Nope, those don't have terribly high capacity and have dismal discharge rates.Quote:
Originally Posted by Hard Time
You want significantly better cells than those.
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Nope, those don't have terribly high capacity and have dismal discharge rates.Quote:
Originally Posted by Hard Time
You want significantly better cells than those.
what kind of batteries do you recommend then?
are overlander batteries good
i would buy from this store on ebay, good prices and good products never had any touble form the cells and the guys there are great for advice
http://stores.ebay.co.uk/componentshop
What about these batteries http://cgi.ebay.co.uk/5-PCS-A123-NEW-18 ... _Batteries or are lead asid better
I think there lipos wich means you need speshal equipment to use them
You'll need a lipo charger and possibly a power supply.
I've got a lipo charger that I use for my RC car that charges at 0.5a, 1.a and 2.5a is that good enough?
Aren't those a123s?
yeah those are a123's
You have to make sure that your charger can charge A123s. Lipos have a different cell chemistry to A123s.
Depends how you configure them but those look like a123 1100mah cells.
Firstly they are an absolute sod to solder, secondly you'll probably need to double up on the packs/cells to run long enough.
We've been really pleased with A123's (Life-po4's) since we put them in hydra and dantomkia but the initial soldering is a real pain. the cells have large bits of aluminium on them which act as a heat sink and getting it up to temperature with less than a 100w soldering iron is hard
You may wish to look into a pre-manufactured pack - http://www.hobbyking.com/hobbyking/stor ... rentCat=85
That said NIMH's and Nicads are available in more configurations of pre-made packs and the chargers are cheaper.
ok might order some to test because theyre cheap
Spoke to my dad today about the batteries and he said I'm not alowed them :( because they're fom Hong Kong.
But what a bout this one: http://www.technobotsonline.com/haze-hz ... -12v-3.3ah
I'm bit confused i dont know what is better for 2-wheel drive 2 electronize 15a, 2 electronize 30a or a sabertooth dual 25a
But whats wrong with the Hong Kong?Quote:
Originally Posted by Hard Time
I think the shipping is more expensive, might be wrong, I've also been taught to steer clear of items from Hong Kong.
Hmm, hobbycity is in Hong Kong. :proud: Best place for cheapest rc stuff!
Hobbyking are also a very good, very reputable company and yes they are cheap. Sometimes things aren't great quality but when you buy a 2.4ghz transmitter for 20 dollars can you really expect something to match the spektrum dx5e which retails at about 75pounds?Quote:
Originally Posted by rallikas
You do get what you pay for but in general most of the stuff is ok.
I'm going to assume you are using two drill motors to provide your drive. The difference between the electronize is the rating or the amount of current that they can handle. The 30A electronize will handle twice the current of the 15A version although the 15A has nice additional processor chip magic in there that means it handles current fine. Basically either one of these controllers will happily handle drill motors all day long. I run 15A (or 12A as they are currently rated if you buy new) in all my machines with no problems even when overvolting. They will happily handle 5 times their rated current for a second or two.Quote:
2-wheel drive 2 electronize 15a, 2 electronize 30a or a sabertooth dual 25a
The sabertooth is a more feature packed controller with some nice tweaking available. However it doesn't handle large stall currents or overvolting of motors very well. It should run a 12v drill on 12v source however if you run it at 18v or 24v you may get the magic smoke.
The electronize are single channel meaning you will need one for each motor whereas the sabertooth is a dual channel so two motors can run off one speedo. Cost wise theres not a huge gulf.
To sum up, electronize, not as many features (still give you all you need control wise) but more rugged. Sabertooth, more features, bit more delicate (if you start using it toward its limits).
Various people have their own opinions about controllers like with any hobby. The final decision is up to you.
it is worthwhile noting that dimension engineering (manufacturer of sabertooth) will replace the controller if it blows within the first year (Even if you decide to screw on the wheel by powering the motor and making sure its tight by stalling it for a number of seconds :rofl: :rofl:).
