Cranking Battery

[Han]

Hi All,

I have to replace my batteries and I'm thinking of changing things up a bit.

I have completely separate cranking and house batteries connected by a Xantrex echo charger and an on/off/emergency-combine battery switch (Blue Sea 5511e). Currently I have a two Trojan SCS150's, one for the house battery and one for the cranking battery, but I'm considering getting a starting type battery for the cranking rather than another deep-cycle. It seems better suited to the task and I could probably get something a bit smaller and (maybe) cheaper. Does anyone foresee a problem with this? and would it be ok to use an AGM type cranking battery with a flooded deep cycle battery in this kind of setup? I don't plan on ever having to combine my batteries, but you never know. Also what type of cranking battery is best for starting a small (28hp) diesel (my engine specs call for a minimum of 500CCA and 80Ah at 12V.)?

thanks!

[djmarchand]

A Group 24 starting battery will work fine with a 28 hp diesel.

It would be better to have all of the batteries, house and starting of the same type. But I have mixed flooded cell and AGMs but the reverse of what you are planning with no problems.

David

[mbianka]

Originally Posted by Han

Hi All,

I have to replace my batteries and I'm thinking of changing things up a bit.

I have completely separate cranking and house batteries connected by a Xantrex echo charger and an on/off/emergency-combine battery switch (Blue Sea 5511e). Currently I have a two Trojan SCS150's, one for the house battery and one for the cranking battery, but I'm considering getting a starting type battery for the cranking rather than another deep-cycle. It seems better suited to the task and I could probably get something a bit smaller and (maybe) cheaper. Does anyone foresee a problem with this? and would it be ok to use an AGM type cranking battery with a flooded deep cycle battery in this kind of setup? I don't plan on ever having to combine my batteries, but you never know. Also what type of cranking battery is best for starting a small (28hp) diesel (my engine specs call for a minimum of 500CCA and 80Ah at 12V.)?

thanks!

No problem having a dedicated cranking battery. The AGM cranking and flooded will work ok together if you need them on occassional "emergency basis" say to start the engine. But, I would not combine them long term because your cranking battery will not hold up for too long. It's for short term load with a quick recharge only. Like starting the engine hence the term "cranking:.

[bill good]

I am going LIFEPO4s for starting. Looking good see the results posted. No more lead batteries for me!!
Han check PM
Regards Bill

[barnakiel]

Toilet rolls are very good. Red top plenty of cca.

b.

[Stu Jackson]

Good idea to never combine the banks UNLESS A CHARGING SOURCE IS PRESENT.

Your dual circuit switch has some inherent issues that you might want to be aware of.

AGM Battery Issues (from Maine Sail) [added 8/18/11]
AGM Batteries - Making The Choice - SailboatOwners.com

AGM Battery Issues and the Blue Seas Dual Circuit Switch (from Maine Sail) "DARN AGM Batteries"
Darn AGM Batteries - SailboatOwners.com

As far as mixing battery types, you can check the charging regimens for each type. Best way I've found to do so is to go to Welcome to Balmar - 2012 and download or read on of their regulator manuals, like the MC-614. Page 12 shows all the charging requirements for different battery types. AGMs and wet cells are quite close.

[bill good]

Just a comment on mixing battery types. It appears on the surface the LIFEPO4 has a very big advantance here as unlike lead when they reach the level of charge for the voltage selected they appear to be disconnected i.e. nil current flow into them & they don't care if not fully charged so a wide voltage of operation within their lower & upper levels.

Regards Bill