I am working on a miniatural EV for a university project. It uses a 3.5kw BLDC motor which has a peak power of 10kW.
The main part i'm missing currently is the battery pack. Though i am aware that lithium-ion is thebest choice, money is a serious problem. Used cells are not so easily available in my country, either.
I was thinking of using 12v car batteries. The battery pack would cost me roughly 120$. I found some 12v, 40Ah batteries with a cold cranking current of 330A.
I was wondering if they are really that bad of a choice.
Now, for the setup:
The car is made out of steel tube (bars), and it weighs 80-90 kg, motor and control electronics included. The batteries would add up an extra 40kg, and, with the driver, the whole setup would weigh 200-220kg, which is close to an average motorcycle's weight.
The motor has a nominal current draw of 80A, but obviously that value decreases when the target speed is achieved, as the motor doesn't have to accelerate anymore. The peak current is less than 200A, so, again, given the fact that the vehicle won't do 0-top speed pulls for hours, i think that shouldn't be a problem either.
I took into account the fact that lead acid batteries are not meant for deep discharges, so I only took into account half of a cell's energy (therefore 20Ah @ 12v). The four batteries would add up to roughly 1kWh of energy.
The car is meant to be only a prototype. Performance driving is irrelevant, i only need it to accelerate to a certain speed (under 30 km/h (~20 mph) ) and maintain it. Range isn't too important either. Reaching 5km (roughly 3 miles) is more than enough. There will be no regenerative braking implied. The car will be used in temperatures higher than 0 degrees at all times.
My question is how reliable would the batteries be under these conditions? I am aware that they will lose their capacity way faster than lithium cells, but how fast would that be?
Do you see any serious flaw with this setup?
https://www.techmezine.com/article/12v-lead-acid-batteries-withdraw-market/
Hi, what settings should I make for this controller (Victor energy Smart Mppt 75/15) with a car battery (sealed lead acid 12v 100Ah) ? I specify that the default settings are for other types of batteries. I need to make a new profile for this battery. More images in links.
Hi doea any one know if i can draw 10amps from a 7ah 12v lead acid battery at one time thanks
I am buying a battery to use with a large inverter to power a TV projector, small leave blower, CPAP, small microwave, etc.
I also like the idea of having a battery that I can use in my car (size "group 24)", especially since the one I have in it is 4 years old and the expected lifespan is 5 years, so my best choice seems to be a 12v "deep cycle" battery, which as much power I can get at a low budget price. I have already ordered the 1500W pure sine wave inverter and a small 110v->12v battery charger.
BUT... I don't know enough about electricity to make a good choice. All websites talk about calculating used based on AH (Amp Hours), but no battery description will tell you that! They only tell you CCA (cold crank amps, function at 0F) or MCA (marine crank amps), and I have assumed that CCA is directly related to MCA, and there are formulas that compute AH from CCA, which is usually 30-100 for car batteries.
And here is where I am getting lost... the "RC" value, which I assumed would be proportional to CCA, but apparently it's not. That's important because there is a formula to compute AH from RC (RC / 2.4 = AH), and the results are wildly different!
So... I'm looking at Duralast Deep Cycle Group 24 batteries on the Autozone website and I have 3 options:
- $94.99 MCA=685 RC=140
- $94.99 MCA=1,000 RC=135
- $74.99 MCA=625 RC=95
Can someone tell me which would be the best choice (or if you know of another Group 23 battery that would work better)?
Also, any ideas on how to compute AH for these batteries?
Bonus question: I saw an article that said Deep Cycle batteries should not be discharged below 50% level -- is that true? I thought 20% was the minimum on these?
Thanks for any help and suggestions on this!
Hi, my bike's battery was really old around 5 years and wasn't holding charge . So i filled it with distilled water from my inverter's battery. Now i charged it and after few days i found water was spilled all around the battery. My question is - Is this water or acid diluted with water ?
It's hard to search in the usual way for this, results tend to be car battery service stations. I'm guessing there are probably places that carry these but would never occur to me, so I'm asking. (Not a Costco member, and would like to avoid Home Depot if possible.) Thanks for any tips!
Hey all. My old battery is Lead Acid... And its dead . Should i buy new AGM for $200 or regular for $94 at Costco?
Thanks
Per title. UPS powers a low-drain setup which I want to stay alive if there's an extended outage. I can attach a factory replacement 3.5Ah battery for $60, or a 90Ah deep cycle for about $150. Batteries are same tech/voltage (sealed lead acid 12v).
The UPS max output is about 3x the actual attached load, so no concerns about heat/burnout that I can foresee.
I'm not running any accessories at present, but I have been encountering a problem where the lead acid battery is dying about every 18 months. I had to warranty my duralast gold purchased in 2017 three times. If there is a better battery option for overlanding purposes, I'd be willing to spend the money now. Any recommendations?
