Flat engine battery (1 Viewer)

jacken

Free Member
Dec 9, 2007
190
2
kent
Funster No
992
MH
c class
Exp
8 years
Hi,

went to start the motorhome to-day and nothing happened, dash lights came on and then dimmed when trying to start. I put a multimeer across the battery and it only showed 12.1 volts. I can't keep it on hook up as I have to keep it on the road. Can any-one confirm what it should read fully charged and read when flat. It is an 88 amp hour battery. I also checked the level of the cells and there was nothing showing so I had to put a whole litre of distilled water in. Is it time for a new battery? this is 5 years old now.

ken
 

Wildman

Free Member
May 30, 2008
0
8,492
Ilfracombe, Devon
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2,913
MH
Amazon Ambassador
Exp
since 1967
13.8v -14v is fully charged, 12.6 is half charge and 12.1v is flat.

Only time will tell if the battery will take a proper charge again as it has been left with a low level of electrolyte for some time. You could always take the battery indoors and leave on a float charge over the winter. Or add a solar panel to keep it topped up however unless you check it regularly and keep it topped up you will lose it. Good luck.
 

Myfanwy

Free Member
Jan 2, 2009
104
25
Cheddar Somerset
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5,275
MH
A Class
Exp
nine years
Hi Ken

Your engine battery is normally 13.8 volts when fully charged. I would suggest that if the battery is 5 years old then a new one is necessary. If you wish to test the battery this can only be done with a specific gravity meter. This is like a large syringe which you draw up the water and sulphuric acid mix and the balls float to tell you the state of the battery.

I would suggest if you are leaving your vehicle on the road that you should purchase a small solar panel from Maplins (£9.99) which plugs in the cigarette lighter socket. This will not charge the battery but will stop it from discharging under its own steam.

All batteries that are left will discharge themselves with time so this will stop that.

Hope this is of use and help with your problem.

Myfanwy's husband Alan
:thumb::thumb::thumb:

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scotjimland

Free Member
Jul 25, 2007
0
8
.
Funster No
15
MH
.
Exp
.
A fully charged battery won't read 13.8v unless it's just come off charge and certainly not after being charged by an alternator .. see chart .. but before taking a reading it must be left off charge for at least four hours..
A fully charged battery will hold it's charge for many months, most problems arise with 'phantom' loads .. eg alarms, radios, etc which take tiny loads but ultimately flatten a battery

battery-SoC-table.jpg
 

Hycon

Free Member
Oct 6, 2008
91
16
N.E Lincolnshire
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4,309
MH
A Class
Exp
just starting
Does electric hook up charge engine battery

My engine battery was flat on my 1994 Hymer Fiat Ducato so I pluged in my electric hook up and expected it to charge the engine battery.It did not seem to charge it but was definitely charging the leisure battery.I had to charge it with a seperate battery charger and it was Ok. Is this how it should be or are some motorhomes wired to charge both batteries and others just to charge the leisure when on electric hook up.When the engine is running both batteries are charged.
 

moandick

Free Member
Jul 28, 2007
1,312
112
Landrake, Cornwall
Funster No
24
MH
Euro-shed
Exp
40 +
I can only really talk about US RVs as that is what I have - and yes, the engine charges both batteries but the hook-up only charges the house battery - unless you buy a modification to allow the hook-up to charge both.

It usually causes a certain amount of consternation amongst RV owners when they find their engine battery dead after a few days on the hook-up. The problem is that there is always something applying a drain to the engine battery - the immobiliser, the engine management system etc., etc., etc. It may only be a small drain but it is always there - so most of us buy some form of supplemantary charger to keep the engine battery topped up. Whether it be a plug-in solar charger or a Halfords battery master is irrelevant - you generally need something extra!

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Last edited:

PeteH

Free Member
Nov 22, 2007
6,860
9,035
East Riding of Yorkshire
Funster No
900
MH
Rapido, 999M.
Exp
18+yrs plus 25+Towing
Simple things?

Hi

I use a Length of Substantial wire with a Croc; clip either end and a Fuse holder with 20Amp fuse in the line,conected between the "house" and "Chassis" batteries this allows the EHU to float the Chassis battery, the Fuse is for the day when I "forget" to disconect before starting as otherwise the Wire will try to take a full start charge and burn out!! (or burn something!!).


Total cost ZILCH, as I had it all in the workshop!.

(other more expensive devices are available!!!)

Pete
 
Last edited:

Tony Lee

Free Member
Sep 28, 2008
274
2
Funster No
4,196
13.8v -14v is fully charged, 12.6 is half charge and 12.1v is flat.

