Gate motor direct feed bypass battery

hi guys, is it possible to feed electricity directly from the ‘charge’ wires to the 12v centurion gate motor? why must it pass through a battery which has to be replaced periodically - especially if there is electricity available 24/4 from the inverter?

edit - solution
thanks for the valuable comment guys, i think that although the lifepo4 12v [img] i have installed is more than capable to do the job, the internal bms protects it from frequent sudden bursts of energy in order to crank the motor - hence a cheap lead acid is the answer. i told the ladies at work that you might compare this with a worker in a suit vs one in an overall - they can both do the job but the guy in the suit is afraid of sweat stains…


I believe it is possible to feed it directly. You would probably have to remove the AC supply then, so that it does not try to charge the battery which is now not a battery. If you do that, the motor will raise an alarm over the missing AC, which I think you can turn off, but I am not sure.

Also remember that the motor packs a punch. At peak operation it can draw upwards of 20A. It should tell you on the display, after you train the end-stops, what the peak current was.

I’m guessing here that the amps available from the AC grid supply wont be enough to get the motor in motion? Cold cranking amps required?

I’ve also wondered about this. Why a gate motor does not come in 230V guise.

Most people want a battery backup. In which case it makes sense to use a 12V motor. And then it makes sense to use the battery for surge current too.

Good engineering decisions coupled with cheap batteries = poor end user experience.

… so how can we improve the latter?

bigger battery??? i just replaced the old 12v with a lithium 12v and the amps are too much for the batt as the gate has to be opened and closed multiple times, being at a business.

That’s indeed one of the things it does. It’s a 7Ah battery (or thereabouts), but at peak it uses 4 times that, although for a really short amount of time. Up to 4C discharge for short periods in other words.

But there should be no reason it cannot be fed directly with a 12V DC supply, as long as it can handle the peak.

I had a quick squizz at the control circuitry for these motors.
It is clear, where the 12 v tapping in point is. (Red & Black)
There is only a trickle charger in the unit, so the battery will be the source for the cold cranking amps.
But if you ditched the charger and the battery and replaced it with a 220Vac to 12Vdc PSU of sufficient capacity it appears very doable.

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If you already have a inverter backup, then just leave the 12V battery. Even if the LA battery is deing it will stil give a little spike of power and never have to supply a few hours. So the best cheapest option is just to leave it there.

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it seems the new 12v lithium from blue nova i installed last week cant deliver the neccessary umph [4C] to kick the motor,it only managed 3 times this morning - and that for a battery which costs more than 3x of an ordinary lead acid…

edit - the battery worked well for about 3/4 closures and was only installed friday afternoon. it is rated at 8ah so should be able to do the job welll BUT wit might be the bms tries to protect the unit from frequent sudden heavy discharges which would make it ok for a couple of openings per day but not every 15 minutes at a business.


Yeah, BMS’es are the bugger with “drop-in replacements” The T&C’s to be studied. I got caught with that, once, with DIY lithium batt.

My suggestion, get the cheapest 7/9ah batt you can get, but not TOO cheap, the circuit is on the inverter, so it may last a very long time.

Or get a 2nd hand car battery … with the right charger for it. You just need a “connection”.

Or what @Phil.g00 said.

Circuits on inverters change the “rules” a wee bit.

That’s my experience as well. If the power never goes out, even a cheapie 7Ah lasts a good 3 to 5 years. They are getting somewhat expensive to replace now (R500-ish from the local guys, “Manvic”), but it seems an acceptable compromise to me.

That is not what i expected, I build a 12ah 12v 2p4s lifeepo4 battery for my gate about 2-3 years ago, December 2021 did some renovation to the carport/garage and the contractors removed my 220v supply line from garage to gate motor. I build another 12v battery but only 6ah, and cycle them in my gate. sunday night the 12ah goes in, and Friday morning the 6ah goes in. gate gets used alot ( wife running a salon from home). the ds3 motor have a 15A rating on it, and its more that the cells can mange the cells are rated for 2c = 12Amps.

the last 20 months or so ive been cycling these 2 batteries from 100% down to 0% (bms cutoff is 2.45v)

they have not lost any noticeable capacity (have not tested with capacity tester) but going on experience that if i do not change the 12ah friday morning when i go to work (05h20), then before my wifes 2nd client the gate battery is flat. all of the cells used were sourced from LBSA in the golden old days when they still sold to the public.

my 12ah have a 25A bms
and the 6ah have a 5A bms,

at my parents house i converted their centurion d3 to function without a battery.
remove batery and charger from gate motor enclosure
put a 12v psu (20 amps to be safe) in the space of the battery and centurion charger.
remove the 220v wires from the charger and fit to the smps ( got a 30A 12v one on BIDORBUY for R200) connect the output of the smps to where the battery is connected on the gate pcb.

thats an even cheaper and better option than replacing an ordinary lead acid 12v!


You guys are referring to one of these?

yes, the best price I saw on BOB today was R275 for the 30A version
have not put a clamp meter on the motor wires to see how much the amps spikes to during startup, but the 30A powersupply I used work 100%

will this thing be ok for the gate motor?

Is there space for such a psu in the control box, even with the battery and charger removed? I have a 20 and 30 amp version of these but doubt it will fit inside.

jackpot question indeed - its a matter of space and if there is enough ventilation… but then again the gate motor has periods of non-operation…

You should be ok replacing the gate operator with a LFP battery (but try it out first if you can)
What is more dubious is a garage door operator. These require a lot more power since they have to lift a heavy door.
Also I notice that these are often 24V motors due to this.

Something else to keep in mind: Moisture. You may think it is in a plastic box and protected from the rain and all that… my gate motor loses its position every few weeks after heavy rains, as a small amount of water gets into the encoder wheel housing. At some point, it misses a pulse from the optical counter, rams the gate into the end stop three times, and then stalls in a collision state.

So the less holes in the box, the better for me :slight_smile: