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Topic: Lithium Upgrade (Read 1289 times) previous topic - next topic

Lithium Upgrade

Our house and coach batteries went completely dead after what Foretravel traced to a failure of the Trimark module that is supposed to flash the side marker lights when the key fob is used to lock the coach. The batteries have now been dead for 3 weeks. The service technicians at the storage facility tried to jump and charge up the batteries with a trailer-mounted generator, and a roadside technician with 27 years experience starting big rigs spent 1 1/2 hours trying to start the coach, All attempts to start the coach attempts unsuccessful. Temps have been as low as 20 degrees F at night.

Yesterday, I decided to replace both chassis batteries, and to replace my 6 8D Fullriver DC210 Ah house batteries with 3 BattleBorn 270 Ah lithium batteries. We were intending on converting to lithium but just not now. BattleBorn has recommended installing a Li-BIM 225 module to protect the alternator while charging the batteries with the alternator. A good friend who has installed his own lithium/solar is concerned that the BIM is not sufficient to protect the alternator from damage. He recommends a DC - DC charger instead. The alternator on my Cummins 600hp diesel is a Leece Neville 270 amp alternator. I also have two VFX2812 Outback Power Systems 2800 watt inverters, and two Foretravel installed 240 watt solar panels on the roof. BattleBorn says the VFX2812 is programmable to properly handle charging the lithium batteries. I have been looking and researching solar and lithium for some time but probably know enough to be dangerous.

Should I be concerned about about BattleBorn's recommendation for the Li-BIM 225? The Foretravel technician said they do not deal with lithium and could make no recommendations for a lithium setup. Any other advice is greatly appreciated.

Re: Lithium Upgrade

Reply #1 –
I can't speak to whether or not BB's recommendation is unsafe (a quick google search seems to indicate there's some validity to the concern) but a couple of DC2DC chargers are cheap insurance given how much you have wrapped up in your coach and batteries. I am running two Victron Orion DC2DC chargers between my alternator and lithium batteries. They're a relatively easy install and produce enough charge to [mostly] keep up with my front AC unit while driving.

Re: Lithium Upgrade

Reply #2 –
Sorry, but I do not believe that your Tri-mark (The tri-mark is used to start the coach engine on coaches that have push button start and to be able to lock and unlock the door and compartments from the keyfob and/or the door handle pushbuttons) took out both your coach and house batteries, unless there is more to this story.  Was the coach not plugged in for 3 weeks?

I have been also considering battery upgrades when my batteries give up the ghost.  I can run my 2nd AC unit off the inverter going down the highway when I do not need to run more then just 1 AC unit. (If I need to run 2 or more I start the generator) My concern was going to the DC2DC chargers was that they do not carry enough amps to handle the AC running.  My  alternator I believe  320 amps 

In reading how the Li-BIM 225 works I think it would work on saving your alternator and let it cool down instead of going the DC2DC route.  For me I am still up in the air since at least the DC2DC would be putting power to the batteries all the time where the Li-BIM 225 stops and starts charging while the AC unit would be discharging all the time.

From my reading the Outbacks will work but may have to change some charging setting.

Re: Lithium Upgrade

Reply #3 –
The big difference between the BB Li-BIM 225 module and a B2B charger is that the BB device is full on for some time and then off for a while and the it repeats.  BB suggests that maximim cycle counts occur when charge rates are 20% of capacity or less.  20% of your 3 - 270 amp hr batteries is 162 amps.  Your LN 270 amp alternator while driving may exceed that going to the BB batteries in full on pulses.

A B2B charger will take power from the alternator and charge the LiFePO4 batteries using a smart 4 stage charge profile the same way your inverter charger and your solar charger will do.  If you use the Victron 30 amp Orion chargers you can wire them up in parallel to get 60 or 90 amp charging. 

I have a Sterling 60 amp B2B charger, it works the same way. I believe those can be wired in parallel too for 120 amps.

We also have 1200 watts of solar on the roof.  They charge both house and start batteries as well all the time.

The way it works for us is that the B2B charger is OFF most of the time.  Solar is sufficient to charge the batteries to 100% and keep them there while driving. I am experimenting running an AC from the inverter too. Solar and the B2B charger ON should put 60-100 amps into the batteries while driving on a sunny day, enough to run an AC from the inverter and use little if any battery capacity.

I would choose the B2B solution, I think it is better for the batteries in the long run. Consider adding more solar, maybe up to 1600 watts. And make sure your start batteries are getting some charge from somewhere.

Roger

Re: Lithium Upgrade

Reply #4 –
Sorry you have an expensive problem.

Can't answer your lithium questions but would first ask why, if plugged in why charger did not prevent battery damage. And if not plugged, in why generator autostart did not prevent battery damage.

And if using inside storage without hookup, then both battery banks need a high amp cutoff to protect batteries. Outside storage with solar may not be enough if a drain is serious, but solar could help.

Primary problem is not likely a Trimark issue, as many things can put unexpected drains on batteries. If not addressed, your new batteries could also be at risk...

Also, both battery banks should be isolated from each other, so you have other problems, also not being found.

Simplest protective protection is to disconnect batteries every time it is stored for many days, also reducing chance of fire. That is what we do...

Re: Lithium Upgrade

Reply #5 –
Quote from: Roger & Susan in Home2 –
...I am experimenting running an AC from the inverter too. Solar and the B2B charger ON should put 60-100 amps into the batteries while driving on a sunny day, enough to run an AC from the inverter and use little if any battery capacity....

