Battery performance in 8043 excavator

[Lauris]

Dear EB members,

I know that the set 8043 motorized excavator ir very popular among Technic fans. I have got mine few weeks ago and two days ago I finally built it and it is awesome.

Nevertheless, I wanted to ask, how long the batteries will last if I drive it around every day for few minutes?

I am asking, because I have created a LEGO Excavator challenge for my friends, that includes picking up a thingy and driving it to the other side of room, over some obstacles to put the thingy down in a marked spot. Of course, the time of the completion will be affected not only by the skills of operator, but by the previous usage time of batteries and the power left in them - so maybe someone has calculated the battery energy loss in 8043 during some time??? If yes, then I could develop some coeficient to make the challenge times more objective

At this point it has regular duracells in it, I'll probably swap them to something rechargable later.

[allanp]

Best thing to do is to time how long it takes to drive it across your living room. Then attemp the challenge yourself a few times then again time how long it takes to drive across your living room and see if there is much difference.

[Morvayn]

I think the best way is indeed to do what allanp suggested. I don't know of an easy way to calculate the energy loss of the batteries, allanp's idea is definitly the easiest way to find out.

The batteries of the 8043 empty pretty fast though, I used mine only to drive around a bit every couple of days and after one or two months they were empty, after that I removed the batteries. Now it is just a display model.

[timslegos]

The batteries of the 8043 empty pretty fast though, I used mine only to drive around a bit every couple of days and after one or two months they were empty, after that I removed the batteries. Now it is just a display model.

5 minutes every other day over a period of 2 months is a long time! Like 6 days of playing time (continuous)! The batteries in my opinion will be pretty much the same each run in the obstacle course.

tim

[Hopey]

If you're willing to do a bit of modification and are slightly handy with a soldering iron, you can make a 9.6V rechargeable battery pack out of the standard PF battery pack by putting 8 AAA batteries.

link to thread

I used very cheap batteries (8 for £4) and it works fine (although I've not done any rigorous testing) and if you spent a bit on some decent ones (I hear eneloops are good) it'd be even better.

[Tadej]

If you use rechargable batteries they will last very long and another thing that is important for you is that rechargables don't loose any power until they are completely empty, that means that there will not be any performance loss during several runs.

[hoeij]

If you use rechargable batteries they will last very long and another thing that is important for you is that rechargables don't loose any power until they are completely empty, that means that there will not be any performance loss during several runs.

This is not quite true, when fully charged, it runs a bit faster (you might not notice the difference, but you can measure it; e.g., measure the time it takes

to lift a fully extended arm from the bottom to the top).

But the voltage-difference between near-full and near-empty is a lot smaller than with alkalines (1.4 --> 1.2 volt, instead of 1.6 --> 1.0 volt).

If the game is supposed to be fair, you should each start with identical batteries. The simplest way to do that is to fully charge them before each player starts.

[AndyC]

Bear in mind, as well, that the performance characteristics of batteries may well vary between differing brands too. For a "fair" competition I think there are two choices: either furnish everyone with a completely new set of batteries each time (potentially very expensive) or replace it with a Li-Ion battery pack, which would typically have a more consistent performance.

At the end of the day, however, the only way to really be sure of the impact is to repeatedly try it out and measure it. Or wing it and just treat it a bit like a handicap mechanism, with those less skilled going first when the batteries are likely to be "fresher"

[Foggy]

what about using the old lego train 9V power supply with just long extended cables or you walk side by side tot he 8043?? I use it to power all my PF models so forgot about batteries inside battery box and bought a couple of rechargable just for remote controls.

Think is lego 4548.

Ciao Flavio

[Rodeown]

or pray for the day when we can transmit power wirelessly to our remote control devices

[Foggy]

or pray for the day when we can transmit power wirelessly to our remote control devices

Can't wait

[Lauris]

thanks for your opinions - the test with driving a certain distance and measuring the time should work well

[hoeij]

thanks for your opinions - the test with driving a certain distance and measuring the time should work well

There's one other way to do it that would also be quite fair:

First, player 1 does the obstacle course.

Then, player 2.

Then, player 2 again.

Then, player 1 again.

Now take the average running time of each player.

(PS. I would expect the speed to drop about 1% for every 3 minutes of running).

[chorlton]

5 minutes every other day over a period of 2 months is a long time! Like 6 days of playing time (continuous)! The batteries in my opinion will be pretty much the same each run in the obstacle course.

tim

Sorry to be picky, but that's closer to 2 1/2 hours. Maybe 30 x 5 minute sessions = 150 minutes.