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> Car Battery Charger, Tender, Maintainer, Any portable ones?

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fireballs
post Nov 7 2019, 01:47 PM

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QUOTE(Fat & Fluffy @ Nov 7 2019, 01:04 PM)
ohh... dont plan to have those... i m just worried bout starting the vehicle
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Just remember to separate battery when u get your inverter.
AllnGap
post Nov 7 2019, 10:21 PM

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QUOTE(System Error Message @ Nov 6 2019, 10:24 PM)
I wonder if this will work https://www.lazada.com.my/products/50800mah...pGNtlT&search=1 . This things are basically a battery with super caps and have capacity to keep the car powered through the night to keep the battery charged. Upon calculating, if a car battery is 500Wh, and it takes a month to get to there, then the car's power drain is 500/(30*24) which is less than 1W. So 50Ah*3.7 is more than 150Wh which means its good for overnight or for a few days. What you can do is when you go off for a few days to not use your car, put a voltmeter that goes into the car's socket and find the voltage. Then before you start the car a few days later, take the voltage reading again. Assuming your battery was fully charged when you turned off the engine for the first measurement, you can estimate how much power was used based on the time, voltage changes and battery capacity (available by reading your battery model and looking up or on the battery itself).

The problem with the jumper starter is if it supplies 12V and not the 13V+ needed to keep the battery charged so its a matter of finding one that outputs the voltage you want. If you have a bit of EEE skill you could make your own DC to DC converter. To cater to worse case scenario incase you decide on making your own, you only need to handle 1A, so a 2A fuse with a 1.5A shunt and a circuit designed to handle 1.5A converting 12V to 13.8V, such a small conversion is efficient and doesnt require many or greater components in the circuit.

When the lead acid is fully charged, it will output above 13V. When lithium is fully charged it can output as high as 3.9V and go all the way down to 3.2V or lower depending on the circuit needs and drain.
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most of china products use recycled batteries, basically they are fake capacities.
trust me because i build my own powerbanks years ago.
System Error Message
post Nov 8 2019, 11:12 PM

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QUOTE(AllnGap @ Nov 7 2019, 10:21 PM)
most of china products use recycled batteries, basically they are fake capacities.
trust me because i build my own powerbanks years ago.
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my point isnt about the capacity, but you dont need much to start a car. Though even if its actual capcity is 50Wh, thats 50-100 hours, so still worth it. The problem is that its 12V not 14V and the common DC to DC laptop PSU adapter has only 12V or 15V or more.
COOLPINK
post Nov 8 2019, 11:17 PM

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Why not just remove ur car battery, take it home and plug it to charger/tender?

System Error Message
post Nov 8 2019, 11:22 PM

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QUOTE(COOLPINK @ Nov 8 2019, 11:17 PM)
Why not just remove ur car battery, take it home and plug it to charger/tender?
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some cars the ECU will go crazy if you do that or it will consider itself stolen when you do. Also without battery how will you keep the alarm powered? Also important to not make it seem like the car is abandoned.
AllnGap
post Nov 8 2019, 11:23 PM

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QUOTE(System Error Message @ Nov 8 2019, 11:12 PM)
my point isnt about the capacity, but you dont need much to start a car. Though even if its actual capcity is 50Wh, thats 50-100 hours, so still worth it. The problem is that its 12V not 14V and the common DC to DC laptop PSU adapter has only 12V or 15V or more.
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I've tried starting car using same 18650 battery cells.
3cells connected together in series can only jump start once.
Battery drained completely after one jump start
System Error Message
post Nov 8 2019, 11:38 PM

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QUOTE(AllnGap @ Nov 8 2019, 11:23 PM)
I've tried starting car using same 18650 battery cells.
3cells connected together in series can only jump start once.
Battery drained completely after one jump start
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did you have a super capacitor to provide the required amps? I imagine this would have quite a few cells considering the size and weight. Even if they have fake cells fake cells typically have 1/3 their stated value.

