My Interstate Lithium Battery Adventures

[amirm]

Originally Posted by LB_3

That may mean it's possible to use one of the SBMS output pins to turn the charger on and off so the 100A charging limit of the SBMS would not be a constraint.

Well, that was my thought and assumption until I checked with Dacian. SBMS has to be in control of all charge input. That is what the two PV inputs are. Using an external charger means it has no means of determining what power is going into the batteries or state of charging.

This is why I am looking elsewhere as what you mention is standard feature of BMS systems.

SBMS is really designed around his application of solar as the main source of energy. In our case we have three different ways of getting charge into the batteries and it just isn't designed for this purpose.

[LB_3]

I hope that doesn't end up being the SBMS's downfall for me. I've grown quite attached to that little yellow box. It would only take a software update to allow negative shunt voltages to be counted as charging current but Dacian isn't exactly trying to expand his market base and his users haven't yet shown the profeciency to tackle a task like that. Of course I'm not sure there is any device on the market that does everything. Maybe I need to study up an the Victron Energy stuff AM solar was selling. It did have a nice big control panel.

So to track my current list of software updates I would like to see:

1.) Ability to support external chargers.
2.) Another monitor view with giant state of charge numbers to make the device easier to read from a distance.
3.) A blinking IO pin to use with an external watchdog timer to turn off the SBMS in case of a software or firmware lockup.

[amirm]

Thanks for the write-up on the Xantrex LB_3. I went ahead and ordered mine. I was hoping to find something a bit smaller but after spending days looking, could not find one that a) didn't have a charger b) was any smaller and c) had a control input. With peak currents well over 200 amps, it was hard to find a way to shut them down without modification.

I am a bit hesitant of Xantrex quality these days. They used to be a top quality brand but got purchased and I see a lot of complaints about their service and support. Like you, I will do some bench testing and really "soak it" to make sure it is reliable before spending a ton of energy mounting it.

[amirm]

Originally Posted by LB_3

So to track my current list of software updates I would like to see:

1.) Ability to support external chargers.
2.) Another monitor view with giant state of charge numbers to make the device easier to read from a distance.
3.) A blinking IO pin to use with an external watchdog timer to turn off the SBMS in case of a software or firmware lockup.

Good list. To that, I would add independent power input so that if you fuse the main battery connection, it doesn't blow up the unit. I don't know why he has combined the two functions when they can be isolated so easily.

It would also need to have remote control/monitoring. Wifi is cool but without ability to make changes, it is not very useful. Again, this works in his situation of powering an off-grid cabin where the device would be visible. In ours, something with thick welding batteries is not one that you could put at eye level and such. I want to keep may cables short and that doesn't allow that.

[LB_3]

I'm pretty sure I want 12 100AH GBS battery cells but I'm a bit frustrated at the retail markup. I understand there is a similar markup on items like the inverters and other components however I don't always get to know what the price is to the retailers like with the GBS batteries.

I figure I could save $400 or more by importing them myself but then I have to learn how to get them through customs. That knowledge could be useful in other endeavors even if it isn't a very good use of my time. Like any good government bureaucracythey have A 200+ page guide for what probably accounts for filling out 3 forms and paying a $25 fee.

https://www.cbp.gov/sites/default/fi...0the%20U.S.pdf

[LB_3]

I wouldn't say I did any significant testing on the inverter. I just plugged in a soldering iron to do functional check to make sure I didn't need to immediately return the device. Before I install any system I plan to perform a complete system test with at lease one complete discharge cycle.

[amirm]

Originally Posted by LB_3

I wouldn't say I did any significant testing on the inverter. I just plugged in a soldering iron to do functional check to make sure I didn't need to immediately return the device. Before I install any system I plan to perform a complete system test with at lease one complete discharge cycle.

No worries. If something goes wrong with mine, I will just send it to you to handle the warranty.

[amirm]

Originally Posted by LB_3

I'm pretty sure I want 12 100AH GBS battery cells but I'm a bit frustrated at the retail markup.

What is the pricing you are seeing?

I am getting my 12 cells from a company I have done business with. They have some slightly used cells which I am buying at a good discount. Send me a PM if you are interested in the same deal and I can provide the contact detail.

[LB_3]

Best I can find domestically is ~$165 per cell shipped. Importing directly will take 2 months or more and can be done for about $130 per cell including shipping but comes with a customs headache.

[LB_3]

Originally Posted by amirm

Thanks for the write-up on the Xantrex LB_3. I went ahead and ordered mine. I was hoping to find something a bit smaller but after spending days looking, could not find one that a) didn't have a charger b) was any smaller and c) had a control input. With peak currents well over 200 amps, it was hard to find a way to shut them down without modification.

Are you now looking for a seperate 120v charger or are you going to be happy with just charging from the alternator?

The Victron Energy system looks capable but it's a mostly closed system designed to only play nice with other Victron components. It may be adaptable but it requires a series of components instead of a single box to monitor the battery, balance cells, and control charging and discharging. Need to do more research but I'm swamped at work this week.

