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Deep Discharge Batteries


johnbutty

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Having difficulty in recognising true Deep Discharge Batteries. My instinct is some Leisure batteries masquerade as DDB's. My last set of Leisure have not really lasted the year and are already down to 70% of quoted capacity. I have been pointed at Trojan, but have noticed US Battery, Crown, Powerline all claim to be true DDb's. Question: are these true DDB's, is there much between them. I continuously cruise, have 450watt of solar and on a bad (24hr) day may use 100amps. Max load washing m/c (hot fill, no heater). I am looking for about 300amphr at C20. I use a small 75 amp engine alternator or 2kVA gennie + Victron both via Smartbank/Guage VSR's.

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Tony. The Smartguage/Smart bank uses a learning algorithm based on battery type. It seems to be about right. I also have an Amp Counter (only ruf) and tend myselve to watch the voltage and wait for the charge to drop to about 2% of installed capacity. The Solar MPPT also have an algorithm 4 stage which peaks at 14.6 and floats at 13.2.

Rusty: Self calibrating, it learns. Checked with battery voltage and charge current as above.

 

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29 minutes ago, johnbutty said:

I have been pointed at Trojan, but have noticed US Battery, Crown, Powerline all claim to be true DDb's. Question: are these true DDB's, is there much between them

Cant help with that, as I only use cheapies. Lots on here seem to favour the Trojan T105s. As a rule of thumb I reckon the heavier the better, but just my opinion.

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56 minutes ago, johnbutty said:

tend myselve to watch the voltage and wait for the charge to drop to about 2% of installed capacity.

So tail current. Yep, that works. 

Smartgauge learns the battery characteristics for sure, but that depends upon the gauge's voltage measurement  being correctly calibrated at the factory. We've become aware of some SmartGauges where that factory calibration has been somewhat lacking, hence Rusty's question. 

Trojan T105s are semi-traction batteries. Full traction are available and in general the more you pay and the heavier the battery the better the quality. Speaking to a quality supplier should leave you with a bunch of options.  

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Tony: Thanks. Pretty sure the Smart Guage system is calibated OK, the Link 10 and my own Multimeter all show similar volts about +- .05v. 

I have used some 135 Liesure from Mid**** Swindl***. These were at 42Kg, Wt being historically my criterion as a choice for batteries. However a mate "in the know", tells me it is the thickness of the plates that counts. That is fewer thicker plates rather than many thin plates (starter) that give the higher available discharge and number of cycles. My 135s he reckons are only good for 300 odd cycles and on a floor of 50% discharge. Deep Discharge, good ones 1500 cycles and down to 30% discharge. If I could fit (Space) I would go for 2nd hand traction 2v which apparently go down to 10% and his are now 12 years old! 

Problem with looking at the wt. is I don't know what it is made up from, lots of thin plates (Starter), fewer thicker plates (Leisure) or a very few thick plates of the Traction/Semi Traction type. I cannot get any difiniative answer to where the battery lies on the starter to traction continuum, they does not seem to be an industry std. Just a lot of Marketing. Any advice, the Powerline, a branded Trojan look attractive, but what is inside!!!!!!

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4 minutes ago, johnbutty said:

Tony: Thanks. Pretty sure the Smart Guage system is calibated OK, the Link 10 and my own Multimeter all show similar volts about +- .05v. 

Perfect. Exactly as it should be :)

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I suspect much re the cyclic life depends upon how well the plates are supported, how well they resist vibration and flexing, how well the plate material is held in the plate and how well they are separated. The more one pays  one would hope the better the internal design but as you have found its the devils own job to get proper technical info. Another thing is how large the sediment traps are. I would not be surprised in some of the extra height of Trojans comes from deeper sediment traps.

When I worked at a battery agent I was always told that typical flat plates buckle and flex when under heavy discharge and this causes the plates to shed material. The stress in the powdery lead oxides as the plate flexes will be less in thin plates than in thicker ones. Hence starting batteries having many thin plates because this is one way of minimising plate shedding without resorting to plate pockets. I am far from convinced thin plates on their own means a short life but I am sure that thin plates together with no pockets, thin separators, small sediment traps and poor plate support will.

I would certainly be looking for pocketed plates in a quality battery.

I also have reservations about the wisdom of powering a 2.5kW inverter from a few thick plate batteries.

 

 

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2 hours ago, johnbutty said:

Having difficulty in recognising true Deep Discharge Batteries. My instinct is some Leisure batteries masquerade as DDB's. My last set of Leisure have not really lasted the year and are already down to 70% of quoted capacity. I have been pointed at Trojan, but have noticed US Battery, Crown, Powerline all claim to be true DDb's. Question: are these true DDB's, is there much between them. I continuously cruise, have 450watt of solar and on a bad (24hr) day may use 100amps. Max load washing m/c (hot fill, no heater). I am looking for about 300amphr at C20. I use a small 75 amp engine alternator or 2kVA gennie + Victron both via Smartbank/Guage VSR's.

