Originally Posted by Maine Sail
Those are my videos.... LiFePO4 community still a small world...
Nice work Main Sail !!
I wish I would have seen that when I first got my batteries.
Early this season I had no faith in what people said about used batteries as my 6 only 4D 150# gel cell batteries died, after only 3 seasons...the company went bankrupt as well.
A neighbor at our Yacht club said why not go with Lithium Ion and I said too costly......he told me where I could possibly get some slightly used ones for 25% of the new cost.
Did a lot of internet
reading and called an electrical engineer
who works on our boats to see if he wanted in on this potential project
. I requested and recieved free to me his hours for his time researching this new to him technology....full pay for his time when on my boat...and I would do all the manual work ,mechanical work, wire making and installing and all the testing as per his verbal instructions and report to him all results
I bought the batteries with the understanding they would pass a test to ensure capacity and health
...went through some 200 batteries to get my solid 100 batteries...lots of hours.
... now I believe many of the low voltage ones I initially rejected to test can probably be brought back...another project
I set up a few trial sets of 4 batteries in series ...tightly strapped together with the original binding in sets on my salon
table and with a controled load of minature 12 volt lights adjustable to draw steady current
...approx 10 amps...I observed and recorded each hour as the batteries drew down to full empty according to the battery monitor
I used ...Simular to your Victron....and then continued to draw them down till the weakest one in the group of 4 hit the 2.7 volts each.
I have since set up groups to precharge and did not have them tied together as I could not put much current
into them and they never got even warm.
I believe this tight binding is unnessary for our house banks as well as for our thruster batteries.
I took an empty plastic milk crate and jammed 8 batteries into it using empty water
bottles with some air let out , enabeling me to lock them in place. I screwed the milk crate to the floor. I did this as a last moment thing and they worked just fine over the summer months and I went through some 80 locks without a problem.....i can not monitor
them as I do my house bank but if they do not work they are not so important...so far so good and they will sleep on the boat unheated this winter
As your video showes my used batteries also went beyond the supposed 60 amps each and gave me confidence to complete the purchase
of the used batteries.
I did notice once they get to the high end or low end of charging/discharging , they either drop off quickly or top off quickly....hence the reason why everyone cautions about overcharging or depleating.
The BMS I installed never had an event and never did the buzzer go off untill I dissambled them a few days ago...nice to know it works.
The upper charge limits on my victron charger/inverter, my main engine alternator
, and both combined when traveling and the genny is running ....all did as my profesional engineer
programed them to do, not overcharge.....Not rocket science ....and he did not spend more than 4 hours on that .... he had to re wire and add something to protect my alternator
which made up for a good portion of that time.
I do not understand the details as an engineer,or a professional as yourself , but having had the Victron charger
with a batterie monitor such as shown on your video, as well as a newer alternator installed 3 years previous I know how to use them for my purposes, on my boat.
The system on my boat was already improved 3 years ago, I paid for the newer programable inverter/charger and the newer adjustable Alternator already back then.I did this to protect and use to the max my new to me at the time gel cells.
So unlike others with an older system on board with no current technology the total cost , expecially the way I got the batteries, was much less . The first 1/2 season using them was a real reward, If I get 2 more seasons out of them and only have to switch out batteries then it has all been worth it.
Your video is so clean and professional looking, hats off to you !
It showes to all there is a profesional way to test used or possibly abused batteries, and it can be done quickly with a heater and a simple system as you have shown.
A side note , after posting
my last post I went to my garage and disconnected all my little individual boards so all the batteries will have the same no load as they sleep waiting for spring.