8878 vs 88000

[davidmull]

Yes this has been covered before i need some answers :)!

I bought 8878 because i was told by many it's great and holds its charge well,also no more buying batteries is a big bonus.

I built the ultimate 8043 and love it but found it slightly lacked power, now maybe i need to fully empty 8878 and then recharge to get the full potential I'm not sure yet.(maybe someone can clarify this)

Iv just played with my original 8043 which has 6 AA ultimate lithium batteries in it and it has more power and no struggle on the right track ether but does with 8878.

Did i just waste 75 dollars on 8878 + charger?

Would i not have more power with the €12 battery pack 88000 + 6 energiser ultimate lithium batteries which cost €14 and last a long time.

Also aaa lithiums are very light so weight the same as 8878.

I'm getting into building mocs and love it but is 7.2 volts enough in the likes of jurgens 8043 and his other models.

I'm building jurgens PF backhoe soon and i don't want it to struggle.

http://www.ebay.ie/itm/6-x-AAA-ENERGIZER-Ultimate-Lithium-Batteries-MN2400-/260769419364?pt=UK_ConsumerElectronics_Batteries_SM&hash=item3cb7119064#ht_2154wt_689

Thanks in advance.

David.

Edited February 11, 2013 by davidmull

[Balrog]

The biggest difference is, that a rechargable battery pack only runs with 7,2 volts and a regular battery pack runs with 9 volts. Less volts means less rpm for the motor(s). Another point is amps, which can vary by the used battery cells. So more expensive batteries can give better amps than cheap ones (usually). That needs to be thought of in concerns of power consumption through the motors. I have no idea what the exact specs are for the recharable pack, but the biggest drawback are the lesser volts in my opinion.

If anyone knows better, please correct me.

[Cwetqo]

Correct. My TT had no chance competing with others which were 9V, when I was running on 7,2 volts.

[Balrog]

A solution would be to use a 7- or 8-cell rechargable battery pack which would have 8,4 or 9,6 volts. The latter being even better than a regular battery pack. But that would need to be custom made.

As far as I have seen, 9,6 volts should not be a problem for the lego electronics.

[davidmull]

Well why has everyone such great things to say about 8878, that's why i bought it, even jurgen highly recommends it too!

Is it best to let 8878 fully run down before recharging i wonder to get full power.

Does anyone know the power output of 8878 vs these in 88000? Amps etc

http://www.energizer.com/batteries/performance-lithium/ultimate-lithium/Pages/aaa.aspx

Edited February 11, 2013 by davidmull

[jadedomg]

You should never ever run lithium batteries all the way down, you can end up killing the batteries to the point they won't take a charge at all.

[Alasdair Ryan]

You you find that the excavator lacks power, why not gear it down more?

[Blakbird]

You should never ever run lithium batteries all the way down, you can end up killing the batteries to the point they won't take a charge at all.

You don't have to worry about that. The battery contains a protection circuit to prevent you from over-discharging the cells. You can just keep using it until it stops working and then charge it. Lithium cells don't have a charge memory so you can pretty much charge it whenever you like and not worry about anything.

The primary advantage of the 8878 is the high output current capacity compared with other cells. If a model is properly designed for it (like Jurgen's Zorex excavator), you will be amazed by the performance. If you try to convert a model which uses the regular battery box, you will be disappointed because the drop in voltage from 9V to 7.2V is a big deal. You really need to change the gearing to use it properly.

[Alasdair Ryan]

You don't have to worry about that. The battery contains a protection circuit to prevent you from over-discharging the cells. You can just keep using it until it stops working and then charge it. Lithium cells don't have a charge memory so you can pretty much charge it whenever you like and not worry about anything.

The primary advantage of the 8878 is the high output current capacity compared with other cells. If a model is properly designed for it (like Jurgen's Zorex excavator), you will be amazed by the performance. If you try to convert a model which uses the regular battery box, you will be disappointed because the drop in voltage from 9V to 7.2V is a big deal. You really need to change the gearing to use it properly.

I built the Zorex and it works great with the rechargeable battery.

Fat Sam42 will agree because he had a go at the lego show last year.

Edited February 11, 2013 by Alasdair Ryan

[davidmull]

You don't have to worry about that. The battery contains a protection circuit to prevent you from over-discharging the cells. You can just keep using it until it stops working and then charge it. Lithium cells don't have a charge memory so you can pretty much charge it whenever you like and not worry about anything.

The primary advantage of the 8878 is the high output current capacity compared with other cells. If a model is properly designed for it (like Jurgen's Zorex excavator), you will be amazed by the performance. If you try to convert a model which uses the regular battery box, you will be disappointed because the drop in voltage from 9V to 7.2V is a big deal. You really need to change the gearing to use it properly.

Yes but it is jurgens ultimate 8043 :)

I think people are missing the point, everyone talks about standard batteries not lasting , I'm talking about lithium aaa batteries, people must have tried them no?

I know my next moc (pf backhoe was designed around 8878 so will work well i hope)

[Blakbird]

Yes but it is jurgens ultimate 8043 :)

I think people are missing the point, everyone talks about standard batteries not lasting , I'm talking about lithium aaa batteries, people must have tried them no?

I know my next moc (pf backhoe was designed around 8878 so will work well i hope)

Lithium AAA batteries will be worse in every way. Lower voltage, lower current output, and less storage capacity than the standard battery pack. Only advantage is being rechargeable. These batteries are not suitable for heavily loaded applications like an excavator.

[davidmull]

Lithium AAA batteries will be worse in every way. Lower voltage, lower current output, and less storage capacity than the standard battery pack. Only advantage is being rechargeable. These batteries are not suitable for heavily loaded applications like an excavator.

Now I understand, thanks blakbird. By the way AAA lithiums are 1.5v.

I'll stick with my 8878 which I'm happy with now.

Can I ask though, is there a proper procedure for charging draining 8878 blakbird? When i got it last week it seemed to come with a charge in it , i plugged it in when i opened it and it was charged after about 30 mins.

Should i let it die now and then give it a full proper charge?

Edited February 12, 2013 by davidmull

[Kronos]

Lithium cells don't have a charge memory so you can pretty much charge it whenever you like and not worry about anything.

If I understand this correctly, it isn't necessary to completely drain it before a recharge.

[hoeij]

You you find that the excavator lacks power, why not gear it down more?

Sometimes you have to fiddle a bit with the axles during the build to make sure that all axles turn smoothly.

After that, it should run fine on the 8878 (mine does). The 8878 is pretty convenient for Technic because

it is light-weight and can deliver plenty of amps (at a slighly lower voltage though).

Edited February 12, 2013 by hoeij

[Jim]

The 8878 is pretty convenient for Technic because it is light-weight and can deliver plenty of amps (at a slighly lower voltage though).

David, I think this is why people (including me) are so enthusiastic about it. It's definitely not a waste of money. I would recommend having both solutions in your inventory, so you can choose the appropriate one for your model.

[Blakbird]

Can I ask though, is there a proper procedure for charging draining 8878 blakbird? When i got it last week it seemed to come with a charge in it , i plugged it in when i opened it and it was charged after about 30 mins.

Should i let it die now and then give it a full proper charge?

A lithium battery will always come partially charged because you can never drop the cells below 3.2V or they will be destroyed. However, you don't have to worry about this because the battery pack has protection to shut itself off before this happens. You can just use and charge the battery whenever you like; it will not be damaged.