Either a very strange battery or very strange measurement technique.

For OP. Correct technique for this condition is to just cover the plates, fully charge with a good three-stage charger and then top up to bottom of ring.

A battery that has uncovered plates for a long time will suffer some permanent damage, but correct treatment in future may give a couple of years more satisfactory performance. If all cells were way down and you did check the levels say a month ago, then you may have a cheap taper charger and left it on for many days.
 
Oct 15, 2007
3,062
5,166
Neckend or North Wales.
Funster No
635
MH
VW T6 Kombi day Van.
Exp
Since 2004
My engine battery was flat on my 1994 Hymer Fiat Ducato so I pluged in my electric hook up and expected it to charge the engine battery.It did not seem to charge it but was definitely charging the leisure battery.I had to charge it with a seperate battery charger and it was Ok. Is this how it should be or are some motorhomes wired to charge both batteries and others just to charge the leisure when on electric hook up.When the engine is running both batteries are charged.

My Fiat Trigano Tribute was the same, now I've fitted a van bitz battery master£58, it is a small electronic box with 3 wires, one to the positive to engine battery, one to positive on leisure battery, and one to earth. When on hook up now, it charges both batteries, if parked up and no hook up it shares the drain load between both batteries so vehicle battery lasts longer. since I brought this, CAK tanks do a similar device which is about £25.

John.

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pappajohn

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Aug 26, 2007
41,625
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172
Exp
Since 2005
Is this how it should be or are some motorhomes wired to charge both batteries and others just to charge the leisure when on electric hook up.When the engine is running both batteries are charged.

our kontiki can charge either battery on hookup BUT not at the same time.
by flicking the 3 way rocker switch from 'cab' to 'house' or 'house' to 'cab' on the control panel it will charge or use either battery.

flick it to the middle position and neither battery does anything but the hookup still powers the 12v side....i think anyway.:RollEyes:

my solar panel kicks out around 7amps on a sunny day so a couple of hours will give my 'cab' battery enough charge for a 'warm weather' start....(wouldnt want to try that in winter though:Eeek:) and keeps the 'house' battery topped up no matter what the weather.
 

Frankia

Free Member
Sep 24, 2007
133
0
Lincolnshire
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393
MH
A class
Exp
15
If your Hymer has the schaudt electro block it is able to maintain a charge for both the house and engine batteries from a mains hook up. (as long as Hymer has wired it for that). The charge to the engine battery is only about half an amp though so it would not be much good for a totally flat battery. Which is possibly why you didn't notice the engine battery recovering.

Again if it is a schaudt there is a connector on it for solar so you could attach a panel to it which would maintain both the house and starter batteries when the 'van is not being used for some time. n.b. it will only charge both batteries from solar when the solar panel is connected to the electroblock - most fditters of solars ignore the EBL and attach directly to the house batteries
 
OP
J

jacken

Free Member
Dec 9, 2007
190
2
kent
Funster No
992
MH
c class
Exp
8 years
Thanks for the replies. Just going on to another point raised in one of the replies, I thought that on electric hook up both leisure and engine battery would be charged. Am I wrong? I have a control panel that has 1 meter and you press a button that shows engine battery and press again it shows leisure battery.

ken

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S

sinbad1

Deleted User
Thanks for the replies. Just going on to another point raised in one of the replies, I thought that on electric hook up both leisure and engine battery would be charged. Am I wrong? I have a control panel that has 1 meter and you press a button that shows engine battery and press again it shows leisure battery.

ken

Not sure wahat model you have ;but when the engine is running it will charge both engine and habitation batteries via a split charge relay system.

To be honest if your battery is five years old its well past its sell by date. if there is a battery drain you can allways check this by switching everything off, then remove the positive battery connection , using a multimeter set to ohm's , connect the two leads of the meter red one to the battery, black one to the disconnected terminal. Any current drain will show on the meter. would suspect a new battery would solve your problem.
 

GJH

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Aug 20, 2007
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Thanks for the replies. Just going on to another point raised in one of the replies, I thought that on electric hook up both leisure and engine battery would be charged. Am I wrong? I have a control panel that has 1 meter and you press a button that shows engine battery and press again it shows leisure battery.

ken

In our Autoquest we have a switch which can be used to power the habitation electrics from either the leisure or vehicle battery but in our case EHU charges only the leisure battery.

I left the switch on vehicle once by mistake and flattened the vehicle battery. Van was on EHU at the time.

