Inventus Rechargeable 12V U1-40 Rechargeable Lithium Battery

[eenlow]

Please forgive me if this has been discussed before, I scanned the topics and didn`t see anything that answered my question. I purchased (10) Inventus Rechargeable 12V U1-40 Rechargeable Lithium Battery...I was hoping to use these is a solar power station, however the manual says the following: Warning: Do not connect in series or parallel. Connecting in series exceeds the voltage limit of the integrated safety protection circuitry and can damage the battery and void the warranty.Connecting in parallel exceeds the current limits of the integrated protection circuitry and candamage the battery and void the warranty. Any help would be greatly appreciated

 

[Supervstech]

These?

 

[eenlow]

These?View attachment 252894

yep....those are the ones.

 

[robbob2112]

They have small BMS and are basically intended as batteries in emergency lights or for small single workstation ups battery.

12.8 * 35ah = 448wh... but no serial or parallel or you fry the BMS.

In series all the current would pass through each battery and kill it.

In parallel they are not closely matched at all when new, used they would be way far apart. Hook them in parallel and the ones with higher voltage would dump current into the ones with lower voltage. They would do this pretty quickly if fully charged and blow the lower voltage ones BMS. You would be lucky if they didn't vent and cause a fire.

Not useful for energy storage at all. Only useful for the original purpose. Size and capacity rating means they were probably made as replacements for regular lead acid doing lighting.

 

[robbob2112]

It occurred to me last night there is one way to use them with their limitations. This would be not for the nervous novice.

First open up a battery and identify the cells and bms being used along with the size wires and bus bars between cells and if those are bolted or welded to the cells. Get the data sheets on the cells.

The bms max out at 20 amps,

Get One of these per battery

TE Connectivity EV200AAANA 500a 0-900vdc Tyco 12/24v

These were recovered from EV battery modules. These are VERY EXPENSIVE online. If you have any project that needs a high current relay this is your chance to save some money. Make a cheap 30a BMS into a 500a BMS. This will work for batteries in the 9-36v range so perfect for Lifepo4 and Lithium...

batteryhookup.com

Then cut them all open. Now rewire them so the BMS leads go to power the coil leads on this. Then connect the battery connection where the BMS connects to the battery to one side. Now check the bus bars between batteries to see how much current they can handle and beef them up as needed.
The ideal being you use the BMS to balance the battery cells and the contactor to control total current. It would also require a shunt trip to ensure you don't exceed whatever the rating of the wires and bus bars.

The second alternative would be to tear everything down to the cell level and assemble into diy battery packs by series/parallel arrangement. And a new bms.


And note, either solution could result in fire or other dangers if done wrong. And could easily cost more than buying a new battery of the same size.

Both solutions would require a YR1035 meter and other tools.

 

[eenlow]

Thanks for the information! I`m only in 45.00 per battery including the shipping, now to figure out the best way to make these units useful. Thanks again!!

 

[eenlow]

Just as a note the cells LFP26650EV 3.2volt 10.24 mw, I have included photos of the batteries.
+

 

[robbob2112]

Those look like something that could build batteries from scratch... and there is a forum section for that. If you can separate the cells and test them individually.

I was assuming they were pouch or prismatic.

 

[bwhark]

I made a similar post involving a similar question about Valence batteries of the same size to another thread, The Valence documentation allows for series but notes nothing about parallel and I shared my experience with Inventus 12V U1-40 batteries I bought BEFORE I realized that the documentation says to not connect in either series in parallel. I saw the price for Inventus used batteries and wanted a cheap addition to my already in place 12v LiFePO4 bank of batteries: I bought 4 batteries. I got them and looked up the data sheet and it specifically states not to interconnect them. The official data sheet is attached as a PDF and it definitely says not to connect them together in parallel or in series

I have had a set up for about 6 months and the batteries are still working well. This does not imply that what I did is guaranteed to be safe, or otherwise recommended. This is a disclaimer. I am not responsible for any negative outcome by a user who would do what I did, or by having used any perceived advice from this post. This post is an anecdote of my workaround.

I connected ALL batteries to a bus bar BUT NOT CONNECTED DIRECTLY TO ONE ANOTHER terminal to terminal . ALSO, I put a 20A fuse inline blade to EACH BATTERY. I chose 20 A because that seems to be the maximum charge/discharge, and would blow if the current might be much greater where the BMS might blow before cutting itself off. Honestly, I'd probably go with 15A each if I ware to do it again.

The bus bar is then connected to the rest of the battery bank with an 80A DC breaker into the already in place RV bank which is about 1380 AH total., so these batteries are not subjected to any massive current discharge or charge alone. A slightly lower rating breaker I would have preferred but I had an 80A on hand. If I were to swap it out, I would find a 60A or 70A breaker.

For initial charging, since the voltages of the ones I purchased were within 0.1V of one another, I did put my 4 in parallel them temporarily with 16 gauge soft copper craft wire and used a 5A LiFePO4 charger, let charger show full, waited overnight with them still connected to one another, with the charger off of them, then:

1. put a 20A fuse onto the positive terminal of each separate battery
2. parallel them TO A BUS BAR and NOT to one another post to post, making sure all the WIRES are EQUAL in gauge and length
3. from the bus bar to the load, put a breaker (or another fuse) with a current rating (or slightly less) to the SUM of all the fuses to each battery before attaching to another bank or load.

Then lastly, if this would be a lone bank connected directly to some load (unlike my situation), whatever the load is, it should not be more than 80-90% of of fuse/breaker rating that was put before the load. Generally, with 12V LiFePO4 batteries that are sold that can be put in parallel, the maximum total is generally 4: For a person that had 10, since each battery will be fused, one could probably make 2 banks of 5 just because if each battery is individually protected from an overload with a fuse, then connected to a bus bar, this seems a plausible solution. The 2 pairs of bus bars with a fuse with each, could perhaps then be connected to a another fuse, rated with the summation of both banks before the connection to the load. This would be a lot of fuses in use BUT again, since we are not supposed to put these in parallel because of a BMS that might not handle a current spike, this should more or less protect each battery in the bank, and each bank.

AGAIN, this is a disclaimer: I am not responsible for any negative outcome by a user who would do what I did, or by using any perceived advice from this post. If it works for the user like it has for me, great. If not, it is not on me because we all agree here that the documentation from the manufacturer says not to connected the Inventus batteries to one another in any way.

ALWAYS when connecting batteries (f the same kind) in any situation, keep all wires of connection to a bus bar the exact same length and gauge, as this keeps all loads more or less equal between the batteries.