Battery Recommendations

[pow2gran]

I have fitted an Optima BT SLI 4.2 which has a spec of 50AH and a 815CCA. The 140hp Suzuki manual suggests a recommended size of 100AH and 512CCA.

Options

1 Replace like with like? I believe the Optima is a good battery and has worked well for the two seasons that I have used it

2 Replace with a battery such as an Exide EP900 which has a spec of 100AH and 720CCA

3 Replace with a conventional battery rather than gel


Any suggestions appreciated.

Nick

[jwalker]

I've always used auto batteries and had no problems with them. The Ah rating is purely the battery's capacity so if it's primarily a starting battery and your engine always starts cleanly with little draw from it otherwise, then that rating is largely unimportant. The CCA is important and since you are already exceeding the Suzuki rating you're free to go with whatever you choose.

Plainly, if one day you have difficulty starting the engine, you might wish you'd bought a larger Ah rating.

[Poly]

Why are you replacing it?

[MatFromPoland]

Originally Posted by Poly

Why are you replacing it?

+1 if it works there is no reason to change it

OPTIMA can works even 5 y so replace it is like throw money to trash I think

[jambo]

Originally Posted by Poly

Why are you replacing it?

Yep beat me to it.......why change??

[Pikey Dave]

For a cranking battery, forget the Ah rating, it's cca that matters. The Optima will be fine.

[pow2gran]

The only reason for thinking about changing it is I don't know how old it is. I have a full season planned and want to avoid any false starts. I know you can test a battery will that tell you wether it is any good ?

The ideal I guess would be to have dual batteries

[steco1958]

How often do you change your car battery ?


exactly, only when it starts to fail


IMO, your wasting your money if you routinely change battery and there are no issues with it.

[Iron Dials]

I get your idea of proactive maintenance.

If this is the only battery would you consider opting for a dual battery set-up?

A conventional battery, in addition to the gel battery, properly wired with automatic charging relay.
All the "house" loads such as vhf/gps/stereo etc are fed from the second battery, and its there as a backup if the gel battery fails unexpectedly.
Blue Sea do "add a battery" kits (smaller one is for rib/outboard set-ups I believe- choice is based on alternator output).
The cost of this option would be similar to a new gel battery I think.

[Poly]

Originally Posted by steco1958

IMO, your wasting your money if you routinely change battery and there are no issues with it.

I do mostly agree (hence my qn above) however, if your car doesn't start it is rarely too serious. That said, even a brand new battery can fail so I'd want an alternative option (rope start? jump start pack?)

[MatFromPoland]

Maybe one more (the same Battery) and VETUS switch

- Accessories - Electricity on board



I have this solution and it works.

[Pikey Dave]

Originally Posted by MatFromPoland

Maybe one more (the same Battery) and VETUS switch

- Accessories - Electricity on board



I have this solution and it works.

Unless the switch is in the "both" position, that will only charge one battery at a time, which defeats the object of having a backup battery. With the Etec, you can use the built in split charging system to charge both batteries independently, otherwise you need a VCR/ACR or similar.

[jambo]

Originally Posted by Pikey Dave

Unless the switch is in the "both" position, that will only charge one battery at a time, which defeats the object of having a backup battery. With the Etec, you can use the built in split charging system to charge both batteries independently, otherwise you need a VCR/ACR or similar.

Dave. If you switch to both when charging and one battery is well down on the other does it not drain the it so they become equal?


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[jonp]

A car battery often gets used daily which is far better for the life of the battery (in fact any battery).

A flat battery in a car is far more easy to sort out than a boat. Nothing worse than the weather turning bad only to find your battery has gone dead.

If you don't have a dual battery system you could carry a jumper battery kit, this could then be used for the car or the boat. If you do get one make sure you get one with enough powere to crank whatever engine system you have (2000A for most diesels).

Jon

[pow2gran]

Thanks for all your comments. I dont want to replace the battery if I don't have to.

The jump start packs look a good idea. Having searched the net the Noco GB40 https://no.co/gb40 looks interesting. There are some impressive Youtube vids.

[jambo]

Originally Posted by pow2gran

Thanks for all your comments. I dont want to replace the battery if I don't have to.



The jump start packs look a good idea. Having searched the net the Noco GB40 https://no.co/gb40 looks interesting. There are some impressive Youtube vids.

Yes I have a dual system but still carry s battery pack which does other things like torch, usb pick ups , pump and power sockets very handy!!


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[Pikey Dave]

Originally Posted by jambo

Dave. If you switch to both when charging and one battery is well down on the other does it not drain the it so they become equal?


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Sort of, the discharged battery will pull down the charged battery & most of the charging current from the alternator will go to the discharged battery due to the lower internal resistance. You can get very high currents flowing by connecting a discharged battery to a charged battery, you are effectively jump starting a dead battery, think about the size of jump leads! An ACR monitors the state of both batteries & only connects them together when the voltage of both is matched.

[jambo]

Originally Posted by Pikey Dave

Sort of, the discharged battery will pull down the charged battery & most of the charging current from the alternator will go to the discharged battery due to the lower internal resistance. You can get very high currents flowing by connecting a discharged battery to a charged battery, you are effectively jump starting a dead battery, think about the size of jump leads! An ACR monitors the state of both batteries & only connects them together when the voltage of both is matched.

I only have battery switch 1-2 or both so I now charge one on road out and the other on the road back unless I know they are similar then I'll do both


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[Paul_S]

I put the add a battery system onto mine with the acr relay. It works great, basically like said, there is no battery 1 or 2, you just have the house/accessory & start battery charging simultaneously without the need to switch from 1 to the other, simple on off switch for turning the batteries off with a position that will combine batteries to start if the starting battery fails. I have a 150 hp mercury and the add a battery mini system works perfectly for this alternator. I have the battery 1 battery 2 switch on my sailboat, and find the add a battery system is much simpler and a lot better.

[Pikey Dave]

Originally Posted by Paul_S

I put the add a battery system onto mine with the acr relay. It works great, basically like said, there is no battery 1 or 2, you just have the house/accessory & start battery charging simultaneously without the need to switch from 1 to the other, simple on off switch for turning the batteries off with a position that will combine batteries to start if the starting battery fails. I have a 150 hp mercury and the add a battery mini system works perfectly for this alternator. I have the battery 1 battery 2 switch on my sailboat, and find the add a battery system is much simpler and a lot better.

That's exactly what I have, works a treat & is idiot proof. Also no danger of blowing the rectifier.