Hi everyone, I'm sketching a project using a DC motor to lift about 4 kg off the ground and keep the weight up for sometime (I got a motor with a gearbox apparently capable of doing this). It is just to lift a fence wire using a IR control.
So I would need the system to go up and down depending on which button I press.
The hardware I'm thinking of is:
-Solar panel 5w
-Battery Charger: Micro Usb 5v 1a 18650 Tp4056
-Pack of batteries to be determined
-Remotely operated 4 channel relay
-2 x Step Up Mt3608 Dc Dc Booster
-12 Vdc motor
And here is a picture of how I think it would look like. Please take a look at it as it would help understand the idea.
Also, what I don't know how to do is how to stop the engine at certain moments without the need to press any buttons on the remote that operates de relays.
I'll research what those are and how I could connect them to the IR relays.
The dc boosters are there because the motor operates at 12v, and I set them after the realys so they are only using energy when they are needed. Though I'm not sure the relays would actually work if there is no previous current before they are actioned.
Those are low power DC boosters and won't run any of the three motors in the table above.
Keep in mind that the input current to the booster is much higher than the output current to the motors (by more than the voltage step-up ratio), and the boosters have to provide the stall current of the motors to get them moving (3 to 7 Amperes).
So, the first step is to research and find a motor/gearbox/battery/booster combination that will not only run the motor, but actually lift the load. A 12V lead acid motorcycle battery would be a good choice.
Ok. Sounds good. There are a lot of 12v 10 amps or so batteries that fit a reasonable budget. I’ve seen some that are gel based, don’t know if that’s good or not.
So. A good setup would be a 12v battery to operate the motor and maybe a step down to operate the relays and IR receiver/relay. But, that presents the issue of how to charge the 12v battery.
From what I’ve seen most Arduino related chargers work on much smaller voltages.
Is there any kind of post for newbies on batteries you could point me to?
The choice of the motor/gearbox is due to the difficulty of getting motors that might lift that kind of weight and hold it mechanically here in my country. So that’s pretty much a fixed variable as I don’t have access to other types of motors that could lift that mass and hold it for potentially large periods of time.
I’ll post a sketch trying to explain the work the motor would be doing.
Thanks for your time!
For some reason I assumed that the motor only around 1amp at all stages. Which now sounds silly haha.
Solar charge controllers for 12V lead acid batteries are popular and quite cheap.
Trickle charging a lead acid battery, using a low power 18-24V solar panel (for example, 3-4 of these in series) does not even require a charge controller, just a diode.
Ok. I’m having a really hard time making sense of how to charge batteries and risks of different types and ways to do it.
apparently I can only buy 12v 7amph gel batteries that are rechargeable. So. How could I charge those?
Could I do it with just solar panels in series and diodes?
the other way I’m thinking of doing this is by setting up regular 18650 3.7 volts batteries and charge them with small solar panels and a regulator.
also thought of buying a couple of solar chargers(power banks. The same as used to charge cellphones) 6v 5000mah and set them in a way to get 12v 10000mah. To operate the system. (This I believe would be about the same cost as buying the separate parts to build it myself) BUT, how would I connect the wiring to achieve the necessary current and voltage? I mean the batteries would be inside an autonomous charging system and I’m not sure it would be ok to connect those in series and parallel.
1- How could I add an end switch to stop the motor from turning more than desired and breaking down?
2- I've looked at your reply number #7 and you talk about lead acid batteries, which I suppose are different to this type of GEL batteries, that's why I asked if GEL batteries can be "trickle" charged too with just diodes (which would by much lower the cost of my project) or if a charge regulator is by all means needed.
From what I could grasp from the website you provided me the link with, I appears to me that GEL batteries NEED to be charged with a regulator, but I'm not certain.
Thanks for your time and patience helping newbies!!
1- How could I add an end switch to stop the motor from turning more than desired and breaking down?
Use a limit switch and some mechanical arrangement to trip it.
I use 12V motorcycle batteries for small projects (like weather stations), rather then gel batteries, and they can tolerate 100 mA continuous trickle charge, with no controller, for years. I doubt if gel batteries are much different for such low currents, but that is just a guess. If you want to be very safe a small circuit to limit the battery voltage to around 13.8V can be put together with about 4 components. Here is the circuit I use:
For higher current solar panels you need a charge controller. But those are not expensive. I use this Sunforce controller for my emergency power setup (100 Watt 21V panel, 135 Ah deep discharge 12V battery) and it has been working well for several years.
Thanks for everyone's help. I've managed to get a prototype working. I'll add a video soon.
The one thing I'd like to improve in terms of making it less expensive is the battery and charger thing.
