Mk powered 8G40 · Wheelchair battery 12V 40Ah GEL
Specifications
| Brand | MK POWERED |
|---|---|
| Part number | 8G40 |
| Voltage (V) | 12 |
| Capacity (C20) | 40Ah (c20) |
| Capacity (C10) | 68Ah (c10) |
| Capacity (C5) | 34Ah (c5) |
| Technology | GEL |
| Length | 197.10 mm |
| Width | 168.10 mm |
This product is priced on demand to offer you the best available price at all times.
Please contact us to request a quote and we will inform you about availability and the best price on the entire website, as well as the delivery time.
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4,74/5★★★★★47 reviewsVerified purchases
- ★★★★★Juan Francisco Gallardo:
Os animo a llamar si necesitais asesoriamiento, a mi me funcionó
- ★★★★★Juan Gomez:
Ya me había encantado que me ayudaran con la elección de la MK 8G40, pero es que encima me asesoraron al momento de instalarla. Todo de 10
- ★★★★★Ricardo Rodriguez:
Gracias a vosotros pude instalar la batería en mi coche
MK Powered 8G40 12V 40Ah is a sealed AGM/GEL battery for daily mobility use: maintenance-free, no risk of spills, and thousands of useful cycles well beyond a starter battery.
Why this wheelchair battery?
- Daily cycling without wearhandles deep discharges without losing capacity
- Sealed AGM/GELno maintenance, no risk of spills
- Thousands of useful cyclesover its full lifetime
Voltage
12 V
Capacity
40 Ah
Dimensions
197×168×174 mm
Technology
GEL
Weight
14,29 kg
Model
MK GEL
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Mobility battery MK Powered 8G40 Mk GEL 40Ah 12V
12VVoltage
40AhCapacity
14.29kgWeight
The 12 V, 40 Ah MK Powered 8G40 from the Mk GEL range with GEL technology is the standard replacement for power wheelchairs, mobility scooters and light electric vehicles. Its 197 × 168 × 174 mm make it the exact replacement for the 40 Ah battery fitted as standard to many power wheelchairs and mobility scooters.
- Sealed AGM/GEL: safe indoors and in transport.
- GEL: excellent resistance to deep discharge and long cycle life.
- Approved for air and sea transport (VRLA).
- No maintenance, no water top-ups.
What the MK Powered 8G40 is for
The MK Powered 8G40 is the usual replacement in power wheelchairs, mobility scooters and light electric vehicles. Recharge after each use and avoid leaving it discharged for days. Check that it matches your current battery in dimensions, terminals and hold-down: this reference has a weight of 14.29 kg.
Dimensions, polarity and mounting
It has external dimensions of 197 × 168 × 174 mm and weighs 14.29 kg. For a direct replacement, the current battery tray must accept these dimensions and the same terminal layout; otherwise adapters will be needed or the hold-down will change.
What MK Powered does differently
MK batteries are the standard in the electric mobility sector: sealed, approved for air transport and with the consistency that wheelchair manufacturers demand as original equipment. We guarantee that every MK Powered arrives new, charged and with the manufacturer's full warranty.
The MK Powered 8G40: Mk GEL range and GEL technology
The Mk GEL is the MK Powered range the 8G40 belongs to: it shares the same construction and quality criteria with the rest of the series, and varies in capacity and format to suit each vehicle.
In a GEL battery the electrolyte is gelled with silica: it is fully sealed, cannot spill and tolerates deep discharge very well. It is the preferred technology in electric mobility, marine service and heavy-cycling applications.
How to make it last longer
GEL batteries need lower charging voltages: always use a charger with a GEL mode so as not to damage the electrolyte. Recharge the wheelchair or scooter after each use and do not leave it discharged for days: lead sulphates and loses capacity.
Official warranty
The MK Powered 8G40 comes with the manufacturer's official warranty against manufacturing defects. If it fails through a defect within the warranty period, we replace it at no cost to you.
Shipping, delivery and returns
Same-day dispatch from our warehouse for in-stock orders placed before 6:00 pm: 24-48 working hours in mainland Spain and Portugal, 3 to 5 days in the islands and the rest of Europe. Returns are accepted for 14 days if the battery has not been used (free collection on the Iberian mainland). You will receive tracking by email.