Just purchased a flx20 and decided to just change it over to a Lithium ion battery off the bat (marcum 12v 12ah). As title suggests, I'm not sure if I should move the red fuse thing off the orginal battery onto the new one. Thanks!
Hello! I'm currently looking for a backup solution for my remote workstation. Where I live power goes out sometimes and I'm trying to figure out a power backup solution that can get me through my workday when needed. I'm trying to figure out which solution is the best and more cost-effective, and if I'm missing any disadvantages. So I was already decided to go for a setup of a 12V Marine Deep Cycle Lead Acid Battery with a 1200W Power Inverter Pure Sine Wave. I already bought the power inverter and it ran me about $223. I'm still missing the battery and where I live the cheapest branded Deep Cycle Marine Battery will run me about $185. So now I'm lookit at $408 for this setup. According to my research, the lead-acid battery backup solution should work with my setup, which consists of a laptop, monitor, and modem and it consumes close to 100W. The other option I just thought of is a LiFePO4 Portable Power Station. I saw one on Amazon that costs about $220. It says that it has a capacity of 299 Wh, so I'm not sure if it can last 5 hours under a load of 100W. I'm also not sure how good will the pure sine wave inverter inside the portable power station be. If anyone has some thoughts on these two setups and which one will work best for my context, I would really appreciate your feedback. If the LiFePO4 Portable Power Station solution is better, I can still just sell the inverter before buying the battery, but I'm just not sure if 299 Wh is enough for 5 hours of 100W consumption of my setup. Thanks!
Is this crack a safety problem on a 10 year old 12v 7ah sealed lead acid battery? The battery is nothing more than a low capacity bench battery now and has been for years due to age, however is this crack where a cell is bulging a safety issue? If its going to leak gas or short then I'd rather take it to the recycling place, it still worked fine for low current projects last time I used it but the crack is new.
Bulge and crack on an old sealed lead acid battery
It's always been charged on a dedicated ctek 800mA smart charger and never discharged too deep, I'm guessing its simply down to the age of the battery (10 years).
Bikes dead and I need to know which setting on my battery tender to use.
Disclaimer: I don't know a lot about batteries but I'm a student who is interested in it.
I'm reading an article about the pros and cons for lead acid batteries and I'm just sitting out here thinking they're pretty as*. It has to be stored at full SoC, only has 200-300 discharge/charge cycles for deep cycling, it can't even be deep cycled, it can't be charged with too high and too low voltage, and its got weak structure on its own so people add additives to strengthen it but that creates more problems. The article says that the reason they are currently used are that they are dependable and are inexpensive. But aren't there Li-ion batteries that are not only pretty cheap, easy to use, and dependable? Why not use them instead?
Article: https://batteryuniversity.com/article/bu-201-how-does-the-lead-acid-battery-work
- i want to charge it with a dc power supply. what is the current limit i should apply?
- in terms of coulombs, how much capacity does it have?
Modern "deep cycle" lead acid batteries and car batteries are designed to fail.
I've recently acquired some golf cart batteries that were in poor condition and have managed to get some of them working. The others had shorted cells so I decided to go ahead and do a flush on all of them starting with those. While doing my flush I'm looking inside the auxiliary holes I've drilled to make flushing easier and I've noticed a few things.
First the sumps on these batteries are only about a quarter of an inch deep. This is really shallow for some deep cycle batteries. Maybe these aren't actually deep cycle batteries and I'm just mistaken to think that they were.
Second, the plate mesh material is thin and brittle.
Third, the bus bars are extremely close to the plates making shorts very easy to occur at the top of the batteries. After a simple flush I seem to have fixed the soft short problem that I had on this first battery that I've started with.
AFAICT lead acid batteries have a bad reputation from poor manufacturing and planned obsolescence. All lead acid batteries deep cycle or not should last anywhere from 10-20 years under normal use and proper maintenance, and yet I can hardly keep a well maintained car battery for more than 5 years without a cell going short. My brother had bought four brand new AGM batteries and one of them has already failed with a shorted cell! They have had hardly any use at all and have been on my solar maintainer since he got them a year ago. The maintainer does not overcharge them as it is using a commercial grade charge controller set for AGM batteries. It wouldn't surprise me at all to find out that there is a battery cartel just like the light bulb cartel of yesteryear. Now watch this posted get heavily downvoted. ;P
Any thoughts?
Hi, what settings should I make for this controller (Victor energy Smart Mppt 75/15) with a car battery (Macht sealed lead acid 12v 100Ah) ? I specify that the default settings are for other types of batteries. I need to make a new profile for this battery. More images in links.
Hi, what settings should I make for this controller (Victor energy Smart Mppt 75/15) with a car battery (Macht sealed lead acid 12v 100Ah) ? I specify that the default settings are for other types of batteries and i cant found the specs of this battery on internet. I need to make a new profile for this battery. More images in links.
