike is 24v the bigger bike 36v?....You haven't got the chargers swapped around have you?

No the plug-ins are totally different

Did the OP state that the batteries are Lithium, I could not find that anywhere, so I will assume (for the moment anyway) that the batteries are Lead Acid Technology.

When a LA charger (in a good state, not damaged) shows that a battery is charged when it isn't, its usually because the battery is defective. The battery goes high resistance and the charger takes this as meaning the battery is full.

I suspect that either the batteries are of Piss poor quality, or the charger, or both.

Check the battery voltage with no charger attached, if its less than 12.0 volts (I think it will be far lower) then its very suspect as it should just charge.

Try and measure the voltage on the battery in that short time when the charger shows green, preferably with a 'scope, did it jump up to 14 volts or more suddenly. If yes, the battery is defective.

I suspect that the chargers, although showing green as being charged are not switching off and the battery was overcharged many times.....eg. Battery is truly defective.

Once the light goes green, take charger off....or use a timer, to only allow charging for a set period....

But all the above is only possibly true for LA batteries, lithium is something else, but could be a similar problem of damage by overcharging.....

As to having a house with possibly no ground, that is tantamount to committing suicide....

I am puzzled by the units used. 350 or 500 watts are much too tame for a dirt bike (being about 0.4 and 0.6 hp respectively). But 350 or 500 amps is too huge in the other direction.

350 and 500 are probably arbitary numbers thought up by some marketing weasel to try and mke you think like errr 350cc 500cc.
You wouldn't believe the problems caused by product naming, hmmm but thinking about it, you probably would.

Del

Yeah, that might well be. 350 and 500 cc would be well suited to dirt bikes, maybe even a bit on the high side,

These motors are rated correctly as watts, and yes, they are 350 and 500. Lot's of low end torque but a top speed of only about 12-15 mph. They are 36vdc systems powered off of deep cycle LA batteries. I'm sure they are sealed batteries, either gel or AGM type. "New", out of the box batteries of this type will sometimes be bad from the get-go. There's several reasons such as "new" doesn't mean fresh. If they've been on a shelf for a couple of years, then they are much more likely to have premature failure than a fresh battery. Also, the manufacturing process for sealed batt's is more complex(read...expensive)so it's easier to get an error in manufacturing. And finally, these batteries should not be taken down to a full discharge state. They can, and will work okay after that, but you are cutting their number of cycles down dramatically. It's like a race horse; yeah, you can whip him to run 3 miles all-out, but he's going to break-down a lot sooner than doing the mile he's trained for. If you have the money, buy another pack or two of batteries to swap out after 50% discharge riding and you will quadruple your battery life instead of running them death.

Correct on all counts, but I would add that the chargers should be on a separate circuit from devices that can produce spikes, or be on a surge protected strip as these chargers are a bit fickle at times. Check the voltage across the batteries for 36 volts, then plug in the charger and see if it jumps it up to about 39vdc. And don't run these sealed batteries down to a no voltage seen state, which should be about 32vdc. You will be replacing a lot of batteries taking them to their maximum.

I agree that it is suspicious that on the same day both batteries should be dead. I'd check the amperage and voltage output of the chargers. The Razors have lead acid batteries, so the cahrger, with battery connected should be putting out about 14 volts (per battery) or a bit more during the first part of the charge. After the batteries have been charged and have rested (charge disconnected) for a day, they should be about 12.7 volts. Both chargers getting fried from a lightning strike on the same day seems more likely than both batteries dying on the same day.

You could charge the batteries individually with a small low amperage charger for automotive use. (For example, I have one that can be set for 2, 4, or 6 amps, and the 2 amp setting would work for the Razor batteries). This is easy to do if you are familiar with working on such stuff, but if you are not, can be somewhat dangerous. (There is the potential for sparks and explosions.)

If these are, in fact sealed lead acid batteries, then you should never use a standard auto battery charger on them. Chargers for sealed batteries cycle the charge to account for the build-up of gases to let them dissipate so as not to blow up the battery casing. Auto chargers do not do this as auto batteries are vented to allow the gas to escape. Also, the build-up of gases in a sealed battery will shorten their capacity as it creates a higher resistance between the plates. Most batteries designed for use on Electric Vehicles will specify sealed batteries so that when the EV turns over, it will not leak acid onto the rider or in the trunk of a car, etc.

Hi,

Check the tightness of connection into and out of the breaker box for your home. In my expereince it seems to be the description of a missing or restricted ground.

I just finished fixing a battery charger like you have, lots of transistors and resistors to go bad. Take your batteries to the dealer and have him put them on a new charger, and see what happens.

Your chargers may be blown, protect electronics with good surge protectors. I like UPS units, they have good protection circuits, and things with clocks in them won't lose settings if the power fluctuates or goes out for a while. Spread them around the house so you will have emergency lights if the power goes out, and computers and tv's are protected. Just don't put printers on them, they don't like the surge it takes to start a printer.