[JCTex]

Forest,

We're moving along. I need to know what impact, if any, my lithium system will have on my cockpit. I remember seeing where you installed a switch in the cockpit to open the circuit from the alternator to the bank when voltage got to X.

I'm installing a secondary 270A alternator/generator on the engine that will be dedicated solely to recharging the bank. I'm going to run the pos/neg wires back to the central battery terminal posts (pos & neg) that receive all the cables that want to connect directly to the batteries. Other contributors to the central lugs will be the Victron 3000 inverter/charger and the Victron MPPT solar controller. Ordinarily, shore power would also be connected; but I'm running all my AC input through the inverter and its automatic transfer switch.

Between the central terminal posts and the batteries, I plan to install a catastrophe fuse (pos side) and an inverter shunt (neg side). On one side or the other of these, I'll install the Battery Management System box.

I was counting on the BMS regulating all the currents coming into it from various sources. I assumed once the regulator in my dedicated alternator started getting "push back", it'd turn off on its own. I am confused why you felt it necessary to put in a manual cutoff switch. I'm not challenging you; I just must be missing something about the function of the Balqon BMS.

2nd Question: IF I'm able to find Balqon cell space for 1000Ah, what size of main catastrophe fuse coming off the battery bank (or BMS) would you use? I know amp hours doesn't equal to amps; so, given that size of bank what's the most amount of amps you'd think would ever come out of the bank/BMS? FWIW, the most I can see ever going UPSTREAM through the cat fuse would be 270A (less actually) from the alternator, 120A from the Victron charger, and ~45A from the MPPT controller.

JC

[folivier]

I didn't put a switch in the cockpit. My system came with an enclosure with the BMS mounted which included a switch, alarm, and a reset button. I just removed everything and mounted it near the battery. The switch disconnects the battery by using a contactor on the positive cable. My system has only 1 set of cables for charging or pulling power. The multiple terminals on the cells would allow a separate charging input and inverter draw. Since I'm using my existing inverter which also charges through the same cables I only have 1 contactor. If you design your system from scratch you can use a contactor on each set of cables to either shut down the inverter on low voltage or shut off your charger on high voltage. My system is not as adaptable but still works well. My BMS is the Housepower system not Balqon. They just supplied it with my cells. My BMS doesn't control the charging, it just monitors each cell voltage and shuts off the battery system on either low or high voltage. I'm not sure how each charging source would work together. The trick would be to get each source outputting its maximum without exceeding the high voltage set point on the BMS. It took me quite a lot of work to get my inverter to charge without exceeding this point which is 14.2 on the Housepower BMS.
My alternator regulator is set up to float at 13.2 v which should basically turn it off. But I haven't had the coach on the road yet since installing the regulator so may have to adjust it if this doesn't work. My wife doesn't know it yet but she'll be spending a lot of time watching the battery monitor over the microwave
The Balmar does have the capability to do what you want but I'm not planning to use that capability. I'd suggest to read up on the www.cruisersforum.com and search for user Maine Sail. He is one of those who has done a lot of research on the Balmar.
I'm not sure how to hook up a solar system in conjunction with the other charging sources. Again some of the guys on www.cruisersforum.com are doing this.
For the catastrophe fuse I'm using the same one that was installed in the coach for the agms. I believe it is a 400amp. Your system if all charging sources are outputting maximum would still be less than 0.5C so shouldn't be a problem for the cells.
But please remember I am not an expert at these. I'm learning as I go so please don't rely on my suggestions without doing additional research to make sure you understand what you're doing.
Hope this helps.

[JCTex]

Got it all, and I do respect and accept your disclaimer.

It looks like I'm going to be a few more rocks further down the creek than you when it's all done. I'll be using the latest Bad Boy Victron, which Balqon really likes best. And I'll be using Balqon's latest and greatest BMS which is due out in March. They supposedly added a bunch more stuff when it became economically feasible to offer it for the RV & small boat world. Third, they've made more strides in putting max/min controls in the cell packs than when you bought. Their philosophy now is to make each pack able to open and close the circuit if over/under loaded REGARDLESS of which BMS the customer is using or inverter/charger. They feel this will protect their reputation more. Having said that, I hope whatever they put in will not conflict with the BMS. Surely, if I buy their new BMS, it will have been tested with whatever cell packs I buy. We'll see. Thanks.

JC

[folivier]

JC I'd love to see the system as you put it together. What size van? I assume you plan to do quite a bit of boon docking?
One of the guys on the cruisers forum said he can run 1 air conditioner on his LiFePO4 system overnight. That would be awesome to do that!
I wonder how difficult it would be to re-wire my basement air conditioners so that I could run 1 on low either while driving the coach or overnight while boon docking?
Anybody know what size inverter would be needed to run 1?

