Adding a second battery?

[Hightower]

If it were me I would upgrade the 75ah you have with a 120ah leisure/starter battery and that's all.

If you are still thinking of a twin set-up I would go as simple as possible, you're more than welcome to come around for a coffee, a chat and to see what I have done on mine. Obviously storing your twin set-up is your main problem, but there are plenty of stand alone options left on the table to discuss.

PM me if you're interested to meet up, I live in Fareham.

[Ovey]

Thanks for the offer Andy, I live in Denmead so not too far away. I probably won't pop round just yet, but maybe in a couple of weeks if that's ok? I have a couple of things going on that I need to sort out first. (It'll give me chance to confirm which battery I actually do have fitted too, as I seem to recall that the 75ah one may have been one I took out of the missus' car at around the same time as the last time I looked at the boat electrics).

[Hightower]

Yeah, no problem! Just drop me a PM if/when you're ready.

[Rokraider]

I have always understood that it is better to have 2 identical batteries, as the smaller capacity one will steal from the larger when linked together, bringing them both to a similar level?

[Ovey]

Yeah, the idea would be to get two batteries of the same capacity. The BEP switches open contacts between the two once one battery drops below a certain level and only reconnects once above another voltage. That way only one battery can go flat theoretically.


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[Hightower]

Originally Posted by Rokraider

I have always understood that it is better to have 2 identical batteries, as the smaller capacity one will steal from the larger when linked together, bringing them both to a similar level?

Never really thought of that. Mine are different capacities but I've not had any issues in 7 years of use. In actual fact 7 years for a battery isn't bad going.

[Wrekindave]

Hello Ovey, was searching for second battery options as I too have a few electrical a to my rib and had the same concerns as you. I have the same console as you and are limited with space.
I have been looking at a "Noco Genius Boost gb30" on Amazon for £93 and it seems to fit the bill without the need for a second battery. It's a lithium battery booster so is small yet powerful.
Anyone have any experience with these?
Sorry using my iphone and not sure how to create a link!

[Pikey Dave]

Originally Posted by Wrekindave

Hello Ovey, was searching for second battery options as I too have a few electrical a to my rib and had the same concerns as you. I have the same console as you and are limited with space.
I have been looking at a "Noco Genius Boost gb30" on Amazon for £93 and it seems to fit the bill without the need for a second battery. It's a lithium battery booster so is small yet powerful.
Anyone have any experience with these?
Sorry using my iphone and not sure how to create a link!

lithium batteries & wet damp environments are a bad mix

[Ovey]

I did wonder! I've gone off the idea of a second battery for the moment though. I've not been able to get the boat out since September through one reason or another so maybe it's a job for next year once Commercialmas is over and I start getting the boat out a bit more regularly.

Thanks for all the ideas & replies!


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[Barrowboy]

Originally Posted by Ovey

I did wonder! I've gone off the idea of a second battery for the moment though. I've not been able to get the boat out since September through one reason or another so maybe it's a job for next year once Commercialmas is over and I start getting the boat out a bit more regularly.

Thanks for all the ideas & replies!


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Weather permitting, I'm planning to get out on 28th December, just as soon as the visiting hordes have disappeared for another year!

For what it's worth, I have a twin 110ah arrangement with a master switch Off-One-Two-Both and keep them in situ on the boat, on the trailer at home, in their purpose-built boxes , terminals all well coated to protect against corrosion and then run a charger on them every three weeks, or so if the boat's stood for a while, just to get some activity through them.

[Wrekindave]

Originally Posted by Pikey Dave

lithium batteries & wet damp environments are a bad mix

I wasn't suggesting that you leave it on the boat! These boosters/ starters are small and light weight. What's wrong with putting one in a dry bag and taking it with you in case of emergency? It claims it's suitable for starting amongst other things boats?

[jyasaki]

Originally Posted by Rokraider

I have always understood that it is better to have 2 identical batteries, as the smaller capacity one will steal from the larger when linked together, bringing them both to a similar level?

You'll only get current transfer if the voltages vary. Assuming 2 different batteries at full nominal voltage, it shouldn't be a problem.

And in truth, even with 2 identical batteries, if you draw from one then switch to both, you have the same scenario you mentioned.

jky

[Pikey Dave]

Originally Posted by Wrekindave

I wasn't suggesting that you leave it on the boat! These boosters/ starters are small and light weight. What's wrong with putting one in a dry bag and taking it with you in case of emergency? It claims it's suitable for starting amongst other things boats?

Ahh! I assumed it would be living on the boat. Still plenty of horror stories regarding LiOn batteries getting wet though. LiOn battery powered tools were banned off several construction sites for a while due to their habit of exploding in the rain


.....sh1t happens.......