New batterry from Tayna not fully charged!

[Zagato]

I bought a new battery from Tayna last week and put it on charge today to make sure it was all right for it's first use but it only registered 50% then 75% after a few minutes. One hour later with a slow battery charger at 4amps and it's still not showing fully charged. It's a slow charger but shouldn't batteries be stored and delivered fully charged. My two identical batteries I bought from Tayna last year where fully charged when delivered! It doesn't matter so much perhaps with a car battery but when your reliant on your GPS and charging isn't so easy on my boat (solar panel) I want to make sure I have a good battery from the outset.

Tayna have asked me to let them know how long it takes to get to fully charged - could be a long time at only 4amps. Shame I haven't got a volt meter...

 

[Pye_End]

The last new batteries I bought (not Tanya) had low electrolyte levels (ie well below level of the plates). Had very little grunt in them (although the rest voltage seemed reasonable), and charging was distinctly odd. Fine when topped back up, but took a while to realise.

How are you testing yours without a voltmeter, and what size is it etc etc?

 

[JohnGC]

Just bought from Tayna, 2 x Trojan T105s and a Varta B36 (all wet).

Electrolyte levels are correct.

I charged the T-105s overnight (connected as a 12V bank). The charge current dropped from 6A to 2A with my bench power supply set to 13.8V at the 6A rate. That's about 50Ah suggesting that the charge as delivered was around 85%. Trojan fully charge before shipping but some self discharge during shipping and storage is normal.

The Trojan user manual specifies the need for an "initial boost charge".

The Varta had a higher charge, but it is a very commonly used battery and I suspect there has been less time between manufacture and me receiving it.

Now I'm waiting for the rest period before measuring the voltages, that will give a reasonable indication of the state of charge. I'm also going to buy a hydrometer and measure the SG.

Completely agree, you need to be sure they are in perfect nick and you're maintaining them well.

 

[Zagato]

The last new batteries I bought (not Tanya) had low electrolyte levels (ie well below level of the plates). Had very little grunt in them (although the rest voltage seemed reasonable), and charging was distinctly odd. Fine when topped back up, but took a while to realise.

How are you testing yours without a voltmeter, and what size is it etc etc?

Enduro EXV90 (90AH) & I havn't got a volt meter unfortunately. 2.5 hrs and still not fully charged. Even my old knackered batteries would be charged by now It's a sealed battery so I can't check the levels!

Thanks for the reply John.

 

[JohnGC]

2.5 hours at 4A is 10Ah which is just over 10% of capacity and nearer 5-7% if you take charging efficiency into account. That assumes the charger is delivering 4A. Not unreasonable so far unless I've misunderstood your figures.

Does the charger have a current meter or is your 4A figure just based on the charger rating? If the later then the actual current could be even less.

 

[Pye_End]

Even my old knackered batteries would be charged by now .

It may well be that your old batteries were not accepting the charge rather than being fully charged.

 

[Zagato]

The charger is just a cheap one that says it delivers 4amps, no meter just indicates low, 50%, 75% and full! Having had 4 new batteries in the last two years that indicated fully charged from new on the same machine I was expecting this new one to be the same and was a bit miffed it wasn't. Perhaps they don't all come fully charged... It's still not on full after 3 hours, have to say I would rather have one delivered that was fully charged... It is obviously an older one probably stored over winter... As long as it's not a duff one.

 

[VicS]

The charger is just a cheap one that says it delivers 4amps, no meter just indicates low, 50%, 75% and full! Having had 4 new batteries in the last two years that indicated fully charged from new on the same machine I was expecting this new one to be the same and was a bit miffed it wasn't. Perhaps they don't all come fully charged... It's still not on full after 3 hours, have to say I would rather have one delivered that was fully charged... It is obviously an older one probably stored over winter... As long as it's not a duff one.

I would complain to Tayna.
It might as you say be one which has been in stock for sometime, although they should be recharged I believe after 6 months.

It might charge up eventually, but Id be looking to charge it at 8 or maybe 10 amps, and be perfectly Ok.

OTOH it may be a dud one which will for ever be loosing its charge.

 

[Zagato]

Well it took 5 hours to fully charge. Glad I checked it first VicS and didn't put it straight in the boat for a seven day rally!

Remind me again about connecting and disconncting is it negative on last for connecting and on first for disconnecting? I always forget

 

[VicS]

Well it took 5 hours to fully charge. Glad I checked it first VicS and didn't put it straight in the boat for a seven day rally!

Remind me again about connecting and disconncting is it negative on last for connecting and on first for disconnecting? I always forget

I d not think it matter what order you connect on a GRP boat.

