The Stack Overflow podcast is back! Listen to an interview with our new CEO.

Questions tagged [lead-acid]

A type of very common chemistry system used batteries using lead and sulfuric acid. fully charged it will have a voltage of 13.8 V. These batteries are used in automotive and robotics environments.

Filter by
Sorted by
Tagged with
27
votes
5answers
4k views

Charging lead-acid batteries?

Are there any special requirements for charging lead-acid batteries?
20
votes
8answers
78k views

How bad is it to undervoltage a 12-volt lead-acid battery?

I had a heated discussion with a few colleagues today revolving around how low of a voltage was alright for 12 volt lead-acid battery; they were in the opinion that the low voltage warning buzzer and ...
11
votes
3answers
57k views

What is a safe max. discharge rate for a 12V lead acid battery?

I've got a 12V 2.4Ah lead acid battery which I plan to connect a water pump to. I've looked at various pumps, but the one I'm most interested in draws 2.2A. I'm not so interested in how long the ...
11
votes
2answers
2k views

How much current can lead acid batteries safely supply?

I have a motor I wish to drive with an 18V lead acid battery. The motor can draw quite a lot of current when stalling and I am worried of overdischarging the lead acid battery. Unlike LiPo batteries ...
11
votes
2answers
15k views

Floating multiple sealed lead acid batteries in parallel

I know with multiple lead-acid batteries you should really charge them separately so that one battery doesn't try and charge another and waste power. But that holds true for the main charging process....
10
votes
2answers
26k views

Can I charge a 12v sealed lead acid with an old wall-wart (not made for charging)?

Will it hurt the battery? If I left it overnight would I run the risk of "exploding" the battery? I have a 7Ah SLA battery that I need to charge, but I don't have a charger and I don't want rake out ...
9
votes
7answers
14k views

Why are lead-acid batteries preferable for submarines?

According to Wikipedia article lead-acid batteries are used for running submarines propulsion engines. Submarines are used by the military and the military can afford very expensive toys. Lead-acid ...
9
votes
6answers
8k views

Why is balancing used for lithium batteries only?

I have never heard of a lead acid battery having any electronics to balance it's cells, or even any manual way to balance them. But I think all lithium batteries have, or at least lithium batteries ...
8
votes
3answers
72k views

What should the voltage of a fully charged lead acid battery be?

I don't have a proper lead acid battery charger... But I own a small Yuasa 7Ah battery. I am using a 13volt 1.5A wall wart to charge it. And I have a volt-meter to check the voltage. At what ...
7
votes
3answers
32k views

Are sealed lead-acid batteries safe to use indoors?

I have a small, 12V sealed lead-acid battery. I know regular lead-acid batteries can be dangerous to use or charge indoors, due to the fumes they release and the potential for acid to leak out or ...
6
votes
4answers
11k views

Why are Li-Ion battery so much safer than lead-acid?

Recently I asked how to charge a (lead-acid) car battery at home and looks like the answer is very dangerous, don't do it unless you really really have to. Meanwhile people charge Li-Ion batteries of ...
6
votes
2answers
8k views

Can the terminal voltage of a lead acid battery be reversed?

I recently acquired a used riding mower. I figured it was dead, so hooked it up to a trickle charge overnight. Next morning, still totally dead. I stuck my voltmeter on it, and measured -11.8V. Check ...
6
votes
2answers
3k views

How does one determine Lead-Acid battery end-of-life?

I have a deep discharge small lead-acid battery bank comprising only 2 batteries in series, whose terminal voltage reads 26.5V. My past method of determining the need to change ...
6
votes
1answer
1k views

Cause of dead cell on a flooded lead acid 12v deep cycle battery

I live on the Gulf coast and am annually under threat of hurricanes, so I have a 12v 125 amp hour deep cycle battery I maintain so in the event of a power failure, I can use an inverter to run ...
5
votes
2answers
3k views

How do I charge a 6V, Lead Acid, 4.5 Ah battery using a 3W solar panel?

I have a solar panel with ratings: Vmp=8.8V and Imp=0.3A Using this i have to charge a 6V Lead Acid battery whose capacity is 4500mAh. I have searched the internet a lot and tried many circuits but ...
5
votes
4answers
16k views

What can be the consequences of charging a lead-acid battery with an excessive voltage?

