Thoughts on an AC overload marked 40 amp 60 Hz on DC supply?

[ericmark]

This is a mobility scooter, the overload has smashed, so clearly needs renewing, marked 40 A 60 Hz 110 - 240 volt and supply is 24 volt DC from two 32 AH 12 volt AGM (VRLA) batteries, I also have a problem charging the batteries as the charger has gone walk about, which is how I found the damage where the battery has jumped up and smashed the overload, as needed to remove casing to gain access to charge batteries with two 12 volt chargers.

I have wanted to modify for ages, as one can't charge the batteries off the scooter, would be better to leave scooter in the car, and only take batteries in for charging, it is a large heavy lump to take in doors for no good reason.

But to replace with an AC overload does not seem right. Looks like this but it seems Amazon where I got picture from is out of stock. Only second hand ones on ebay. And would like to mount where not damaged if battery bounces.

 

[bernardgreen]

A starter in the search is this thermal breaker from RS and made by ETA who probably do a 40 Amp version

RS stock number 344-5333

1658 Single Pole 250V Voltage Rating Panel Mount​

 

[Rodders53]

Make and model of scooter would be a starting place to source the correct item from a Mobility place?
https://www.chinadaier.com/40-amp-circuit-breaker/ is the one you have posted a picture of. https://uk.rs-online.com/web/p/thermal-breakers/7827953?gb=b is a DC 40A device from RS. eBay has a different brand and google found me at least one mobility place selling similar DC rated breakers.

Replacement mobility scooter chargers are usually readily available -- ensure it is a decent quality VRLA smart charger though (if you can tell such a thing from aftermarket manufacturer specs).

Batteries should be fixed / strapped down with something. My wife's Pride GoGo has Velcro strips under the two 22Ah 12V batteries (and under the battery pack housing on the scooter frame). I renew the strips in the cases when renewing the batteries.

Fit a suitable mains inlet to the vehicle to charge in situ? I used to run a mains lead into our car boot to charge the scooter in situ when we caravanned as the batteries took up too much room inside. I could even close and lock the boot without crushing the cable (rubber strips in the boot opening).

 

[ericmark]

I need a three pin socket fitted to one battery, so I can charge off scooter, and a new overload, but scooter not used much, so may simply sell it.

But it seems strange to use 230 volt overloads, there were a range made for wagons, I assume one can still get them likely Durite?

 

[Harry Bloomfield]

The breaker will not care whether it is triggered by ac or dc, what matters is the type and size of current it has to break.

 

[Adam_151]

The breaker will not care whether it is triggered by ac or dc, what matters is the type and size of current it has to break.

And a breaker designed for AC might be unable to supress the arc after breaking DC

 

[ericmark]

And a breaker designed for AC might be unable to supress the arc after breaking DC

This was also my thought, which is why I started thread. This one nearly the same, designed for DC so why use AC model. Part Number Durite 0-381-90 not as shown in picture.

 

[Harry Bloomfield]

And a breaker designed for AC might be unable to supress the arc after breaking DC

Yes, that is what I pointed out.

 

[Adam_151]

Personally I'd try and change it like for like, the designer of the equipment has obviously assessed it as suitable for the function dispite it being used outside the manufacturer's spec....

 

[bernardgreen]

And a breaker designed for AC might be unable to supress the arc after breaking DC

which is why the AC rating is 250 V and the DC rating is much lower at 40 V.

Also some circuit breakers that are rated for DC operation use a "forced break" where a sheet of non conductive material is forced between the contacts to ensure they separate.. This also extends the length of the arc to be long enough to ensure that it quenches.