Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: cb750stu on September 01, 2013, 09:20:09 AM
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Hi Folks I'm looking for a new gel battery I noticed that the one that was in the bike is a 12v 14 ah one is this the correct ah for my 76 cb750 or do I need more or less ???
Cheers
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Hi Stu, CB14L-A2 is the right one for your bike ;) cheers Mick.
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Cheers Mick I'm after a small ish battery so I can fit it under my cafe seat so that one is too big !!!
Cheers
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Hi Stu,
Can I recommend you email Phil & Pete of Carrots Batteries
info@carrotcycles.co.uk
- these guys appear to know their stuff & are most likely to advise you correctly of what you're after.... standard lead acid or new fanged LIPOFe etc.
Friendly / helpful... worth a try. (& nope, not related, no 'interest'; just recently had informative & good service from 'em!
Their main website...
http://w.carrotcycles.co.uk/index.php?_a=category&cat_id=217
Good luck,
Simon.
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14ah is a minimum if you want to use the electric starter mate
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Ok cheers Bryan I'll have a look for a 15 or 16ah
Cheers
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cb750stu,
A 12v14Ah is indeed the spec battery for the '750; but by going for a 15/16Ah option, it is likely only going to be bigger - not smaller, which is your goal?
The Amp/hrs rating is only part of the picture; and in using the spec battery you should expect it'll supply 14Amps..... for one hour.
Fine, except the starter motor will draw anything from 120 -280Amps... and thus you need to consider another (battery) spec... ie CCA (cold cranking amps). Not all batteries are able to deliver very high currents, hence this CCA spec. Definition "The rating is the number of amps a new, fully charged battery can deliver at 0° Farenheit for 30 seconds, while maintaining a voltage of at least 7.2 volts, for a 12 volt battery. The higher the CCA rating, the greater the starting power of the battery."
Point I'm trying to make is, if you're not needing to leave parking lights on an unattended bike etc, and your starting circuit etc is in good order, you may be able to get away with a smaller (eg) 10A/h battery.... so long as its CCA rating is sufficient (140 -200 CCA seems to be the typical replacement battery value). And if you only use a kickstart... well, a small'ish battery is easily on the cards as the (standard) CB750 alternator output is 13A (according to my manual) - ie well upto the job of supplying all standard CB750 running loads.
My #1 attachment below shows the stater motor current draw - ie 120A normally, and stalling @ 280Amps.
From the 2nd attachment below, for a bike in good order you'll note that the only time the alternator is not charging the battery is @ night (high beam) / 2000rpm. At all other times the battery is accepting charge - rather than 'being used'.
Finally, I'm no tech guru on this, and as I earlier suggested the fellas at Carrot Batteries may advise you of a suitable battery given the dimensions you supply them. Failing this there are likely far better informed folk on this site (K2-K6?) who may be better qualified to help.
Simon
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Lobo, its not as easy to get the cca for a bike battery as it is for a car so we have to use the Ahr most of the time, the people you link to sound knowledgeable and may well have all the relevant specs to hand
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So as to keep weight to a minimum I have a 12v 5ah rated battery fitted to my Exup1000. It does start the bike okay & so long as I give the bike a good run it'll start okay after a few hours leaving the bike to cool down.
I found this website quite useful for battery dimensions & for buying batteries from
http://www.tayna.co.uk/Motorcycle-Batteries-C7.html
Prompt delivery as well
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As previous posts the correct battery is a CB14L-A2 battery (14 amp hour)
The field coil & spark plug coils will always demand 2-3 amps per hour. Battery charging on these bikes starts gradually after 2K revs. Depending on your lighting design on your 'café' your may have problems with a 5 amp hour battery.
I have assumed that you intend to kick start only, if you do go for a low amp battery, fit an line switch to the black wire on the regulator-switch OFF when you kick start the bike-once warmed up switch it back ON to charge the system. The field coil will always demand 2 amps which will reduce the amount of current available for the ignition coils
Alan
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Cheers folks for the useful info !! I found this one I know it pricey but it will fit nicely under my cafe seat
http://w.carrotcycles.co.uk/index.php?_a=product&product_id=1722
Any downfalls apart from the price ??
Cheers
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You'll be amazed at its weight ~ like an empty box. Only downside I can see is trickle charging is a big no-no, needs remembering. I've got two of these batts on my CBs, and so far no probs / very pleased. Big plus for me is that I'm away from the bikes for long spells, and on return no noticeable discharge.
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Cheers Lobo yeah it's ideal for my needs and if I need to I'll charge it with my car charger !!!
Cheers
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I know this sound dumb, but don't forget to factor in space for the cables up to the battery! ie you'll need slightly more than those bare dimensions. Apologies for stating the obvious - but the sort of 'doh' moment I occasionally suffer!
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Only downside I can see is trickle charging is a big no-no, needs remembering. .... Big plus for me is that I'm away from the bikes for long spells, and on return no noticeable discharge.
Hi Simon - what does "remembering" mean?
I have fitted the MotoBatt replacement spec to my std 400F. It's a tight fit into the battery box and I had to omit the rubber sleeve over the upper retaining tang but I was wondering what to do with it over winter. I only have an old-school car charger so I was thinking just to disconnect it and leave it.
But as to normal (that is occasional) use and starter motor performance - really good.
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Er, ah, yeah I see. I had ideas of charge/discharge memory - reading too much into it, obvoiusly :D
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Hiya Tom,
Yup, perhaps an unfortunate choice of words what with batteries & charge memory!
Anyways, agreed, if not using the bike best to isolate the battery completely: if the blurb is to be believed they'll go a year with no appreciable discharge.
I too only have a good old fashioned car charger... and will use this if necessary. One other possible thought is my multi battery type / voltage electric RC Heli charger - a fancy bit of kit & in all likelihood adaptable - given a bit if research. Better informed comments on this out there pls?
Cheers,
Simon
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Hello Simon, thanks for your vote of confidence a few posts back there. I'm less equipped than others on here in electrical theory though so I'll learn just as much from this as anyone. My training is principly mechanical engineering, so it's more valid to advise in that field.
I'm ok working with and diagnosing faults but certainly less skilled toward specifying elctrical systems than other members so will just watch this one with interest.
Interesting you mention RC batteries as I'm just getting more familiar with those as my son has started flyng small helis with LiPo, so trying to look after those.....apologies to the main questions for being off topic.
Nigel.
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...slight thread drift, tho' an indication of the power of modern Lithium based batteries.
http://m.youtube.com/watch?v=0BS_qI4lFU0
These things have 60-120Amp speed controllers to their brushless motors.
And nope, not me. I wish...