What car did you try? What was the capacity of the cell? if you multiply it by 3.7*3 (3 cells) will give you how much energy needed in watt hours (which if you convert to joules gives you how much energy needed)
AllnGap
post Nov 9 2019, 05:30 AM

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QUOTE(System Error Message @ Nov 8 2019, 11:38 PM)
did you have a super capacitor to provide the required amps? I imagine this would have quite a few cells considering the size and weight. Even if they have fake cells fake cells typically have 1/3 their stated value.

What car did you try?  What was the capacity of the cell? if you multiply it by 3.7*3 (3 cells) will give you how much energy needed in watt hours (which if you convert to joules gives you how much energy needed)
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Never use capacitor, just 3batteries in series.
Forgot 3-4 batteries d.
One cell rated at 4.2v, 2600mAh.
Total is 12v, 2600mAh.

Old kenari.
TSFat & Fluffy
post Nov 9 2019, 10:35 AM

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QUOTE(COOLPINK @ Nov 9 2019, 01:17 AM)
Why not just remove ur car battery, take it home and plug it to charger/tender?
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as mentioned by some the ecu will go crazy...
Pichu00
post Nov 9 2019, 06:17 PM

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QUOTE(AllnGap @ Nov 9 2019, 05:30 AM)
Never use capacitor, just 3batteries in series.
Forgot 3-4 batteries d.
One cell rated at 4.2v, 2600mAh.
Total is 12v, 2600mAh.

Old kenari.
*
How to use power bank to jump start car?
AllnGap
post Nov 9 2019, 06:30 PM

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QUOTE(Pichu00 @ Nov 9 2019, 06:17 PM)
How to use power bank to jump start car?
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Can't do direct.
Need to rewire battery in series

Power bank internally is connected in parallel
Pichu00
post Nov 9 2019, 06:32 PM

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QUOTE(AllnGap @ Nov 9 2019, 06:30 PM)
Can't do direct.
Need to rewire battery in series

Power bank internally is connected in parallel
*
Ooo i tot got extention thing can plug into power bank to use it as jump-starter lol
AllnGap
post Nov 9 2019, 06:33 PM

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QUOTE(Pichu00 @ Nov 9 2019, 06:32 PM)
Ooo i tot got extention thing can plug into power bank to use it as jump-starter lol
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Dont know about that, even if got also I think will fry powerbank circuitry internally as it needs to draw a lot of amps in a pulse
System Error Message
post Nov 9 2019, 10:29 PM

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QUOTE(AllnGap @ Nov 9 2019, 05:30 AM)
Never use capacitor, just 3batteries in series.
Forgot 3-4 batteries d.
One cell rated at 4.2v, 2600mAh.
Total is 12v, 2600mAh.

Old kenari.
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so it takes about 108KJ to start the car and i suppose its not a 1.5L engine, probably smaller. How long did it take to crank? Was it instant? This really sounds promising but batteries hate being drained quickly.

QUOTE(Pichu00 @ Nov 9 2019, 06:17 PM)
How to use power bank to jump start car?
*
Powerbank out is 5V, you need a range of 11-14V as thats what the starter motor (or in some cases alternator too) is designed to handle. Too low volts and it wont help and could spoil the motor, but you need the amps too.


At the moment lead acid is used because its the battery in between capacitors and other batteries. Its not so good at storing charge compared to lithium but its not as good as capacity either to provide amps. Thats why i want to break it up into 2 parts to have the best of both worlds. Its been done before years already and the instant crank is a big plus not to mention longer lasting and cheaper. My goal is to make such a battery cheaper and commercially available but its difficult because of the lead acid battery ecosystem.

