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Asked — Edited

How To Power Ez Controller To A 12V Car Battery


I am new to ez and am awaiting the arrival of my new best friend, the complete kit. I have very specific plan in mind and I was wondering if some one can advise me on the proper way to connect up a 12v car battery to the controller. Can it be connected directly or not. I'm sure the answer is in here somewhere but I'm having trouble navigating the forum on my phone.

Thank you in advance for any assistance given and whole heatedly look forward to chatting more with the good people on this forum.


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Welcome to EZ-B forum please take a look at https://synthiam.com/Community/Questions/2907

Personally I use a similiar power source,but I use re chargeable batteries in the holder supplied with kit to power up ez-b ,I prefer to do that and use a seperate source from 12 volt battery for servos, using this regulator User-inserted image

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Thank you glad to be here. Thank you for that I think it may be the kind if thing I'm after. I'm primarily going to be using motors as I don't think servos can handle the amount of weight required by each. I need them to be able to hold about 5 kg


Jchadw, Welcome.

The EZ-B can only handle up to 9 volts. You can use something like this to power the board if you want to run it off of a car battery. As far as the motors go, you can use any size motor that you want, but you cannot power them directly off of the EZ-B. You need to buy motor controllers that can handle the voltage and amperage of the motors that you choose. The controllers take power directly from the battery, and supply it to the motors, but a low current signal from the EZ-B controls them (hence the name).

DJ sells 2.5 amp controllers in the store here. If you need bigger, you will have to shop elsewhere. The EZ-B software works well with Sabertooth controllers.

My robot uses car batteries. This is the route I have taken.

You will find a lot of answers in the forum, but the first thing you need to do is click on the link "Tutorials" and read them, and watch the videos, start to finish. Good luck with your project!

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@Bravia Is that a 12v to 5v reducer? The EZB really should have 6V minimum.

@Danger! The EZB can handle up to 17v not 9V.

@Jaychadw you could feed it direct from the battery however car batteries have a tendency to vary from around 10v to as much as 15v so I personally would add something in between to regulate the voltage and give a nice steady voltage. Something like this would do it, give a nice constant 9v.


I stand corrected. I don't know where I got 9 volts in my head. I used a 6 volt step down converter myself, and it worked fine.


Rich I only use the regulated 5v supply for the Servos The ez-b has its own supply from 4x 1.5volt batteries, I prefer to have a seperate supply for ez-b then one cannot hit it with too high a voltage or current. Lets say that has it own in built limits.This card is too valuable to me. Can't imagine living without one now Pat

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Hi. Thank you everybody for all the assistance and I apologise for only just now getting back on. All your help is sound and u agree with Bravia and the card is too valuable for me to risk a mistake although I cannot get around my need for strength. I think the plan is going to be to power my motors completely separately from the card itself. That being said, I do feel drawn to the idea given by rich. Has anyone had any issues with this kind of setup?


@ Rich I run EZb on the fish tank at 5 volts regulated , works awesome.

It is coming from a PC power supply that insures that there is practically zero chance of brown out ( too little current and Bluetooth disconnects)

If you use it in a car I recommend using a DC to DC converter to give your ezb a regulated source.


@jaychadw why would you use a car battery battery,first very heavy ,but second it very dangerous ,car acid leaking


Also about DC-DC converters they are not great for robotics ,there is a lot of guys here that use them because just attach 4 wires and you are done.

But they have a few problems one the mostly big,but main item you lose battery life (current)

Best item and easy to use is the same used in EZB LDO (LOW DROP REGULATOR) it saves a lot of battery life low drop voltage. (can expain it better if you need it) 3 terminals gnd ,V-IN ,v-out, and stays very well regulated

I am electronic enginner who designs battery power equipment,if you look at any battery power toy,design or tester or anything the uses batteries not one will use a DC-DC converter

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What kind of batteries do you put in your car?!.. Car batteries aren't prone to leaking acid, they haven't been for a long time since you no longer need to top them up. A typical 12 battery is 17Kgs but gives 70,000mAh for the cost of 3 2S 5000mAh LiPo batteries. There are many reasons why one may be used. Not every robot is mobile either...


YES i i know ,only asked the question just to see what he was using in for i seen others using car batteries for robots and they had problems with it,,fumes and very heavy

HIS design might be for his car,or mobile only he can answer it

Leaky car battery not a real problem mostly when you try to charge it and fumes problems

one of the best batteries is GELL CELL is sealed,very few problems using it,kinda heavy depending on th AH rating 17kg is 37 lbs

ON GELL CELL you can put on any side and not have a problem,second on the high current of a car battery it not needed ,unless you are make a EZB car ,with i have seen designs using it .but with a laptop and a lot of sensors

second to charge a car battery it takes a good sizeable charger

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@RobotMaker it is going to a fairly large mobile robot. It us going to use a large number of powerful motors. The points you raised on weight and recharge are the very same things that concern me. I need to provide the power for all motors as well as try to maintain a decent battery life without the need to recharge every hour or so. I am more of a software developer and used to play around with animatronics some ten years ago. The things I did before were always connected to mains but that is in no way an option for this. I just figured for these reasons a small car battery would be ideal. If you have any suggestions for running ten strong motors I would more than pleased to hear them. I am focusing on shall we say a mobile domestic robot. So mobility is essential.

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@robotmaker I am interested in what you said here "Best item and easy to use is the same used in EZB LDO (LOW DROP REGULATOR) it saves a lot of battery life low drop voltage. (can expain it better if you need it) 3 terminals gnd ,V-IN ,v-out, and stays very well regulated"


LDO is very cheap and depends on current is needed,what is meens if you have a battery with 12 volts outs and using a LDO dropout voltage is about .2 volts or less on dc-dc or other regulators is about 1.25 volts

So the battery will last about twice as long before recharge ,now even with high current motors still can easy use LDO,nmight need one per motor

ON battery how many motors are you using and the run current (not stall current) and then about how many hours do going to use them.