Inverter Battery Load Tester 300A 12V — SAMCO LOAD PRO 300
The SAMCO LOAD PRO 300 inverter battery load tester applies a real 300 amp fixed load, so you can see how a 12V inverter or tubular battery (75–200 Ah) holds up under load in 10 seconds. It also tests tall tubular banks and solar batteries block by block.
What the LOAD PRO 300 Inverter Battery Load Tester Does
The SAMCO LOAD PRO 300 applies a 300A fixed load to reveal the voltage sag of the 12V deep-cycle lead-acid batteries used in inverter, tubular and solar systems. The same 300A load makes it equally suitable for 12V inverter batteries and tall tubular batteries from 75 Ah to 200 Ah in home and office backup systems.
A 48V pack is only as strong as its weakest 12V battery. Testing each block separately keeps the comparison consistent and means you replace only the battery that has actually failed, instead of a whole set.
Why a multimeter is not enough: a battery at rest can read 12.6V and look fine while collapsing the moment current is drawn. A 300A load exposes that hidden weakness. See the full comparison in our load tester vs multimeter guide.
These are SAMCO’s practical interpretation thresholds for a fully charged 12V lead-acid battery tested with the LOAD PRO 300 for approximately 10 seconds, not an industry standard. Battery manufacturer specifications should take priority where available.
Who Uses the LOAD PRO 300
Home Inverter Owners
Check a 150Ah or 200Ah tubular battery before the next long power cut, instead of discovering the fault mid-outage.
Inverter & Battery Dealers
Settle warranty claims at the counter with a 300A load reading rather than an argument over resting voltage.
Solar Installers
Commission and service 12V solar battery banks by testing each block on the same load, at the same temperature.
Battery Service Centres
A 10-second test per block keeps workshop diagnostics fast, with a 60-second cool-down between pulls. Battery health is recorded per block, not per bank.
Housing Societies & Offices
Screen backup banks on a schedule and retire only the failing blocks, not the entire set.
Second-hand Battery Buyers
Test a used tubular battery under load before you pay — resting voltage alone does not reveal how well a battery performs under load.
Signs Your Inverter Battery Needs a Load Test
Backup Time Has Dropped
A tubular battery that once gave three hours of backup now gives forty minutes. Short backup time is one of the most common reasons to load test.
Inverter Beeps or Cuts Out Early
The inverter trips on low battery within minutes of a power cut, even though the charge indicator showed full.
Battery Charges Too Fast
A battery that reaches full charge in an hour or two has lost capacity — the plates can no longer hold what they used to.
Frequent Water Top-Up
One cell in a tubular battery drinking far more distilled water than the rest usually points to an internal fault.
Bulging Case or Corroded Terminals
Visible swelling or heavy terminal corrosion means the battery is near the end of its service life.
Battery Replacement Quoted
Before paying for a new battery bank, load test each 12V block — often only one has failed and the rest have years left.
Choosing the Right Load for Your Battery
For this product range, SAMCO uses a practical comparative load of approximately 300A for 75–200Ah 12V deep-cycle batteries, held for 10 seconds. This is a comparative diagnostic method, not a standards-defined CCA test.
| Battery | Ah range | Load needed | Tester |
|---|---|---|---|
| Small / mid car | 30–50 Ah | ~100A | CBLT-100 |
| Large car / SUV | 55–70 Ah | ~200A | BCT-200 |
| Inverter / tubular | 75–200 Ah | ~300A | LOAD PRO 300 — ideal |
| Truck / commercial | 200 Ah+ | up to 450A | BCT-700 HRD |
The LOAD PRO 300's fixed 300A load suits 12V batteries from 75 Ah to 200 Ah. On smaller batteries a 300A pull is too harsh — choose the 100A or 200A tester instead. Not for lithium (Li-ion / LiFePO4).
How to Use the Inverter Battery Load Tester
Charge and rest the battery
Each 12V unit should read about 12.6–12.8V open-circuit before testing.
Isolate each 12V block
Test one 12V block at a time — never a full pack at once. Series connections should only be isolated following the battery or system manufacturer’s procedure.
Apply the 300A load for 10 seconds
Keep terminals clean, clamp firmly, and hold LOAD for a full 10 seconds.
Read the voltage while the load is on
Note the reading at the 10-second mark — it is a key indicator of that block's condition under load.
Cool down
Allow about 60 seconds before moving to the next block.
Voltage & Health Status — Reading Under Load
| Loaded voltage | Status | Action |
|---|---|---|
| 10.0 V and above | Good | Healthy — keep in service |
| 9.9 – 9.0 V | Caution | Weak — recharge & retest |
| Below 9.0 V | Critical | Recharge fully and retest; replace if it repeats |
Temperature note: the pass threshold sits slightly lower in cold weather and slightly higher in hot weather. Compare blocks at the same temperature. For 12V and 24V thresholds across every battery type, see the battery load test readings chart.
SAMCO LOAD PRO 300 Specifications
| Model / MPN | SAMCO LOAD PRO 300 (LOADPRO-300) |
|---|---|
| Test load | 300A fixed — approx. 10 seconds (10s on, ~60s cool) |
| Rated voltage | 12V per block |
| Suitable batteries | 75–200 Ah deep-cycle (inverter, tubular, solar) |
| Display | Digital meter |
| Not suitable for | Lithium / LiFePO4 · two-wheeler (≤35 Ah) · full 48V/60V pack at once |
| Country of origin | India |
| Price | ₹5,757 (GST included) |
Frequently Asked Questions
Can the SAMCO LOAD PRO 300 test a 48V or 60V inverter battery pack?
Which batteries is this inverter battery load tester for?
How long should I apply the 300A load?
How do I read the result?
Which load tester is best for home inverter batteries in India?
Can it test Exide, Luminous and Amaron tubular batteries?
Can I test a solar battery bank with it?
Why is a load tester better than a multimeter for inverter batteries?
Is Cash on Delivery available? What about UPI?
What is the warranty and return policy?
More Battery Load Testers
Chargers for Inverter & Tubular Batteries
Inverter Battery Guides
Where to Buy in India
Samco Battery — 21 Gokhale Market, near Kashmere Gate Metro, Delhi 110054
Founded by Arender Siali, CECRI electrochemist and SAEST life member. · GSTIN 07ANCPS2983B1Z0
+91 99539 35912 · WhatsApp · Google Maps · Mon–Sat 11 AM – 5 PM
Free delivery across India in 3–7 working days. Cash on Delivery and UPI accepted.