Salt water battery looks promising to replace lead acid in backup power applications as theres no acid so its safer to maintain and work with, but i first gotta build it try it and test it including figure out how to test it, and a job to afford to be able to do it. If its promising enough could be cheap enough to replace lead acid and long lasting enough when combined with capacitors. Whats interesting is that you get HCL and NAOH making it neutral and hopefully recharging it wont cause an electrolysis if aiming for a single larger battery with 12V. Tap water is impure though would be better if it worked well with it but still need to build and test it first.
AllnGap
post Nov 9 2019, 10:35 PM

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QUOTE(System Error Message @ Nov 9 2019, 10:29 PM)
so it takes about 108KJ to start the car and i suppose its not a 1.5L engine, probably smaller. How long did it take to crank? Was it instant? This really sounds promising but batteries hate being drained quickly.
Powerbank out is 5V, you need a range of 11-14V as thats what the starter motor (or in some cases alternator too) is designed to handle. Too low volts and it wont help and could spoil the motor, but you need the amps too.
At the moment lead acid is used because its the battery in between capacitors and other batteries. Its not so good at storing charge compared to lithium but its not as good as capacity either to provide amps. Thats why i want to break it up into 2 parts to have the best of both worlds. Its been done before years already and the instant crank is a big plus not to mention longer lasting and cheaper. My goal is to make such a battery cheaper and commercially available but its difficult because of the lead acid battery ecosystem.

Salt water battery looks promising to replace lead acid in backup power applications as theres no acid so its safer to maintain and work with, but i first gotta build it try it and test it including figure out how to test it, and a job to afford to be able to do it. If its promising enough could be cheap enough to replace lead acid and long lasting enough when combined with capacitors. Whats interesting is that you get HCL and NAOH making it neutral and hopefully recharging it wont cause an electrolysis if aiming for a single larger battery with 12V. Tap water is impure though would be better if it worked well with it but still need to build and test it first.
*
1L, instantly crank. Just that it takes hours to charge those battery and single start to drain it dry.
Probably bad for the 18650 battery as discharge might be way too high
System Error Message
post Nov 9 2019, 10:37 PM

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QUOTE(AllnGap @ Nov 9 2019, 10:35 PM)
1L, instantly crank. Just that it takes hours to charge those battery and single start to drain it dry.
Probably bad for the 18650 battery as discharge might be way too high
*
yup, they wont last long under those loads, probably a year instead. Though just 3 batteries alone would be a lot lot cheaper than the lead acid for your car which lasts for 2-3 years. Combine with capacitors and they'll lost a lot lot longer.
TSFat & Fluffy
post Nov 9 2019, 11:24 PM

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i have seen a 20,000 ma power bank... but can crank car batt.. so i assume there's 12v output... is it any good for my case?
System Error Message
post Nov 9 2019, 11:34 PM

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QUOTE(Fat & Fluffy @ Nov 9 2019, 11:24 PM)
i have seen a 20,000 ma power bank... but can crank car batt.. so i assume there's 12v output... is it any good for my case?
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if it has a 12V output, can be used but you would have to disconnect the lead acid battery.

I still wouldnt try it because the amp drain will significantly shorten its life and cause them to expand, potentially piercing the internal battery and causing an explosion or fire in the future.
TSFat & Fluffy
post Nov 10 2019, 01:11 PM

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QUOTE(System Error Message @ Nov 10 2019, 01:34 AM)
if it has a 12V output, can be used but you would have to disconnect the lead acid battery.

I still wouldnt try it because the amp drain will significantly shorten its life and cause them to expand, potentially piercing the internal battery and causing an explosion or fire in the future.
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you mean gotta disc the batt from the car?

shorten the life of which device?
System Error Message
post Nov 10 2019, 10:26 PM

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QUOTE(Fat & Fluffy @ Nov 10 2019, 01:11 PM)
you mean gotta disc the batt from the car?

shorten the life of which device?
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you disconnect the lead acid battery so that the car drains the lithium instead without the lead acid losing some capacity. Some 12V outputs are not direct and switched resulting in constant 12V which means the lead acid will charge the lithium and power the alarm till it reaches 12V at which it is then balanced and wont perform its purpose. Lead acid battery when not connect stores its charge well, and likes being kept at 100%, the self discharge is low so for long term storage that is literally what you do.

 

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