Having had 2 sets of cheapo leisure batteries that didn't last long despite a exemplary charging regime, we now have Trojan T105s and I'd never go back. They are still at full rated capacity after 3 years (admittedly leisure, but frequent) use, whereas the cheapo s started losing capacity after 6 months or so.

Trojan, US battery and Crown all seem to be similar quality, the latter two perhaps slightly better but a bit more expensive. There is also Rolls.

The 6v Trojan T105s are usually the best value due to their ubiquity in golf carts, but the downside is they are  non-standard size and you are stuck with multiples of 225AH. With your inverter I'd say you want 2 sets ie 450AH. Being American they have unfortunately become significantly more expensive with the loss of value of the £.

They do require a high finishing voltage (14.8v, temperature compensated) and occasional equalisation at 15.5v so make sure you have the ability to do that.

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Tony, Nicknorman: Many thanks info interesting and informative. (note my inverter is 12/1600/70, Gennie is a 2.2KVA). I am struggling for room to get 4 * T105 plus a starter, (have a metal welded tray with large lips welded to the transom?, flat bit above the swim.) 

Are the 12v monoblocks of a lesser quality that anyone is aware of as I can get to my nominal 300amps with 3 of these even at a higher price.

Once again TVM

John

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1 minute ago, johnbutty said:

Tony, Nicknorman: Many thanks info interesting and informative. (note my inverter is 12/1600/70, Gennie is a 2.2KVA). I am struggling for room to get 4 * T105 plus a starter, (have a metal welded tray with large lips welded to the transom?, flat bit above the swim.) 

Are the 12v monoblocks of a lesser quality that anyone is aware of as I can get to my nominal 300amps with 3 of these even at a higher price.

Once again TVM

John

I have 3 Trojan TMX 27's as part of the Boat's Domestic Bank,they are just starting to get weary after 3 years of Summer use and 2 dry periods when Topping up was ,er ,Omitted

Would have them again but the price has risen a bit much in that time,have ordered Yuasa 12 Volters,will look after them(unlike MtB!)

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19 minutes ago, johnbutty said:

Tony, Nicknorman: Many thanks info interesting and informative. (note my inverter is 12/1600/70, Gennie is a 2.2KVA). I am struggling for room to get 4 * T105 plus a starter, (have a metal welded tray with large lips welded to the transom?, flat bit above the swim.) 

Are the 12v monoblocks of a lesser quality that anyone is aware of as I can get to my nominal 300amps with 3 of these even at a higher price.

Once again TVM

John

I think the 12v versions are of the same quality, just more expensive per watt hour.

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True deep discharge batteries are "Traction" batteries. These are tall and thin and each is a single 2volt cell.

Next best is "Semi Traction", usually 6 volts. Most famous is Trojan, US and Crown are alternatives. Powerline are a slightly cheaper version (and so slightly lower quality) but actually made by Trojan (I think). Anything that looks like a car battery is pretty much exactly that despite what the labels and advertising might say.

..............Dave

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1 hour ago, dmr said:

True deep discharge batteries are "Traction" batteries. These are tall and thin and each is a single 2volt cell.

Next best is "Semi Traction", usually 6 volts. Most famous is Trojan, US and Crown are alternatives. Powerline are a slightly cheaper version (and so slightly lower quality) but actually made by Trojan (I think). Anything that looks like a car battery is pretty much exactly that despite what the labels and advertising might say.

..............Dave

This ^^^

The ultimate arbiter of battery quality is weight. The heavier a battery is, for a given size, the more lead it will contain and the better the quality it is.

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17 minutes ago, cuthound said:

This ^^^

The ultimate arbiter of battery quality is weight. The heavier a battery is, for a given size, the more lead it will contain and the better the quality it is.

Sorry but I disagree, however unless you can get   proper technical details its probably the best you can do.

A flat plate traction battery thick, heavy plates, very shallow sediment traps and poorly supported/separated plates would probably last little longer than a so called leisure battery. Its just that makers of traction and semi-traction batteries tend to sell them into knowledgable markets so have to build to a good design.

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You can get full tractions in lots of heights but most are taller than semi or leisure's, mine are 475mm high that fit on the counter with enough room above, but you need self watering caps to fill.

PS they are no more expensive than Trojans.

Neil

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1 hour ago, Neil Smith said:

You can get full tractions in lots of heights but most are taller than semi or leisure's, mine are 475mm high that fit on the counter with enough room above, but you need self watering caps to fill.

PS they are no more expensive than Trojans.

Neil

What make are they Neil ?

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1 minute ago, jddevel said:

Rusty. Read it but not sure whether I really understood it all. It was just a general interpretation I think I got. Am I therefore "adrift" on my apparent understanding?

As I understand it Trojan batteries seem to be a good compromise if you haven't the space/budget for full traction batteries and you don't want budget leisure batteries. The T105's(6 Volt) are usually cheaper than the 12 Volt you have linked to. 

CT above says he has three years summer use out of his tmx 27s.

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