Trojan Batteries?

sailorman said:
quite so but i an stating he will never ever get anywhere near 80A from it, he will be lucky to see 12A a @ 12v
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True, he'll be lucky to see 12A from the DC (12V) output. But that's not what he's using. He's using the AC.

Or are you suggesting there's no point anyone buying a gennie with an output of more than around (12A x 12V nominal = ) 150W? 'Cos that really would be news.
 
Mistroma said:
Not certain where you are getting 12A from as I didn't mention the model of Honda generator.

It's a 20Eui rated at ~1.6kVa (230V model).
AC(230) 7A
DC(12V unregulated) 8A

Perhaps you thought it was a 120V model where output is 13.3A

Doesn't really matter, an 80A 12V charger would run using my 1.6kVa genny.

80A @ 12.7V ~1.02kVa allowing for effic. rating on charger that's only ~1.25kVa, so no problem running the charger.
Anyway, the actual output wouldn't be 80A with my batteries even with parasitic items (ignoring initial startup).
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macd said:
True, he'll be lucky to see 12A from the DC (12V) output. But that's not what he's using. He's using the AC.

Or are you suggesting there's no point anyone buying a gennie with an output of more than around (12A x 12V nominal = ) 150W? 'Cos that really would be news.
Click to expand...
he is using 240v @ 7A
 
Mistroma said:
Not certain where you are getting 12A from as I didn't mention the model of Honda generator.

It's a 20Eui rated at ~1.6kVa (230V model).
AC(230) 7A
DC(12V unregulated) 8A

Perhaps you thought it was a 120V model where output is 13.3A

Doesn't really matter, an 80A 12V charger would run using my 1.6kVa genny.

80A @ 12.7V ~1.02kVa allowing for effic. rating on charger that's only ~1.25kVa, so no problem running the charger.
Anyway, the actual output wouldn't be 80A with my batteries even with parasitic items (ignoring initial startup).
Click to expand...

macd said:
And it which parallel universe will that make him "lucky to see 12A a @ 12v"?
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The charger will never have sufficient power to out put 80A from that gen set
 
GrahamM376 said:
If they're knacked after only one year, have you tried a claim under guarantee? £70 isn't cheap, most motor factors have them cheaper than that and something seems wrong if they don't last longer, have you checked charging voltage? Are they gassing a lot?
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Just bought a new battery with a 2 year garantee. It states they are only covered if you don't discharge below 80% capacity and this is supposed to be a leisure battery. How they would Know I'm not sure.
 
Mistroma said:
Not certain where you are getting 12A from as I didn't mention the model of Honda generator.

It's a 20Eui rated at ~1.6kVa (230V model).
AC(230) 7A
DC(12V unregulated) 8A

Perhaps you thought it was a 120V model where output is 13.3A

Doesn't really matter, an 80A 12V charger would run using my 1.6kVa genny.

80A @ 12.7V ~1.02kVa allowing for effic. rating on charger that's only ~1.25kVa, so no problem running the charger.
Anyway, the actual output wouldn't be 80A with my batteries even with parasitic items (ignoring initial startup).
Click to expand...

macd said:
Ah, I see: you're psychic.

Which would "that gen set" be? The OP hasn't said.
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Ah i see your point :rolleyes::o

it was #12 where another poster mentioned "His" genny :D
 
sailorman said:
The charger will never have sufficient power to out put 80A from that gen set
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I'm afraid that it will, you are forgetting Watts = Volts x Amps. Ignoring AC to DC conversion and inefficiency in charger for now, just apply the formula.

Charger can output around 80A @ 12V and that is 960W (Watts = Amps x Volts, 960 = 80*12)
So the charger needs to be fed with a little over 1000W @ 230V and the current would be 4.4A (Amps = Watts / Volts, 4.4 = 1000/230)

Generator can put out around 1600W @ 230V so max. current is around 7A (Amps = Watts/Volts, 7 = 1600/230)

I run a 40A mains charger from the generator at present and the generator supplies less than 2.6A to achieve that (it's only 85% efficient). So an 80A charger would probably only need about 5.2A at 230VAC from the generator and even that would only happen briefly with my battery bank size.

Apologies about the thread drift. Ah, just spotted someone else saying the same thing.
 
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Sailorman, you keep saying the same thing over and over without sharing the thought process which gets you to your conclusion.

