The cells had all be swollen. Some more some less. Its in line with the capacity degradation. Because its LiFePo chemistry, I really don't worry much. They are save, and installed far back on the garden wall. If my other 10kWh Li-Polymer battery would start to give off some smell, I would surely be alarmed
So yeah, I have really no idea, but as I do not ask much from the pack (max. 0,15C at charging, 0,12C at discharging), they do perform well. No balancing issues, no heating, etc... just that stink, haha
The odor is somehow a very special one. Definitly nothing burnt. Nothing electrical like coming from arcing. Somewhat sweet. Somebody mixed a few chemicals together out of a backing recipe.
Unfortunately its a bit difficult to get proper information about Chinese products. It is as well not very likely to get information directly at the manufacturer. They often don't get it what you are talking about. Need to wait for a phone with smell sensor first, to submit a sample by chat
I am charging my pack to a maximum of 55.4V (3,46V), and then disconnecting them. The cells will then drop to their resting pack voltage of 53.4V (3.34V) and wait a few hours to be used for discharging (not going below 49V there, pack will rest at around 50V (3.12V) and wait for charging again). I have put my nose close to the cells and the smell is definitly coming out of this red rubber vents. Else nothing to see at the cells. Those cells had surely been used hard in their first life. Here in Thailand, nobody is giving away expensive items like that, if the end is not reached yet in their application. I do assume the cells where powering a telecom station somewhere in the jungle. If they had really been 100Ah at the day of first install, then they have lost 15Ah each. If there was an installation mistake at that time, I of course cannot tell. But maybe this is a special type of cell. Ment for outdoor use as replacement of lead acid batteries (those release gas as well).The cells had all be swollen. Some more some less. Its in line with the capacity degradation. Because its LiFePo chemistry, I really don't worry much. They are save, and installed far back on the garden wall. If my other 10kWh Li-Polymer battery would start to give off some smell, I would surely be alarmedSo yeah, I have really no idea, but as I do not ask much from the pack (max. 0,15C at charging, 0,12C at discharging), they do perform well. No balancing issues, no heating, etc... just that stink, hahaThe odor is somehow a very special one. Definitly nothing burnt. Nothing electrical like coming from arcing. Somewhat sweet. Somebody mixed a few chemicals together out of a backing recipe.Unfortunately its a bit difficult to get proper information about Chinese products. It is as well not very likely to get information directly at the manufacturer. They often don't get it what you are talking about. Need to wait for a phone with smell sensor first, to submit a sample by chat
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It’s been a little over a year since we built and installed our DIY LiFePO4 pack into our Sprinter van. We built a 280Ah LiFePO4 12.8 volt pack using new, grade A prismatic cells I bought from AliExpress. Using a 4S Daly BMS and an active cell balancer, our pack was built at less than half of the price of a comparable commercially made pack. We also added temperature sensors, a cooling fan as well as 12-volt silicone heating pads to make it safe to use in extreme weather conditions. It is designed and built to be much more capable than most off-the-shelf commercially made battery packs. But of course, as a DIY project, there is no warranty against failures so if you plan to build your own, make sure you understand all of the safety measures and assume all of the risks yourself.
How Did We Use It Over This Past Year?
So a lot of people have been asking just how well the pack has held up over regular use. Well, we wanted to wait until we have had at least a year under our belts before sharing our experience. So here it is.
In this past year, we have traveled all across Croatia from Korcula Island to the south all the way up to Zagreb to the north. We left Croatia six months ago and made our way across western Europe through Slovenia, Austria, Germany, and France before taking a ferry to Ireland for the summer months.
In Ireland, we drove along the entire island on the coastal route and explored the world-famous Wild Atlantic Way. We ferried from Belfast to Scotland and drove the North Coast 500 route in the highlands before making our way back to mainland Europe. During that time, we experience plenty of rainy and overcast days which put our battery to the test.
How Our Camper Consumes The Power
Our 280 Ah of LiFePO4 never failed us. We only charged it using our 400 watts of solar on the roof, occasionally supplemented by a 200-watt ground deployed array and our 20A DC-to-DC charger when the engine is running.
We rarely dip below 50% capacity during the entire year. To give you an idea of what we run off of this electrical system so you can predict whether or not this would be enough for you, here is the complete power audit of the van’s electrical system. Your setup will likely be somewhat different but this includes all the appliances and electronic devices that most people will have in their camper vans.
