Classic with Lithium Ion?

[StrataNetNZ]

Hi all,
We're looking to buy a classic charge controller to replace a Chinese one that we bought which is not sufficient for our requirements. My main concern is that we are running Lithium-Ion batteries as opposed to SLA. Would the classic work with these type of batteries?

Thanks,
Richard.

[boB]

Yes, you bet !

This is possible because most Li ion batteries come with a BMS as standard.  (Battery Management System)

The BMS is absolutely necessary for any serious Lithium ion battery system.

I think this has been covered in another thread so you may want to search for this topic.

boB

[StrataNetNZ]

Thanks very much!

I tried searching but couldn't find anything! Your help is very appreciated.

Cheers,
Richard.

[boB]

OK, maybe it was discussed on another forum ?

Basically, the BMS is required because if the Lithium batteries get unbalanced, different
voltage between cells, etc,  individual cells can get very hot and lithium is hard to
put out if they catch on fire.  (just ask Boeing !)

So, that is why they typically have this BMS.  I will try to remember the few companies that
do well with Li Ion types of batteries.  There was one in Australia than come in a lunch
box looking container....  Another one in the US we talked with that looks like a regular
battery, etc.

Sometimes all that is necessary is to adjust the Classic (or any charge controller) to
stop charging when the battery voltage gets to a certain point and then just stop.
Sometimes they need to tell the charge controller to stop themselves.  This is why
the Aux 2 function can be set to turn off when its signal goes high.  Don't know
the battery company's name on that one either.  Somebody here asked for it
I thought ?  Must have been that other forum !??

boB

[StrataNetNZ]

No problem - thanks again!

Yeah I know about the balanced charging thing and I've (intentionally!) blown up a few small ones myself!

We already have a bank (I think 4x) of very good Li-Ion batteries. I've seen them briefly but I didn't do the install. I'm sure they'll be fine though!

Thank you.

[philb]

Here's a compairison of Lithium ion BMS's.

http://liionbms.com/php/bms_options.php

[StrataNetNZ]

I just thought I'd follow up and mention...

We trialed a Classic, and couldn't get it to work! It turns out that whoever did the initial install had connected things the wrong way around (we were only upgrading the charge controller from an older Chinese one which didn't work as it was supposed to).

We swapped the Classic for a Studer unit, which is when we discovered the wiring problem. We decided to go ahead with keeping the Studer - while a similar price as the Classic (including the Studer LAN monitoring module) it is a fully sealed unit which is much more preferable for our environment. The unit is housed in a cabinet, however we have had issues with rodents and insects finding their way in (although I think I found where the mice were getting in) so a sealed unit was preferable for us. Yes we know that there are grill covers available for the Classic, but the Studer just seemed to be the best option for us. Also our supplier had never worked with MidNite units before and had no idea about programming them, whereas the Studers he sells a lot of and programmed it for us in his workshop. So for us the local support was much better for Studer also.

Thanks for everyone's help though!

[dgd]

I just thought I'd follow up and mention...

We trialed a Classic, and couldn't get it to work! It turns out that whoever did the initial install had connected things the wrong way around (we were only upgrading the charge controller from an older Chinese one which didn't work as it was supposed to).

You couldn't get it to work because the connections were wrong from previous install? So did you get it to work when the wiring was sorted out ?

We swapped the Classic for a Studer unit, which is when we discovered the wiring problem. We decided to go ahead with keeping the Studer - while a similar price as the Classic (including the Studer LAN monitoring module) it is a fully sealed unit which is much more preferable for our environment.

Interesting. When I looked at the two Studer charge controllers (60A and 80A) and the remote programming/metering unit the overall price was way way above a Classic 150. I always get suspicious of suppliers who will not openly publish prices and Reid Technology in NZ ask for an email enquiry. The overall specs were also not up to the Classic.

The unit is housed in a cabinet, however we have had issues with rodents and insects finding their way in (although I think I found where the mice were getting in) so a sealed unit was preferable for us. Yes we know that there are grill covers available for the Classic, but the Studer just seemed to be the best option for us.

I thought the Classic was both largely rodent and insect proof if unused knocked out knockouts are covered with the supplied grill vents.
And using proper cable glands where cables enter/exit preferably in some conduit will deny those openings to rodents/insects.
And for more serious infestations you can't beat a cat/rodent bait/insect traps etc
Although with opossum infestation her in NZ cables to PV arrays etc need to be in conduit and sometimes unchewable (metal) covers over PV junction boxes etc..

Also our supplier had never worked with MidNite units before and had no idea about programming them, whereas the Studers he sells a lot of and programmed it for us in his workshop. So for us the local support was much better for Studer also.

