Trojan T-105 battery charging tips

[Graham.m]

If you have got the time etc it will do them no harm, particularly as they are wired in series

[tommyleyland]

I'll give it a go tomorrow or on the next charge

[tommyleyland]

So after charging it to 99% it has dropped to 79% over a couple of hours. Annoying. I know it does drop somewhat after you finish charging but that seems like a lot. The only

Other thing I could have done is left it charging at 99% for as long as possible or even an equalisation charge but otherwise I'm stumped.

[Graham.m]

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So after charging it to 99% it has dropped to 79% over a couple of hours. Annoying. I know it does drop somewhat after you finish charging but that seems like a lot. The only
Other thing I could have done is left it charging at 99% for as long as possible or even an equalisation charge but otherwise I'm stumped.

 

Sounds as if the Smartgauge gave you a false reading when it said 99% when it dropped so quickly to 79%.

How long did you charge for?

[tommyleyland]

It was charging for about 4-6 hours.

[ditchcrawler]

It was charging for about 4-6 hours.

Was that the first cycle?

[Graham.m]

It was charging for about 4-6 hours.

I am surprised for the first charge it was so short. I would have expected 8/9 hours

[nicknorman]

When I first fitted my new Trojans I was very disappointed with them. However after 3 or 4 fairly deep cycles they improved dramatically and are now fine. According to the manufacturers blurb it takes up to 100 cycles to reach full capacity.

 

So for that reason, and also because the Smartgauge will have defaulted to 75% when you reconnected it and needs to "learn" your new batteries, I wouldn't pay too much attention to the Smartgauge reading until you have done 2 or 3 cycles.

Edited December 26, 2015 by nicknorman

[Richard10002]

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Sounds as if the Smartgauge gave you a false reading when it said 99% when it dropped so quickly to 79%.

How long did you charge for?

The manual says that Smartguage can be 10% out when charging.

 

I'd guess it needs to say 99% for a while before it actually is 99%.

[tommyleyland]

I'll discharge to 60% and give it a full day charge with equalisation and do so a few times to make sure everything is reading right. The percentage seems to be dropping at the same rate the old batteries did using my laptop charger which is worrying.

[nicknorman]

I'll discharge to 60% and give it a full day charge with equalisation and do so a few times to make sure everything is reading right. The percentage seems to be dropping at the same rate the old batteries did using my laptop charger which is worrying.

I think you'll find things improve significantly after a few cycles. It's too early to start worrying yet!

 

I took my new Trojans down to 30% SoC and then fully recharged, that good kicking seemed to do the trick, they were much better after that. I think they had been sleeping!

Edited December 27, 2015 by nicknorman

[tommyleyland]

Oh ok I might give that a go as they can safely discharge to 30% anyway

[Graham.m]

Oh ok I might give that a go as they can safely discharge to 30% anyway

How are you going to know when you are down to 30% SoC?

 

And how are you going to know when the battery is fully charged?

Edited December 27, 2015 by Graham.m

[WotEver]

I'd guess it needs to say 99% for a while before it actually is 99%.

That's also in the manual. For the first few cycles SmartGauge may well over-estimate the SoC during charging by (as you said) up to 10%.

[bizzard]

How are you going to know when you are down to 30% SoC?

 

And how are you going to know when the battery is fully charged?

With everything switched off, a simple and cheap little £3 digital volt meter will tell him when the batteries are down to 30% SoC, about 12.04volts.

[WotEver]

How are you going to know when you are down to 30% SoC?

 

And how are you going to know when the battery is fully charged?

SmartGauge will accurately tell him about both once he's done a couple of cycles.

 

The important part is that the discharge must be (I think, from memory) to below 75% and the recharge must be to above 90% to enable SmartGauge to synchronise itself with the bank.

 

As has repeatedly been stated in this thread Tommy has to perform a few cycles before he can begin to rely on the figures. He doesn't have to flatten the batteries, just go through a few discharge/recharge cycles. The manual actually states that the user should 'forget that SmartGauge is there' for 48hours, after which, assuming the batteries have now gone through 2 or more cycles, he will have accurate figures to rely on.

 

Full charge to 100% should be confirmed in the early stages with an ammeter if he doesn't have an intelligent charger which can tell him.

Sounds as if the Smartgauge gave you a false reading when it said 99% when it dropped so quickly to 79

Nope.

 

If Tommy has gone through at least 2 cycles then SmartGauge wouldn't possibly be that far out. I suspect there was a load on the batteries.

[Graham.m]

Trouble is Tommy is discharging new batteries to 30% SoC without a reliable means of knowing when he is there. He needs an accurate measurement now not in several cycles time.

 

30% SoC on a Trojan Flood according to the manufacturer is 11.81V open circuit, no load on the batteries.

 

There is always a good chance of a load on the domestic batteries of a boat. Are you suggesting that the smartgauge does not give a reliable reading if the batteries have a load on them?

Tommy did you get a hydrometer?

Edited December 27, 2015 by Graham.m

[WotEver]

Best advice to Tommy is to not take them anywhere close to 30%. 60% or even 70% followed by a full charge will do it.

 

There is always a good chance of a load on the domestic batteries of a boat. Are you suggesting that the smartgauge does not give a reliable reading if the batteries have a load on them?

Nope. I am suggesting that the load quickly dragged the SoC down from wherever it was to 79%.

 

Or perhaps Tommy hasn't even done two cycles yet so SmartGuage is still waiting to synchronise.

[Graham.m]

Best advice to Tommy is to not take them anywhere close to 30%. 60% or even 70% followed by a full charge will do it.

 

Nope. I am suggesting that the load quickly dragged the SoC down from wherever it was to 79%.

 

Or perhaps Tommy hasn't even done two cycles yet so SmartGuage is still waiting to synchronise.

 

Of course Tommy has not done two or three cycles, I would have thought the previous posts made that clear

[nicknorman]

The Smartgauge is pretty good on discharge straight out of the box. It will read 30% when the actual SoC is close to that. Maybe 27%, maybe 33% but who cares?

 

The important point is that it already has a battery model inside, the only "learning" is between a generic flooded lead acid battery, and tommy's particular batteries. A small difference.

Edited December 27, 2015 by nicknorman

[WotEver]

 

Of course Tommy has not done two or three cycles, I would have thought the previous posts made that clear

It was 3 days ago that he said they were fitted and he was going to start charging them. I'd have therefore assumed at least 2 cycles if not 3.

[WotEver]

The Smartgauge is pretty good on discharge straight out of the box. It will read 30% when the actual SoC is close to that. Maybe 27%, maybe 33% but who cares?.

Spot on. Plus as I said above there's no need to go anything like that low at this stage. Just down to 60% will do, followed by a good long full charge.

[Graham.m]

Don't know who influenced him to go down to 30% SoC. But to me it is way too low, 70% SoC would be enough

[nicknorman]

Spot on. Plus as I said above there's no need to go anything like that low at this stage. Just down to 60% will do, followed by a good long full charge.

Don't know who influenced him to go down to 30% SoC. But to me it is way too low, 70% SoC would be enough

 

Just based on my experience with new Trojans. At first they didn't want to take nor give charge. After a couple of cycles I gave them a good spanking down to 30% SoC and recharged, then suddenly they were great. As I said at the time, it was clearly a case of replacing those old stale American electrons with funky fresh British ones.

[tommyleyland]

When you say there's a load on the batteries, do you mean something plugged in whilst charging as I regularly charge my laptops at the same time.

 

It's in the middle of a recharge which will be another 4 hours today which should take it to 100% if the Smartguage is accurate.