I am no expert, however, I think it works like this:

80 amp battery charger on 230v ac supply from 1.6kva genny, 80 div by 230/12 = 19.16 = 4.17 amps except that there are losses involved, so, at 90% efficiency the charger will draw 4.7 amps from the "mains" supply, well within the rated 1.6kav genny's capability.

oops typing to slow
 
I've been using Trojan SCS225's for the last 12 months no problem, they do drop down to 50-60% at times but they come back up no problem and hold a great charge all the time. I check the water levels monthly as I've found this makes a big difference to performance.

Also I have solar panels and a wind generator to keep them topped up - I run my engine about once every 7 - 10 days at the moment and they to 100% 3 or 4 times a week.

Trojan, I would think would exchange them if you haven't abused them.
 
OP said he'd bought cheap 110Ah open lead batteries for £70 each so doubt they were Trojan batteries. I'd guess that there's zero chance of anything from a warranty. However, he should try to sell them as scrap if he can (I think he mught get up to £15 each in UK but haven't check prices recently). I considered various Trojan 12V batteries but the 6V ones were so much cheaper per Ah and Trojan quoted 2x discharge cycles vs. the 12V ones.

Always a balance though cheap, throwaway or more expensive with poss. longer life. I guess everyone just makes their own choice, balancing expected usage, cost and space available. Boat electrics are great fun (not) as every single change you make affects lots of other things and gives you the option of spending more money.... which in turn changes the system again. :)
 
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Thanks for all the replies - checking the space I've got, and will probably bite the bullet and get 4 x Trojan T-105s.

Will probably mean moving the starter battery, but I think it makes sense to get true deep cycle/traction batteries, given my useage profile.
 
Don't expect miracles of the T-105s.
They are heavily built very traditional batteries designed for good cycle life in floor cleaning machines with daily discharge and daily recharge.
This does not mean they are automatically more resistant to an adverse regime with poor charging. In fact as they use a traditional high antimony alloy because it's better for cycling, they suffer its drawbacks of higher self discharge rate and higher float current, both of which will increase through life, compared with low antimony or calcium, so in some respects the charge requirements are more exacting.
So they are very good and tough used correctly but you won't get the best from them if they are inadequately charged and left partially charged for significant periods. No lead acid battery likes that.
Comments made as a battery industry man, not a liveaboard!
 
Very good point about charging regime.

I didn't ask for more detail from OP as it did sound as if he was going to treat the batteries reasonably well. He said no shorepower and that's obviously a problem.

However, he talked about working in the 50%-85% range and doing a long monthly equalise. That made me feel that he did know about the problems. Doesn't mean he can overcome them of course.

Most of his charging is via alternator or by using his Honda generator to run his 80A mains charger. Not certain how he will do a long equalisation, presumably by using his Honda. My 20Eui would use a fair bit of fuel if mains charger was actually putting in 80A. However, it would be pretty economical when charger was equalising batteries. Of course long runs are a nuisance (for self and neighbouring boats).

Some questions for OP:
1) How long to do the eq. cycle?
2) What's the peak Voltage with your 80A charger?
3) Did you disconnect all equipment during the cycle?

I can only manage a short eq. but better than nothing. Toubador, any comment on relative importance of eq. cycle and min. duration? It's always going to be a problem to do it properly when living on board. I don't eq. monthly though, just 1-2 times a year if SG in cells still vary by more than 0.03 after a few days charging in a marina.
 
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sailorman said:
your honda will out put about 12Amps no matter how big the onboard charger is. 12 Amps is 12Amps. then the loss`s through the charger will also drop that 12Amps
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Surely using the 240 volt output from the genny to drive a charger will make many more watts available?
 
johnphilip said:
Surely using the 240 volt output from the genny to drive a charger will make many more watts available?
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sailorman said:
amps are not watts
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Sailorman seems to specialise in cryptic, unhelpful responses, even when correct.

This is very, very basic but Watts = Volts x Amps.

So, say gennie is rated at 1kW (1000 Watts) and outputs this at 250V (for ease of arithmetic):
that's 1000W = 250V x 4A
Then you convert to 12V:
The same 1000W = 12V x 83A

This of course excludes the inevitable efficiency losses.

What's much harder to work out is how such a simple piece of arithmetic could generate so much angst.
 
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