It is a no quibble guarentee and it works well (if they have the stock and you may also get stung for additional custom charges).
I would agree that for the 10A ones they can be very delicate but haven't heard that much in terms of this on the 25A ones.
Lol blew two of the 25A ones. Ran them on 20 nicad cells (24v). The stats say don't run it on more than 25V (fine for 20 cells in theory), in practice you are told to run them on 18 cells because they can't handle the extra little bit of voltage you get with a fully charged battery pack, ie don't run them near their limits.
I'm only going to be using the sabertooth on 12v at 3.3a so hopefuly it wont blow up.
The reason I cant get the batteries from hong kong is because it's shipping is expensive and they normmally give you rubbish things.
I assume you mean you are using 3.3Ah batteries? That doesn't mean that they will only give 3.3Amps. What it means is that they are in theory able to give 3.3Amps continuously for 1 hour before they will be drained. They will therefor give 6.6Amps for a half hour (again in theory) and so on. You need to look at the rough power output of your motor.
For example a 120Watt motor running on 12Volts. Current = Power / Voltage therefore the current that this motor will draw in continuous operation will be roughly 10Amps.
Now that is again in an ideal world. In reality a motor draws a large current at startup as it is temporarily stalled (stopped) and once it is up to speed the current draw drops off considerably. Basically a motor will try and suck as much current from a battery pack as it can get its hands on.
Hong Kong doesn't give you rubbish things, your budget does. I can almost guarantee that most things in the room you are currently in came from the far east in some way. You get what you pay for. I can understand being hesitant about buying from abroad but having ordered parts from the USA, China, Japan, Australia and many others I can say that you get what you pay for. If you know what you are looking for you will be fine.Quote:
shipping is expensive and they normmally give you rubbish things
I do trust Hong Kong and I will get things shipped from America but ir's my dad that does'nt like hong kong but some things that are dirt cheap from hong kong you can sometimes not trust them.
Now to the good news, I'm selling things on ebay tonight so hopefully in the next few days i'll have enough to buy some 12mm thick HDPE so i can start building the frame for my new robot, I also got a drill motor for using on the electric lifter and I'll be going to the local car scrap yard to get the threaded rod from a sissor jack.
buying things from hong kong is usually a bad idea. they sell alot of fakes and items made with poor materials.Quote:
Originally Posted by Hard Time
if your dont have much money though its really great.
Quote:
Originally Posted by elobire
I have ordered stuff from hongkong for several years. (only from http://www.hobbycity.com)
I never had any failures during flights (rc planes). Read user reviews about the products!
QC is just lower on hongkong/chinese stuff, if youre unlucky you may get a bad product.
Ok where can I get a 500x500x3mm thich peice of aluminium, and where can I get a 500x500x1mm thick peice of steel.
try a local metal stockists (yellow pages). Technobots can give you the ali
ebay sometimes have metal offcuts etc
Thanks guys, and how heavy is 500x500x1mm piece of hardox going to be?
Hardox doesn't come that thin it's 3mm minimum and even then you have to have a special agrement, you'll have to mill it to that thickness or get some Docol (same manufacturer) which comes in 0.5 to 3mm so you're not wasting material.
4mm is the easy stuff to come by. 3.2mm is a special arrangement. Any thinner would be pretty useless as a wear plate to industry so they don't make it.
where is a car scrapyard near Ipswich
google it
Breadfield
where about in breadfield alex?
can't remember, near the caterey?
OK next time I see you I'll ask you where it is.
http://maps.google.co.uk/maps?f=q&so...47198&t=h&z=10
The magic of the internet :proud:
I've got all the bits for the lifter (except the esc) but how would I control the motor? How would i wire it up?
My dad says that we use microswitches and make a bang-bang speed controller and at either end of the threaded rod
we have a limit switch that when the nut reaches the extent of its travel the motor cuts out to stop the motor ripping the lifter mechanism and itself apart.
We need to be able to control it so when the lifter reaches the extent of its travel the motor cut outs.