Roger,
In my testing, to run 1 a/c on inverter pulled approx 150 amps. This was the original a/c on our '91 U300. Maybe your newer a/c units are more efficient. You can easily verify with a DC clamp amp meter.

Re: Lithium Upgrade

Reply #6 –
Quote from: prfleming –
In my testing, to run 1 a/c on inverter pulled approx 150 amps.
This is accurate for most 15k BTU units.

You're not going to break even with 60 amps coming off the DC to DC chargers but a big enough battery bank in conjunction with solar panels will allow you to last for a very long time. I do it regularly.

Roof AC while driving, no generator.

Re: Lithium Upgrade

Reply #7 –
Quote from: turbojack –
Sorry, but I do not believe that your Tri-mark (The tri-mark is used to start the coach engine on coaches that have push button start and to be able to lock and unlock the door and compartments from the keyfob and/or the door handle pushbuttons) took out both your coach and house batteries, unless there is more to this story.  Was the coach not plugged in for 3 weeks?

 My 2018 Foretravel does not have push button start. However, the fob when used to lock the coach is supposed to cause the marker lights to flash before going off. The marker lights stayed on. The coach was not plugged in at the storage lot due to no hookups. Foretravel said that both house and chassis batteries are linked to some extent even when the battery disconnect is on. At this point I do not know who is correct. All I know is that this is the first time I have found the coach and house batteries dead or low since having the coach in storage mostly since July. The two solar panels appeared to do a good job of keeping the batteries charges up. However, at this time of year we have had lots of clouds and the sun is low on the horizon.

Re: Lithium Upgrade

Reply #8 –
Well maybe it is as much as 15 amps AC loads when starting but with soft start modules the short term starting loads are  less (according to the soft start folks) and the running loads are usually less than the staring loads.

"Micro-air EasyStart can deliver 65-75% start current reduction"

So it might be more that the 60 amps plus whatever I get from solar to run an AC without using much battery resource.  I could go as much as 120 amps from B2B chargers but that plus solar exceeds the 20% of capacity limits for max battery cycle life.

Where is the balance? Max loads on your inverter and charging system to run an AC vs using the generator vs reduced inverter life and battery life?

I am still going to give it a try for occasional short time use. 

Re: Lithium Upgrade

Reply #9 –
I currently have 400 Ah of Battle Born lithium installed, and I am adding another 300 Ah. I went with the Li-BIM 225 as that is what Battle Born recommends for larger battery banks. As I understand their recommendation, a B2B charger will not provide enough current for a large battery bank. Battle Born's recommended charge rate is 50 amps for each 100 Ah of battery capacity. In your case, you are installing 810 Ah of batteries. Even if you were to deliver the full 270 amps from your alternator, you would not be in danger of charging the batteries at too high of a rate. As far as protecting the alternator, that is why the BIM cycles on and off. As long as your alternator is not already weak, you should not have a problem. I would go with the recommendation of the battery manufacturer, as they are the experts on their products. They sell both the Li-BIM 225 and B2B chargers, and the latter are more expensive items, so I see no reason they would want to steer you toward the BIM if it were not the preferred option.

Also, if you go with the BIM, you should remove the current battery isolator. That is not clear from the Battle Born web site, but I was advised to do so by their tech support.

Re: Lithium Upgrade

Reply #10 –
The maximum amp  capacity of the Li-BIM 225 is 225 amps.

Charging 50% of capacity is a maximum charge rate recommended by Battle Born. Any more than that can decrease battery life.  Charging at this rate will get you the minimum number of expected battery cycles

Charging at 20% of capacity is the recommended charge rate to maximize the number of charge cycles or battery life.  About 50% more battery life. There is no practical reason to exceed this rate under almost any condition. 

Either way will work.  If you have solar panels as we do, we don't charge from the alternator while we drive except in rare circumstances.  If we stayed overnight at a Walmart and the next day is rain all day, the B2B charger is enabled. If it is going to be sunny then the B2B charger is off and we will be at 100% when we get where we are going anyway.

Re: Lithium Upgrade

Reply #11 –
Quote from: Roger & Susan in Home2 –

Charging 50% of capacity is a maximum charge rate recommended by Battle Born. Any more than that can decrease battery life.  Charging at this rate will get you the minimum number of expected battery cycles


The Battle Born web site states that "our batteries have a recommended 50 amp charge rate per battery." The 50 amp rate appears to be referring to their most common, 100 Ah battery. I cannot find any place on the web site that states that is the maximum charge rate and a lower rate is recommended. Am I missing something on their site?

Re: Lithium Upgrade

Reply #12 –
If you go watch the interview Will Prowse did with the CEO of BB you will learn much more about all lithium batteries (not just BB).  https://www.youtube.com/watch?v=ywn-vBjKblI

BB says their batteries have a cycle life of about 3500 cycles.  They also say that cycle counts over 5000 are possible when charge rates are in the 20% range.  Less heat, less stress on the cells, longer life. In actual use 20% is sufficient in almost every day to day situation.  Our 600 amp hr BB batteries and the start batteries are charged primarily by solar even in January.  If it is really cloudy or rainy I will turn on my 40 amp smart Sterling charger to help. We get to 100% SOC almost every day.

BB batteries can operate in any SOC range.  Don't let them completely discharge or store them at low SOC.  BB recommends recharge to 100% when it is possible.  Lots of things happen at 100% that don't happen at lower SOC like cell balancing, another key thing to maximizing cycle counts.

The BB web site pages (like most web sites) are just a start.  Keep doing your research.  You have a lot of bucks tied up in batteries. Make sure you know how to use them in the best way possible for your circumstances.