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Hello fellows :),
I am trying to get in motion my homecockpit. Therefore I have three 24v dc motors of 550 watt, which I want to make run at 2 12volt accu's in serial or ofcourse one 24 volt accu.
There are many accuload equipment, but what is the best way to keep the accu's in condition while using the motors ?
Should I buy a drip-charger, or a normal charger?
(Sorry for my restricted english)
Thanks for your advice.
Bram Stikkel
As far as I know, lead acid car batteries are best kept fully charged for long lifetime.
I run my platform from three 12V batteries each 7Ah. In a balanced 150kg platfrom, avererage power is low, around 100W. That gives me at least 2 hours before batteries are getting low. In those cases I run a lab power supply that has max voltage set at 3x13.5V=40.5V and max current limit at 3Amps. This setup keeps the batteries at almost full condition continuously, without risk of overcharging.
Not sure what average power your rig is going to consume. Lets assume 100W: In that case you'd need CC/CV (constant current / constant voltage charger that can deliver about 4A at 27V. This would work. Other chargers probably also work, as long as they have a max voltage limit.
Thanks for your advice, Roland !
Bram
Hi Roland,
Are you using Deep cycle SLA or just convential car batteries?. I was going to use standard car ones(cheapest) and leave an intelligent charger permanently
connected. Although i have been told that they should be Deep cycle as conventional ones are not designed for discharging like we would in a motion platform. It would be good to hear from someone like yourself who have used motion platforms for a while and to see what has been used and how long batteries have lasted.
Thanks and look forward to your comments.
Regards
Les
I have recently learned, there are also semi-traction accu's, a in between version between the car accu and the expensive deep-cycle accu. A semi-traction accu is a third of the price of a deep-cycle accu. The diiference betwee normal accu, semi-traction and deep-cycle is, that the lead elements in the accu are vulnarable to become bended in the normal accu, and become less vulnarable to that in a semi-traction and deep-cycle accu.
By the way. With all kinds of accu's you need to take care of very good ventilation, since dangerous gasses are produced anyway with lead and acid accu's. Jellyaccu's do not have that problem, but they are more expensive again.
Consider to do what I now choose to do.
Try to find used but good transformer electricity supplies on Ebay or something like that.
Greetings and succes !
Bram
Hi Bram,
Thanks for the reply. Had been considering a main operated supply.Have some 10amp transformers here, will use 3 to maybe achieve a regulated 30amp supply.Hadnt heard of Semi-traction ones,will do some research.
Best regards
Les
I'm using three Yuasa NP7-12 see spec http://www.houseofbatteries.com/pdf/NP7-12
They are not expensive, can handle big surge currents, and still run fine after 3 years of regular use.
I had also thought about power supplies, but the nature of a motion platform requires VERY large sudden peak powers, and in some cases, the driver tends to dump some current into the supply. Batteries handle these requirements w/o difficulties, whereas an AC supply would have problems with both. I need 100W average, and ~1500W peak!
Adding a huge electrolitic capacitor to the output of a beefy AC supply could be a possibility, but it then resembles my setup: a 40V / 3A CC-CV supply that is connected to three 12V batteries.
Hi Roland,
Thanks for replying.Im really in a quandry as i have just built Ian Hoppers mini platform and dont know what to buy in the way of batteries. I know i should be going for SLA but these are expensive for 38ahr ones.I really dont even know if i need this high a capacity ones.I have a intelligent 5amp
charger that i was going to connect in parallel with the battery. My thoughts were with buying two cheap 12v 38ahr standard ones to see what current i will be running then deciding what i need. Your power requirements seem very low.
I do like your latest design,how is it comming along?.
Any further comments you can make would be gratefully appreciated.
Regards
Les
Hi Les,
Ian's mini platform is similar to mine: it relies on bungee for weight balancing. Correct weight balancing is really the key to low power consumption. So if you do it right, you'd get similar power levels as I have. 38Ah batteries sounds a bit overkill to me. It won't hurt (except your wallet), but 15Ah would probably do just as well. Of course, it depends on the motor types.
My new platform design is progressing steadily: the system has been tested with 150kg payload, and performance looks OK, see http://www.youtube.com/watch?v=OfI-_RTExBc
From the video you can also see that average power for the slow 0.15Hz heave is indeed around 100W. Could even be lower, as I still have to fine tune the bungee force a bit.
Currently re-doing the complete motion cockpit with improved visuals, flight yoke, new throttle, and a more modular setup for easier assembly/dissassembly. Sufficient stuff to keep me busy!
Thanks Roland,
Im using 24volt 350watt motors with a max current of 18amps.I intend to balance the platform as closely as possible.
I have seen the video of your new platform and WOW it performs beautifully.You really put some thought into the mechanics
and only wish i had your skill level.Im following your new platforms progress with interest.Look forward to more updates,your
web page has been bookmarked for a while now and i visit it quite often.
Regards
Les