[folivier]

Thanks Larry. You should have been there.

[jim butler]

Have installed 32 kwh's of lithium batteries (2,500 ah's X 12 volts) from Balqon along with their bms system. It's in a United Specialties motor home with a Volvo D16 cab. Unfortunately, we've received this from Balqon without any kind of instructions. Now they don't answer calls or emails, now that the products have been delivered. We have Magnum inverts and are currently installing solar panels. I'm seeking info on how to adjust the charging sources parameters, and the bms to end up with the proper results. I look forward to hearing from anyone that can give me info on this.

[folivier]

Jim, I sent you a pm with contact info.

[JCTex]

It took me a while to,find you guys again. I wanted to come to your rally, but my coach wasn't ready for prime time. I'm in it now and want to proceed w Balqon's 9Kwh battery pack (BMS built in). However I read above where even after selling a very large setup, they are still up to their old tricks of being poor with customer service.

I can get Mr. Samra to email me and even phone, once. Haven't tried either in several weeks, though. Therefore, before I actually spend $3,400 for what I believe to be pretty much a plug-and-play with my new Magnum 3012, BMK, and ARC50, and Victron controllers (x2), what exactly am I getting in to?

Are they actually conducting a going concern business, or not? How could they POSSIBLY sell one of these packs with proprietary BMS with no instructions? Help,me understand and, if possible, reassure me.

Jerry Lewis
2008 Country Coach Allure 470 38' tag
McKinney

[folivier]

I think Balqon is the USA distributor for these LiFePO4 cells. But they also will sell to anybody. As such you can get a wholesale price but with very little support. The system I bought from them had a Housepower BMS. Is Balqon producing their own BMS now?
The BMS is basically a board and individual cell sensors that monitor the pack voltage and individual cell voltage. If the voltage exceeds the set point (either high or low) it will shut off the contactor which isolates the pack thus protecting it. A very simple system.
For charging you want to prevent the high voltage from exceeding 14.0vdc. And on discharge you want to prevent the voltage from getting below 12 vdc or so. Again the BMS contactor will isolate the pack if this occurs. Any other control will come from your inverter. On my system (now Richards) the only difficult part was setting the older Freedom inverter to charge it correctly. Again you want to charge at as high an amperage rate as your inverter allows until the amps get down to 10-20 and the voltage starts to rise, shutting off charge at 13.8-14.0 vdc. Float charge voltage is an unknown right now. Some sources say to not float, others say to float at just below the resting voltage which is about 13.3-13.4 vdc.

[Richard]

I thought I would take the time to provide an update on the battery install, since I have had them for about six months or so. I guess the overall take is that no news is good news. They work.

Seriously, my biggest task for a battery bank was to provide power through the night for a winter boondock. As you know the Aquahot is a huge power hog that pulls directly from the DC supply. Add to that the typical inverter loads for an evening, and I was never able to do that with either this coach or the previous coach using a 6 8D size bank.

I can tell you the 1000aH bank powers everything including AH through the evening, will make coffee the next morning, and doesn't seem to care.

I haven't had to do anything since the original setup. I have checked the cell to cell balance and each cell is within 0.004 volts. I did have an incident during winter storage where the coach lost plug in power for an extended time, so the batteries powered the inverter until the battery management system (BMS) automatically disconnected them to prevent them from a complete discharge. So the BMS did it's job to protect the bank from a dangerous discharge.

I am sorry that I don't have a lot of excitement to add to this saga, but as I have read of others installing a LiPo system, this pattern seems to be common. There is a lot of info in the beginning as the user is setting up the charger, BMS, and monitoring system. Then a bit of data on how many amp hours the user gets out of the bank compared to the old lead acids, and then silence. The silence is because they work, and there's not much to report.

So, if you are reading this and wondering if you should go this way when it's time to replace batteries. My opinion, and I stress opinion, is the following. This technology works, and is far superior to lead acid. However, it is not a drop in for lead acid. If you decide to adopt the technology, you will have to modify your existing charger parameters, install a battery protection system to guard against high and low voltage, and you will have to relearn all your years of using a lead acid system. For example, I always judged the level of charge by the voltage. You just don't do that with the LiPo's. You have to learn to count the amp hours you have used. The Link controller for Xantrex, the controllers for Magnum and Outback also allow you to do that. I just didn't know to do it before.

