Lithium charger

[T1 Terry]

I wonder how Bill is getting on with his lithium set up, if you are still reading here can you give us an update please Bill

T1 Terry

[Bill]

Very little forward progress. I lucked onto 2 N70 LA batteries for the 24 v side of my system. I'm waiting on Trev to get fresh stock to repair my lithium line-up. He says no 100 ah cells will be in the next batch of Winston cells delivered.
I need at least 2 x 100 ah cells to allow a parallel string of 12 v lithium to bring up the amp capacity to run my microwave. My existing lithium cells all have high internal resistance to the point that the 1300 w draw sags the voltage to dropout of the inverter. 800 w is do-able but no more.
The microwave is important to reheat coffee. I make the coffee with a 700 w Birko, but never drink it fast enough.
http://aussiemotorhomers.com/forum/show ... p?tid=6490 is a link to the start of the story as to why.

[T1 Terry]

Very little forward progress. I lucked onto 2 N70 LA batteries for the 24 v side of my system. I'm waiting on Trev to get fresh stock to repair my lithium line-up. He says no 100 ah cells will be in the next batch of Winston cells delivered.
I need at least 2 x 100 ah cells to allow a parallel string of 12 v lithium to bring up the amp capacity to run my microwave. My existing lithium cells all have high internal resistance to the point that the 1300 w draw sags the voltage to dropout of the inverter. 800 w is do-able but no more.
The microwave is important to reheat coffee. I make the coffee with a 700 w Birko, but never drink it fast enough.
http://aussiemotorhomers.com/forum/show ... p?tid=6490 is a link to the start of the story as to why.

Which style 100Ah cells do you have? there are 2 different sized 100Ah Winston cells, the WLYP100AHA-A and the -B the A is narrower but thicker, about the same size as the 90Ah in height and width, the B size is wider but thinner and the more common.
What did you do to the existing cells to cause such high internal resistance? Normally a microwave can be run for as small as a 100Ah pack, Peter Mannins did just that for quite some time before he upgraded to a bigger motorhome.
I can't look on the AMH forum cause I'm not a member and was quite unlikely to be accepted as a member for various reasons, but I thought that forum had all but died when the CMCA reopened their forum

T1 Terry

[Bill]

My cells are 62 mm across. Yes, a 100 ah 12 v lithium pack will drive a microwave with a suitable inverter. My cells have been severely mistreated.

I had 8 cells arranged as 12 v 200 ah pack charged by 1 kw of 24 v solar panels. Charge control was with a 70 A relay as an on-off switch controlled by a voltage sensor set to 12.8 v on and 13.8 v off. There was a voltmeter at the controller but no remote voltmeter. On a long sunny day the relay welded closed and thoroughly overcharged all cells. All cells swelled, 1 failed, with no sign of fire. The other cells all squashed back to size with much persuasion, but 2 tested out to 65 ah capacity. All the other cells still yield 100 ah but all cells have raised internal resistance. That fantastic holding voltage under high load is now quite droopy.

My present setup has the solar feeding el-cheapo PWM controllers feeding 24 v LA battery banks x 2. Bank 1 is 6 old N70 arranged 3 x 2 paralled with bank 2 of 2 new N70 LA batteries. These feed a bank of buck converters paralled and diode isolated with the capacity to feed 50 amps into the 12 v lithium pack made up of the 4 best of the surviving cells. These cells then drive all 12 v items and the 1.3 kw inverter. When on the 200 ah pack the microwave was powered quite well. All controlled manually at the moment. The search is on for a suitable control system to switch on and off as required. Parked it is no problem but auto control is needed on the road.

The AMH forum is still very active. Some left when the CMCA reopened but reports from users of the new forum are not encouraging. I joined CMCA just to access the forum, and then they closed it. Nothing I see to entice me back yet.

[dapope]

Would suggest a suck and see for yourself on the CMCA forum. Some of the biggest complainers are found on AMH. Mostly about the software, because its differnt from what they are used to. Like any forum software, it has its faults, but also has its strengths. The reson they use that particular type is that its the only software that would talk to the rest of the CMCA system. 100ah cells are currentlý hard to find in Aus.....

[native pepper]

Bill, when you get your system set up again, you should look at getting a dedicated lifepo4 charge controller and a 4 cell battery equaliser which are now available and called hao2 equalisers. Been down the relay track and I'm not much of an electrical bloke, so try to steer clear of complicated setups. My late mate used these equalisers and know his kids were looking to have them made in china, now they have appeared from china and you can get them for about $100. They will save you so many worries, if you have a proper lifepo4 controller, it should be single stage bulk charge to either 13.8 or 14v then switches off completely, the equalisers start operating when the cells get out of balance slightly and continue moving energy from one cell to another until they are equal. This goes on even after charge is stopped if they are still out of balance, which I've found never happens with my packs.

It's the same with large capacity cells, lose a 100amp cell and you've lost your energy pack, but if you use 50amp x 12v cells, all you lose is 50amps from you pack as you can take out one series line, another reason my mate always stressed running 12v systems through inverters instead of having 24 or 48v.

Same with inverters, for a MH, you would have only 1 or 2 circuits, mostly one but if more, use an inverter on each circuit. That way you can control you usage, have a spare inverter if one packs it in and know your system is safe. On my house we have 3 inverters of different capacity for different usage. Also have my packs in 500amp banks, again for the same reason of safety, control and in case a pack goes down, you still have energy you can use.

[bagmaker]

HAO2 equaliser? $79
https://www.aliexpress.com/store/produc ... 27736.html

[jon_d]

Martin, do you have cmca and amh reversed?

[T1 Terry]

I wonder how 4 units would go over a 48v battery? Actually it would require 5 units so there was an overlap. Bruce has a 48v battery bank we could try them out on, I will look further into that with my China contacts. 12v batteries really remain in balance if condition charged correctly and not over voltage charged, 24v batteries can have their moments and 48v batteries are like herding cats.

Bill, if you charge the cells to 3.6v then disconnect the cells, do they hold better than 3.4v for a couple of days, you may need to repeat the process a few times to get them to hold better than 3.5v, but about 4 times is a fair indication of what can still be used and what has gone to the grave.
The system we make is full auto, 4 levels of protection with the final level being battery disconnect to save it from damage. I've never tried putting damaged cells with new cells, but if the cells hold voltage then I can't see a problem. The new cells will be doing all the heavy work though so just one new cell and one damaged cell might be a bit much where 2 new cells and a damaged cell would probably be ok.

The LYP100AHA-B are 179 x 62 x 218, that does sound like the cells you have. I have some coming but I think they may all be spoken for already. How many do you need?

T1 Terry

[dapope]

Martin, do you have cmca and amh reversed?

I probably worded that badly. Theres a group who use amh to complain about cmca. To be fair they do some complaining on cmca too