12V 18Ah, 12V 19Ah, and 12V 20Ah+ Lithium and Lead-Acid Batteries
12V 18Ah, 12V 19Ah, and 12V 20Ah+ lithium and lead-acid batteries are deep-cycle, general-purpose rechargeable batteries typically used in wheelchairs, scooters, small electric vehicles/toys, entry-level off-the-grid solar systems, security systems, medical equipment, etc.
As such, 12V 18Ah, 12V 19Ah, and 12V 20Ah+ lithium and lead-acid batteries are offered by many battery brands, and the end user should have problems finding the new battery, however, not all the batteries are the same ...
Published: May 17, 2023.
12V 18Ah, 19Ah, 20Ah+ Lithium And Lead-Acid Batteries Features and Specifications
12V 18Ah, 12V 19Ah, and 12V 20Ah+ batteries feature physical dimensions of (L x W x H) ~7.15 x 3.03 x 6.59 inches (~181 x 77 x 167 mm) and come with a pair of battery terminals with a positive (red) battery terminal on the right side of the battery.
Unlike smaller 12V batteries, which generally use the same battery terminals, for example:
- 12V 7Ah battery: mostly F1 battery terminal,
- 12V 9Ah battery: mostly F2 battery terminal,
- 12V 12Ah battery: mostly F2 battery terminal,
12V 18Ah+ batteries use mostly nuts&bolts or M5/M6 battery terminals, but there are other terminals in use as well, requiring the users to verify the exact battery terminal of the battery before purchasing one.
And if there are different battery terminals on the battery and battery wires, terminal adapters are the way to go - they can be found at most online shops and very often in local hardware stores.
As their labels suggest, 12V 18Ah+ rechargeable batteries feature a nominal voltage of 12V and a capacity of 18Ah or slightly more - these batteries were originally 18Ah wet/flooded lead-acid batteries, but over time they were phased out in favor of maintenance-free Absorbed Glass Mat (AGM) and Gel-Cell Sealed Lead Acid (SLA) batteries.
In the last few years, lithium batteries based on Lithium Iron Phosphate (LiFePO4) chemistry are becoming more and more popular due to the following:
- 2-3x lighter weight,
- no capacity loss due to the high current discharge,
- faster charging,
- 8-10x more supported charging/discharging cycles,
- larger nominal capacity, often 20Ah+,
- can be discharged down to 100% DoD with no adverse effects on the battery; however, even LiFePO4 batteries last longer when being discharged down to 80% DoD.
- truly maintenance and corrosion-free batteries that can be mounted in virtually any position, etc.
However, lithium 12V 18Ah+ batteries also have a few cons, including:
- they initially cost more than AGM and Gel-Cell SLA batteries,
- they should be recharged using lithium battery chargers,
- built-in Battery Management Systems (BMS) protect the battery from unwanted events (which is good), but also, if there is a glitch in a system or there is a surge of some kind, it is easily possible for the BMS to shut off the battery.
Personally, if your application is not power demanding, for example, it requires less than 15-20 Amps continuously and less than 40-60 Amps for less than 1-3 seconds, and You are looking for a 12V 18Ah+ battery that cycles well, go for LiFePO4 battery - get a fine lithium battery charger and your battery will last for a very long time.
