Numax m110 batteries

[WotEver]

Just a quick word of advice, most of us on here have an attention span of a gnat, informative but lengthy post, yawn.

I must admit that when I saw the length of the post I only skimmed it. It didn't appear to contain any new information or anything that we haven't heard ad infinitum albeit generally in smaller chunks.

 

Tony

[bottle]

Strange is it not how we all have different thoughts of how good or bad batteries are, a few posts have have derided Numax batteries.

 

I have six wired for 24v giving a bank of aprox 339 amp.Hrs.

 

I also have two others (Numax different type) as start batteries for the engine and generator

 

They have been in use for the last two years, fitted to boat about two months before launch.

Have never been discharged below 50% SOC (not quite true have been to 45% SOC twice )

 

We are live aboard with an all electric boat, never used the shoreline.

 

As the man that fell from a skyscraper said on his way down, " So far so good".

[larkshall]

I've been meaning to play with those for a while, but haven't got round to it.

 

I do know that even bog standard truck batteries have seen a massive improvement over the last ten years and they handle our sort of cycling infinitely better than they did (say) 20 years ago. I see no reason why these new ones wouldn't be even better.

 

Gibbo, you are already doing a long term test on some other battery, hows that one going?. If they are as good as you suspect, I'll be investing in a set.

[Keeping Up]

When we had two sets of 4 the latest Vartas fitted earlier this year, and they each died within a month, they were replaced with Numax batteries. They are certainly performing better: after 6 weeks of use they still have almost 65% of their original capacity left.

 

No I am NOT impressed with them either.

[smileypete]

When we had two sets of 4 the latest Vartas fitted earlier this year, and they each died within a month, they were replaced with Numax batteries. They are certainly performing better: after 6 weeks of use they still have almost 65% of their original capacity left.

 

No I am NOT impressed with them either.

Are the new batts sealed?

 

Also when the alternator hits it's regulated voltage and the batts are taking a fair charge current, try measuring the terminal voltage on each battery.

 

cheers,

Pete.

Edited September 2, 2011 by smileypete

[Keeping Up]

Are the new batts sealed?

 

Also when the alternator hits it's regulated voltage, try measuring the terminal voltage on each battery.

 

cheers,

Pete.

 

Yes they are sealed, so I cannot measure their SG, I can only read the voltages. The alternator is controlled by an Adverc, and it hits 14.4 volts at the terminals on each and every battery. I also checked that they are all being discharged too.

 

One odd (to me) feature I have noticed when testing them is that when they are partially discharged their terminal voltage drops a long way on even a small load (2.5A per battery); there is not much immediate change when the load is removed, but it recovers by almost half a volt over the next hour which seems a lot to me.

[WotEver]

One odd (to me) feature I have noticed when testing them is that when they are partially discharged their terminal voltage drops a long way on even a small load...

I've always thought that is a sign of a knackered battery.

 

Tony

[Keeping Up]

I've always thought that is a sign of a knackered battery.

 

Tony

 

Me too. These have had 6 weeks of very careful use.

[smileypete]

Yes they are sealed, so I cannot measure their SG, I can only read the voltages. The alternator is controlled by an Adverc, and it hits 14.4 volts at the terminals on each and every battery. I also checked that they are all being discharged too.

OK, as they're sealed I'd speak to a technical representative at Numax and ask them the recommended absorption charging voltage for deep cycle use (but since they're a relabeller they may not themselves know!)

 

Also would be handy to measure the charge voltage across the batt terminals to 2 decimal places, and know what the overall charge current is.

 

One odd (to me) feature I have noticed when testing them is that when they are partially discharged their terminal voltage drops a long way on even a small load (2.5A per battery); there is not much immediate change when the load is removed, but it recovers by almost half a volt over the next hour which seems a lot to me.

 

Can you measure the terminal voltage across each batt, to 2 decimal places ideally, while you're drawing 10A overall?

 

cheers,

Pete.

 

ETA: I think either they're not being charged at the right voltage and/or the bank is out of balance due to a poor connection (I expect they're being charged for a decent time and the bank is a 'ladder' connected at opposite ends).

Edited September 2, 2011 by smileypete

[Keeping Up]

I can't make any more tests for a week or so - the boat is away being blacked - but I've sent my results to the distributor and I'm waiting for his response.

[nb Innisfree]

Me too. These have had 6 weeks of very careful use.

 

What do you describe as very careful use?

[Keeping Up]

What do you describe as very careful use?

 

 

I've watched them extremely carefully after the problems I had with the Varta's.

 

They have been in daily use while we have been on our travels. Our cruising pattern is to travel for at least 3 days out of every 5. On the non-cruising days, charging has always continued until the current taken by the bank of 4 at 14.4 volts was less than 8 amps; on cruising days the engine has been running usually for at least 2 or 3 hours beyond this point by which time the charge current is less than 4 amps, and sometimes continues for up to 8 hours extra when we've had a really long day.

