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.

204 questions
234 views

### What is the actual capacity & charging current of a given deep cycle lead acid battery?

Firstly let me say that this is with a view to using a lead acid battery for backup purposes in case of power outage (mains power, a few lightbulbs but with daily outages lasting a few hours) So let'...
200 views

### Understanding C20 value of lead battery for a low power circuit

I've developed a simple circuit using a Photon to send data to my database. It has to be a portable device and because of this I looked into lead batteries. My circuit runs on 5V and draws a maximum ...
89 views

### Will a 4 Ah 12 V battery be fine for a 2 A 12 V diaphragm pump + a Raspberry Pi?

I've got a 4 Ah 12 V lead acid battery which currently runs a Raspberry PI. I'd like to connect a diaphragm pump to this battery as well. The pump has a max. rating of 2 A. Assuming a fully charged ...
262 views

### Powering a 5v raspberry pi, a 12v motor and a 24v motor using 2 batteries charged with a solar panel

I want to control a 250W 24v motor, as well as a 12v 1W motor using a raspberry pi. It needs to all be powered by 2 lead acid batteries which are being charged when not in use. My plan is to use two ...
33 views

### What is the optimal cable length for connecting 4 x 12V lead acid batteries in parallel using a balanced draw configuration? [duplicate]

I understand that the best method of connecting 4 x 12V lead acid batteries in parallel in order to achieve the most even and balanced draw is illustrated by the diagram below. Should the cables ...
121 views

### What is the lowest voltage a 12V lead-acid battery in a car could be?

I'm trying to design a product that is powered from the 12V rail inside the car. In normal driving (engine running, electronics on etc.), what would be the minimum voltage of a low battery? Reading ...
38 views

### MPPT lead acid over voltage

As I understand it, an MPPT algorithm adjusts the charging voltage until it finds the point where maximum power is delivered into the battery. If a 12V lead-acid battery is used, is there an upper ...
63 views

I recently found a great appreciation for the long battery life of my newly acquired mac book pro and was thinking how I can scale that up even more (since I travel and work on site a lot), by ...
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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, ...
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### CSB batteries Constant Current Discharge Characteristics

I'm comparing batteries for use in UPSes and during my tests I was consulting the datasheets of 2 manufacturers. The datasheet from SunLight is crystal clear but CSB's datasheet is using terminology ...
145 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-...
122 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 ...
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 ...
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### Battery Discharging and Effect on Lifespan

I have noticed that some times during the day when my solar system panel is shaded it starts using the battery bank power (a few ampers) for a few seconds and then recharges the battery after the ...
54k 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 ...
13k 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 ...
83 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 ...
14k 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 ...
107 views

### Battery Disconnect Switch

I'm an Electrical Engineering student still new to power systems. I'm working on a project that uses a 24V and 200Ah battery bank made up of 4 AGM lead acid batteries. The batteries are supplying four ...
50 views

### What is 'DOC' in terms for Depth of Discharge for SLA batteries?

I'm trying to understand the spec of a SLA battery. There's a chart which is titled "Cycle Life in Relation to Depth of Discharge": Can I ask what 'DOC' stands for and the chart is read? How come ...
72k views

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 ...
131 views

### Does mobile charger and buck converter have any basic difference?

I have a 2 cell(4.2V)/12Ah deep cycle flooded lead acid battery that i usually charge by 5V/2A smartphone charger. By using this charger it takes 200mA current for charging. Today i got my CC/CV buck ...
61 views

### Which AGM battery terminals should be used when wiring 3 or more batteries in parallel?

With a 12V AGM battery bank of 3 or more batteries wired in parallel, is charge able to be drawn by attaching to any random positive and negative terminal across the battery bank? Is it optimal to ...
99 views

### What is the effective equivalent battery capacity between Lithium Ion and Sealed Lead Acid batteries? [closed]

I was told by a battery salesperson that a Lithium Ion 100Ah battery is equivalent to a 260Ah lead acid battery bank. Is this correct? I understand that lead acid batteries should only be discharged ...
58 views

I want to monitor a 12V lead-acid battery using an ADS1110 ADC. This ADC has a reference voltage of 2.048V. Thus, I (think) need to condition my input from, say a 10V-15V level range to 2 volts (0.4 ...
46 views

### Substitute 12v Lead Acid Battery with Nominal 10.8v Lithium Ion Battery?

I am looking to replace an existing 12v Lead Acid battery configuration (two 7.5Ah batteries in parallel) for an old practice tennis ball machine. The machine consists of 12v dc motors and sensors to ...
40 views