[JCTex]

It's a matter of Amps. Determine how many amps at any given minute your coach uses at night, probably all phantom AC loads. Be sure to check if any of those have any higher start up amps (res refer). Determine how many start up amps your A/C wants when it kicks off. Add the two and that's your minimum actual inverter output. A 2000W pure sine will probably put out 13.33 Amps (1600 /120). This is the reason I'm buying the expensive 3000W Victron. I don't need 22.5 Amps usually (2700 / 120), but to kick start the window A/C I'm modifying to fit the van, I might if I have the TV DVR or microwave on.

The van was to have been an E350 regular body; but that's all changed now. It looks like my project will be going in a Super C Thor Outlaw. I'll be like you, having to re-fit an existing OEM electrical system. I think I'll be all right. My biggest concern is having now to get into the solenoid/isolator quagmire because the 2-battery Ford 6.7 diesel won't have room for another alternator to dedicate just to the battery bank. I don't think it'll be necessary, anyway, especially if I take out the OE alternator and upgrade to a higher amp one. The coach has a residential refer and alternator big enough to run it already; so, I fully expect to find enough AGM's on board to provide plenty of space for my lithium's. FINAL problem is I can't do this lithium project until at least a year from now. I want to wait until after my mfgr's warranty runs out, first. By summer of 2015, you lithium guys will have worked all the bugs out, anyway.

Having said that, I still may be back with questions and comments. I'm going to tow a Jeep 4-dr Rubicon behind it which I CAN put in a smaller lithium system. Smaller, however, doesn't make it much different. I'll still need to solve all the same problems.

JC

[77newell]

Here are some thoughts from a deranged mind; given the characteristics of lithium batteries and the abilities of modern electronics to monitor and control what they do to have just one set of batteries for both the house and chassis. Knowing the outside temperature should provide enough information to limit discharge to the point that leaves enough charge to start the drive engine which also insures being able to start the generator. It occurs to me that my chassis batteries probably never get discharged more than 5-8% except in cold weather and its capacity is largely wasted.

Also, the Roadtrek eTrek eliminates the separate generator and uses the main engine to drive an enlarged alternator that through an inverter supplies the necessary 120v juice. Maybe some version of this would work for some us depending on how we use our coaches. If we aren't using our generators alot then this setup would not be hard on the drive engine and would overall be more efficient.

[folivier]

Good points Jon. I hadn't considered eliminating the start batteries and using the LiFePO4s for both. The BMS system shuts down the battery when it reaches a certain voltage and there is a bypass to turn them on again. So I could probably do that.
Might be something to work on in the future.
Maybe we could do some tests using the LiFePO4s to start the engine at the rally?

[Richard]

Another way to protect against stranding if you use one bank for house and chassis is to put an independent battery on the generator

[arcticdude]

Does your 6.7 have the dual alternator option? I have it on my 7.3 and my 6.7. Iirc, it's capable of pushing 350 amps. That should be enough to handle the needs.

[acousticart]

I have been looking at Balqon's web store for a few months now, and all I can see is the 1000AH cells for $1000 apiece with no mention of connectors or BMS being included. May I ask, how did you purchase yours? Is there somebody specific to ask for that is in the know? I don't want to be rude, so since this is my first post and by way of introduction;

Greetings all! I want to say that although we don't have a Newell coach, I have walked through a few and admired their build quality at Motorhomes of Texas
I have searched off and on for a long time and this is only the second hands-on do it yourself install of this technology I have come across (the first being Technomadia) I have a keen interest in increasing our usable off grid power and have joined this forum in search of more first hand information on the topic of Lithium Iron Phosphate battery installs.
We have a 36' 99' Foretravel (tiny by Newell standards, to be sure, but it does get us into state parks and the like where space is limited). I have upgraded (or am in the process of upgrading) various systems in our coach with an eye to off grid camping as well as all round improved functionality wherever possible. I am installing 832 watts of flexible peel and stick panels, a Midnight Solar Classic charge controller, a Magnum MSH3012M inverter/125amp Charger, and various supporting components before I change out the batteries (2 MK 8D Gels). I want to get all the systems working together and learn how to tweak everything before inserting these expensive 1000AH cells into the matrix.

I don't mean to be a forum crasher, but my perusal of this forum shows it to be as welcoming of other brand or even types of RV enthusiasts as any that I have seen. After all, we face many common problems and solutions no matter the make or genre of our chosen conveyance...
Don Fera