Yes that's right, for 2P it is simple. As long as you connect positive to one of the two cells and negative to the other cell, it will be balanced.On further reflection since I am only using 2 cells in parallel, how I was originally planning to do things is good. If I wanted to parallel more cells then I would need to change how I wire them.
Correct on both points.Yes that's right, for 2P it is simple. As long as you connect positive to one of the two cells and negative to the other cell, it will be balanced.
Plus I'm guessing you'll have equal-length bus bars joining the 2P cells. The bus bars will be much lower resistance than say 8' long cables running from one side of an RV to the other, so any imbalance will be a much smaller effect.
The god damned maxxfan / fan-tastic fan ? this is the only commonly used component for a van or vehicle based build I have run into that can be found in 12v not 24v. Basically everything else I've identified at least one 24v alternative.Some components are not available in 24V, for example the Maxxfan that almost everyone uses is available in 12V only. Not a big deal, the converters are very efficient, for example the Victron Orion 24/12 converters range from 92 to 96% efficiency.
I bought a MaxxAire vent hood and added my own 24V fan to it.The god damned maxxfan / fan-tastic fan ? this is the only commonly used component for a van or vehicle based build I have run into that can be found in 12v not 24v. Basically everything else I've identified at least one 24v alternative.
Great solution! I hadn't considered that.I bought a MaxxAire vent hood and added my own 24V fan to it.
That is an interesting article.
Has implication for DIY batteries with parallel and series cells. For example I am building a 2P7S NMC battery pack consisting of 16 3.7V, 60AH cells, resulting in a a 25.6V, 120AH battery. I was planning on using his second wiring scheme which would end up resulting in uneven usage of the cell. I am going to rethink how I wire these cells to ensure the most even utilization of the cells possible.
I am using the Maxxair Mini. It fits under my luggage rack.Great solution! I hadn't considered that.
Just another reason to switch to 24V or even 48V. Easier and cheaper wiring. Plus your solar charge controller can be a lot smaller and cheaper also.I know that article is good for Lead Acid. For LiPso (lithium phosphate) it would be too, but at some point the Battery Management system could make up for this. I admit I know very little about BMS and I assume that a BMS that could make up for resistance in parallel strings, but I'm sure each battery would need to be monitored individually to compensate. I've seen posts where Battleborn with their each battery having a BMS compensates for resistance, but I don't see how that's possible without a wire going between each Battleborn Battery.
I will eventually upgrade to Lithiums, probably 24 volt at 400 - 600 AH's worth, but I will take my time learning about the BMS.
I think diagram #3 is the best way to wire the batteries, and if I did this with six batteries, I would get a 7 post bus bar for the positive, and seven post busbar for the negative, and hook the six terminals to their own post and run the paralleled power to the system from the seventh post.
Diagram #4, I don't see a good way to turn it into actually being wired. To me it comes back to having at least two cables on one terminal, and its good in theory but I am using 2/0 and 4/0 wiring for my batteries, and with wire that thick, just becomes too difficult. I have enough trouble making cables with wire that thick to fit one cable on, never mind two or three.
Also wish there was math with the resistance for diagram #3 and diagram #4 to see what the batteries are losing.
Hah, that is ironic. I just (as in literally 2.5 minutes ago) recommended this precise product for this precise purpose on another forum. What are the odds ?I am using the Maxxair Mini. It fits under my luggage rack.
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what 24v fan did you use?I bought a MaxxAire vent hood and added my own 24V fan to it.
I got this surplus 24V Comair fan.what 24v fan did you use?
Tanks! so you felt that it moved the same volume of air? Did you just clip the wires on maxxaire fan and reconnect 24v fan? Is it louder than original Maxx fan?I got this surplus 24V Comair fan.
Really moves the air. It is a noisy than I would like though.
COMAIR PD24B6 24VDC Axial Cooling Fan - Enclosure Fan
ROTRON PD24B6TDNX Volts: 24VDC Current: 1.0A CFM: 23 Plastic blades, Metal housing. 52dB noise. Ball bearings. 4inch leads with 3Pin connector. UL/CSA/TUV listed. RED: +24V, BLACK: -24V, Blue/White: Tach. Output 5VDC TTL 2Pulse/Revwww.mpja.com
I bought the no fan version of the Maxxair Mini and mounted the fan to a piece of plywood.Tanks! so you felt that it moved the same volume of air? Did you just clip the wires on maxxaire fan and reconnect 24v fan? Is it louder than original Maxx fan?
Excellent article at Smartgauge. Thanks.This is a good article that explains the drawbacks of paralleling batteries, the math to back it up, and different ways to overcome this resistance.
I did not want my batteries being sloppy, so made my own cables. For my battery charger, it is 26 amps and I'm not concerned about lug size on that, but when I am running a microwave and drawing 130 amps from the batteries, I want a nice, secure connection.
I thought about the same idea. What motor did you use? Thanks!I bought a MaxxAire vent hood and added my own 24V fan to it.
I got this surplus 24V Comair fan.
Really moves the air. It is a noisy than I would like though.
COMAIR PD24B6 24VDC Axial Cooling Fan - Enclosure Fan
ROTRON PD24B6TDNX Volts: 24VDC Current: 1.0A CFM: 23 Plastic blades, Metal housing. 52dB noise. Ball bearings. 4inch leads with 3Pin connector. UL/CSA/TUV listed. RED: +24V, BLACK: -24V, Blue/White: Tach. Output 5VDC TTL 2Pulse/Revwww.mpja.com