In my field-operating device I use a simple PWM step-down to charge a 6V 3.9Ah lead-acid battery from a 5W solar cell with a voltage of 7.2V. Unfortunately the DC regulator got damaged today and the ...
5
votes
2answers
269 views

Engine cranking corrupts SPI driven 7segment display

I am driving six 7-segment displays with SPI using MAX7219 and ATmega128. This is for displaying various engine parameters like rpm, oil pressure etc. for large marine diesel engines (>100 kW). The ...
5
votes
1answer
2k views

How good is the advice to run the car headlights before starting the car in cold weather?

I'll do my best to formulate this as a purely electrical problem so that it isn't claimed to be belonging to Vehicle Maintenance SE. We have a lead-acid starter battery (not a deep cycle fashion) ...
5
votes
3answers
3k views

What is the most efficient way to power a solar computer (5V) from a 12V lead acid battery?

My project: Power a Beaglebone Black (BBB) entirely from solar energy. Obviously energy efficiency is crucial here. My setup so far: PV panel connected to a deep-cycle lead acid battery. Now I need to ...
5
votes
3answers
2k views

To pulse or not to pulse

It is accepted practice to maintain lead acid batteries at a float voltage of roughly 2.3 Volts per cell. The precise value depends on battery type and battery chemistry and ambient temperature. We ...
4
votes
5answers
2k views

A Battery Charger which can extend LEAD ACID Battery life

I am making a battery charger for a 45AH LEAD Acid Car Battery. That I will use with 100 W (1 A 100 V AC) UPS. I need to know that what things I should keep in mind so that the battery charger ...
4
votes
3answers
5k views

Are sealed lead acid batteries water-resistant?

I am going on a climbing trip in the Canadian Rockies for 20 days starting this weekend. I am bringing a 12volt 7Ah SLA battery that I am going to use to charge my GPS, iPod, Camera, and Sat Phone. ...
4
votes
1answer
19k views

What's the max discharge (in “C”) of a Pb-acid and LiFePO4 (lithium iron phosphate)?

I know that lead acid batteries can handle massive loads, and they are even used to power houses with solar panels, but what is the maximum safe discharge for one of these? I've done some Googling ...
4
votes
1answer
911 views

How to detect low battery of a lead-acid battery?

I've heard that discharging a lead-acid battery to 0% is bad and wears it out. I have a 10Ah 12v lead-acid battery, is there a circuit to tell me when the battery is low?
4
votes
1answer
2k views

Connector for a certain type of lead-acid battery

I need to connect some lead-acid batteries together, to form a bank. A fair amount of current will be drawn from them. However, I haven't seen the terminals used in those batteries before. What ...
4
votes
2answers
3k views

Solar cell trickle charging lead-acid without charge controller

Can somebody comment on sizing a solar cell for trickle charging a lead-acid battery bank without a charge controller for several months? I found a non-authoritative source that claimed that cells ...
4
votes
1answer
1k views

Long term storage of sealed lead acid battery

I was given some brand new sealed lead acid batteries. I have no real need for them right now, but I don't want them to go to waste. I'm trying to figure out the best way to store them, unloaded, for ...
3
votes
3answers
9k views

Can be lead-acid battery charged using NiMH or NiCd charger?

I would like to check total capacity of 64Ah lead "car battery" ^ by fully charging it and currently I have only older intelligent charger (Robbe Power Peak 8467). It directly supports charging ...
3
votes
1answer
287 views

Voltage drop on batteries when connected to ups/inverter

I have recently installed a solar system and trying to understand the voltages of batteries when they are being charged and when they are providing power to load. Here is what I observed: I have 2 ...
3
votes
1answer
497 views

Charging four 12 V lead acid batteries in series or parallel?

I just installed a 48 V ebike conversion kit on one of my bicycles. I will power it with 4 12 V, 12 Ah, lead acid batteries connected in series because of the cost of 48 V, 12 Ah lithium batteries ...
3
votes
3answers
3k views

Is there an instrument that can measure the capacity of lead acid batteries

Background I have an electrical scooter with 6 x 12Volt lead acid batteries (72 Volts total), which are now in such a condition that they can barely get me to my work and back. I got a bunch of used ...
3
votes
1answer
3k views

Charging 12v 9ah lead acid battery [duplicate]

I'm new to electronics, and need some assistance :) I need to charge a 12v 9Ah lead acid battery from 12v input. How should I start with this? 1. step up to 14V? how much do I loose if I try to ...
3
votes
3answers
6k views

Decrease a voltage from 24-27VDC into 18VDC using a 7812 and a bunch of other home supply parts

I have one 7812 1A linear regulator, bunch of resistors and zeners at home. My input voltage is 27VDC from two 12V lead batteries. Desired output voltage is 18V and the maximum current consumption of ...
3
votes
1answer
631 views

Creating a battery backup unit

I live in a area with frequent power failures lasting up to 5 hours. During this time I would like to power my router so that I can still use the internet with my phone/PC. I've looked at UPS ...
3
votes
0answers
55 views

How does the charging curve of a deep-cycle lead-acid battery change as it degrades?

