battery label info?

[dahunt]

Hi all,

I bought these grade B CATL cells from www.18650batterystore.com and they seem to work great. They sell them as 302 Ah batteries. However i was wondering if this label on the side means there were previously tested to 306ish Ah? Whats your thoughts? FYI... i'm a newbie at lifepo4 batteries....

tia!

 

[Steve_S]

That appears to be the results of a Gros Capacity Test which tests the Gross Capacity of the cells from 2.500 to 3.650 Volts. For a 302AH cell, 306AH Gross is just about right where it should be.

LFP like ALL battery chemistries has an Allowable Voltage Range which is from 2.500 to 3.650 Volts per cell. This is the range where there is no harm being done, above or below that voltage range is causing damage. Also like all other chemistries, LFP has a Working Voltage range, which is the range that delivers the rated AH capacity of the cells. This range is from 3.000-3.400 Volts per cell with Nominal Voltage being 3.200 Volts (50% SOC)

LFP have a Very Flat voltage curve and this is why teh working range seems odd but it is proper.
See links in my signature for Voltage Charts and more.

Hope it helps, Good Luck.

 

[dahunt]

This is great info Steve. Thanks for your time. I'm down in the ottawa area but we do lots of boondock camping up around deep river to matawa region.... well when there isn't a fire ban

 

[TomC4306]

Please put an insulating tubing or heat shrink on your threaded rods.

 

[Brett V]

It looks like there's no insulation on the all thread or metal binding plate at the end of the cells. That is absolutely a disaster waiting to happen!

 

[dahunt]

It looks like there's no insulation on the all thread or metal binding plate at the end of the cells. That is absolutely a disaster waiting to happen!

this pic was taken during top balancing on a workbench and is not the final installation. I installed end plates, cell insulator sheets and placed it all in a custom box with the bms in separate compartment on the top of the box. Never thought to take a final installed pic

**pic is on coffee table in garage, but was on workbench during top balancing

 

[dahunt]

Please put an insulating tubing or heat shrink on your threaded rods.

I didn't do this tho... what is the reasoning if you don't mind me asking?

 

[Steve_S]

This is great info Steve. Thanks for your time. I'm down in the ottawa area but we do lots of boondock camping up around deep river to matawa region.... well when there isn't a fire ban

I hear ya, we have several fires burning still and ATM the sky is quite orange here until the wind shift again. Everywhere has Fire bans and it looks like they will stand for the entire summer. Sadly "stoopid" does it anyway... The Centennial Lake fire was started by idiots clearing dead brush on an Island by burning it... never occurred to them that Embers can fly a great distance... and voila... one very costly fire... I'm just glad that nothing is too close to me and finally not hearing aircraft every hour of the day...

BTW, I don't know if you noticed on your adventures "Up the Line" (colloquialism used by locals) but a lot of properties are becoming available as folks are escaping Urban Containment all along the whole River Valley and inlands from there.. Some good deals to be had right now but also some that are nutz. Even where I am, many of the smaller roads are getting "lot's" for sale as farmers are slicing off "road front properties" to sell.

 

[Brett V]

The aluminum case of the battery is electrically connected to the negative post. With batteries in series, any contact between the case of two batteries creates a short with undesirable consequences.

 

[dahunt]

I hear ya, we have several fires burning still and ATM the sky is quite orange here until the wind shift again. Everywhere has Fire bans and it looks like they will stand for the entire summer. Sadly "stoopid" does it anyway... The Centennial Lake fire was started by idiots clearing dead brush on an Island by burning it... never occurred to them that Embers can fly a great distance... and voila... one very costly fire... I'm just glad that nothing is too close to me and finally not hearing aircraft every hour of the day...

BTW, I don't know if you noticed on your adventures "Up the Line" (colloquialism used by locals) but a lot of properties are becoming available as folks are escaping Urban Containment all along the whole River Valley and inlands from there.. Some good deals to be had right now but also some that are nutz. Even where I am, many of the smaller roads are getting "lot's" for sale as farmers are slicing off "road front properties" to sell.

Some people are so stupid. I hope the ban isn't all summer... but not looking good now... We always keep an eye out for properties that way, but in recent years, they seem to be quite costly... likely due the exodus from the city during covid. I'm hoping to nab up one of those properties when the price falls a bit from people running back to the city when they realize that they can't work from home anymore

 

[dahunt]

The aluminum case of the battery is electrically connected to the negative post. With batteries in series, any contact between the case of two batteries creates a short with undesirable consequences.

Well i guess i'm taking it back out!lol Thanks for the info. I make the wrong assumption the casings were electrically isolated from the terminals.
quick fix with heat strink!

 

[Supervstech]

Well i guess i'm taking it back out!lol Thanks for the info. I make the wrong assumption the casings were electrically isolated from the terminals.
quick fix with heat strink!

They are sort of isolated, as in no direct connection, but there is definitely some current leakage, which can result in cell depletion, or, in the worst case, a fire.

Also, the aluminum shell under the wrap is thin, and any wear can expose the electrolyte, or even some plates to atmosphere…

 

[dahunt]

They are sort of isolated, as in no direct connection, but there is definitely some current leakage, which can result in cell depletion, or, in the worst case, a fire.

Also, the aluminum shell under the wrap is thin, and any wear can expose the electrolyte, or even some plates to atmosphere…

Certainly good knowledge to have considering I put it in my RV. It will be exposed to much vibration to take any chances. Thanks again