Maintenance free battery causing overcharging??

Nordburg2001 · 12 October 2016, 21:48

I replaced the battery on my Northcraft with a maintenance free type, My engine is a 1993 100hp v4 Suzuki, I didn't notice any problems with overcharging last week but on my 2nd outing at the weekend, having just fitted a chart plotter and dsc radio, and charging the battery just to be sure! While cruising or WOT I noticed the voltage reading 18v and an over voltage warning on the radio, I spent the rest of the day just mainly idling, the engine does have a rectifier/regulator which I changed for another 2nd hand one (that now doesn't charge at all) I'm begining to suspect the battery is at fault as I have checked all earth connections, battery connections and replaced the isolator and any non marine connections I have found! Have any of you guys had a similar experience??

beamishken · 12 October 2016, 22:15

I'd very much doubt it's the battery (although could be fried from overcharging) sounds more like a voltage regulator problem

Poly · 12 October 2016, 22:25

Quote:

Originally Posted by Nordburg2001

I replaced the battery on my Northcraft with a maintenance free type, My engine is a 1993 100hp v4 Suzuki, I didn't notice any problems with overcharging last week but on my 2nd outing at the weekend, having just fitted a chart plotter and dsc radio, and charging the battery just to be sure! While cruising or WOT I noticed the voltage reading 18v and an over voltage warning on the radio, I spent the rest of the day just mainly idling, the engine does have a rectifier/regulator which I changed for another 2nd hand one (that now doesn't charge at all) I'm begining to suspect the battery is at fault as I have checked all earth connections, battery connections and replaced the isolator and any non marine connections I have found! Have any of you guys had a similar experience??

I've been getting weird warnings of over voltage, that sound similar to that - the battery seems fine, the connections all look good etc. What I *think* I have discovered is actually the cable from the isolator switch to the battery is goosed inside. Not enough to give open circuit, but enough that the regulator isn't really seeing the battery. (Fortunately its only a 20HP and designed to run with/without battery so not blown the alternator). Its not been afloat to test since "fixing" this.

Nordburg2001 · 12 October 2016, 22:41

All cables look spot on and as I say I replaced anything that remotely looked dodgy, in fairness I can't rule out the rectifier/regulator yet as I bought 2nd hand. I have read that the older engines don't like gel or maintenance free batteries as it can (confuse?) the regulator!
I've also read that cdi wont cover warranty on any of their regulators if a maintenance free battery is used. When I bought the boat 2 weeks ago the battery in it was on old lead acid type but wouldn't take a charge, I never suspected for a minute that a modern battery would make any difference!
I'll pick one up tomorrow and try it just to rule it out and let you guys know how I get on.

jyasaki · 12 October 2016, 23:14

Gel batteries require a different form of charging circuit (though I don't recall what's different.) AGM should be fine with standard.

Jky

beamishken · 13 October 2016, 00:05

Maintenance free just means no topping up its still a lead acid battery
The charging system senses the state of the battery and adjusts accordingly if the regular is knackered it will either not charge or will continuously charge at its max
Simple test would be to swap your old battery back on and see what happens

Nordburg2001 · 13 October 2016, 00:29

As I say the old battery was totally goosed, the boat had been lying for a few years prior to me getting my hands on it. Never heard anything relating to battery problems in the motor trade but I've heard a few marine guys all say the same thing about batteries. Don't understand it myself. I'll double check battery cables tomorrow front to back and at isolator if all else fails I'll try a battery before ordering a new regulator. If more than one marine technician has mentioned it there must be some truth in it?

jwalker · 13 October 2016, 09:36

Could your old battery have failed because it's been over charged and you have an ongoing problem? Over charging for a while will almost boil the battery electrolyte and its level will fall. Did/Does the old battery have low electrolyte level?

For info: if the electrolyte level falls below the top of the plates, it's possible to explode the battery because there will be a fair amount of hydrogen in there. Arcing across the top of the plates can ignite it and the next thing you know you've got a battery box full of pieces surrounded by sulphuric acid....don't ask me how I know this!

My money is on regulator failure or improper regulator wiring.

jeffstevens763@g · 13 October 2016, 09:39

old battery shorted out blown regulator?