I am designing a circuit inside a UPS that periodically tests how long the battery can power the load. It does this by breifly disconnecting the power from the UPS and extrapolating from the measured ...
3
votes
0answers
203 views

Parallel connection of old and new gel batteries [closed]

I have a battery system shown in the picture, 6 parallel branches of 4 batteries connected in series. The first 3 consist of old batteries which are 2 years old, the fourth branch consists of 1.5-...
3
votes
1answer
742 views

Many questions about charging a lead acid battery

Well, I have a 12V 9AH SLA Battery, and I use a 7815 + a diode in series to charge it, (I really wanted to build a charger using the L200 or the LM317 but I couldn't find any of those in my city). So, ...
2
votes
3answers
479 views

Car battery (lead acid) discharges much, much faster than it charges?

Let's assume a lead acid car battery (12V, 50Ah, 250A output). According to BatteryUniversity article BU-403: The charge time is 12–16 hours and up to 36–48 hours for large stationary batteries. ...
2
votes
2answers
666 views

UPS for home router [duplicate]

Sometimes we have power outages that last about 100 ms that are long enough to discharge capacitors inside router, when that happens we need to wait about 10-15 minutes for DNS, which is pretty ...
2
votes
2answers
69 views

Lead acid battery increasing current under constant voltage

I've found an old lead-acid battery and decided to check if it still is in a decent condition. I've opened all rubber caps and checked that the water level was still OK. It measured 10.5 V before I ...
2
votes
3answers
36k views

Lead acid battery boiling during charging: this is bad, right?

I'm an electrical engineer who could use some help understanding lead acid batteries. I recently bought an old motorcycle and charged the battery on my trusty automotive style battery charger after ...
2
votes
3answers
5k views

What happens if I connect two lead acid batteries in series, one fully charged and one half charged?

I am interested in several things: What happens right when I connect them? How does this behavior affect the batteries, both short term and long term?
2
votes
2answers
5k views

Do I need to fully drain lead acid battery before charging them? [closed]

This is a follow up question based on this. I have an ebike which uses lead acid battery, my question is do I need to fully drain it before charging it again? How about when the battery is newly ...
2
votes
1answer
182 views

What is the effect of pulsed discharge on watt hour (Wh) efficiency of lead-acid batteries?

When discharging a (lead-acid) battery you see a voltage increase (volts rise) as soon as the discharge is paused. source: http://uu.diva-portal.org/smash/get/diva2:461718/FULLTEXT01 In the quest ...
2
votes
3answers
636 views

Charging 12V SLA from Single Solar Cell

I'm interested in charging a 12V Sealed Lead-Acid battery from a single monocrystalline solar cell. The solar cell's voltage is only 0.5V at maximum power point, but it supplies 8A. I will need a 32X ...
2
votes
1answer
440 views

12V Sealed lead acid battery level sensing

I know that you can easily determine the percent capacity remaining in a battery using an arduino by dividing the voltage down to something that the ADC can read. What I'm stuck on is how the voltage ...
2
votes
1answer
1k views

Can I Run An Appliance From a 24v Battery?

First, a little backstory. My wife is planning to operate a booth at some craft fairs and we require power for a piece of equipment (Silhouette Cameo, a computer controlled vinyl cutting machine). We'...
2
votes
2answers
828 views

Is this a viable mini wind turbine setup?

I'm going to build my first wind turbine. I have already constructed the prop, 5 blades 50cm long from PVC pipes. I've searched for a decent sized motor and charge controller. The turbine will be ...
2
votes
2answers
186 views

Reserve Capacity Testing On Lead-Acid Car Battery

All car batteries have Reserve Capacity ratings instead of Ah ratings for deep-cycle batteries. Using this data to test the health of the car battery a good way to estimate life left? Let say I have ...
2
votes
2answers
2k views

Smart Lead Acid Battery Charger Circuit - Is this practical?

I have thought of making a Smart Lead Acid Battery charger using the following schematic. I am not sure, if the circuit would work the way I am expecting it to, or not. My expectations are: The ...