My battery builds

999zip999 said:
I put an extra set of sense wires on for ez checking and can manually balance thru the sense wires. You could put cells in large parallel group and charge all to one set voltage for all cells befoe building.
Click to expand...

Yes I think ill do that with subsequent packs.
I'm considering buying one of these for balance charging as needed. Just run 2 sets of 7s balance wires.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com.au%2Fulk%2Fitm%2F192358059119

I'm currently bulk charging with a 900 watt boost module with a 12v LiFePO4 charger on the input

Thanks for your comment
 
I have the una-9 without battery nanny. But Now would get this https://www.fpvmodel.com/una9-plus-intelligent-parallel-charger-set-with-charging-nanny-protection-_g460.html.
 
Buy it for me and let me know. I can only use it at 6s or less. For 24s or 20s. Maybe with new batteries in high-power 18650 cells will change things. Hey if I was over on your side of the pond I be sweeping your floor and pick it up the spare sales that drop off the table
 
Okay I'll blow out my thoughts and remember there's no scientific proof behind my thoughts. Group all same cells Samsung 25 Panasonic PF Panasonic ga excetera excetera. Now the same voltage of like cells put them in large parallel charge them all to save voltage if I 4.1v charge to 4.1v but before you Parallel Group them make sure your parallel groups are of same voltage and then charge the same voltage so all cells are up to same voltage. Do not put a 2.5v with a 4.2 volt cell this is the danger. This is why your buddy was trying to tell you to buy new cells as they all come the factory at what 3.56 3.85 or something the whole box. I wish I bought the una-9 plus + with battery nanny.
Plus charge thru yhe sense wires only No backing the pack.
 
999zip999 said:
I have the una-9 without battery nanny. But Now would get this https://www.fpvmodel.com/una9-plus-intelligent-parallel-charger-set-with-charging-nanny-protection-_g460.html.
Click to expand...

That charger looks pretty good. Doesn't look like I could get one here and postage would not make it worthwhile.
Will probably stick withe the isdt. I have another of their chargers and am happy with it
 
999zip999 said:
Okay I'll blow out my thoughts and remember there's no scientific proof behind my thoughts. Group all same cells Samsung 25 Panasonic PF Panasonic ga excetera excetera. Now the same voltage of like cells put them in large parallel charge them all to save voltage if I 4.1v charge to 4.1v but before you Parallel Group them make sure your parallel groups are of same voltage and then charge the same voltage so all cells are up to same voltage. Do not put a 2.5v with a 4.2 volt cell this is the danger. This is why your buddy was trying to tell you to buy new cells as they all come the factory at what 3.56 3.85 or something the whole box. I wish I bought the una-9 plus + with battery nanny.
Plus charge thru yhe sense wires only No backing the pack.
Click to expand...

I test all my cells by fully charging, then rest them for 2 weeks or so.
If at 2 weeks they are above 4.14v, they get capacity tested at 1 amp per cell, charged to around 3.5v ready to go in a pack.
Due to the large quantity of cells I get I can cherry pick the best for my batteries 8)
 
That's good. I think the battery nanny would be great for a used cell battery builder. Or I wish I saw it when I brought the una9 plus +. But now its to much with shipping. Plus my 5yr old A123 20ah 24s pack is always balance after 1182 cycles no bms. And bulk charge. Plus I gone thru a hyperion 1420 two 1220 always balancing at first. That's way the sense wires for ez checking. And you can get a thru the sense wire balance charger like una6 or bc168 stlye. I'm more interested how your pack stays in balance without bms, but you would have to be the human bms . plus I would only do it with a 15ah or bigger pack.
 
EbikeAus said:
I have around 200km on my 30Q pack now.
Thought I'd record some voltages before and after charging.
It has performed better than expected so far and not bad for cells destined for landfill 😎
I may try a few full charges to see if the bms brings the 2 weaker groups closer.
49.7v 58.1v
3.564 4.183
3.575 4.162
3.566 4.174
3.568 4.178
3.569 4.171
3.586 4.177
3.458 4.090
3.565 4.162
3.489 4.094
3.539 4.172
3.572 4.127
3.577 4.186
3.545 4.190
3.500 4.131
Click to expand...

Super happy with the 30Q pack overall. Does exactly what I need in terms of distance and power. Obviously more of both are welcome :lol:

The two lower cell groups (7 & 9) are the only thing that could be improved but is it worth it?

This pack cost me about $70 to build so not complaining! Also these are of course recycled cells, so shouldn't expect perfect balance anyway.

I have considered replacing some or all of the cells in the 2 lower groups as they probably have higher resistance or more use than the rest.
The only tool I have for checking cells resistance is the imax b6 and not sure how accurate that will be?

I'm interested to hear your thoughts. Would you guys bother, or just work at getting next packs better?
 
balance the pack properly first... then you will be able to determine under-performing cells after a number of cycles. The golden rule is to always balance the pack well before putting it to use.
 
Willow said:
balance the pack properly first... then you will be able to determine under-performing cells after a number of cycles. The golden rule is to always balance the pack well before putting it to use.
Click to expand...

Thanks for that.
So I did balance the cells before building the pack after testing them.
These two lower cell groups seem to be where the under-performing cells are.
I should add that I only charge this pack to 57.5. At this voltage the groups are very close apart from the two which are consistently lower.

This brings me back to the question. Would you bother replacing cells for this amount of voltage delta?
 
Willow said:
here in lies the problem of building packs from used cells.
Click to expand...

That's ok I'm happy to work with recycled cells, I have large quantities and they are waay to good for landfill :D

I'm not about to spend $100s on a new pack when I can build packs for next to nothing.