Nordburg2001 · 13 October 2016, 10:08

It worked fine the first week I was out with the new battery, the only difference the second week was that I had charged the battery fully and added electronics

Nordburg2001 · 13 October 2016, 10:11

Not convinced the battery is at fault, and I know it's impossible to diagnose on a post, was just wondering had anybody else had problems with a battery causing overcharging. It would seem not, I'll get a proper look later and post what I find. Could still be a poor connection, I'll get the meter out and go through it with a fine tooth comb

beamishken · 13 October 2016, 11:24

Quote:

Originally Posted by Nordburg2001

It worked fine the first week I was out with the new battery, the only difference the second week was that I had charged the battery fully and added electronics

If the battery was low and required charge on the first outing that might explain why you got no overcharge warnings as the battery was absorbing the overcharge.
Second trip with a full charge then you would see the full overcharge
As said probably the reason the original battery was fried & will fry the new battery if not sorted

Nordburg2001 · 13 October 2016, 21:09

Update so far!! All connections and wiring are ok, fitted another battery which seemed to lower the voltage at higher revs but probably due to battery having been sitting on a shelf for months and absorbing the charge!
I then replaced the regulator for the second hand unit I bought and the readings were at the other end of the scale reading only battery voltage even at higher revs!! At this point I assume the worst, that I have been taken for a mug and relieved of £30!!
As it was getting late and I live in a built up area I decided to call it a night but looked online for a Suzuki manual, after searching for a while I found something of interest, it states not to expect the charging system to charge a battery that is already above 12.5v ( both are 12.7+12.9 )
Even when running for a while with my multimeter connected the newest and lowest voltage battery never dropped below 12.6v
The manual recommends draining the battery by turning on all components and using PT+T to achieve sub 12.5v and then checking the system again!
I will report back tomorrow on my findings, does this ring true with any of you guys??

Nos4r2 · 13 October 2016, 21:37

Run the motor up on muffs/in a tank/water.
At tickover check the voltage with a multimeter. Blip the fast idle and see if the voltage rises. Should top out at 13.8-14.5v and drop again as the revs drop.

If it doesn't do that then your rec/reg unit is goosed. it sounds like it is anyway, but that'll tell you for sure.

It's not your battery.

Poly · 13 October 2016, 21:40

Quote:

Originally Posted by Nordburg2001

looked online for a Suzuki manual, after searching for a while I found something of interest, it states not to expect the charging system to charge a battery that is already above 12.5v ( both are 12.7+12.9 )
Even when running for a while with my multimeter connected the newest and lowest voltage battery never dropped below 12.6v
The manual recommends draining the battery by turning on all components and using PT+T to achieve sub 12.5v and then checking the system again!
I will report back tomorrow on my findings, does this ring true with any of you guys??

No - it sounds like a way to ruin batteries. I must be misunderstanding what you are doing or reading. With the engine on your voltage at the battery should be a little over 14V. If it is only 12.?V then you aren't charging it.

Nordburg2001 · 13 October 2016, 21:57

A quick blip still just showed battery voltage only, I'm used to working on motors, MX bikes, road bikes and commercial vehicles for 20+ years and would ordinarily instantly diagnose a regulator fault! But due to not being familiar with outboard charging systems I thought I'd try and do a bit of research first. The mind boggles!!! Some say only use lead acid, some say agm batteries won't work and the others just have no clue!!
My reason for even suggesting that the battery voltage may be too high for the regulator to start charging was due to an extract from a Suzuki workshop manual, I have tried to attach a photo to show you all that I'm not mad....😂

Poly · 13 October 2016, 22:30

Quote:

Originally Posted by Nordburg2001

it states not to expect the charging system to charge a battery that is already above 12.5v

that is not what it says!

it says you must have a battery with <12.5V to TEST the charge system output. Presumably because with an almost dead (<12.5V) battery it puts out a bigger current than when the battery is nearly full.

Nordburg2001 · 13 October 2016, 22:38

So there is no marine trickery? It's all just the same as anything else I've ever worked on and I just need to fork out for a new regulator! Got it...😂😂
Thanks for putting me straight👌

Nos4r2 · 13 October 2016, 23:12

Quote:

Originally Posted by Nordburg2001

So there is no marine trickery? It's all just the same as anything else I've ever worked on and I just need to fork out for a new regulator! Got it...��
Thanks for putting me straight��

Pretty much. The only real differences are the cooling,the mechanical advance, the ignition being an independent system from the battery on most outboards and quite how many bolts you'll break...

Too many people overcomplicate these things. 1st principles work

Nordburg2001 · 14 October 2016, 07:59

Similar to MX or trials bikes then! I'll pick up a regulator later if I can and let you know how I get on