humpback of Notre Dame (battery q)

[simensays]

ok, I've searched the forums for this, but couldn't really find the answer I'm looking for. I have a few of the old humpback batteries, but they're not really holding the charge that long any more and I wanna run my Willy 1 for more than 5 minutes!

Does anyone have any experience with rebuilding a modern 7,2V battery pack (or maybe it's better to start from scrach) to the shape of the humpback?

[Bltz-Bret]

I have 2 1500mah 7 cell battery packs that i bought back in, jeeze, late 80's early 90's and they still give me almost full runtime.

Yesterday, since I am rebuilding my truck I figured I would try my batt packs out to see if I have to replace them. Neither would hod much of a charge until I deep cycled them about 5 times.

What I would do is charge and then tun around and discharge them until they were almost a the 1 mark on my charger.

((( not mine it is the only pic I could find of it until I get my digital cam replaced)))

I would then charge for 30 min. (yes two charge cycles)

Then discharge until near the 1 mark.

Last charge I hard-wired in a motor "Kyosho 540st" and it ran with no load for over 14 min. Did this with stock and another nameless motor on both battery packs twice. The stock motor lasted 16 min.

When I first started they were pretty shot, now I will not have to fork out anymore $$$ than I really need.

Just an Idea.

[miramar]

Simen, as you're indicating between the lines yourself, old batteries are......well...old batteries![]

There are ways of reconditiong them to perform a little better, but the old humppacks are 1200mAh only, and whatever you do, they will hardly ever again deliver even close to that. It's not really so much the lack of capacity. As long as the load is small and the voltage window not critical (for instance emergency lighting), even very old batteries can perform very well and deliver the nominal* capacity or more.

In RC-models however, with high loads and the demand for a stable "high" voltage, old batteries will normally surrender long before they are really discharged. Voltage drops quickly and the battery gives the impression of being totally discharged, although most of the capacity is still "in there" but usable only at low loads and a lower voltage.

(*The nominal capacity is measured at a 5 hour or alternatively 10 hour discharge (industry standards), and isn't really more than an indication of what the user can expect for the high loads in RC-models.)

As for your need for a humppack in your Wild Willy, I would suggest you assemble a pack yourself using new cells, or visit Small Size Hobby Shop, they are assembling batteries to customers specifications all the time, including humppacks. They also have the experience, knowledge and equipment to make you a sturdy humppack with low resistance. 2400mAh Sanyo's would be my choice for the WW "sport" application, for a good price/performance ratio.

[simensays]

quote:Originally posted by miramar

..As for your need for a humppack in your Wild Willy, I would suggest you assemble a pack yourself using new cells, or visit Small Size Hobby Shop, they are assembling batteries to customers specifications all the time, including humppacks. They also have the experience, knowledge and equipment to make you a sturdy humppack with low resistance. 2400mAh Sanyo's would be my choice for the WW "sport" application, for a good price/performance ratio.

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id="quote">id="quote">

Thanx Erik, I was actually thinking about going down there today and ask if they could make me one - although I do like to do stuff myself - but since they're in the middle of rebuilding the store I thought I might wait until things calmed down a bit. I was there last friday, and it was a chaos (I didn't want to bother them at the time, but I know they'd be happy to help). I will ask them next week and enjoy the five minutes runs with the old Willy[]

[Shodog]

simen, You can buy them ready made from tower hobbies. but whay go through the trouble as they are real easy to make. I had to make one for my Rough rider. Next time though I think I will just cut a slot in the radio box so a stick pack will fit.

Jim

[Stevenchat2000]

Get 3300 mah cells you will be amazed at the performance and run time gains []

[Shodog]

quote:Originally posted by Bltz-Bret

I have 2 1500mah 7 cell battery packs that i bought back in, jeeze, late 80's early 90's and they still give me almost full runtime.

Yesterday, since I am rebuilding my truck I figured I would try my batt packs out to see if I have to replace them. Neither would hod much of a charge until I deep cycled them about 5 times.

What I would do is charge and then tun around and discharge them until they were almost a the 1 mark on my charger.

---

id="quote">id="quote">

Cool old school charger. I have the same one. I still use it because my fancy shmancy quasar pro won't charge some of my older battery packs

[simensays]

quote:Originally posted by Shodog

simen, Next time though I think I will just cut a slot in the radio box so a stick pack will fit.

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id="quote">id="quote">

Jim, that sounds more expensive than buying a humpback style one, I guess radio boxes for the SRBs cost more than the batteries! [] Besides, there's no room for mods like that on the old Willy...

[WillyChang]

quote:Originally posted by simensays

Does anyone have any experience with rebuilding a modern 7,2V battery pack (or maybe it's better to start from scrach) to the shape of the humpback?

---

id="quote">id="quote">

Its not hard... just did one last week with used 2000s.

Have you assembled any battery packs before?

Had loose cells from the usual side-by-side packs "///",

then glued 5 in a row like "///" - noth the "//"!

When the glue dried put the 6th cell on top between #3 & #4.

Resolder them all with battery bars.

Note Tamiya's cable comes out from the right side of the battery,

not sure if it makes any difference to most cars... ie

____//|/

Shrinkwrap the lot... hardest job is trying to find some

shrinkwrap that is big enough to fit a humper.

