I'm trying to build a house bank of batteries in a small boat where space is very limited. I'd like to use two Trojan T-105 6-Volt batteries each having 225-Ampere hour at 20-hour [discharge rate]. The problem is I'd like to have both a 12-Volt system with only the two batteries with the combined 450-Ampere-hour. Whether they're wired in series, parallel, or series-parallel it seems impossible to achieve.
Is there a converter that would make the two 6-Volt batteries into a 12-Volt unit yet allow the combined 450-Ampere-hour?
Or am I dreaming?
Building 450-Ampere-hour House Battery Bank
Re: Building 450-Ampere-hour House Battery Bank
The Ampere-hour rating of batteries does not add when in series.
When batteries are in parallel their Ampere-hour rating is additive.
When two 6-Volt batteries of 225-Ampere-hour are in series they make a 12-Volt battery of 225-Ampere hour.
The only device that can be connected to two 6-Volt 225-Ampere-hour batteries in series to make a 450-Ampere-hour battery is two more of the 6-Volt 225-Ampere-hour batteries in series connected in parallel to the first two.
When batteries are in parallel their Ampere-hour rating is additive.
When two 6-Volt batteries of 225-Ampere-hour are in series they make a 12-Volt battery of 225-Ampere hour.
The only device that can be connected to two 6-Volt 225-Ampere-hour batteries in series to make a 450-Ampere-hour battery is two more of the 6-Volt 225-Ampere-hour batteries in series connected in parallel to the first two.
Re: Building 450-Ampere-hour House Battery Bank
Thanks Jim, I didn't think it would work even with a convertor.
I'll search for a single 12 volt with the highest Ah I can find with the same footprint as the two 6 Volts
I'll search for a single 12 volt with the highest Ah I can find with the same footprint as the two 6 Volts
Re: Building 450-Ampere-hour House Battery Bank
I anticipate your search for a single 12-Volt battery with a rating of 450-Ampere-hours will be unsuccessful.
One alternative might be the ODYSSEY PC1800-FT. It is rated for 214-Ampere-hours, and it weighs 133-lbs. The battery case is much larger than most batteries. Two of these in parallel would give you 428-Ampere-hours. You can find the dimensions and other specifications at
http://www.odysseybattery.com/marine_battery_specs.aspx
In a single case, you might consider the ROLLS 12 CS 11P, which weighs 272-lbs and would provide 357-Ampere-hours. For details see
http://www.rollsbattery.com/wp-content/uploads/batteries/12CS11P.pdf
If space and weight are important, you should consider Lithium-Ion batteries. However, be prepared to spend thousands of dollars and to purchase a dedicated battery management system to regulate charging and discharging. For example, a 12-Volt 450-Ampere-hour Lithium Ion battery system is available at an introductory price of $5,477. See more at:
http://www.bruceschwab.com/uploads/ope-li3-intro-price-ope-1.pdf
One alternative might be the ODYSSEY PC1800-FT. It is rated for 214-Ampere-hours, and it weighs 133-lbs. The battery case is much larger than most batteries. Two of these in parallel would give you 428-Ampere-hours. You can find the dimensions and other specifications at
http://www.odysseybattery.com/marine_battery_specs.aspx
In a single case, you might consider the ROLLS 12 CS 11P, which weighs 272-lbs and would provide 357-Ampere-hours. For details see
http://www.rollsbattery.com/wp-content/uploads/batteries/12CS11P.pdf
If space and weight are important, you should consider Lithium-Ion batteries. However, be prepared to spend thousands of dollars and to purchase a dedicated battery management system to regulate charging and discharging. For example, a 12-Volt 450-Ampere-hour Lithium Ion battery system is available at an introductory price of $5,477. See more at:
http://www.bruceschwab.com/uploads/ope-li3-intro-price-ope-1.pdf
Re: Voltage Convertors
peterd wrote:...I didn't think it would work even with a convertor.
A voltage "convertor" can only lose power, never create power.
Re: Building 450-Ampere-hour House Battery Bank
The least expensive approach to assembly of a large Ampere-hour house battery bank is probably to use two 6-Volt batteries in series, and to use relatively inexpensive flooded cell lead-acid batteries. These batteries are often targeted for use in golf carts.
I found literature from battery manufacturer TROJAN to be very informative. See
https://www.thesolarbiz.com/media/catal ... _Guide.pdf
I found literature from battery manufacturer TROJAN to be very informative. See
https://www.thesolarbiz.com/media/catal ... _Guide.pdf
Re: Building 450-Ampere-hour House Battery Bank
Thanks for for the Trojan link Jim.
Rolls Surette have nice 6 volt battery. I like the weight, the dimensions and the 230 Ah. The 6 FS 230
http://www.rollsbattery.com/wp-content/ ... 6FS230.pdf
I've noticed on a number of cruising sites the Trojan T-105 PLUS 6V Deep Cycle Golf Cart Battery is still very popular
Both have attractive pricing compared to most
I appreciate your input
Rolls Surette have nice 6 volt battery. I like the weight, the dimensions and the 230 Ah. The 6 FS 230
http://www.rollsbattery.com/wp-content/ ... 6FS230.pdf
I've noticed on a number of cruising sites the Trojan T-105 PLUS 6V Deep Cycle Golf Cart Battery is still very popular
Both have attractive pricing compared to most
I appreciate your input