BCOM-MK-8G40
Data sheet
- Brand
- MK
- Reference
- 8G40
- Model
- MK GEL
- Voltage (V)
- 12
- Length
- 197.10 mm
- Width
- 168.10 mm
- Height
- 174.80 mm
- Weight
- 14.29 Kgs
- Technology
- GEL
- Capacity (C20)
- 40Ah (c20)
- Capacity (C10)
- 68Ah (c10)
- Capacity (C5)
- 34Ah (c5)
Specific References
- MPN
- 8G40
4,74/5
Verified purchasesLatest verified reviews
★★★★★Juan Francisco Gallardo
26/06/2026Me asesoraron en la batería
Os animo a llamar si necesitais asesoriamiento, a mi me funcionó
★★★★★Juan Gomez
08/02/2026La ayuda muy útil
Ya me había encantado que me ayudaran con la elección de la MK 8G40, pero es que encima me asesoraron al momento de instalarla. Todo de 10
★★★★★Ricardo Rodriguez
24/01/2026facil de comprar y llega en tiempo
Gracias a vosotros pude instalar la batería en mi coche
★★★★★Juan Antonio Ruiz
30/12/2025Llega al día siguiente
Me alegra que cumplen con los tiempos de envío
Recommended accessories
How to change the battery
Guide to replace a cyclic battery (12V 4-30Ah) for UPS, mobility scooter, alarm or backup device. Estimated time 10-15 minutes. Important: discharge residual voltage before handling.
Step 1. Power off and unplug the device
Unplug the device (UPS, scooter, alarm) and leave it off for at least 30 seconds to discharge residual capacitor voltage. Work on an insulating surface.
Step 2. Locate the battery compartment
Usually under the seat (mobility scooter/wheelchair), in the rear module of the UPS, or behind a side panel with screws. Check the device manual for unusual models.
Step 3. Disconnect the negative (−) first
With insulated gloves, remove the negative (−) cable first. Some UPS have protection fuses — note their position before removing.
Step 4. Disconnect the positive (+) terminal
Repeat with the positive cable (red, marked +). Important: never let a terminal touch metal of the car while the other is still connected.
Step 5. Remove the old battery
Typical weight 1-15 kg depending on capacity. Many cyclic batteries are AGM/GEL — keep them upright. Do NOT invert the battery: even sealed, residue may exist.
Step 6. Fit the new battery
Same orientation and type (AGM, GEL or flooded). Polarity must match the device, not a chassis (this is not a car). Make sure terminals do not touch metal parts of the compartment.
Step 7. Connect the positive (+) first
On cyclic devices the order is reversed compared to cars: positive (+) first, negative (−) afterwards. Tighten without forcing — the plastic terminal housing of cyclic batteries damages easily.
Step 8. Initial charge before first use
Cyclic batteries ship at 60-80%. Before first use, connect the device charger for 8-12 hours (or use an AGM/GEL smart charger if available). This avoids short cycles and extends lifespan.
Frequently asked questions
Is the MK Powered 8G40 a GEL battery? What is GEL used for?
Yes, this model is a GEL battery: sealed lead-acid where the electrolyte is in gel form. It tolerates deep discharges very well and is ideal for cyclic use (solar, motorhomes, electric wheelchairs, motorcycles). Requires a GEL-specific smart charger — max charge voltage ~14.1 V (vs 14.4-14.7 V for AGM). Lifespan 6-10 years.
How do I fit the 8G40 model in my device?
In most devices it fits in 15-30 minutes with a 10 mm wrench; if the battery is under the seat or in the boot the time can double. See the step-by-step guide on this page. Quick summary: 1) switch off the engine and remove the key; 2) locate the original battery (engine bay, boot or under seat); 3) disconnect the negative (−) terminal first, then the positive (+); 4) loosen the hold-down clamp and remove the old battery; 5) fit the new one in the same orientation — match the polarity shown on the product sheet; 6) connect the positive (+) first, then the negative (−). On devices with Start-Stop or BMS, register the battery via OBD so the alternator applies the correct charging profile.
How long does the MK Powered 8G40 battery last?
Expected lifespan of the MK Powered 8G40 is 6 to 10 years in cyclic use (marine, caravan, solar) with controlled discharges. In cold regions it drops slightly due to cold-start stress; in very hot regions it also drops because of electrolyte evaporation. To extend its life: avoid deep discharges (headlights on with engine off), have the alternator checked yearly, and keep the battery clean and properly secured.
What are the dimensions of the MK Powered 8G40 battery?
Dimensions (length × width × height) are 197×168×175 mm — also written as 197x168x175 mm — following the European DIN standard. Always measure the space in your device before buying: even one extra millimetre can prevent the hold-down clamp from closing. The height shown includes the terminals.
Which batteries are equivalent to the MK Powered 8G40?
Directly interchangeable batteries (same dimensions, same polarity, same Ah and CCA) are the OEM equivalents from leading brands: Bosch, Tudor, Exide and, depending on the model, Banner or Yuasa. Exact equivalence depends on technology — an EFB cannot be replaced with a conventional battery in Start-Stop devices. See the "Equivalents" section to view recommended options at the same performance level.
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