### Do I need a cut off circuit for my battery

Do I really need an auto cut off circuit for my battery when my charger only outputs 13V and 1A at max. The battery I want to charge is a 12V 7Ah Sealed Lead Acid. I heard that the cut off for lead ...
48 views

### trickle charge backup battery

I would like to know if the schematic below would work to keep a 12V SLA battery at or close to float voltage to be used as a backup battery? R1 will limit the charge current to the battery, but am I ...
154 views

### Lead acid battery charging current dosent become zero

Here I am charging a 6V 4.5Ah lead acid battery by using a 8V-10V LM317 input supply for the circuit. I'm using the BD139 transistor to cut off and a 6.8V zener diode. As the battery voltage reaches ...
17 views

### Using SLA in place of LFP to test an LFP charging device

I'm testing a solar charge controller for LiFePO4 that uses absorption and float stages. By design, power-on initiates the absorption stage, and a timer terminates absorption and initiates the float ...
69 views

### Sealed lead-acid battery UPS indoor?

I bought a BX700UI APC UPS for my linux arm server setup (40 watts) to protect it from power cut. - I have the server in the bedroom is it dangerous to have such an Ups in a small bedroom? - Thinking ...
51 views

### charging 12v lead acid battery with OEM charger [closed]

I have an ExpertPower 12V 7 Amp EXP1270 Rechargeable Lead Acid Battery (link on Amazon here) and would like to safely charge it. Do you think this charger (Battery Tender 021-0123 -- link here) is an ...
11k views

### Charging Lead Acid Battery from dynamo

I want to build a Lead acid battery charger. for that I want to use a small IC engine coupled to a dynamo and the dynamo I got is rated at 12V, 35A and I want to charge 12V 7.5 Ah Lead Acid battery. ...
4k views

### pulse charging lead acid battries effects and side effects

I am developing a solar charger which charges lead acid batteries.I would like to clear a few of doubts on this issue. I am using IR2110 gate driver for driving 2 n-channel mosfets in an half bridge ...
30k views

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 ...
1k 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 ...
500 views

### Mixing Lead acid and Lithium ion in series, after charging them separately

Can I connect a Lithium ion battery battery pack with a Lead acid battery bank; in series. I will charge both separately cells strings separately (not to mix the chemistries) before putting them in ...
26 views

### Designing an effective extensible solar cell + car battery setup [closed]

I've got a cabin that I visit on weekends and because I need to charge my computer and tools there, I decided to bring an old car battery and bought a solar panel to charge it. Right now I use a cheap ...
4k views

Are there any special requirements for charging lead-acid batteries?
467 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. ...
108 views

### Charging a lead acid battery with a lower bulk voltage

Will a lead-acid battery completely charge when using a bulk voltage below the one indicated on the specs sheets for it, even if it takes longer? In my case the battery is in a place with temperature ...
102 views

so I got a ups with a 12v lead acid battery that was constantly on so the water inside the cells has disappeared, initially the reading voltage was 0.3v, and when I added distilled water it generally ...
5k views

### Charging lead acid battery using boost/buck converter

I plan on permanently connecting a 12v lead acid battery to my home made wind turbine (dc). I already have a dc-dc buck/boost converter so I wonder if i can use that to charge the battery. ...
220 views

### How to limit HV capacitor charging current?

I have a voltage doubler, which is connected to mains (without galvanic isolation): It enticed me with its simplicity, configurability and option between charging speed or desulfatability. The ...
96 views

### Using li-ion battery in place of a lead acid one in a desk lamp [closed]

I have a rechargeable desk led lamp with USB power input. Although it's supposed to hold charge, it only works when plugged. I opened it and found that the problem is about included lead acid ...
3k views

### Lithium Ion and Lead Acid battery in series

I have a 12v trolling motor (55 lb) that is rated for 50 amps. At speed I only pull < 30 amps in my inflatable boat. I know that increasing the voltage will make the prop spin faster, which will ...
174 views

### Can lead acid battery be used as a capacitor between power supply and equipment?

I have a lead acid battery from an old broken ups. And I have a WIFI router with power adapter. Can I connect the battery directly in the middle between the power adapter and the wifi router like ...
129 views

### How much input voltage is required to get 12v from LM2596?

I am trying to run WiFi router from a 12v lead acid ups battery. To get a stable 12v output from the battery I used LM2596. Problem is output is always 8.28v-8.50v. No matter how many times I spin ...