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Posted (edited)

Hi all I was wondering what are the best batteries to use in the 8881 battery box. Is is rechargeable or alkaline or something else? Also if it's alkaline could you tell me what make is best. Thanks everyone!

Edited by MrNumbskull13
Posted

If you use 6 ea. new AA, 1.5V Alkaline batteries in the common 8881 Power Functions Battery Box, you will initially get a full 9V (good for high-torque applications). If you use 1.2V Rechargeable AA batteries, you will only get 7.2V but you can recharge them over and over for long-term economy. Even the 8878 Rechargeable Power Functions Battery Box only delivers 7.4V.

8881-1.jpg8878-1.jpg

When you ask what is "best", it depends on whether you need MAXIMUM POWER or not. From Philo's Power Functions Motors Power Curves webpage, you can see the effect that low voltage has on Mechanical Power. Here's the effect using either the Version 1 PF Receiver or the newer v2 PF Receiver) -- you're giving up at least 1/4 of possible Mechanical Power by using Rechargeable batteries:

pfmedium.gifpflarge.gifpfxl.gifrc5292.gif

Posted

I have had success with eneloop batteries and powerex charger. A good charger like a powerex is important for battery health. Otherwise grab the 8878 if you don't own anything else that requires AA.

Posted
When you ask what is "best", it depends on whether you need MAXIMUM POWER or not. From Philo's Power Functions Motors Power Curves webpage, you can see the effect that low voltage has on Mechanical Power. Here's the effect using either the Version 1 PF Receiver or the newer v2 PF Receiver) -- you're giving up at least 1/4 of possible Mechanical Power by using Rechargeable batteries:

Note that these curves use a laboratory power supply with fixed voltage. NiMH fares better in real life tests (I plan to do some tests about this), alkaline cell voltage drop rather fast as they discharge...

Posted
I'm really buzzled why there not used more by technic fans.
Price? :sceptic:

Otherwise, LEGO Lipo battery packs perform quite well too (but indeed with lower voltage).

I thought Lithium batteries have a voltage of 3-3,7V, not 1,5???
There are many lithium battery chemistries, some of them have lower voltage.
Posted

I have the best answer, energiser lithium batteries, great power and not drop in power ether,also they last a long time.

I'm really buzzled why there not used more by technic fans.

http://www.amazon.co...r/dp/B00003IEME

their cost is the prohibitor at a guess for us tight legoholics?? i have started using 'energiser industrial' AA's they are cheap enough and have good power. there is a comparrison somewhere online that checks out around 20 AA makes of battery and the energiser industrial is very near the top below the lithium types and a couple of other expensive alkaline types. bang for buck they are a good option.

Posted

Prices varies around the world but price/performance tend to place IKEA high up.

not near Duracell in range (30-40%) difference but you do get 10 IKEA for less than 4 Duracell costs

Posted

I just try to avoid using batteries whenever possible, and use long cables tethered to models if needed. Hooking up a speed regulator or control center (and using the PF battery box as a pass-through) is the best way to get a consistent 9V output. As Philo's graphs show, the motors are much more powerful at 9V than 7.2V.

Posted

Also i forgot to add, lithium AA batteries are very light in comparison to alkaline batteries.

Win win all round :)

I have just bought the 8878 rechargeable pack and yes it is good and has good power but the downside is 7.2 volts.

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