 

The charging is from a 70-amp alternator controlled by an Adverc (which cycles from about 14 to 14.4 volts).

 

Discharging is typically 80 to 90 amp-hours before recharging and has never been more than 150 amp-hours (33% of the nominal 440 Ah capacity). The maximum current drain has never exceeded 30 amps; I've deliberately avoided using any high-powered electrical devices from the inverter, just so that I can make this statement. The longest period ever between the completion of one day's running and the start of the next has been 22 hours, 16 hours is typical.

 

I reckon this constitutes very careful use, but if anyone can spot a flaw in this 'd be interested to hear it. Yet each morning I see the voltmeter hovering around the 12v mark (on a slight residual load of about 1.8 amps).

[larkshall]

I've watched them extremely carefully after the problems I had with the Varta's.

 

They have been in daily use while we have been on our travels. Our cruising pattern is to travel for at least 3 days out of every 5. On the non-cruising days, charging has always continued until the current taken by the bank of 4 at 14.4 volts was less than 8 amps; on cruising days the engine has been running usually for at least 2 or 3 hours beyond this point by which time the charge current is less than 4 amps, and sometimes continues for up to 8 hours extra when we've had a really long day.

 

The charging is from a 70-amp alternator controlled by an Adverc (which cycles from about 14 to 14.4 volts).

 

Discharging is typically 80 to 90 amp-hours before recharging and has never been more than 150 amp-hours (33% of the nominal 440 Ah capacity). The maximum current drain has never exceeded 30 amps; I've deliberately avoided using any high-powered electrical devices from the inverter, just so that I can make this statement. The longest period ever between the completion of one day's running and the start of the next has been 22 hours, 16 hours is typical.

 

I reckon this constitutes very careful use, but if anyone can spot a flaw in this 'd be interested to hear it. Yet each morning I see the voltmeter hovering around the 12v mark (on a slight residual load of about 1.8 amps).

 

This 'slight residual load of 1.8 amps' from what?. thats 28.8 amps gone if you typically aren't using anything for 16 hrs.

[nb Innisfree]

I've watched them extremely carefully after the problems I had with the Varta's.

 

They have been in daily use while we have been on our travels. Our cruising pattern is to travel for at least 3 days out of every 5. On the non-cruising days, charging has always continued until the current taken by the bank of 4 at 14.4 volts was less than 8 amps; on cruising days the engine has been running usually for at least 2 or 3 hours beyond this point by which time the charge current is less than 4 amps, and sometimes continues for up to 8 hours extra when we've had a really long day.

 

The charging is from a 70-amp alternator controlled by an Adverc (which cycles from about 14 to 14.4 volts).

 

Discharging is typically 80 to 90 amp-hours before recharging and has never been more than 150 amp-hours (33% of the nominal 440 Ah capacity). The maximum current drain has never exceeded 30 amps; I've deliberately avoided using any high-powered electrical devices from the inverter, just so that I can make this statement. The longest period ever between the completion of one day's running and the start of the next has been 22 hours, 16 hours is typical.

 

I reckon this constitutes very careful use, but if anyone can spot a flaw in this 'd be interested to hear it. Yet each morning I see the voltmeter hovering around the 12v mark (on a slight residual load of about 1.8 amps).

 

We have 8x120ah AGMs connected to give 24v(480ah) After a couple of years without shore power and doing a monthly long absorption/equalisation we noticed a drop in voltage, batts seemed effectively knackered so I tried doing a weekly raised absorption (29 -29.4ish volts) for 8 hrs or more with a gennie and our Victron, big improvement and they are still hanging on two years later, should have done that from new!

 

So maybe your occasional 8 hr charge from the alternator isn't long enough or would be better with a higher voltage, say, 14.8 - 15v (assuming you have FLAs) and keep an eye on the electrolyte level. You could perhaps just charge with the alternator alone and set the Sterling to a higher voltage and switch it in weekly when doing a long absorption?

Edited September 2, 2011 by nb Innisfree

[WotEver]

... keep an eye on the electrolyte level.

Sealed batts.

 

T.

[Keeping Up]

This 'slight residual load of 1.8 amps' from what?. thats 28.8 amps gone if you typically aren't using anything for 16 hrs.

 

Strictly speaking, of course, it's 28.8 amp-hours gone - but yes you are quite right. It's a noticeable drain but one I'd be happy to put up with if the batteries could take it.

 

The main element of that (just under 1 amp) is the standing current of the 240v inverter together with a couple of small items that it powers permanently; for several reasons it is always on 24x7. In addition there is a significant current taken by the LPG alarm with its two sensors (each sensor takes 175 mA for example), and then there are small currents taken by various other devices which make the total up to just under 1.8 amps.

