NiMH packs to fit Mad Bull and Lunchbox

[Peter_B]

While I'm on my way to our week away (other half is driving), I've been pondering which batteries to get for my boys Mad Bull and Lunchbox (when I get it).

Currently I have 2 Powertech 4500mah NiMH packs. They're a tight fit in my Twin Detonator and Boomerang and although they fit into the Mad Bull, they can't be secured as they are slightly too long.

So, can anybody recommend some reasonably priced, decent capacity, readily available in the UK, NiMH stick packs that will fit in the Mad Bull (if they fit in there I'm pretty sure they'll fit in a Lunchbox)?

They don't have to be quite as high capacity as my current ones but they do need to last reasonably well. I don't want to be getting grief off the boys if their batteries dump too soon.

I know somebody will say "get LiPos" but at this stage I'm quite happy to stay with NiMH. The boys are only 3 (and a half) so chances are things will get crashed, kicked, dropped, thrown etc.

[GregM]

I had the same issue with Carson 7.2V 4500 mAh NiMH batteries, it won't fit the Mad Bulls battery compartment lengthwise if I wanted to lock the battery "door". Sticking with a Carson 7.2V NiMH 3000 mAh helps, since their cells are slightly shorter and less chubby than the large capacity cells. I have two of these, but both haven't stood the test of time, unfortunately, since my charger refuses to top them up sufficiently now.

With LiPo, you'd have to stick with stickpack shaped battery packs that do not exceed 134 mm in length, to make it fit the Mad Bull. I have one that has a capacity of 5000 mAh, made by Jamara. More common are 138 mm long LiPo stickpacks.

[Buggyjam]

I've got one of those basic Nimhs that came with a starter pack on a tt02b that fits the lunch box. I haven't got it with me. I thinks it's 2000 mah. They're fairly common, it's the six batteries lined up inside clear plastic with the end caps. They must be standard ish size. You see them on modelsport and wheelspin etc. They'll give adequate run time on a single silver can running the lunch box's feather weights. 

[ThunderDragonCy]

Overlander batteries in the UK. They're great and cheap. I use their 3300mAh NiMH packs and they fit all my buggies and trucks no problem.

[Peter_B]

@ThunderDragonCy what sort of runtime are you getting from a 3300 pack?

[werewolf]

If the packs are only a couple of mm's too long, one solution for the Mad Bull might be to replace the battery 'door' with a simple servo horn. Depending on which way around you install it, it allows for several millimeters and it makes a good alternative to the regular 'door'. That won't solve the problem with your Lunchbox, however...

[Peter_B]

7 minutes ago, werewolf said:

If the packs are only a couple of mm's too long, one solution for the Mad Bull might be to replace the battery 'door' with a simple servo horn. Depending on which way around you install it, it allows for several millimeters and it makes a good alternative to the regular 'door'. That won't solve the problem with your Lunchbox, however...

Are there any details of the servo horn trick on a mad bull? My packs are 4-5mm too long IIRC but it might be a useful thing to know for future reference.

[werewolf]

Nope, no tricks... just secure a servo horn with a screw in the same hole where you would screw in the battery compartment 'door'. Pivot it forwards to release yoyr battery pack and pivot it backwards to secure the pack. It will not cover the whole side of the pack, but it will hold. If you bash really long and hard with your Bull, I would recommend getting an aluminium one.

[Peter_B]

59 minutes ago, werewolf said:

Nope, no tricks... just secure a servo horn with a screw in the same hole where you would screw in the battery compartment 'door'. Pivot it forwards to release yoyr battery pack and pivot it backwards to secure the pack. It will not cover the whole side of the pack, but it will hold. If you bash really long and hard with your Bull, I would recommend getting an aluminium one.

Thanks, I found some pictures of it. I wish I'd known about it the other day, would have saved my battery falling out and getting dragged down the road a few feet

[ThunderDragonCy]

3 hours ago, Peter_B said:

@ThunderDragonCy what sort of runtime are you getting from a 3300 pack?

On 13.5T brushless in my Grasshopper3 I get 15-20 mins easy and that's with throttle wide open the whole time on loose surface. In my kids silvercan Rising Fighter it lasts what seems like indefinitely. Certainly longer than they have interest in playing!

[Peter_B]

1 hour ago, ThunderDragonCy said:

On 13.5T brushless in my Grasshopper3 I get 15-20 mins easy and that's with throttle wide open the whole time on loose surface. In my kids silvercan Rising Fighter it lasts what seems like indefinitely. Certainly longer than they have interest in playing!

Sounds like a couple of those will be just the job then. The boys cars will only be running silver cans and for a while with have throttle limited from the transmitter, so it should cover them for a good while.

[StrokerBoy]

Got an HPI Plazma 4300 NiMh in my Lunchbox.  Didn't know the sizes varied, so maybe I was lucky.

[Peter_B]

13 minutes ago, StrokerBoy said:

Got an HPI Plazma 4300 NiMh in my Lunchbox.  Didn't know the sizes varied, so maybe I was lucky.

I haven't got the Lunchbox yet so it might be that it isn't as restrictive as the Mad Bull.

[GregM]

3000 mAh NiMH will last around 15 minutes with kit supplied silvercan motor offroad. The Mad Bull's gearing is to blame with the large wheels. They make the motor suffer a bit, taking more current than with buggy sized wheels.