Jennie

[T1 Terry]

The real loss was all the heat that they subjected them to. They finely finished them off in storage.

I don't think the heat was an issue as such, here in Australia the house batteries get to see a lot more heat than that each day through late spring to nearly winter. Poor quality cells, not properly knowing what they were doing resulting in a very poor battery management system being employed. There was every chance the cells could have been recovered, again, if they truly knew what they were doing.
Members of our private forum have brought cells back from the dead that a poorly designed BMS system in a number of electric delivery scooters had dragged down to below 1vdc and these cells have continued to perform well for many yrs since. It all comes down to the age old saying, a little knowledge can be very dangerous, in this case, a severe attack to the wallet.
Sometimes it requires a bit of flexibility that you really don't know it all and accept guidance when it's offered ...... well at least keep an open mid and investigate the validity and possibility the guidance could be right

T1 Terry

[grizzzman]

Good to know. Thanks for the correction.

[native pepper]

I've run into a few people who have complained about their lithium batteries losing capacity over just a few years, yet when I've pointed out the things I see as contributing to their demise, they get really uppity and tell me that the installers know more than me because they are qualified installer/suppliers. They seem to completely ignore the fact all my lifepo4 packs are well over ten years old and still have 100% capacity. I mentioned to a person who had a lifepo4/solar system installed that he should get some active cell balancers and change the charge-discharge parameters to more like mine, got laughed at because the supplier knows best and what would I know. After 3 years, he had at least 2 x 200ah cells dead and has to replace most of the between cell BMS/balancers which as Terry says, only drains cells, doesn't move energy from one cell to others.

Many may disagree, but in my opinion, most suppliers and installers don't have a clue and are still in lead acid la la land with their approach and understanding.

[Vik351]

So what have you done here...??? " I mentioned to a person who had a lifepo4/solar system installed that he should get some active cell balancers and change the charge-discharge parameters to more like mine, got laughed at because the supplier knows best and what would I know. After 3 years, he had at least 2 x 200ah cells dead and has to replace most of the between cell BMS/balancers which as Terry says, only drains cells, doesn't move energy from one cell to others."

I gotsta know ...

Have a date with T1 once I can breathe again...

vik...

[Greynomad]

Have a date with T1 once I can breathe again...

vik...

I hope you are both very happy with your relationship.
(No heavy breathing, now!)

[Vik351]

Have a date with T1 once I can breathe again...

vik...

I hope you are both very happy with your relationship.
(No heavy breathing, now!)

Well... If it isn't "Our Clown" chippin in with SFA...

vik...

[native pepper]

So what have you done here...??? " I mentioned to a person who had a lifepo4/solar system installed that he should get some active cell balancers and change the charge-discharge parameters to more like mine, got laughed at because the supplier knows best and what would I know. After 3 years, he had at least 2 x 200ah cells dead and has to replace most of the between cell BMS/balancers which as Terry says, only drains cells, doesn't move energy from one cell to others."

I gotsta know ...

Have a date with T1 once I can breathe again...

vik...

I only use 50ah or less cells, have active cell balancers on my packs, set my charge and discharge cut off parameters at 14v and 12v, charge restart at 13.4v and disconnect at 12v. Have packs no bigger than 500ah, so my house has one pack at 400ah and one at 300ah, it runs on 4200w through 6 x 60amp mppt solar chargers. The packs are separated but drive the same 3/6kw inverter, or can drive a number of inverters depending on the situation. My bus only has 480ah, 2 x 40amp mppt controllers and 1kw solar.

Only my 120ah portable pack has gone below 12v in all their years and that was because the mulitimeter I was using stuffed up and kept telling me the pack was over 12v, as there are no controls or gauges on the pack. Put another multi on it and showed 11.8v. House and bus pack have never gone below 13v, bus pack has the ability to charge from the engine through a 60amp controller, and house has a 500w wind generator which provides enough input when the sun doesn't shine for more than 3hrs a day.

[Vik351]

So what have you done here...??? " I mentioned to a person who had a lifepo4/solar system installed that he should get some active cell balancers and change the charge-discharge parameters to more like mine, got laughed at because the supplier knows best and what would I know. After 3 years, he had at least 2 x 200ah cells dead and has to replace most of the between cell BMS/balancers which as Terry says, only drains cells, doesn't move energy from one cell to others."

I gotsta know ...

Have a date with T1 once I can breathe again...

vik...

I only use 50ah or less cells, have active cell balancers on my packs, set my charge and discharge cut off parameters at 14v and 12v, charge restart at 13.4v and disconnect at 12v. Have packs no bigger than 500ah, so my house has one pack at 400ah and one at 300ah, it runs on 4200w through 6 x 60amp mppt solar chargers. The packs are separated but drive the same 3/6kw inverter, or can drive a number of inverters depending on the situation. My bus only has 480ah, 2 x 40amp mppt controllers and 1kw solar.