 

The other item which I regard as a standing current drain, although it clearly isn't, is the fridge because that also stays on 24x7. The compressor motor takes 3 amps when running normally, and it is usually on for about 50% of the time, making its average around 1.75 amps so I work on an average total drain of 3.5 amps when I want to make a quick-and-dirty approximation. That is 56 Ah in 16 hours, or basically one battery's-worth of my 4 (to 50%), which should leave me the capacity of the other three for all my optional equipment such as lighting, TV, water pumps, laptop charging, etc.

[nb Innisfree]

Sealed batts.

 

T.

 

Oh right, missed that!

 

So sealed FLAs? Then got to careful with voltages unless they are AGMs.

[Keeping Up]

Oh right, missed that!

 

So sealed FLAs? Then got to careful with voltages unless they are AGMs.

 

Yes they're sealed but not AGMs so I'm not increasing the voltages unless the manufacturer specifically tells me to do so - because then if I dissolve my engine in exploding acid he can buy me a new one

[Gibbo]

Gibbo, you are already doing a long term test on some other battery, hows that one going?. If they are as good as you suspect, I'll be investing in a set.

 

So far the tests show that they are indestructible! Obviously they're not, but so far I can't break them, and I've seriously abused them.

 

These are Hawker Armasafe. Damned expensive, but the one on deep cycling test is now way past the manufacturer's life cycle spec and it's still producing the full original capacity.

 

Sooner or later it will break, but for comparison the Yuasa lesiure battery that I did the same things to lasted less than a week. This Armasafe is now into something like 6 months (that's a guess by the way) of the same treatment.

[nb Innisfree]

Strictly speaking, of course, it's 28.8 amp-hours gone - but yes you are quite right. It's a noticeable drain but one I'd be happy to put up with if the batteries could take it.

 

The main element of that (just under 1 amp) is the standing current of the 240v inverter together with a couple of small items that it powers permanently; for several reasons it is always on 24x7. In addition there is a significant current taken by the LPG alarm with its two sensors (each sensor takes 175 mA for example), and then there are small currents taken by various other devices which make the total up to just under 1.8 amps.

 

The other item which I regard as a standing current drain, although it clearly isn't, is the fridge because that also stays on 24x7. The compressor motor takes 3 amps when running normally, and it is usually on for about 50% of the time, making its average around 1.75 amps so I work on an average total drain of 3.5 amps when I want to make a quick-and-dirty approximation. That is 56 Ah in 16 hours, or basically one battery's-worth of my 4 (to 50%), which should leave me the capacity of the other three for all my optional equipment such as lighting, TV, water pumps, laptop charging, etc.

 

IMO you need a bigger bank (and bank balance more like!)

 

We have a similar usage to you and we average about 65-70ah @24v, 100ah if we do a wash, it's only down to the fact we have double your capacity that we are hanging on, only 4 batts and they would have died on us long ago.

 

Don't know what inverter you have but ours is a 3kva Victron and they recommend a min of 200ah (24v) so 4 batts would only just exceed that (when new)

[Keeping Up]

IMO you need a bigger bank (and bank balance more like!)

 

We have a similar usage to you and we average about 65-70ah @24v, 100ah if we do a wash, it's only down to the fact we have double your capacity that we are hanging on, only 4 batts and they would have died on us long ago.

 

Don't know what inverter you have but ours is a 3kva Victron and they recommend a min of 200ah (24v) so 4 batts would only just exceed that (when new)

 

Bigger bank balance and bigger space to put them in too. OTOH applying the 50% rule seems to suggest that 4 batteries is optimum for us.

 

We actually have 2 inverters, a small one rated at just 350 watts which is always on and is well within the capacity of a bank of 4 batteries, plus a big old-fashioned Rediline rotary converter which takes negligible standby current (and is the one I haven't used since fitting these batteries)

[Gibbo]

...plus a big old-fashioned Rediline rotary converter...

 

What? This is the 21st century!

[nb Innisfree]

Bigger bank balance and bigger space to put them in too. OTOH applying the 50% rule seems to suggest that 4 batteries is optimum for us.

 

We actually have 2 inverters, a small one rated at just 350 watts which is always on and is well within the capacity of a bank of 4 batteries, plus a big old-fashioned Rediline rotary converter which takes negligible standby current (and is the one I haven't used since fitting these batteries)

 

Is that optimum figure based on new batt capacity? In reality you will probably have quite a bit less than that, as boaters tend to go down to something like 50% before replacement it would suggest batt capacity generally is much less than when new.

[WotEver]

These are Hawker Armasafe. Damned expensive...

And seemingly impossible to find a price for them online.

 

Tony

[Gibbo]

And seemingly impossible to find a price for them online.

 

I'm not certain of this but I think they are for MOD purchase only. I don't think you can buy the Armasafe as a normal person. However, they do a "commercial" version of it. It's orange and is identical apart from some internal "toughness measures" so they don't break when a bomb goes off under the vehicle. This is what I was told at the factory.