12V 18Ah+ Comparison Chart
The following cross-reference chart lists some of the most popular 12V 18Ah+ lithium and lead-acid batteries with their most important features and specifications:
| Model | Cell Type Terminals |
Discharge Currents |
Weight | Review |
| AJC D18S | AGM NB |
- | 12.1 lbs; 5.5 kg | - |
| Casil CA12180 | AGM NB |
- | 12 lbs; 5.43 kg | - |
| Chrome Battery 12V 20Ah | AGM | - | 11.26 lbs; 5.1 kg | - |
| Chrome Pro 12V 20Ah | AGM NB |
- | 12.45 lbs; 5.64 kg | - |
| Chrome Zipp 12V 18Ah | AGM T3 (NB) |
- | 10.55 lbs; 4.78 kg | - |
| Dakota Lithium 12V 23Ah | LiFePO4 M6 |
24A max. cont. 60A <3s |
6.4 lbs; 2.9 kg | Review |
| ECO Worthy 12V 20Ah | LiFePO4 M5 |
25A max. cont. | 4.85 lbs; 2.3 kg | - |
| ExpertPower EP1220 | LiFePO4 M5 |
20A max. cont. 45A 2s |
5 lbs; 2.27 kg | - |
| ExpertPower EXP12180 | AGM NB |
43.89A 10 min down to 9.6V 10.85A 1h down to 10.5V |
11.68 lbs; 5.3 kg | Review |
| ExpertPower EXP12180-Gel | Gel M5 |
- | 11 lbs; 5 kg | - |
| ExpertPower EXP12200 | AGM M5/NB |
12.05A 1h down to 10.5V | 11.9 lbs; 5.4 kg | - |
| Hailong 12V 20Ah | LiFePO4 | 25A max. cont. | 6.17 lbs; 2.8 kg | - |
| Interstate SLA1116 | AGM NB |
180A 5s | 11 lbs; 5 kg | - |
| JITA 12V 18Ah | LiFePO4 | 20A max. cont. 40A 5s |
5.1 lbs; 2.31 kg | - |
| Lachy LFP1218 | LiFePO4 M5 |
40A max. cont. | 5.2 lbs; 2.36kg | - |
| Lossigy 12v20Ah | LiFePO4 M6 |
20A max. cont. | 4.4 lbs; 2.0 kg | - |
| Mighty Max ML18-12 | AGM F2/F3 |
42.8A 10 min down to 9.6V 10A 1h down to 10.5V |
11.2 lbs; 5.1 kg | - |
| Mighty Max ML18-12 Gel | Gel M5 |
41.3A 10 min down to 9.6V 11A 1h down to 10.5V |
11.2 lbs; 5.1 kg | - |
| Mighty Max ML-22-12 | AGM F3 |
53.5A 10 min down to 9.6V 13.0A 1h down to 10.5V |
12.98 lbs; 5.9 kg | - |
| Mighty Max ML22-12 Gel | Gel M5 |
- | 12.98 lbs; 5.9 kg | - |
| Nermak 12V18A | LiFePO4 M5 |
20A max. cont. 60A <5s |
5.07 lbs; 2.3 kg | - |
| Nermak 12V20A | LiFePO4 M5 |
20A max. cont. 60A <5s |
5.5 lbs; 2.5 kg | - |
| NPP NP12-18Ah | AGM T3 (NB) |
270A 5s | 11.5 lbs; 5.2 kg | - |
| Pionergy 12V 24Ah | LiFePO4 | 24A max. cont. | 6.08 lbs; 2.75 kg | - |
| PowerSonic PS-12180 NB | SLA NB |
- | 13.2 lbs; 5.98 kg | - |
| PowerStar PS12-18 | AGM NB |
- | 11.35 lbs; 5.14 kg | - |
| Roypow 12V 18Ah | LiFePO4 M6 |
20A max. cont. | 5.3 lbs; 2.4 kg | - |
| Sigmastek SP12-18 | AGM T2(F2)/NB |
41.7A 10 min down to 9.6V 10.6A 1h down to 10.5V |
11.9 lbs; 5.4 kg | - |
| TPE 12V 20Ah | LiFePO4 | - | 5.73 lbs; 2.6kg | - |
| UPG UB12180 | AGM NB |
- | 11.40 lbs; 5.16 kg | - |
| UPLUS LP12-18 | AGM T2/F2 |
270A 5s | - | - |
| UPLUS LP12-20 | AGM T3/F3(NB) |
300A 5s | 12.46 lbs; 5.65 kg | - |
| VICI VB18-12 | AGM NB |
- | 11.9 lbs; 5.4 kg | - |
| Vision CP 12180 | AGM NB |
- | 11.85 lbs; 5.37 kg | - |
| XZNY 12V 20Ah | LiFePO4 M5 |
20A max. cont. 40A 5s |
4.85 lbs; 2.2 kg | - |
| Weize TL1218 | AGM F3(NB) |
- | 11.25 lbs; 5.1 kg | - |
| Weize TL1220 | AGM T8 |
- | 12.76 lbs; 5.78 kg | - |
Note: Amazon links ("Model" column) open in the new window, feel free to check them for the most up-to-date offers and prices. Also, we have really tried to verify every single bit of information in this chart and to update it periodically, but things change over time without prior notice, so please, do your own due diligence before buying new batteries and other related items.
