BCI Group 35 Batteries

BCI Group 35 batteries are popular general-purpose and starting batteries, often used in marine, automotive and even industrial applications where space is limited, but one needs a strong and reliable power source for cranking gas and diesel small-to-medium large engines, for medical and security systems, for electric vehicles and similar.

BCI Group 35 batteries are sometimes used as backup batteries for smaller sump pump systems, for smaller off-the-grid applications and for other purposes where their size, capacity, and performances fit perfectly.

optima 8020 164 w300

BCI Group 35 Batteries - Features and Specifications

The physical dimensions of the BCI Group 35 batteries are approximately (L x W x H) 9.0625 x 6.875 x 8.875 inches (230 x 175 x 225 mm), while their electrical features depend on the battery design, chemistry, intended use, etc.

On average, BCI Group 35 batteries feature nominal (20h) capacity in the 40-65 Ah range, they are able to provide 600-900 CCA, 700-950 MCA, and feature RC values between 90-130 minutes.

Most popular BCI Group 35 batteries are AGM (Absorbent Glass Mat) batteries, with Gel-cell and especially wet/flooded models being far less popular and available.

However, lithium BCI Group 35 batteries are gaining in popularity thanks to their ultra-lightweight design, offering great weight savings.

On the other hand, lithium batteries are still much more expensive than AGM batteries, at least initially, and are not yet in widespread use.

The following comparison chart lists some of the most popular BCI Group 35 batteries, with their most important features and specifications:

Model Battery Type Chemistry Ah CCA MCA RC Weight Review
Arc-Angel Group 35 LiFePO4 Battery Starting LiFePO4 40 900 - - 16 lbs; 7.3 kg -
Delphi BU9035 AGM Dual Purpose AGM 50 680 - 100 40 lbs; 18.1 kg -
DieHard 38275 Dual Purpose AGM 50 650 - 100 42 lbs; 19.0 kg -
NORTHSTAR NSB-AGM35 Dual Purpose AGM 60 740 880 115 49 lbs; 22.2 kg -
Optima 8020-164 35 RedTop Starting AGM 44 720 910 90 31.7 lbs; 14.4 kg -
Optima 8040-218 YellowTop Dual Purpose AGM 48 620 770 98 36.4 lbs; 16.5 kg -
Odyssey 35-PC1400T Dual Purpose AGM 65 850 950 130 50 lbs; 22.7 kg -

Note: Amazon links ('Model' column) in the comparison chart open in the new windows, feel free to check them for the most up-to-date offers and prices.

odyssey 35 pc1400 w300

Starting BCI Group 35 batteries are used exclusively as cranking/starting batteries in marine, automotive and industrial applications. As such, they are able to crank medium-to-large gas and diesel engines - starting BCI Group 35 are able to provide up to 900 Cold Cranking Amps (CCA) and up to 950 Marine Cranking Amps (MCA), with pulse (3-5 seconds) currents being even stronger than that.

Dual-purpose BCI Group 35 batteries are general-purpose batteries that are able to provide large cranking currents (but they are not as strong as 'pure' starting batteries), but they also tolerate well deep discharges and are commonly used as deep cycle batteries.

As such, dual-purpose AGM BCI Group 35 batteries feature Reserve Capacity (RC) rating between 100-130 minutes - they are able to provide 25 Amps for 100-130 minutes without their voltage dropping below 10.5 volts at 77°F (25°C).

Lithium Iron Phosphate (LiFePO4) batteries support a much larger number of charging/discharging cycles than AGM batteries, but they initially cost much more. However, in the long run, deep cycle lithium batteries are more cost-effective. Also, they are much lighter.

When starting lithium batteries are used as vehicle starting batteries (so-called 'drop-in replacement batteries'), they must have Battery Management System (BMS) that monitors and protects the battery from undesirable events like overcharging, over-discharging, high and low temperatures, short circuit and similar.

Such drop-in replacements may be recharged by the vehicle's electric system, but should NOT be recharged using lead-acid battery chargers that feature advanced charging modes like desulphation - it may damage the battery.

If the drop-in replacement lithium battery is recharged outside of the vehicle, use either lithium battery charger or advanced AGM battery charger that features lithium battery charging mode.

Note: before connecting lithium battery to ANY electric system, be sure to read thoroughly the manual of that battery and be sure to know what are you doing ...

 BCI Group 35 As Inverter Batteries

When the BCI Group 35 batteries are used for powering smaller inverters, fore example, up to 25 Amps (300VA), one may expect runtime in the 100-130 minutes range.

When the AGM batteries are discharged faster, for example, one hour period, 1h capacity of the AGM batteries drops down to 55-70% of their nominal 20h capacity.

northstar nsb agm35 w300

In that case, for example, NorthStar NSB-AGM35 features an actual capacity of 35-40 Ah (depending on the condition of the battery and its initial charge) and may provide 35-40 Amps for the entire hour - that is ~420-480VA for one hour.

If more power is required for longer periods of time, go for larger AGM or lithium batteries, for example, Group 31 or even Group 4D/8D batteries.

Just be aware that these batteries are also heavier and more expensive.


Long Story Short: BCI Group 35 batteries differ not only in capacity, CCA/MCA, and RC values but also in price, warranty terms, and other important details.

The best overall performers are also the most expensive ones: NorthStar and Odyssey. On the other hand, Optima batteries are very popular batteries since they offer excellent performances at affordable prices and have been tested by countless users in many real-life situations.

Model Battery Type Chemistry Ah CCA MCA RC Weight Review
Arc-Angel Group 35 LiFePO4 Battery Starting LiFePO4 40 900 - - 16 lbs; 7.3 kg -
Delphi BU9035 AGM Dual Purpose AGM 50 680 - 100 40 lbs; 18.1 kg -
DieHard 38275 Dual Purpose AGM 50 650 - 100 42 lbs; 19.0 kg -
NORTHSTAR NSB-AGM35 Dual Purpose AGM 60 740 880 115 49 lbs; 22.2 kg -
Optima 8020-164 35 RedTop Starting AGM 44 720 910 90 31.7 lbs; 14.4 kg -
Optima 8040-218 YellowTop Dual Purpose AGM 48 620 770 98 36.4 lbs; 16.5 kg -
Odyssey 35-PC1400T Dual Purpose AGM 65 850 950 130 50 lbs; 22.7 kg -

Note: Amazon links ('Model' column) in the comparison chart open in the new windows, feel free to check them for the most up-to-date offers and prices

When choosing your next Group 35 battery, be sure to choose according to your own needs and requirements.