A list of battery charging figures

[WotEver]

Sure the knee is soft but the principle remains the same.

 

It will depend

That's the most definitive work yet written about battery operation.

 

Tony

[swift1894]

So......... What I decided to do in the end, was get 6 X T105s (as opposed to 8) and make em work hard.

I've got them on charge now (traction setting on my Mastervolt charger), currently on 14.4v in absorption mode.

So when they go into float tomorrow do I give them an equalising/boost? I'm on mains at the mo but usually rely on my 6kva genny and 800w solar.

[nicknorman]

Yes, looking at that document it is a good idea to "equalise" a new set before use, I would flip the diode switch and/or put it into equalise mode - although personally I've never had much success with the MV built in equalise mode.

Edited February 23, 2016 by nicknorman

[swift1894]

Yes, looking at that document it is a good idea to "equalise" a new set before use, I would flip the diode switch and/or put it into equalise mode - although personally I've never had much success with the MV built in equalise mode.

Thanks so......Tomorrow is Equalisation day!

[Loafer]

Put it in your iPhone to remind you every month!

[swift1894]

Put it in your iPhone to remind you every month!

What a good idea!

[Loafer]

I actually don't need the iPhone App myself. I just know that when Mrs Loafer starts to get a bit gritty, intolerant and occasionally abusive, I know it's time to desulphate the batteries!

[swift1894]

I decided to contact Trojan themselves to get the answer from the horse's mouth.

 

Question:

Hi Can you answer this question please? 8 x T105s versus 6 x T105s, if the same amount of charge is taken from either bank ( example 100Ah), which bank would recharge back up to 100% the quicker, using the same size battery charger? My instinct says the bank with 8 batteries because it's depth of discharge would not be as low as the bank of 6

 

Response:

100 amp-hours is 100 amp-hours. If your recharge rate is the same, then it would take about the same amount of time. If you were talking about discharging to a percentage DOD, then that would be different.

[nicknorman]

I decided to contact Trojan themselves to get the answer from the horse's mouth.

Question:

Hi Can you answer this question please? 8 x T105s versus 6 x T105s, if the same amount of charge is taken from either bank ( example 100Ah), which bank would recharge back up to 100% the quicker, using the same size battery charger? My instinct says the bank with 8 batteries because it's depth of discharge would not be as low as the bank of 6

Response:

100 amp-hours is 100 amp-hours. If your recharge rate is the same, then it would take about the same amount of time. If you were talking about discharging to a percentage DOD, then that would be different.

Personally I think the difference would be small, but 8 would be slightly quicker. In Trojan's eyes probably not enough difference to consider relevant.

[WotEver]

Response:

100 amp-hours is 100 amp-hours. If your recharge rate is the same, then it would take about the same amount of time. If you were talking about discharging to a percentage DOD, then that would be different.

Which is exactly what we said a couple of pages back.

 

Tony

[Loafer]

Often, we don't use more than about 35Ah in one day. (450 Ah T105s)

 

If I want to charge up every day, then that'll take say 4hrs to 100%SoC.

 

If I keep running things for 6 days without charging, that'll take me down to 210Ah used - and it's time to recharge.

 

The ensuing charge will probably take 8-10 hrs - which is LOADS less generator running than charging every day.

 

So which of the following statements are true:

 

1. My battery bank is too big

 

2. I'm saving on petrol but going to need new batteries sooner

 

3. The batteries will spend 6 days sulphating

 

4. It won't really harm the batteries and it's not a bad idea

[WotEver]

1, 2, and 3 are true.

4 is false.

 

Tony

 

Every 3 days would be much better.

[smileypete]

Often, we don't use more than about 35Ah in one day. (450 Ah T105s)

 

If I want to charge up every day, then that'll take say 4hrs to 100%SoC.

 

If I keep running things for 6 days without charging, that'll take me down to 210Ah used - and it's time to recharge.

 

The ensuing charge will probably take 8-10 hrs - which is LOADS less generator running than charging every day.

 

So which of the following statements are true:

 

1. My battery bank is too big

 

2. I'm saving on petrol but going to need new batteries sooner

 

3. The batteries will spend 6 days sulphating

 

4. It won't really harm the batteries and it's not a bad idea

 

I don't normally recommend this, but with your expertise it may be worth considering a split batt bank solution.

 

Bear in mind shallow charges can be less efficient as more time is spent at the higher charge voltage plus any gassing.

 

cheers, Pete.

~smpt~

[Loafer]

1, 2, and 3 are true.

4 is false.

 

Tony

 

Every 3 days would be much better.

 

 

Just mastered the multi-post!

 

I thought 1-3 being true too. I guess it's time to let her use the coffee machine without running the engine!

 

 

I don't normally recommend this, but with your expertise it may be worth considering a split batt bank solution.

 

Bear in mind shallow charges can be less efficient as more time is spent at the higher charge voltage plus any gassing.

 

cheers, Pete.

~smpt~

 

What, and switch from one to the other periodically? That sounds like a bit too much arse for me, Pete. I'll just use more power. I have a PS3 and the wife has a coffee machine, neither of which we normally run unless charging.

[George94]

Disconnect one battery. Get a small trickle charger to keep it topped up. Every six months, change the outcast for one of the others so that they all spend part of ther time as an exile.

[swift1894]

What is interesting, reading it again, is the "boost charge" that you are supposed to give new batteries, or ones that have been stored. Hours at high voltage by the look of it. That is probably why I, and others who failed to do that, have found the performance poor for the first several cycles. RTFM is always a good idea!

OK I've had my 6 x T105s on mains charge now for 2 days. Not yet fitted on the boat. Actually I switched the charger off and back on again to give em another Bulk charge. Hydrometer reading is 1275. So should I now up the voltage to 15.5 and give em a few hours on an Equalisation charge?

[WotEver]

OK I've had my 6 x T105s on mains charge now for 2 days. Not yet fitted on the boat. Actually I switched the charger off and back on again to give em another Bulk charge. Hydrometer reading is 1275. So should I now up the voltage to 15.5 and give em a few hours on an Equalisation charge?

I would. Limit it to a couple of hours though.

 

Tony

[swift1894]

I would. Limit it to a couple of hours though.

Tony

Thanks. Will do.

[smileypete]

What, and switch from one to the other periodically? That sounds like a bit too much arse for me, Pete. I'll just use more power. I have a PS3 and the wife has a coffee machine, neither of which we normally run unless charging.

 

Fair enough, why not go for a smaller bank and charge it more frequently, then play it by ear.

 

Should be better to do an hour or two of genny each day then a long run weekly...

 

Subject to correct charge voltages and necessary equalisation of course!

Edited February 25, 2016 by smileypete