Feedback request Xuba battery build (HS senior project)
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lmwilco1
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You can do a capacity test of individual cells without the BMS, if you are charging or testing anything other than a single cell or multiple cells in parallel then you run the risk of having one cell get overcharged or under discharged. At the cost and lead time of these batteries killing one would suck.
So is it a bit risky to do a capacity test on a single cell? Would it be better to get the BMS and test all of the cells at once?
I am planning to do the capacity test with the heater fan that Will has the video on and he did not indicate a big risk of doing it individually. If you do them all at once, how can you tell which cell is bad if there is a problem. I thought it would be easier to see how each cell performs by doing them one at a time.
I am planning to do the capacity test with the heater fan that Will has the video on and he did not indicate a big risk of doing it individually. If you do them all at once, how can you tell which cell is bad if there is a problem. I thought it would be easier to see how each cell performs by doing them one at a time.
If you want to do things properly then follow the instructions given to you. Parallel top balance to 3.65 volts. Then hook up your batteries in series with the BMS and proceed to play. This is the safest way and you will be able to tell if you have a bad cell from the information you get from the BMS. Other than shipping damage I have noticed only one who received a bad 280ah cell. As I recall he was only getting 175ah from it. That's the only one I know of.
The heater fan is something like this? It's called a capacity tester.
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I am also planning on getting the BMS from Overkillsolar since he has customizations for the wires and lugs and has a good reputation for support. As much as I have loved watching Wills videos, you don't have to buy anything he recommends. He doesn't have the time to test everything that's out there. As you know forum members have tested a lot of stuff and I tend to look at those posts closely.
BTW, are you planning on using an inverter in the camper? Just curious since I don't think you have mentioned it.
lmwilco1
New Member
You can test each cell individually without a BMS, the load tester will count the power used and will stop at the voltage that you set. The problem is it will take forever. Once you have a BMS you can build a 12v battery you can do faster load testing. Do you have a plan for monitoring your system? There are a few options, Will has a good assortment on his website. If you have one of these monitors you can use an inverter and put a higher load to reduce the amount of time it takes to do a load testing.
I like the Juntek coulomb monitor I am using. The capacity reading 0-100% isn't all that accurate which is the case with most of the cheap meters. Of course spending $200.00 for a Victron solves that. But the wattage, amps and volts are accurate from what I have been able to tell.
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There are several YouTube video reviews of the meter. It has it's design flaws but I like it a lot especially since it has wireless capability. I noticed Overkillsolar has one.
If you want to do things properly then follow the instructions given to you. Parallel top balance to 3.65 volts. Then hook up your batteries in series with the BMS and proceed to play. This is the safest way and you will be able to tell if you have a bad cell from the information you get from the BMS. Other than shipping damage I have noticed only one who received a bad 280ah cell. As I recall he was only getting 175ah from it. That's the only one I know of.
The heater fan is something like this? It's called a capacity tester.
US $29.0 35% OFF|8 in 1 150W usb meter Digital battery capacity tester voltmeter adjustable constant current electronic load charger indicator|Battery Testers| - AliExpress
Smarter Shopping, Better Living! Aliexpress.com
I am also planning on getting the BMS from Overkillsolar since he has customizations for the wires and lugs and has a good reputation for support. As much as I have loved watching Wills videos, you don't have to buy anything he recommends. He doesn't have the time to test everything that's out there. As you know forum members have tested a lot of stuff and I tend to look at those posts closely.
BTW, are you planning on using an inverter in the camper? Just curious since I don't think you have mentioned it.
I ordered two of the capacity testers that you mentioned and have not ordered a BMS yet. I initially had planned to order all the parts separately and build the system but it looks like this has everything and it was much simpler:
Hybrid Inverter 2400W 3KVA 24V 110VAC Grid Tie Solar Inverter 80A MPPT Charger
I had not seen too much mention of BMS's that folks liked but read about the Overkill one yesterday. Since it is available I will look at it again and might get it as that would enable me to get all hooked up before school gets started back up.
Well I sure see it now and missed it in your previous post. There is no need to use large bolded fonts!
newbostonconst
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Gazoo = grumpy old man......
Prefersdirt
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I went with the other from Ian in Utah, as I wanted the faster grid charge ability plus the surge capacity.
I did not see anything about Ian in Utah. I just bought mine off of Ebay. I did not go about ordering everything properly as I was a bit excited and initially had planned on getting the BattleBorn's but the cost savings overruled. I bought the inverter first...
Hybrid Solar inverter 2400w 24V 110V 80a MPPT solar charger 60a battery charger is the description of what I bought.
Hybrid Solar inverter 2400w 24V 110V 80a MPPT solar charger 60a battery charger is the description of what I bought.
I have been thinking about this one:
US ship. PIP-2724LV-MR 24V 2.7kW 110/120Vac Solar Inverter with 600W MPPT & Utl | eBay
Ideal for RVs and Portable camping units where roof/solar space is limited (600W solar input capacity Max 60V dc PV Input MPPT). Solar Panels plug right into the Inverter with MC4 connectors. The more I look at this unit, the more I like it.
www.ebay.com
Not sure yet. All I want to do initially is build a UPS. It's for my apartment so it might be a good fit and the price is reasonable. Or I might settle on a good inverter/charger. I can't do much for solar here but I could put a panel out on the deck every once in awhile to get acquainted with solar. It will be at least 30 days until I get my batteries so lots of time to think about all of this although I have been thinking about it for months...lol.
I just bought the Overkill BMS...hopefully it will not take too long and I can sort the batteries and then assemble everything....getting a bit nervous
You will be fine and if you need any help you are in a good place. I am sure I will be nervous too when I get going with my project. I have done this type of stuff but on a much smaller scale. Going big is going to be a new experience for me. Glad you ordered the BMS and I am looking forward to more updates.
I plan to build a box to give slight compression to the batteries Wednesday and am still waiting on the Overkill BMS but I hope that arrives soon. I ordered 2 capacity testers on 8/2 and they have still not shipped. What other ways are there to run a capacity test on the cells after I top balance them?
lmwilco1
New Member
Once your cells are balanced and have your BMS you can assemble the battery and do load testing if you have a way to monitor the output. You need one of the power monitors that Will shows on his site or a similar device . If you have an inverter you can connect it to the battery and use a 110v load to do your testing. Remember that the inverter may have a different low voltage cutoff as compared tot he BMS so you may not reach your full capacity if the inverter disconnects before your BMS setting. If you don't have an inverter then find a 12v light of some sort, maybe a fog light or driving light and use that for the load.
I built a box and have the cells under slight pressure and connected in parallel. I connected all in parallel about a week ago and they self-balanced to 3.331 per cell. I started charging them early yesterday morning and I think they should all be charged to 3.65 in a few more hours. The BMS and capacity testers are arriving today so hopefully I can hook up and do capacity tests tomorrow. Fingers crossed that all cells are good.
newbostonconst
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At 3.331 volts the cells are low on the charge scale. You have 280Ah in parallel so 280*16=4480ah total, so if you have a 30 amp charger? 4480/30=~150 hours to charge.....
That is if they charger can push in the full 30 amps at the end. I am guessing 173 hours.... keep track I would like to know, I didn't do it this way but should have....
FYI 173hours/24hours in a day=7.2 days....let me know if I am not calculating this right.... keep up the great work.
That is if they charger can push in the full 30 amps at the end. I am guessing 173 hours....
keep track I would like to know, I didn't do it this way but should have....FYI 173hours/24hours in a day=7.2 days....let me know if I am not calculating this right.... keep up the great work.
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