That's why I'm thinking of using two of these, but I'm not sure if it is possible or advisable to put them in series and or parallel to get the desired 12v and 7 amp.
Some thoughts on batteries:
Firstly you should size your battery based on what you require for your load and then size your charging system based on what the battery requires.
So questions to be answered are:
what is total current draw when lifting or lowering the weight (including inrush current which can be multitudes of the run current)
How many lifts/lowers per hour. this is the duty cycle
How many hours a day does this work
is this a permanent installation or just a temporary thing
From this data you can calculate the battery size required.
Because the 12v loading is going to significantly larger than the controller loading build the battery system around 12 volts and set down to run the controller.
You mention difficulty in getting access to some items in your country, can I ask where you are?
Actually your location will affect your solar availability figures too.
The battery Lead acid battery you show is most likely Absorbent Glass Mat (AGM) technology not Gel but both are Sealed Lead Acid (SLA) and have similar requirements. SLA's are tolerant of higher charge current current than the batteries that can be topped up, BUT are sensitive to higher voltages particularly at higher ambient temperatures.
For a short term use a couple of 12 volt panels connected to the batteries will work but the batteries won't last for very long. A cheapish PWM regulator in the system will be a good investment if you want a long life solution.
I wouldn't look at series connecting Lithium batteries unless they are specifically designed to connected that way, Lithium has a lot of good points but it also requires good management to get the best results.
For the 7ah AGM type 12 volt batteries maybe look to security (alarm) installation companies or their suppliers as this size battery is a staple in house alarms.
Once you know you load requirements and duty cycle etc post it here and I will take a look at sizing the Solar and batteries (its what i do for a living).
Kiwi_Bloke:
Some thoughts on batteries:
Firstly you should size your battery based on what you require for your load and then size your charging system based on what the battery requires.
So questions to be answered are:
what is total current draw when lifting or lowering the weight (including inrush current which can be multitudes of the run current)
How many lifts/lowers per hour. this is the duty cycle
How many hours a day does this work
is this a permanent installation or just a temporary thing
From this data you can calculate the battery size required.
Because the 12v loading is going to significantly larger than the controller loading build the battery system around 12 volts and set down to run the controller.
You mention difficulty in getting access to some items in your country, can I ask where you are?
Actually your location will affect your solar availability figures too.
The battery Lead acid battery you show is most likely Absorbent Glass Mat (AGM) technology not Gel but both are Sealed Lead Acid (SLA) and have similar requirements. SLA's are tolerant of higher charge current current than the batteries that can be topped up, BUT are sensitive to higher voltages particularly at higher ambient temperatures.
For a short term use a couple of 12 volt panels connected to the batteries will work but the batteries won't last for very long. A cheapish PWM regulator in the system will be a good investment if you want a long life solution.
I wouldn't look at series connecting Lithium batteries unless they are specifically designed to connected that way, Lithium has a lot of good points but it also requires good management to get the best results.
For the 7ah AGM type 12 volt batteries maybe look to security (alarm) installation companies or their suppliers as this size battery is a staple in house alarms.
Once you know you load requirements and duty cycle etc post it here and I will take a look at sizing the Solar and batteries (its what i do for a living).
Kia Kaha
Ok Guys, thanks for your time.
At most, current should be 4amps, probably 4amh
The system would be used, probably a few times a day, by all means, it should be used between 5 to 10 times a day, if used.
It shouldn't work for hours but just seconds until the rope is up or down. probably 10 seconds until it is up, and a bit less to lower the rope that holds the electric fence wire.
For version 2 of the system I've changed some stuff, and this is the bill of materials:
DC Motor. It's a car window motor, with a worm gear that is supposed to have a really high torque. 12V 4A. (apparently, no manufacturer or specifications whatsoever)
IR Remote. relay switch. The previous version used an RF switch, but I changed this because I wouldn't want to mistakenly open a nearby fence, as I don't manage yet how RF frequencies work, so this way seemed the easiest one whilst sacrificing operating distance.
This module works at 5V.
5V voltage regulator to operate the relay module. L7805CV.
A kind of BMS, which I believe it is just a protection board for 4 battery cells. 12V 30A. YH11047A.
A diode to prevent backwards current at night on the solar cell. 1N4007.
4 3.7V 6800mah (stated) batteries. (Tested the motor with 4 batteries and works really fine).
So, the reason to do this, is that using 4 batteries uses less space than a gel battery, and the batteries could be charged using the YH11047A module instead of buying a solar cell charger which costs about 3 to 4 times than the said module.
Also there is the IR instead of the RF remote controllers, which reduces the chance of operating an unwanted fence due to proximity of each other.
For those who asked I'm located in Argentina.
Below is a sketch of how I'd wire things up. Any ideas are appreciated.
