Author Topic: Changing from SLA to LifePo4 batteries  (Read 269 times)

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Offline dochubert

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Re: Changing from SLA to LifePo4 batteries
« Reply #15 on: March 17, 2021, 06:34:55 pm »

I did get one 16s active balancer so unplugged the bms on one 48v set and plugged in the balancer in its place temporarily.  I'll give it a few days and see what results I get with it. 

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Same plug on bms and balancer, but of course they are wired backwards from each other so had to slice off the alignment tabs on the plug to get it to go on the balancer 'backwards' for correct hookup and operation.
An illegitimate head of government based on a stolen election.
An illegitimate and corrupt legislation rubber stamped a stolen election and is currently demonizing anyone questioning it.
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Offline dochubert

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Re: Changing from SLA to LifePo4 batteries
« Reply #16 on: March 20, 2021, 08:32:08 pm »

It's been 3 days since I added the 16s active balancer.  Hard to tell if things are improving.  Lights come on indicating it is balancing. Lights are out most of the time.  Since the 48v sets don't go much above 54v, they may or may not be doing me any good.  More time needed.

On another note, I put in my order for 8 more of the byd 24v modules.  This time from Battery Clearing house.  These will add to my 48v bank, doubling the size.  Its probably big enough already so this addition should be overkill.  I'm aiming to have enough capacity to handle the short days/long nights of Idaho winters better.

My original modules are the plain type.  The ones on the way are the type with heatsinks and fans attached.  My plain modules don't even get warm (so far) so heatsinks and fans seem superfluous.  Wondering if I can remove them to simplify things and save weight and space?  Besides, I already have a use for the heatsinks....

Anyway, planning to add larger gauge wire for balancing and paralleling the additional 8 modules, ending up with one 16s4p setup that will have one 5a balancer and will then be paralleled to the existing bank.  If the balancing works better that way will probably eventually reconfigure the original 8 the same way (the current setup is 4 sets of 16s1p paralled together, each of the 4 sets balanced separately). 

Then there is the question of the method for balancing.  In discussion with Sid on the Genetry forum, I'm coming to realize the limitations and possibly design flaws of active balancers.  He makes a convincing argument of the possibility of damage caused by some types.  He has designed a shunt balancer system that bleeds off excess cell voltage as heat.  Wasting power but safer for the system.  So if he makes it available soon might try one.

Keeping these modules balanced as much as possible seems to be the key to them lasting a long time.  I knew nothing about lithium when I started, have learned a great deal in a short time, and still know very little.  Working on it, though....
An illegitimate head of government based on a stolen election.
An illegitimate and corrupt legislation rubber stamped a stolen election and is currently demonizing anyone questioning it.
A corrupt court system that refuses to examine mountains of evidence.

USA = Banana Republic

---  dochubert --

Offline dochubert

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Re: Changing from SLA to LifePo4 batteries
« Reply #17 on: April 06, 2021, 03:08:02 pm »
It's been a few days since I attached the 16s 1.2a active balancer on one leg of my 48v bank.  It seems to be an improvement over the bms, but only a slight improvement.  Planning to go ahead with paralleling all the cells and then attaching a 16s 5a active balancer.  The installed original balance wires should handle it ok, especially since the bank doesn't go above 54.4v.  Might gradually increase voltage after some settling-in time.  We'll see.

Also got and installed the 4 remaining 8s 1.2a balancers on my 24v bank byd modules.  Each module now has one balancer, plus one of the cellmeter8 gadgets so I can tell what's going on.  It's been a few days and they seem to be doing ok.  Above 27v they still go somewhat out of balance but probably good enough for my needs.  Still could parallel all of the cells on these but not right away.

My shipment of 8 additional byd modules is scheduled to arrive today.  Waiting (mostly) patiently.
An illegitimate head of government based on a stolen election.
An illegitimate and corrupt legislation rubber stamped a stolen election and is currently demonizing anyone questioning it.
A corrupt court system that refuses to examine mountains of evidence.

USA = Banana Republic

---  dochubert --

Offline dochubert

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Re: Changing from SLA to LifePo4 batteries
« Reply #18 on: April 06, 2021, 08:33:37 pm »
Here's a pic of my 24v bank with active balancer and cellmeter on each module;

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The next two are front and back of the 5a balancer to be installed on the 48v bank;

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An illegitimate head of government based on a stolen election.
An illegitimate and corrupt legislation rubber stamped a stolen election and is currently demonizing anyone questioning it.
A corrupt court system that refuses to examine mountains of evidence.

USA = Banana Republic

---  dochubert --

Offline dochubert

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Re: Changing from SLA to LifePo4 batteries
« Reply #19 on: April 08, 2021, 08:36:56 pm »

The 8 additional byd 24v modules finally arrived.  I have already started removing the heatsinks on one.

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These heatsinks are massive!  They are 1.5 inches thick, 21 inches long and 12 wide.  They must weigh 10-20 pounds each. 

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Then there is a high speed 24v fan on each module.  They must have really used these modules under heavy loads to need such massive cooling power.  My existing set of modules has not even gotten warm to the touch, and they are the version with no heatsinks/fans.  Hence my removing the heatsinks on these.  I don't expect these to get warm either, especially since I'm adding them to the existing set which already stays cool.

Besides the reduction in weight, removing the heatsinks reduces the overall size of each module to approximately the same size as the original set.  I have limited space where these are going.  My first set of modules just barely fits so I had to make the new ones fit also.
An illegitimate head of government based on a stolen election.
An illegitimate and corrupt legislation rubber stamped a stolen election and is currently demonizing anyone questioning it.
A corrupt court system that refuses to examine mountains of evidence.

USA = Banana Republic

---  dochubert --

Offline Pete

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Re: Changing from SLA to LifePo4 batteries
« Reply #20 on: Yesterday at 02:26:36 am »
Hope they work out for you Doc.
It seems that using lithium batteries is a very complicated process. I hope that they last a long time.
You are on your way to becoming an in house expert on these things
Good luck
Pete