I think the RV user who occasionally boondocks will probably be better off sticking with AGMs. In our coaches they will run you through the night except with AH use in freezing weather. If you don't do that often, then run the gennie on those occasions.

Who will get the best use of this technology? The serious boondocker who wants to run the gennie as little as possible to recharge. The LiPo's will play nicely with solar systems given the correct settings on the charger.

Would I do it again? At this point, a resounding yes. I have enjoyed learning about the whole world of battery management. If the experiences of others apply to my use, I won't be replacing these batteries in five years, so I don't think the long term cost will be as high. My CFO has told me to plan on keeping this coach so I see the upgrade paying off in the long term.

If you take the time to read the unbelievable volume of stuff on the cruisers forum and electric vehicle forums, it can make your head spin. After digesting some the postings, it dawned on me that the debate and use profiles of both those communities is unlike the RV world. One, the sailboat guys want to extract the last bit of power of a battery, and have limited charging capability. So they focus on advanced charging strategies, and push the banks to extremes. Two, the EV guys want to charge and discharge at insane rates in our world. Again, their debates do not apply to our use. The RVer is going to operate the LiPo bank well within the extreme, is not interested in extracting the last 2% of power before recharging. The experience base says that operating the LiPos in the middle 80% of the range prolongs the life. No one knows for how long, because there is little failure data out there.

[travelite]

Hi Richard,

Thanks for the write-up. It's great to hear some real world Li-Ion experience in a motorhome application. I think you nailed it. We motorhome user's by nature discharge our battery banks at fractional C-rates which makes a lot of things easier. Simple things like fuel-gauges work better if we don't have to correct for variable and extreme discharge rates. I like what you're doing with using your batteries in the middle 80% of their range. Given the replacement cost of Li-Ion's,  I'd probably go a step further and treat them much like we treat our AGM's; that is, limit the DOD to even less. Here's a paper that talks about LFP battery degradation when they're used in a more extreme manner:

LiFePO4 Cycling Degradation Battery.pdf Size: 1.38 MB  Downloads: 7

My next battery bank will be Li-Ion, but I have a split 24/12V system which needs to be provided for. My house is separate from the chassis and is composed of a 24V AGM bank, two 24V Trace SW4024 Inverters, and a Vanner Equalizer which converts the 24V to 12V for house use. My house has 120VAC, 24VDC, and 12VDC loads. The 12V loads are circuit breaker protected at 100A. What I need is a good quality 24V to 12V DC to DC Converter rated for over 100A, preferably 150A plus since efficiency can taper off when used at peak capacity. Of course not all loads will be on at the same time, but as you know you can approach a good DC draw with the Aquahot, nightime lighting, fans, and such running. Volta sells a rebranded Sensata converter that I haven't seen the specs for but the price is around $3500.  

Do you actually use your bank in the "middle 80%" range or do you use the top 80%. IOW's, do you stop charging based on the quantity of charge put back into the batteries using your fuel gauge? I also noticed that this type of middle band DOD prolongs life.

[whatsnewell]

Richard, I don't recall if you have, but would you care to share your total costs for the installation of your LiPo system?

[Richard]

Well, first of all I see David has left the Bluebird building. Congrats on your new ride. David, I set the charger to stop at 13.8 pack voltage, which results in a resting pack voltage of about 13.3. So I am not really charging them to the max. And I cut the charger back on closer to 70% discharged than 80%. I am not very worried about it any more. They just don't seem to care.

Clarke,

For a 1000aHr system, you could plan on about 4k for the batteries, and another 500 for BMS and fru fru. If you have to change your charger inverter then another 2000 for that. The battery cost is easy to estimate, the peripheral stuff will depend on the capabilites of your charger, and your solar charger.

[travelite]

Thanks Richard,

That sounds like a very good charging profile and DOD for our motorhome use. You should get many cycles of use, which to me is the important part. Yes, I traversed over to the 'dark' side with my H3 ownership. I've had it for almost a year now. It's a phenomenal bus and the Prevost Car Service is an extra treat. Back in 2004 when I bought my Wanderlodge the factory was in full swing and it was great taking the bus there for service. I really wanted to have that factory service ability again. My bus is built on an '03 chassis so it's a non-EGR S60. It was late enough in the '03 build cycle that it got some key features that weren't formally introduced until 2004 and that's 365's on the steer and tag, 18K lb steer axle, and hub centric wheels. My only frustration is with the kids in school we don't get to use it as much as I'd like! Next time you're in Asheville look me up!