As one can see, lead-acid batteries usually feature a nominal (20h) capacity in the 18-20Ah range, while lithium batteries feature a nominal capacity of up to 23-24Ah, which is very close to their 1h capacity.
But, most lithium batteries support maximum discharge current up to ~1C - up to 18-20Ah continuously, while lead-acid batteries can easily provide 35-40A currents for up to 10 minutes, albeit with great capacity loss (down to ~30% of their nominal capacity, when discharged at that rate).
How To Charge 12V 18Ah+ Batteries
When the 12V 18Ah+ battery is connected to a vehicle or device that feature internal combustion engine and alternator with a charge controller, let the vehicle/device recharge the battery.
When the 12V 18Ah+ battery is used in a toy, wheelchair or similar applications with external charger, use the charger that You already have, unless You changed the battery chemistries.
While most lithium 12V 18Ah+ batteries are designed to be a so-called drop-in replacement for AGM and Gel-Cell lead-acid batteries, typical lead-acid battery charger can't fully recharge lithium batteries.
Thus, if You have the need to recharge 12V 18Ah+ batteries with the battery charger, then recharge:
- AGM and Gel-Cell lead-acid batteries using advanced lead-acid battery chargers that feature different charging modes for AGM, Gel-Cell, and wet/flooded lead-acid batteries with maximum charging currents up to 4-6 Amps, preferably up to 3-4 Amps. Also, these advanced battery chargers should also feature a temperature sensor/probe for temperature voltage compensation, maintenance mode, and desulphation mode, just in case.
- Lithium LiFePO4 batteries with lithium battery chargers or advanced AGM battery chargers that also feature lithium LiFePO4 battery charging mode, with the maximum charging currents in the 5-8 Amps range - most lithium 12V 18Ah+ batteries support charging currents up to 10-15 Amps, but even they last longer when not overstressed with strong charging/discharging currents.
12V 18Ah+ Batteries as Trolling Motor Batteries
Although lead-acid 12V 18Ah+ batteries can provide 30-40 Amps easily required for trolling motors up to 35-40 lbs of thrust, the such load would discharge these batteries rather quickly.
Thus, if You have smaller trolling motors with maximum currents of up to 15-20 Amps, go for a good lithium 12V 18Ah+ battery (for example, Dakota Lithium 12V 23Ah Battery - Amazon link, opens in the new window) which is able to power such trolling motor for one full hour, with some energy still left as a good safety margin.
Similarly, if You are looking for a lightweight, general-purpose battery when going fishing with your kayak or similar small boat and You need to power a fish finder, navigation lights, and similar smaller loads, consider lithium 12V 18Ah+ batteries.
Long Story Short: 12V 18Ah+ batteries are compact and affordable batteries commonly used in many, often mission-critical applications.
While AGM 12V 18Ah+ batteries are tough, durable, and reliable batteries that can, if required, provide 50-60 Amps for 5 minutes or up to 250-300 Amps for a few seconds, for applications that require batteries that cycle well and are able to provide currents up to 15-20 Amps, lithium LiFePO4 batteries should be considered as a better choice, even if that means getting a new battery charger (just in case).
When looking for a new 12V 18Ah+ battery, go for a battery from reputable brands with as many as possible good reviews ...