Mixed battery chemistry

[GILow]

Hello cruisers,

Well, I have started back on boat tasks today, and number one on the list was pulling out the battery bank. On paper, the 12V house bank has about 450 amp hours capacity, in practice, from observation, I am guessing it has more like 4.5 amp hours capacity. Seriously fried, we survive on the solar panels and the wind generator, both of which seem to keep us going for now as our power demands are trivial.

I had to pull one of the batteries to get to the shaft seal (separate job), which struck me as strange, as up to date none of the really critical boat items have been hard to get to in a hurry. Then I noticed that the battery I had to remove was AGM, whereas all the other batteries in the bank are Calcium (still reading up on those). And the AGM battery was very poorly installed, would have gone for a walk if we'd rolled the boat, whereas the calcium batteries would have stayed put through rollovers and earthquakes. So I suspect it was added later to boost capacity. (ironic)

The batteries are all less than five years old, but were connected full time to a pretty crappy generic car battery charger, and I know the boat had been sitting in its pen connected to the mains for years, so I suspect the charger has destroyed the whole bank, and I am just looking at around 100+ kg of lead scrap now.

But, I am also curious, I would have thought this mixed battery chemistry was a bad idea, I thought that each chemistry had a preferred charging voltage, different to the others. Is this the case, and if so is there even any point of getting any of the batteries tested before I take them to the recycling depot for scrap value?

Matt

[Stu Jackson]

Matt, the best voltage for charging I've found is in the regulator instruction manuals you can find at Welcome to Balmar. Download, say for example, the MC-614, and there will be a chart there showing recommended voltages. AGM and LA are pretty close. Of course, and as always, check with your battery manufacturer to make sure.

[Wraith_Mac]

Mate, it can't hurt to attempt charge them individually before you dump them.
Borrow or rent a 'proper' shore charger, set it to the appropriate regime as Stu advises and charge each one separately.
NB: The AGM has a separate setting to the others.
After you've determined what batts you will have for sure, buy a proper shore charger.
Cheers,
Mac

[GILow]

Thanks guys, that link with the charging voltages was terrific, had no idea how many stages you could define when it came to charging. Certainly a lot more than the current one-charge-suits-nothing-at-all charger, which is no longer on the boat, but has been relegated to the shed for when I forget to turn off the lights on the ute.

All the current house batteries come up to their proper voltages ok, it's just that they VERY quickly drop back down to very poor voltages, indicating no capacity remaining.

Time to look closely at the various battery threads for some ideas on what to replace the house bank with. I have an advantage of starting with a relatively clean slate, all the batteries are cooked and for the bin, I have a good sized wind generator and a decent set of solar panels. Toss the solar reg and put in a MMPT reg with enough smarts to understand the chosen battery chemistry, and I am good to go. Now... what to use as a house bank...

I am going to read that thread on LiFePO4 batteries again with interest.

Matt

[Wraith_Mac]

GILow,
I'd be the last person to turn you away from LiFePo4 but in the mean time...
Did you de-sulphate the FLA batts you have?
Sitting that long on a car charger they probably need a really good deep charge to clean the plates.
You may get some extended use out of them until you decide what to do.
Here's a link to what Nimrod did and why, Bob Ebaugh and Mainesail's setups are well worth studying, almost required reading.
Check suppliers for the latest Aussie cell prices or import direct yourself, it's not very hard to do. They should be cheaper now than in Nimrods case.
Lithium Batteries
Cheers,
Mac

[GILow]

Thanks Mac, I'll look into that document from Nimrod, but I am interested in the de-sulphating remark. I would have thought the problem with the existing battery bank is that they had spent the last couple of years overcharging, the charger had them at 14.6 V when fully charged. I thought sulphating occurred from undercharging. Do I have that the wrong way round?