In a vehicle it is negative on last /off first to avoid the dangers associated with accidentally shorting the spanner to the car body work etc

 

[JohnGC]

Well it took 5 hours to fully charge.

5 hours x 4A is 20Ah.
If the charge efficiency is 90% then you have increased the charge by 18Ah maximum.
That's 20% of the battery capacity meaning it was delivered with 80% charge.

But the current from your charger will have been falling over the 5 hour period from a maximum of 4A to about 0.9A.
That makes the charge delivered to your new battery much lower, say half.
Meaning the battery was delivered with around 90% charge.

The self discharge rate for wet lead acid is around 13% / month = 12Ah for a 90Ah battery.
So your battery has been on the shelf for less than 1 month since it was fully charged.

NB. The figures for charge efficiency and self discharge rate are from Trojan, I can't find the data for your batteries.

I have now measured the no load voltage on my own, new, boost charged and rested T-105s and that indicates a SOG of 100%.

Connecting positives last and disconnecting first prevents damage to touching bodywork when jump starting one vehicle from another.

I'd recommend buying an inexpensive multimeter; a case of "knowledge is power" - literally

 

[sailinglegend420]

5 hours x 4A is 20Ah.
If the charge efficiency is 90% then you have increased the charge by 18Ah maximum.
That's 20% of the battery capacity meaning it was delivered with 80% charge.

Charge efficiency is quoted as an overall charge efficiency as it changes depending on the State of Charge.

From 0-80 SoC the efficiency may be 90%, but from 80-100 SoC the efficiency will be less than 50% on average. So you only have only put in 10 Ah to the battery, the rest has been lost as heat etc...

I do hope you are not adding your "New" battery to an old bank - not a good idea.

 

[JohnGC]

Charge efficiency is quoted as an overall charge efficiency as it changes depending on the State of Charge.

From 0-80 SoC the efficiency may be 90%, but from 80-100 SoC the efficiency will be less than 50% on average. So you only have only put in 10 Ah to the battery, the rest has been lost as heat etc...

I suspect it's even less because the current fall off will approximate a decaying exponential curve and I made a guess based on a straighter line. I think my estimate is worst case.

 

[Neil_Y]

With most chargers they will only be charging at their rated current (Max) when the battery voltage is less than 12.5V, as the battery voltage rises the charging voltage remains the same probably 14.40V ish and the current decreases. So the last few hours will probably be at less than an Amp. The rate of charge is not linear and the last few % can take an hour or two. Something like this graph.

The rated Max charging current is probably a no load state so a completely flat battery, my old but simple chargers have ammeters and you can almost see the current drop to a steady state of 0.5-0.75 Amps for the last few hours.

But the battery should have been charged or pretty near it when purchased.

 

[JohnGC]

With most chargers they will only be charging at their rated current (Max) when the battery voltage is less than 12.5V, as the battery voltage rises the charging voltage remains the same probably 14.40V ish and the current decreases. So the last few hours will probably be at less than an Amp. The rate of charge is not linear and the last few % can take an hour or two. Something like this graph.

The rated Max charging current is probably a no load state so a completely flat battery, my old but simple chargers have ammeters and you can almost see the current drop to a steady state of 0.5-0.75 Amps for the last few hours.

But the battery should have been charged or pretty near it when purchased.

I chose the 0.9A figure because it is the current equivalent to 1% of capacity at the 20hour rate (90Ah). That corresponds to 100% SOC in some multi-stage chargers and according to some battery manufacturers. After that the charger should enter the float stage and the current will fall further.

We don't know how the OP's charger works, so this is guesswork to some extent.

My worst case "fag-packet" calculation suggests the SOC on delivery was at least 90% and probably higher. The remaining question is, was that acceptable?

 

[VicS]

Connecting positives last and disconnecting first prevents damage to touching bodywork when jump starting one vehicle from another.

I'd recommend buying an inexpensive multimeter; a case of "knowledge is power" - literally

The over-riding consideration when connecting jump leads is that the final connection made, and the first broken, should be away from the battery, eg directly to the engine, so that there is no danger that a small spark could ignite any hydrogen gas.
A battery exploding in your face will spoil your day!

 

[ianj99]

Enduro EXV90 (90AH) & I havn't got a volt meter unfortunately. 2.5 hrs and still not fully charged. Even my old knackered batteries would be charged by now It's a sealed battery so I can't check the levels!

Thanks for the reply John.

Knackered batteries equals reduced capacity. That's why they charge up so quickly. I find it puzzling why this simple fact of battery life escapes so many.