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diy solar

Upgrading 15s Battery to 16s

Also looking at your other post. it looks like you have a seplos BMS.
You can easily swap that one for a new one (available in 16s and 15s). Everything should just fit fine. Maybe throw in a Neey balancer as well.

Still a very cheap and good deal.
 
boarder2k7 said:
Thanks all.

@Robbert my plan is to add the battery to the front left spot in my picture there, on the negative end as you mentioned. As I'm already replacing the damaged BMS I figure they might as well match so I'm not going to get in to reprogramming the cheapo one that's in there.

@chrisski It seems to me that 15s is common in the dirt cheap batteries. Saves them a little money and is still nominally 48 volts. The advice on the forum is of course not to parallel 15s and 16s batteries as the voltage is different.

@sunshine_eggo Thanks for those links! The first one looks like 16 cell minimum, but the second appears to sell individually with quite reasonable shipping. I'll place an order later. Taking the couple notes here on not using Daly, I won't. What would you recommend? JK or Overkill seem to be the top choices I'm seeing currently.
Click to expand...

I just bought 4X Topband 25Ah 3C cells and an e-bike battery from them. Everything arrived and was in good condition. The topband cells are testing better than datasheet.
 
boarder2k7 said:
That puts me at $180 more batteries plus about $300 for 2 BMSs, bringing my total cost for two rack batteries to $880, so a bit better than half price. Maybe I'll use cheaper BMSs though to save some off that.
Click to expand...
To keep costs down what about rebuilding them into 2p16s configuration - then you only need one BMS?
 
SeaGal said:
To keep costs down what about rebuilding them into 2p16s configuration - then you only need one BMS?
Click to expand...
A couple issues I see.

1) I personally don't like paralleling large (ish) cells.
2) They're in two different cases, and use welded busbars. It already will be some work to upgrade to 16s, trying to parallel them too you're looking at a ton of rework, new cases, etc.
 
@Robbert I quickly googled a seplos BMS and I agree it looks like what I have. They don't have pricing on their website but the Amazon listing has it at $240 which is more than the Overkill BMS and seems like a worse choice overall. To be fair one Seplos is less than two Overkills, but I think the Overkills would be a better choice overall.

@SeaGal @SparkyJJO I agree with the ending thought there about not reworking into a parallel bank. Modifying the welded bussbars would be very difficult and then I would also have a Franken battery with a load of wires between the cases which seems less than ideal.
 
TomC4306 said:
I have 2 Overkill and they work great. Except balancing. Consider JK with active balancer included.
Click to expand...
Do you have a recommended source for the JK BMS?


Also found this from the link that @sunshine_eggo provided and I'm assuming general consensus might be to avoid such a cheap and unknown BMS?

batteryhookup.com

Li-ion/Lifepo4 3s-21s 100a BMS W/ LOW TEMP CUTOFF

--------------------Here are 100a BMS units. We carry 3s-21s and both Lithium Ion (Li-Ion) and Lithium Iron Phosphate (Lifepo4). The lithium ion version also works with Lithium Polymer (Li-Po) since they both have the same parameters. (WIRING DIAGRAM BELOW!) Some of the BMSs arrived without the...
batteryhookup.com batteryhookup.com
 
boarder2k7 said:
Do you have a recommended source for the JK BMS?


Also found this from the link that @sunshine_eggo provided and I'm assuming general consensus might be to avoid such a cheap and unknown BMS?

batteryhookup.com

Li-ion/Lifepo4 3s-21s 100a BMS W/ LOW TEMP CUTOFF

--------------------Here are 100a BMS units. We carry 3s-21s and both Lithium Ion (Li-Ion) and Lithium Iron Phosphate (Lifepo4). The lithium ion version also works with Lithium Polymer (Li-Po) since they both have the same parameters. (WIRING DIAGRAM BELOW!) Some of the BMSs arrived without the...
batteryhookup.com batteryhookup.com
Click to expand...

That's likely a JBD.
 
sunshine_eggo said:
I have purchased JBD from these guys:

BMS Archives | SRIKO Batteries | Online store for electronics | Online battery store

srikobatteries.com srikobatteries.com

I would go with a sure thing rather than a guess. :)
Click to expand...
Looks like the choice would be either of these?

srikobatteries.com

JBDBT 16S LFP 100A Smart Common Port BMS

JBDBT 16S LFP 100A is offers a powerful battery management system solution, enabling you to manage and maintain the performance of your cells.
srikobatteries.com srikobatteries.com

srikobatteries.com

JKBT 8S-16S 100A 1A Active Balance inverter BMS

JKBT 8S-16S 100A 1A Looking for the best JK smart active balance inverter in the US? Shop from Sriko Batteries, the top online store in the US.
srikobatteries.com srikobatteries.com

I bring up the JK because I think that is still a respected BMS and it has a higher balance current capability which may be useful with my mixed cell setup?

Also I downloaded the manual for the JBD and while the manual is in English, the app appears rather sketchy and entirely in Chinese? Looks like something I wouldn't want to load on a phone that also has my banking info on it you know?

Does one of these manufacturers have a better way of setting up a BMS that doesn't feel like a security risk? Is anything say open source that could run on a Linux distro?

Thanks
 
boarder2k7 said:
Looks to me like with Overkill you pay a $100 premium for a JBD with better US support and a less sketchy app
Click to expand...
If you go for JBD/Overkill/JK, I would go for the JK.
App in the regular google app store.
Perfect active balancer
Build in Bluetooth and a 'port' free for eg Solar Assistant while using Bluetooth.

I have 2 JKs with 2 amp balancer and they run flawlessly for almost 2 years now
 
boarder2k7 said:
@Robbert You mean that the JK app also would work with that cheaper JBD BMS linked above?
Click to expand...
No. Jk app only works with jk bms

Wrt the Overkill app, that might work on some JBD bms-ses. Check Andy's channel for that.


With the JK, you might save some money in the long run.
Quite some people with jbd/overkill add an active balancer later.
JK had that already build-in.
 
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