Matt

[a64pilot]

Why would you want LIFE batteries? I ask because I am pretty familiar with both them and LIPO batteries, both of which when weight is the primary consideration are excellent choices, LIPO is the power to weight king, but way expensive and way too unsafe to be put on a boat, unless in a SCUBA DPV that is. LIFE are way safer, but still expensive.
I think from every perspective that plain ole SLA batteries are very hard to beat, downside I guess is that they can make chlorine gas when flooded with salt water? But they are very well understood, widely available don't require special chargers, cell balancing etc. and actually pretty cheap.

[GILow]

Originally Posted by a64pilot

Why would you want LIFE batteries? I ask because I am pretty familiar with both them and LIPO batteries, both of which when weight is the primary consideration are excellent choices, LIPO is the power to weight king, but way expensive and way too unsafe to be put on a boat, unless in a SCUBA DPV that is. LIFE are way safer, but still expensive.
I think from every perspective that plain ole SLA batteries are very hard to beat, downside I guess is that they can make chlorine gas when flooded with salt water? But they are very well understood, widely available don't require special chargers, cell balancing etc. and actually pretty cheap.

Oh no, I am NOT going into that here. That whole argument has been done to death on plenty of other threads, I'm still sitting firmly on the fence and reading more. Thank you for the caution, I hear you, but let's NOT get started on the pros and cons, I don't want to have to unsubscribe from a thread I started.

Matt

[a64pilot]

Sorry I'm new here didn't know anything about that having already been beaten to death. I'm a cave diver and "scooters" are near and dear to our hearts and scooter manufacturers have tried every possible battery there is. The small battery in my scooter is a kilo-watt hour battery made by these people. Submerge Scooters
If fuel is needed to add to the fire, Rodney at Silent Submersion is awfully knowledgeable about different battery chemistries used in real world situations.

[GILow]

Originally Posted by a64pilot

Sorry I'm new here didn't know anything about that having already been beaten to death. I'm a cave diver and "scooters" are near and dear to our hearts and scooter manufacturers have tried every possible battery there is. The small battery in my scooter is a kilo-watt hour battery made by these people. Submerge Scooters
If fuel is needed to add to the fire, Rodney at Silent Submersion is awfully knowledgeable about different battery chemistries used in real world situations.

Ha ha, no prob. Tip to the new guy, watch out, there are a few angels-fear-to-tread subjects here. LiFeP0-xxx-whatever is one of them, anchors are definitely another. I think docking and sail setting can get a bit dramatic from time to time too. Actually, silly me for mentioning the LiFePO-whatsit thread at the start of the post, brought that one on myself really.

I've never tried a scooter before, but they look like a lot of fun. My wife and I are recreational PADI divers licensed to 30m, but are a bit too chicken to cave dive. There are a few serious divers on this forum and I enjoy reading about what they get up to and dream of doing similar one day. We even have a little crane assembly on our boat fitted by the original owner who was a PADI dive instructor, to lift dive gear out of the water. One day.... sigh...

Matt

[a64pilot]

I've done a little reading now and see your point, you guy's are WAY beyond where I thought you would be, especially with the Hybrid type, and I thought Diesel-Electric was just for submarines
Might be a little optimistic thinking going on but hey, that's how advances are made.
On the cave diving thing, it's not extreme at all, truth is most of us are middle aged and over weight, the Red Bull type of kids have no use for scooters, but us old fat guys do. If you are ever up near the panhandle of Florida, I can get you a taste of cave diving by a professional instructor, it's called Cavern diving, but it's enough to get you a taste.

[GILow]

There's some cutting edge stuff here, I realised after while that CF was full of people with two commodities that are usually in scarce supply. Ideas and TIME. Makes for some lively debate but some really great solutions to problems.

You make cave diving sound a little less dramatic than perhaps I expected, if you really enjoy it may I return the invitation and suggest the underground caves near Mt Gambier in South Australia? I am told they are very good.

Matt

[a64pilot]

That will have to wait until I'm cruising, and that is five years away I'm afraid. I have two more to get through college, then I'm off