I could just leave it as is, it's actually working really well!
I've done around 220 km on this pack so far with no issues.
 
What I'm saying is that you will struggle to, if ever, be able to keep them in balance.

Great to recycle the cells, but there are inherent issues, which in the worst case may lead to a fire. Hopefully the BMS will work as it should to prevent a cell group getting too high or low by cutting power. Use the packs as they are, flog them till they are spent, and build the next one.
 
Willow said:
What I'm saying is that you will struggle to, if ever, be able to keep them in balance.

Great to recycle the cells, but there are inherent issues, which in the worst case may lead to a fire. Hopefully the BMS will work as it should to prevent a cell group getting too high or low by cutting power. Use the packs as they are, flog them till they are spent, and build the next one.
Click to expand...

Yes I agree, I don't think I'll achieve perfectly balanced packs.

The next pack I'll use a bluetooth bms but may also add balance wires for balance charging when needed.
The bms will be more for High and Low voltage cutoff and monitoring with the app
 
While my 30Q pack is going great I think my OCD is gonna to be too strong to leave the 2 weak cell groups :lol:

First I'll strip back the heat shrink in that area and try charging them up to meet the voltage of rest of pack.
While I'm at it I'll test IR of those cells to see if anything stands out.

If they drop in voltage again I'll punch the lower 8 cells out and replace them with cells from a good looking 6ah tool pack
Stay tuned 😊
 
Have done around 260 km on the 30Q pack now.

I cut some 'windows' in the clear heat shrink last night and charged the 2 low cell groups up to meet the rest.

I noticed one of the cells I hadn't soldered the fuse wire to the busbar, so it was just resting on the busbar. This may have been the cause of one of the low groups.

I'll cycle it a few more times and see where voltages are at.
 
Hey Guys I've just brougth two Aeg 58v battery packs and I can't get anywhere close to 58v when fully chargered with the Aeg charger measured packs and can only get 51.9 and 52.4v. Out of box voltage was 45v. The date on the box is from 2016. What are ya thoughts about this...
 
Micklemax said:
Hey Guys I've just brougth two Aeg 58v battery packs and I can't get anywhere close to 58v when fully chargered with the Aeg charger measured packs and can only get 51.9 and 52.4v. Out of box voltage was 45v. The date on the box is from 2016. What are ya thoughts about this...
Click to expand...

I have about 7 of those batteries.
The first 2 I stripped for the cells, which were all as new!
I've kept the rest intact for ebike batts.

I don't have a factory charger but that voltage sounds a bit low for hot off the charger I think.

Were they new when you got them?
 
Micklemax said:
Hey Guys I've just brougth two Aeg 58v battery packs and I can't get anywhere close to 58v when fully chargered with the Aeg charger measured packs and can only get 51.9 and 52.4v. Out of box voltage was 45v. The date on the box is from 2016. What are ya thoughts about this...
Click to expand...

Maybe the pack is badly out of balance and the BMS is shutting it down early. Time to check the individual cell voltages.
 
Hey Guys I've just brought two Aeg 58v battery packs and I can't get anywhere close to 58v when fully charged with the Aeg charger measured packs and can only get 51.9 and 52.4v. Out of box voltage was 45v. The date on the box is from 2016. What are ya thoughts about this...
[/quote]

I have about 7 of those batteries.
The first 2 I stripped for the cells, which were all as new!
I've kept the rest intact for ebike batts.
I don't have a factory charger but that voltage sounds a bit low for hot off the charger I think.
Were they new when you got them?
They were brand new when I got them got them replaced by Aeg with two more brand new and they charged upto 58.2v these are working as they should be. Nice one Aeg
 
Quick update on my 30Q pack.

KT4ZbUd.jpg


I manually charged the 2 lower cell groups with imax b6 to meet voltage of other groups. After a few more bulk charges they are staying equal.

This pack has exceeded my expectations in every way! Have over 300 km on it now.

The weather is starting to improve here so looking forward to getting out more soon :D
 
Bit of an update on my 14s 4p 30Q pack..I've put 400 km on it now and still going strong. No issues

I have completed my 14s 5p 25R (recycled cells) pack for my Mongoose conversion build.
Changes/ improvements I made on this next pack are :

On this one I added a layer of Kapton tape underneath the clear shrink wrap.
I used a 60 amp Bluetooth BMS, which I'm very happy with so far.
I used 15 amp fuse wire instead of the usual 8 amp.
I have tested this pack with the LR small block and it handles the 50 amps no problems.

I wired this one the same as the last pack so I can interchange them between my two bikes.

If anyone is scared of soldering their first pack I would say go for it, I can see no detriment to the cells so far. I would also highly recommend cell level fuses for added safety.


3HwrCeZ.jpg


7NTQTkR.jpg


ICqOTh7.jpg


ACtCVAD.jpg


UQYtqQi.jpg
 
999zip999 said:
Ain't that fun do you have a link that BMS ?
Click to expand...

Yep I enjoy it..and save a lot of money. That last pack cost me under $100 to build.

Sure here it is :thumb:

Next time I buy one it will cost less as I won't need to order the PC interface, I already have one now.
 
You must log in or register to reply here.

Similar threads

amberwolf
Cordless conversion for Black & Decker MM850 Mower
Replies
9
Views
1,495
amberwolf
amberwolf
T
DIY surron 72V battery build (my first battery build)
Replies
15
Views
10,153
Mike Sr
M
Philtek
    • Like
Electric outboard 6kw Flipsky 65161
Replies
4
Views
2,767
kerosene
K
E
Used high drain cells in Melbourne
Replies
4
Views
630
EbikeAus
E
W
are my cell soldering drawings ok building a battery expandable
Replies
8
Views
735
want to build
W
Back
Top