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Grid Battery Rebuild

J

joshuaparkour1

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May 5, 2022
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41
I recently cut open my dead GRiD battery pack with hopes of rebuilding it, but I am not sure what type of replacement would be appropriate as the cells are not labeled.
(I know not the greatest work with the Dremel, going to sand away and fill the rough edge once rebuilt)
If anyone has rebuilt one before and knows the best substitute cell, I would appreciate it.
PS: The cell with the plastic cutaway within the cardboard tube was unlabeled on the plastic.
Would these standard cells work? https://voltaplex.com/lg-m26-18650-battery-inr18650m26


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Those would be nicads. You can use NiMH in place of the old nicads if you wish. I'll guess they are around 900mah each. You see the same batteries in old cordless drills. Each tube should be 2 batteries.

Each tube should be 6v if I recall correctly. They would be like these batteries...

17978 6v Sub C NiCAD Battery Stick | Emergency Lighting |ELSC

ELSC - 6v sub c nicad battery stick. Here is a list of the product variation: 850.0034, 17978 6v Sub C NiCAD Battery Stick, 17978-974, USA-EL17978-R, USA-EL17978-974, 17978-R, 17978, USA-EL17978
www.emergencylighting.com www.emergencylighting.com


Personally I wouldnt bother using nicads or nimh and would just grab a charge controller and lithium ion pack. Be cheaper, lighter , and more power dense.

Something like this 18v charge controller would work well, and some 18650s...
www.ebay.com

Lithium Battery PCB Circuit Board for Makita 18V 1.5/3 Ah BL1860 Charging Board 603004794953 | eBay

L Universal suitable for Makita 18V 1.5/3/6/9Ah BL1815 BL1830 BL1860. M18 PCB Charging Protection Circuit Board for Milwaukee 18V Li-ion Battery USA. For Milwaukee 18V Li-ion Battery Parts M18 PCB Charging Protection Circuit Board.
www.ebay.com
 
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Thanks for the info, so I am assuming that the as long as each tube is 6v it doesn't matter if I use NiMH?
 
Project Update for anyone interested:
I discovered that the cells were actually standard nicad sub c batteries which were 1.5 V each and this pack has 9 of them or three per tube.
I decided to rebuild with standard sub c nicads to keep the standard charging architecture on the 1520 (the computer can recharge the battery with the external barrel connector)
There are two options to go about this
1: Spot weld the sub c nicad tabs together or pay Batteries Plus Bulbs to do it which would cost 22$ per tube or 66$
This would have been the best option as that's what the battery was configured as from the factory and would cause the least parasitic loss and most durability.
I don't have a spot welder though and I don't want to pay that much money to them to do it for me, so I decided to buy sub c's from Amazon which cost half as much and crimp them together. Crimping them is way more secure than just soldering them.
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This worked and I was able to run my 1520 from the battery pack.
I am waiting on the pack to dry from a sealant I applied and am going to sand to perfection to finish the job. :)

Does anyone know what this guy is?
(Thinking it's something that tells the 1520 that the battery is low)

IMG_0734.JPEG
 
Thats a thermal fuse, meant to blow if the battery overheats while charging, to prevent a fire. Make sure to put one back into your rebuild.
 
Paging @joshuaparkour1 How have the batteries held up after two years? I'm seeing lots of cheap cells and Amazon Specials but I've been hesitant to buy into any of them due to previous issues buying cheap cells.
 
Well, I did mine today.
Works nicely, structural kapton tape keeps both battery halves together.
Is there any tool that runs on grid that can check battery state/charging/voltage level?
My 1520 runs off the batter, but the question is, does it charge it? If so, how long does it take to charge it?
 

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Hmm, so what is the voltage for the battery? It seems my GRiDCase 1520 with plasma charges mine to about 11.6V and when it runs off the battery it reboots around 10.8V for about 20 minutes of runtime. Which seems kind of low, I think it should be around 60 minutes?
Also, considering that fully charged NiCDs should be around 1.4V I would expect gridcase to charge the battery pack to like 12.6V ?
 
12.5 or 12.6v is the theoretical maximum voltage of the pack but I just can't believe GRiD would sell a battery option that only lasts 20 minutes. Are you able to load and curve out each cell to confirm they are actually rated for 2200mAh?
 
I do not really have time for that and the pack is already assembled. But I think the main problem is that the pack is not charged to max voltage. My understanding it these packs would last maybe 1 hour at most. My 1520 has plasma which is probably power hungry, and FPU. But then I am probably also saving some on compact flash and gotek vs hdd and floppy.
I think if it charged to 1V more it would be maybe additional 20 minutes of runtime? So the question is, why does my GRiDcase stop charging at 11,6V? Is it by design, can this be adjusted?
The manual says the 32111 powerpack provides 20 watt hours of power to the computer.
According to table 4-2 my gridcase 1520 uses (6mb ram)
4+2+12+1.5(6mb ram)+2(gotek+cf) = around 20w so I should see around 1 hour.
I would use more ram but the SIPs are too thicc and dont all fit together ;-)
Also, it seems my gridcase was only charging the powerpack when the machine was on, otherwise the charge led was off.
Anyways, I will try charging this battery in GRiDCase 3P today to see if there is any difference.
 
GRiDcase 3P charged the battery to 12.4V. But it didn't seem to increase the runtime much, 1520 rebooted when running off it after 10 minutes this time. ;-)
 
0xDEADBEEF said:
GRiDcase 3P charged the battery to 12.4V. But it didn't seem to increase the runtime much, 1520 rebooted when running off it after 10 minutes this time. ;-)
Click to expand...
Doesn't make sense.
Either the cells are "bad" (not up to spec?) or you should try NiMH instead (I know--have to rebuild the whole pack).
If you're going to go to that trouble, you might want to take the advice of an earlier post and go Lithium; I run my GridLite off a (single) 11.6v (nominal) racer/drone battery (you just need to modify the interface cable/connector).
 
This still tracks with what I've been noticing with rebuilt batteries.
The cells are rated for equal or greater capacity to the spec of the original and yet they fall short of what the printed runtime is both in the documentation and the product reviews. I can only assume the cells themselves are being over-rated for their actual capacity.
 
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