Only my 120ah portable pack has gone below 12v in all their years and that was because the mulitimeter I was using stuffed up and kept telling me the pack was over 12v, as there are no controls or gauges on the pack. Put another multi on it and showed 11.8v. House and bus pack have never gone below 13v, bus pack has the ability to charge from the engine through a 60amp controller, and house has a 500w wind generator which provides enough input when the sun doesn't shine for more than 3hrs a day.

MPPT... glowing reports again ...

vik...

[T1 Terry]

Have a date with T1 once I can breathe again...

vik...

I hope you are both very happy with your relationship.
(No heavy breathing, now!)

Well... If it isn't "Our Clown" chippin in with SFA...

vik...

No need to be nasty Vic, a bit of humour goes a long way when stuck at home in lock down.

As far as NP's set up, he uses single 12v batteries to build up his capacity, very different to the method we use, build capacity at cell level and link them in series to build a single 12v, 24v or 48v battery as required.
This means in the 12v battery systems, active balancing is not such a great issue because we only have one battery for a cell to go high voltage, not multiple batteries. This means we have a bigger window of variation possible between the highest and lowest cells before the upper or lower battery terminal voltage compared to cell voltage becomes an issue. ... yeah I read it a few times and that only made sense to me because I know the subject
This is why we use the cell voltage upper and lower voltage alarms as a secondary control rather than the primary control, we leave that to the chargers themselves, and use the recording the same high and low cell 3 days in a row if an over 150mV out of balance cell voltage is seen before recommending any action being taken. Even at that stage it is not a critical "Act now or else" item and correction is easy by simple topping up the lowest cell and the problem goes away.
After all the yrs of experience we know that a high cell voltage today will often not be seen the following day, or even a high cell in the morning will often not still be a high cell in the afternoon. There are a lot of complex things happening within each cell group and only time will allow that to sort itself out, trying to fix something that isn't broken will cause more problems than it cures.
This is why NP restricts his cell size per battery to 50Ah where we can build batteries with 1200Ah per cell and still have the same control system with no requirement for any sort of continuous cell balancing for a 12v battery, they just don't cause that many issues. We have customers return for a system service after more than 3 yrs telling us they have never needed to use the single cell charger, others needing to use the rebalance 7 yrs after the system install and ringing for a refresher course on how to do it because they had forgotten, so now we include that in part of the info pack Margaret gives each customer when they pick up their vehicle.
We do have minimal cell balancing for 24v batteries, because they can be a bit like herding cats, and a more serious cell balancing set up for 48v batteries because they are like herding feral cats on a polished floor using a number of Dingo packs to keep them in a close group, a number of dead ones is sure to be the result
I wasn't actually planning the post to be that long or complex, you can see why Margaret writes the articles on the website

T1 Terry

[T1 Terry]

I only use 50ah or less cells, have active cell balancers on my packs, set my charge and discharge cut off parameters at 14v and 12v, charge restart at 13.4v and disconnect at 12v. Have packs no bigger than 500ah, so my house has one pack at 400ah and one at 300ah, it runs on 4200w through 6 x 60amp mppt solar chargers. The packs are separated but drive the same 3/6kw inverter, or can drive a number of inverters depending on the situation. My bus only has 480ah, 2 x 40amp mppt controllers and 1kw solar.

MPPT... glowing reports again ...

vik...
[/quote]
A lot of variables Vik, the 2kW system on the big bus using s/h rooftop solar panels and a single 250/100 Victron MPPT controller works a treat, yet the 100/50 on Tom & Carmel's van isn't performing as well as the Dingo and SSR's were performing, but that could be because the people who replaced some of the 60w panels with a 160w panel didn't actually understand what they were doing resulting in current reverse flow into the smaller panels and serious arcing across the modules resulting .... but because they had moved all the cabling under the roof skin when the fitted the new roof and decided some of it could be eliminated , increasing the voltage through each set of cables and back to an MPPT controller was the only way we could get the 160w panel off and replace it with 4 x 60w panels and replace the tired 135w panels that were part of the original system with 5 x 60w panels. Even though the system has now been increased to 960w, it isn't out performing the original smaller capacity system. Maybe when we can replace the damaged panels at a later date the harvest will improve, but at least it is now keeping the battery charged and all the systems are working again. Acid leaking from a dead brake away system lead acid battery eating the circuit board on the Victron shunt didn't help, nor did using the wrong cable links, RJ12 cables require RJ12 joiners ... but that's another story
The set up in Erich & Lesley's new rig seems to be working well, so that supports my thinking that the poor result in Tom and Carmel's rig might be due to the panel damage

T1 Terry