And if you don't want to spend $$$ buying new cells, hang

around some serious racers at the track who always have used

cells to move on. You can usually buy these packs for less

than what a new "lesser" cell would cost loose.

ps: if you're building packs for the WW1... keep in mind

that there is room for a dromedary (two humps)... 7 cells? [|)]

[wildwillydriver(2)]

Hi Simen

that's the same problem i had at the beginning....[]

Now i use 2000 or 2400 Sanyo humpbacked and the willy seems to last forever, with a very good punch.

I have some used 2000 Sanyo loose cells with still a very good punch and also a 2000 (TOPAZ) pack already humpbacked if you are intrested let me know. They can give you a good 20/30 mins run.

Bye

WWD

[]

[simensays]

quote:

Originally posted by WillyChang

ps: if you're building packs for the WW1... keep in mind

that there is room for a dromedary (two humps)... 7 cells? [|)]

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id="quote">id="quote">

WillyChang - hmmm that made me think!

quote:

Originally posted by WildWillyDriver

Now i use 2000 or 2400 Sanyo humpbacked and the willy seems to last forever, with a very good punch.

I have some used 2000 Sanyo loose cells with still a very good punch and also a 2000 (TOPAZ) pack already humpbacked if you are intrested let me know. They can give you a good 20/30 mins run.

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id="quote">id="quote">

Thanx Federico, I'll have one made, maybe the double humpback like WillyChang said? I look forward to enjoy those 20+ minutes runs with the ol'Willy!

[malcolm(2)]

quote:

Originally posted by simensays

ok, I've searched the forums for this, but couldn't really find the answer I'm looking for. I have a few of the old humpback batteries, but they're not really holding the charge that long any more and I wanna run my Willy 1 for more than 5 minutes!

Does anyone have any experience with rebuilding a modern 7,2V battery pack (or maybe it's better to start from scrach) to the shape of the humpback?

---

id="quote">id="quote">

The problem with your old packs may be the way you are charging them. As they get old, Ni-Cads, if they still work, go high voltage during the charge, so on a simple resistor clockwork charger the charge current goes very low and in the usual 15 to 20 minutes on a clockwork you get very little charge in. What charger do you use? the old "how warm do they get" test is usually a good start, if the cells never get warm during the charge they aren't getting any charge in.

[wildwillydriver(2)]

quote:Thanx Federico, I'll have one made, maybe the double humpback like WillyChang said? I look forward to enjoy those 20+ minutes runs with the ol'Willy!

---

id="quote">id="quote">

Nice! Be careful to ceck if the old "Black endbell" (if u have it as motor) likes the 8,4 V treatment of the double hump.....[]

I'm not sure about that. [?]

Bye

WWD

[]

[simensays]

I got my new humpback from a real cool guy at Small Size (Terje) - he made it for me in about 10 minutes, it's a 6 cell SANYO 2400 mAh - I didn't want to do the 7 cell now, cause I needed a humpback that I could also use in my SS runner (in parts at the moment like all my SS).

Federico - there's no black endbell on the motor in my runner Willy.

here is the charger I use - and the infamous new humpback

[wildwillydriver(2)]

Good choice the 2400 they are strong battery and have a fantastic punch for terrific wheelie power and running time!! []

If u don't have the black endbell motor (the stock one) what kind of motor you have??? [?]

A Black sprint (red endbell) a Black endurance (blue endbell) or another motor with an adapter to fit the motor mount...[?]

Update me on the 2400 performance, i think u will like'em. [8D]

Bye

WWD

[]

[WillyChang]

quote:

Originally posted by simensays

...the infamous new humpback

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id="quote">id="quote">

Note your pack has the wire coming out the 'other' side (left)

compared to the Tamiya original (right). Technically speaking

the hump-cell should have been put on the other side.

Probably makes no difference to a WW1, but other cars are

more finicky. eg Its easier to stick the right-wired pack

into a Hornet/GH.

[simensays]

quote:

Originally posted by WillyChang

Note your pack has the wire coming out the 'other' side (left)

compared to the Tamiya original (right). Technically speaking

the hump-cell should have been put on the other side.

Probably makes no difference to a WW1, but other cars are

more finicky. eg Its easier to stick the right-wired pack

into a Hornet/GH.

---

id="quote">id="quote">

Willychang Da Man, I know! I actually told Terje (the guy who made it at Small Size Hobby Store) over the phone before making it, I guess he's an authority when it comes to RC here in town (old collegue of Erik/Miramar - like you know, they do know their stuff!) so I didn't stress the fact about what side the wires are coming out, but I did mention it.

As I had him make the humpback for my WW - it's actually better to have the wires on this side, rather than the "original" side that Tamiya made 'em - so he might have done it premeditaded, but honestly, I think it just happened?

Anyway - the new humpback kicks a**! Whattapunchya'll!!! []

[WillyChang]

Yes, it'll fit on WW1... but having the wire come out the other side of the LHS rear bodypost makes it a little easier to stow the wires away under the shell. []

I built up 1 pack that way too, then decided to swapover. Simple job of taking off the humpcell and reattaching it to the other side of the battery then reshrink the lot.

Then I discovered doing this makes it a lot easier to put the battery into a Hornet - bonus!