Well I suppose if you are locked into one supplier then you have little choice but to go with their product recommendations.  Although the instructions and support for the Midnite Classic is excellent. Any reasonably  competent technican would have no problems with the Classic.

dgd

[StrataNetNZ]

Hi, I think it's easier for me to answer your questions with bullet points:

• Yes, unfortunately the wiring was a bit messed up on this one! We had already returned the Classic and swapped it for the Studer, and were more than happy with the Studer so we decided to stick with it. Also as an electronic engineer (solar normally isn't quite my thing!) I liked the Studer more as it uses proper toroids as opposed to solid state, as the Classic appears to be.
• For us the pricing was fairly similar, in fact I think the Studer was a touch cheaper. The only thing I'm not a fan of with the Studer is the web interface, however an upgrade was released last week and next time we're up at the site we're going to upgrade our unit. I'm expecting that this will make the web interface a lot more user friendly.
• Yes that's true, but it was just a hassle trying to get the grill covers etc, and our supplier was pushing us towards the Studer anyway. Haha and a cat is not an option for us as it's a site in the middle of a paddock about an hour from our office! As for rodent baits etc, while this isn't a bad idea, before a couple of months ago nobody had been to the site in about 3 years. Fortunately possums haven't been a pest for us (yet)!
• We're not hard and fast locked into one supplier, but that supplier has been very good all around - excellent advice and also lets us borrow new controllers when we need them, as well as crimpers etc.

Thanks for your input - always good to hear from a fellow NZer!

[cpm]

I'm aware of LiFePo4, LiCoO2, LiNiMnCoO2, LiCoO2, LiNiCoAlO2 and a few other lithium battery chemistries,
All of which use different charging profiles.

I'm really unclear on what a Li ion battery is exactly.

[boB]

I'm aware of LiFePo4, LiCoO2, LiNiMnCoO2, LiCoO2, LiNiCoAlO2 and a few other lithium battery chemistries,
All of which use different charging profiles.

I'm really unclear on what a Li ion battery is exactly.

Each battery will have its own specifications for charging of course so you would adjust the controller
to suit that spec.

Also, each Lithium battery should be contained in its own system with its own BMS (management) so
you should  not have to worry too much about overcharging usually. Just do what they say to do
and if necessary, the Classic can take an input on Aux 2 (up to 15 volts) to tell it to stop and start
charging if the Li ion batteries' BMS requires that.

boB

[cpm]

I'm aware of LiFePo4, LiCoO2, LiNiMnCoO2, LiCoO2, LiNiCoAlO2 and a few other lithium battery chemistries,
All of which use different charging profiles.

I'm really unclear on what a Li ion battery is exactly.

Each battery will have its own specifications for charging of course so you would adjust the controller
to suit that spec.

Also, each Lithium battery should be contained in its own system with its own BMS (management) so
you should  not have to worry too much about overcharging usually. Just do what they say to do
and if necessary, the Classic can take an input on Aux 2 (up to 15 volts) to tell it to stop and start
charging if the Li ion batteries' BMS requires that.

boB

I'm not trying to be dense, I just can't help it.

But, a battery is a battery, and a lot of battery *packs* using cells of these technologies/chemistries will have a bms, sure.
But, , , again, what the heck is a lithium ion battery? There are *plenty* of things out there called lithium ion, that *don't* have BMS.
In the EV world especially, (where you find very interesting pricing).

For instance, 700ah balqon LiFePO4 cells go 'ding' at the cash register at a flat $700 + shipping, need 8 of'em for a solid 24v bank, that's (in round numbers) $3600 for a 17kwh 24v battery bank. Not too shabby given the duty cycle of these things, even at way deep  (80% DoD) cycles.

But, there is No BMS, as you are buying cells, not a battery pack.

[Westbranch]

For instance, 700ah balqon LiFePO4 cells go 'ding' at the cash register at a flat $700 + shipping, need 8 of'em for a solid 24v bank, that's (in round numbers) $3600 for a 17kwh 24v battery bank. Not too shabby given the duty cycle of these things, even at way deep  (80% DoD) cycles.


Did you mean $5600 ? (rather than $3600)

[dgd]

I'm aware of LiFePo4, LiCoO2, LiNiMnCoO2, LiCoO2, LiNiCoAlO2 and a few other lithium battery chemistries,
All of which use different charging profiles.

I'm really unclear on what a Li ion battery is exactly.

There is an excellent explanation on wiki of what Li-ion means and the different Lithium chemistries.
The lower density and safer Lithium Iron Phosphate type seems the most popular in RE systems with cell capacities from about 20Ah to over 1000Ah available.

dgd

[RossW]

The lower density and safer Lithium Iron Phosphate type seems the most popular in RE systems with cell capacities from about 20Ah to over 1000Ah available.

This is the technology I'm about to spring for myself. Initially a "modest" bank of 16 x 300AH cells. I figure that with a 66% DoD, that will give me the same "energy" out as 20% DoD with a 1000AH lead acid, in about 15% of the space.
If it works out as well as I hope it does, I will probably double it in a year (given the poor state of my existing AGMs, it should pay its way fairly quickly in reduced generator run hours)