6v Golf Cart Batteries In Series - How Many?

demonboy

demonboy

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Battery head-scratching continues as the CEO of the company who makes the AGMs here has told me personally not to install them on my boat! He has some other options which I'm picking up on tomorrow but in the meantime I have heard there is a shipment of Trojan T125 6v batteries (details here) arriving in India soon.

My question is: if I want the equivalent of 450-500aH 12v domestic bank, how many do I need and how do I wire them all up? I know of course that two must be in series to make 12v, but I'm sure I read somewhere that 2x6v 100aH batteries does not equate to 200aH. Also if I wire up two in series to make 12v, how do I then wire up these two to the other sets of two? Is it a case of two in series then joined in parallel to another two in series?
 
demonboy said:
My question is: if I want the equivalent of 450-500aH 12v domestic bank, how many do I need and how do I wire them all up? I know of course that two must be in series to make 12v, but I'm sure I read somewhere that 2x6v 100aH batteries does not equate to 200aH. Also if I wire up two in series to make 12v, how do I then wire up these two to the other sets of two? Is it a case of two in series then joined in parallel to another two in series?
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You need 4 batteries. Two in series will give you 12v and 240Ah. Join these in parallel to another pair in series and you get 12v and 480Ah.
 
As the two posts above said: the T125 is 6V/240Ah, yes? Two in series gives 12V/240Ah. Two pairs gives 12V/480Ah.

Simply wire them as two pairs in series, then regard the pairs as single 12V batteries which you'll then wire in parallel. Basically with each pair of 6V batteries, you're wiring 6 cells in series, just like your current 12V batteries (6 top-up holes, one for each cell, yes?). Each cell gives a nominal 2V; 6x 2=12.
 
demonboy said:
Battery head-scratching continues as the CEO of the company who makes the AGMs here has told me personally not to install them on my boat! He has some other options which I'm picking up on tomorrow but in the meantime I have heard there is a shipment of Trojan T125 6v batteries (details here) arriving in India soon.

My question is: if I want the equivalent of 450-500aH 12v domestic bank, how many do I need and how do I wire them all up? I know of course that two must be in series to make 12v, but I'm sure I read somewhere that 2x6v 100aH batteries does not equate to 200aH. Also if I wire up two in series to make 12v, how do I then wire up these two to the other sets of two? Is it a case of two in series then joined in parallel to another two in series?
Click to expand...

6 volt Trojans are designed for golf carts and therefore can take a fair amount of abuse ie they can drain and then be recharged , however what they can not take is the water getting to low this will in effect kill them. It is therefore very important to check them on a regular basis I if you wish them to last.
 
Read http://www.smartgauge.co.uk/batt_con.html for good advice on connecting multiple banks. Better to equalise current paths, not quite like Salty John's drawing. i.e. move either the pos or neg output wire to the other bank, don't have them both on the same one. Not critical, but it's no harder to do it right! If you can look at Trojan's manual at http://www.trojanbattery.com/pdf/TRJN0109_TRJNUsersGuide.pdf fig 2.4.3 shows it.

Would be interested to know why the Southern Batteries boss said no and what his alternative is.

I'm sure the Trojans would be excellent - and expensive - but you were determined not to have wet ones!
 
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pagos said:
what they can not take is the water getting to low this will in effect kill them. It is therefore very important to check them on a regular basis I if you wish them to last.
Click to expand...

Am I missing something here? I thought golf cart batteries were a type of AGM so what am I checking exactly?

Troubadour - the boss man explained that their AGM technology was not as advanced as in the west and he did not have confidence that they would be suited to deep-discharging. He has tubular, which are not practical, and another deep-discharge alternative which he is sending me info on tomorrow. He also said he may be able to put me in contact with Indian golf cart battery manufacturers so the Trojans are not a definite go-ahead, just another idea I'm flirting with. I'm still waiting for the price on them.
 
nimbusgb said:
Those trojans are 240 A/h at around 10 amps draw. If you can keep your current max to say 5 or 6 amps I'll bet that they will deliver more like 300 or even 350 A/h
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The 240Ah capacity is already at the 20hr rate. You will not see much increase on that. In any case it would be unwise to utilise it. More Ah taken out will do more cycling damage whether it's at 5A or 10A current. It's the same amount of active material conversion and consequently the same volumetric change causing physical damage.
 
demonboy said:
Am I missing something here? I thought golf cart batteries were a type of AGM so what am I checking exactly?

Troubadour - the boss man explained that their AGM technology was not as advanced as in the west and he did not have confidence that they would be suited to deep-discharging. He has tubular, which are not practical, and another deep-discharge alternative which he is sending me info on tomorrow. He also said he may be able to put me in contact with Indian golf cart battery manufacturers so the Trojans are not a definite go-ahead, just another idea I'm flirting with. I'm still waiting for the price on them.
Click to expand...

1 Golf cart battery is as meaningless a term as leisure battery! People use anything from car batteries through leisure to real deep cycle! (EDIT - flooded or sealed.) Trojan do offer this one as a very superior golf cart battery as well as as a marine battery.
2 This model Trojan is definitely wet. They also make a 200Ah AGM in the same dimensions model 6V-AGM.
3 That's very honest of Southern! I imagine their alternative will be a wet deep cycle flat plate corresponding to the Trojan. Their range is called ALIGHT but biggest seems to be 12V 190Ah.
 
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pvb said:
You need 4 batteries. Two in series will give you 12v and 240Ah. Join these in parallel to another pair in series and you get 12v and 480Ah.
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If the batteries are 6V 120Ah, then 4 will give 240Ah at 12V not 480. Two in series will give 12V 120Ah not 240Ah.
You will need 8 Batteries to get 12V 480Ah
 
BGW said:
If the batteries are 6V 120Ah, then 4 will give 240Ah at 12V not 480. Two in series will give 12V 120Ah not 240Ah.
You will need 8 Batteries to get 12V 480Ah
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I wonder whether you read the original post? It mentioned Trojan T125 6v batteries, and gave a link to Trojan's website, which showed that they are 240Ah batteries. So, as I posted earlier, the OP only needs 4 of them.
 
pvb said:
I wonder whether you read the original post? It mentioned Trojan T125 6v batteries, and gave a link to Trojan's website, which showed that they are 240Ah batteries. So, as I posted earlier, the OP only needs 4 of them.
Click to expand...

That would be correct - I didn't follow the link and incorrectley thought that the T125 meant circa 120Ah - My apologies.
 
Jamie, Check this out, http://www.rollsbattery.com/content/tech-faqs. It might answer some questions for you. I use the 6volt S600 range. IMHO I would not use anything other than flooded deep cycle batteries. He who pays makes his choice though and it is also down to price or budget. Apart from the above Trojan are along the top self of makes. G

___________________________________________________________________
 
Morning all, and thanks for the various comments and links. I especially liked the thread provided by Stu because it's a no-nonsense thread written by someone with a lot of experience with all types. It's helped knocked a couple of things off my shopping list and, more importantly, it's swinging me back round to the idea not only of wets but also the idea that topping up once in a while is a small price to pay for performance and longevity.
 
I have exactly the battery configuration described: 4 x Trojan T125 in series/parallel. For info, here is picture of my installation.
TrojanBatteries.jpg
 
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