Some of you might wonder so let me tell you that we currently do not use induction cooking powered from ours. We only use it when we have electric hookups. They can draw a huge amount of power and will require about twice our current battery and solar capacity in order to sustain it.
Here is a list of everyone that uses battery power in our van and how much it uses each day:
There are other things like a Viair 450P air compressor and wifi extender that we sometimes use but these are the devices that are more frequently draw power.
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Note that out of all of these devices, only the laptops and the drone charger requires the use of our 1,000-watt inverter. We have designed our system to not rely too much on AC power so it is only turned on when needed. This helps to cut down on parasitic draw.
Something I haven’t shared any information about is a DIY home automation system. There are a handful of smart devices and a Raspberry Pi 4 that is always on as well. The draw is minimal but since I have not talked much about them, I will leave the details for a future post where I plan to share more about how I incorporated home automation technology to some parts of the van and how it has helped out day to day lives.
Our Feedback On The System
So how well has the battery pack been working? the short answer is that it’s been great. It has practically been a seamless and maintenance-free transition from our old 225Ah AGM batteries that we replaced.
The new charging profiles from our solar and DC to DC charger have been doing a great job of keeping the pack topped off. Even during extended days of overcast skies, the extra capacity has kept us from worrying about losing power and as long as we drive every couple of days, we can sustain these less than ideal solar days.
I will get charged back to 100% on most days during the summer as long as the sun is out. In Europe where the latitude is higher and the sun is steeper in angle, it’s not as easy as the United States, particularly in the southern states.
We only experienced a couple of nights of near-freezing temps after the heating pads were installed and everything did its job to keep the battery from suffering temperature-related degradation.
I have heard lots of positive feedback from many of you who watched the battery build videos on YouTube, Instagram and even crossed paths and met some of you in person while we were on the road. I’ve got a lot of other projects planned for this coming year and look forward to sharing them with you.
Data From Victron Smart Shunt
Let me share with you some of the data logged in the Victron SmartShunt and how it breaks down over this period of use.
- Deepest discharge: 282Ah (Achieved during the initial capacity test)
- Average discharge: 149Ah (This is not a daily average. It is only counting when a charge cycle is recorded)
- Cumulative Ah consumed: 15,886 Ah – Averages to about 40 Ah over roughly 400 days since initial installation. About half of those days were on the road while the other half were stationary here on Hvar Island. This is not counting all of the power consumed directly from the solar panels during the day while the battery is already full or while driving when the DC to DC charger is supplying power directly.
- Charged energy: 219kWh – 547 Watt Hours of power input per day. We have had days where we’ve collected more than 2,000 Wh from the solar panels and some days less than 100. This represents an average of over 400 days.
- Total Charge Cycles: 10 – Victron algorithm counts a charge cycle only when the battery’s state of charge meets certain criteria. It has to do with a predetermined low state-of-charge point and when it recharges fully afterward. I’ve not read all of the SmartShunt manuals so I don’t know for sure the specifics of that algorithm, but this number coincides with roughly how often my state-of-charge has dipped below 50%. I assume this is also how it comes up with the -149Ah discharge average. As you can see, for a 280Ah pack, this is roughly at 47% state-of-charge when it logs a charge cycle.
- Full discharges: 1 – This has only happened when I first built the battery and ran a complete discharge cycle from 100% down to 0%. I have not even come close to a full discharge cycle since and likely never will.
- Synchronizations: 146 – This counter logs each time the battery achieves a full charge and the shunt automatically runs a synchronization cycle to keep the state-of-charge meter from drifting over time. That means this has happened more than a third of the days since I installed the battery. Most of these days were in the summer months but since I was in Ireland and Scotland during the bulk of that time, we saw plenty of overcast days that prevented us from reaching 100% charge.
Conclusion
So that is everything. Hopefully, this helped answer some of your questions about how a DIY LiFePO4 pack performs in the real world. I will keep you guys updated with how it is working especially if I come across anything usual and unexpected so don’t forget to subscribe if you haven’t yet.
So far after a year, I am very happy with how this has worked out. I also offer personalized online sessions to help you design and build your system if you happen to need any help.
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