[amirm]

Originally Posted by LB_3

Are you now looking for a seperate 120v charger or are you going to be happy with just charging from the alternator?

No, I like to have both. Not sure where the heck I am going to install the unit but I will need to get it there .

I think I will go ahead and order the LiPo charger I linked to earlier. It doesn't have a control to turn it on/off. My plan is to put in the solid state relay both on the DC output and AC input as redundancy. I will post the details once I get it working.

The Victron Energy system looks capable but it's a mostly closed system designed to only play nice with other Victron components. It may be adaptable but it requires a series of components instead of a single box to monitor the battery, balance cells, and control charging and discharging. Need to do more research but I'm swamped at work this week.

Yeh, I have been to their site a few times and seeing the same thing you mention.

[amirm]

As I continue my intense research and buying spree , on this project, landed on a very useful write up: http://www.pbase.com/mainecruising/lifepo4_on_boats

I don't agree with everything he says and the author is yet another self-taught person, it does highlight everything one needs to know. And an interesting strategy of slightly under-charging the cells to make them more reliable and not reliant on BMS to shut the charger off. I would not duplicate everything he is saying but it is mandatory read regardless.

[amirm]

LB_3, question for you. These cells naturally swell from charging and as such, require restraint in their broad dimensions. Do you have any ideas of the easiest way to build such an enclosure for them? There is a nice one in the link above on the third page with blue aluminum and threaded rods. Not being a machinist, would love to know of a lightweight mechanism to hold the cells tight together and stop them from expanding.

In other places I have seen metal shipping straps used.

[amirm]

Here is another excellent reference showing the charging performance of the Sprinter alternator. It seems very excellent as is: http://www.sprinter-rv.com/wp-conten...nformation.pdf

[InterBlog]

I am partly to blame for this thread going temporarily dark. My husband LB_3 and I experienced a big change in future travel plans, which caused our project schedule to shuffle. Lithium moved down the priority list and another major undertaking skyrocketed to the top. We are a few days away from finishing that one at which time normality will resume.

I'm trying not to get excited about it - don't ever count your chickens before they are hatched. A project is never a success until it is successfully delivered in full. If this one executes successfully, it'll be another game-changer for us.

[Boxster1971]

Originally Posted by amirm

As I continue my intense research and buying spree , on this project, landed on a very useful write up: http://www.pbase.com/mainecruising/lifepo4_on_boats

I don't agree with everything he says and the author is yet another self-taught person, it does highlight everything one needs to know. And an interesting strategy of slightly under-charging the cells to make them more reliable and not reliant on BMS to shut the charger off. I would not duplicate everything he is saying but it is mandatory read regardless.

The author is more than self taught. He is a certified master marine electrician. He is a legend in the cruiser sail boat community and posts on the Cruisers Sailing Forum under the handle "Maine Sail".


- - Mike
2013 Interstate Lounge EXT on 2012 Sprinter

[amirm]

Originally Posted by Boxster1971

The author is more than self taught. He is a certified master marine electrician. He is a legend in the cruiser sail boat community and posts on the Cruisers Sailing Forum under the handle "Maine Sail".

My comment was specific to knowledge of Lithium battery systems. There, what he knows is self-taught. He has not gained that knowledge from working in the industry, nor does he have lots of experience with actual systems. He has his own and a few others that he has installed. He mentions the same in the preamble of the link I provided:

"It is the sharing of my learning, experimentation & Installation/implementation of LiFePO4 batteries on boats. I DO NOT consider myself an expert on the subject of LiFePO4. If even the Chinese manufacturers don't fully understand this technology, inside and out, how can I? If there is no solid data on fractional C use then how am I to be an expert on it? Again this article is the sharing of some of what I have learned about LFP..."

So while some of his comments on alternators, fusing, etc. draws on his professional knowledge, the rest is from reading what he has learned and the few installs. I call that self-taught and not definitive on the topic. Of course others can choose otherwise.

[Boxster1971]

I see your point. When it comes to subject of lithium batteries we are all self taught - including most of the manufacturers. 😀


- - Mike
2013 Interstate Lounge EXT on 2012 Sprinter

[LB_3]

Originally Posted by amirm

LB_3, question for you. These cells naturally swell from charging and as such, require restraint in their broad dimensions. Do you have any ideas of the easiest way to build such an enclosure for them? There is a nice one in the link above on the third page with blue aluminum and threaded rods. Not being a machinist, would love to know of a lightweight mechanism to hold the cells tight together and stop them from expanding.

In other places I have seen metal shipping straps used.

My understanding is that swelling occurs when charging at 2C or higher (or was it discharging). Some manufacturer warranties require you to have the cells restrained which is one reason I'm interested in GBS batteries. They come with aluminum compression plates and straps:

I haven't seen these plates or straps sold separately. Anyway, I've been swamped at work recently and I'm working the night shift for another week so I haven't been able to get back to this thread. That and trying not to set myself on fire, but I'll let IB unveil the next project after the fourth.

[lewster]

Viltron's lithiums don't require banding or cell restraints as do all of the modular cells that are being sold. They even look like a real battery.

http://www.amsolarrv.com/lbats/94v-200