I subsequently bought a Tronic T4X charger as sold by Lidl (I think they've been selling them again recently and Aldi have been selling their version as well). At this time of year, if I think the vehicle battery might need a boost before we need to use the van, I use that overnight to give the vehicle battery a float charge.

Graham
 

scotjimland

Free Member
Jul 25, 2007
0
8
.
Funster No
15
MH
.
Exp
.
To be honest if your battery is five years old its well past its sell by date. if there is a battery drain you can allways check this by switching everything off, then remove the positive battery connection , using a multimeter set to ohm's , connect the two leads of the meter red one to the battery, black one to the disconnected terminal. Any current drain will show on the meter. would suspect a new battery would solve your problem.

disconnect the negative rather than positive ,it's much safer when doing a 'drain' check

set the meter to DC mAmps, setting to Ohms will destroy the meter..

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PeteH

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Nov 22, 2007
6,860
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East Riding of Yorkshire
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Rapido, 999M.
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18+yrs plus 25+Towing
Battery Drain etc;

Hi

Don`t lose sight of the fact that Euro "charge" units ONLY maintain a battery. they are not designed to "boost" charge as under normal (EHU) conditions you would "cook" the battery.

A good 3 stage battery charger is essential, disconect the battery when using as it IS possible to "bu***er" the electronics during the "bulk" charging phase, which CAN be as high 15volts.

pete

P.S I currently have a neighbours caravan battery on my 180amp boost charger, it was showing 9.4 volts when connected and is probably "dead", but I said I`d try it!!. the van had been in storage for over 6 weeks without charge. I suspect his "zig" unit is defective.

p

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OP
J

jacken

Free Member
Dec 9, 2007
190
2
kent
Funster No
992
MH
c class
Exp
8 years
Just come back from a nice long drive to Hastings and back. Put a multimeter across the terminals and the reading was 12.85 volts. I will check it again to morrow night.

ken
 

Jaws

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Sep 26, 2008
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Thetford Norfolk
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Today I was called out on a bike job and the chap had a MH in the drive.. he said it was driving him nuts as the battery kept going flat.. After I got his bike sorted I wandered over and found a fairly big drain was taking place..
Ten minutes later it was sussed. The relay that isolates the cab battery from the fridge had stuck on.. he had left the fridge on 12v and THAT was draining the battery.
The reason I sussed it so quick was cos it is not the fist time I have seen it..
Moral is just double check the fridge is REALLY off when you park up ! :winky:
 
OP
J

jacken

Free Member
Dec 9, 2007
190
2
kent
Funster No
992
MH
c class
Exp
8 years
Justt put the meter on the battery and the reading to-day is 12.41 volts. Mind you, I do leave the alarm on.

ken

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chewy

Free Member
Apr 11, 2009
36
0
Funster No
6,232
flat battery

Hi,

went to start the motorhome to-day and nothing happened, dash lights came on and then dimmed when trying to start. I put a multimeer across the battery and it only showed 12.1 volts. I can't keep it on hook up as I have to keep it on the road. Can any-one confirm what it should read fully charged and read when flat. It is an 88 amp hour battery. I also checked the level of the cells and there was nothing showing so I had to put a whole litre of distilled water in. Is it time for a new battery? this is 5 years old now.

ken
Probably 5 years and "testing" it at this time of year what you expect (new battery) is reasonable. I 've been searching forums for Fiat owners (08 2.3 the models with dodgy reverse) ..My New battery goes flat in 3 weeks ..Fiat main agent has given me a written letter saying this is normal...first vehichle I've had where this is normal ..wonder what others experience is?
 

lunarman

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Sep 23, 2008
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I had a new fiat 2.8 in sept 05, in oct 06 the battery kept going flat so I took it to the fiat main agent. They tested all electrics nothing found. 2nd time they put a tester on the battery and said that it was broke. They fitted a new battery and all was well. I thought that it would be covered by the warrenty (3 years) but no Battery not covered. Had to pay for battery to get van back and try to get the money from Fiat - no chance.

They said that the van could have been supplied to the converter (Adria) 2 years previously and 'consumables' were not covered. I think that the user manual for Fiat now has a section that says batteries are not covered by waranty.

So it is not surprising that your battery keeps going flat it may be broke!
 

chewy

Free Member
Apr 11, 2009
36
0
Funster No
6,232
Fiat /flat engine battery

In the words of Wogan Is it me? I have had since new a Fiat based camper..(It's now 13 months old)I have disconnected every leisure element of useage from the starter battery and made some elementary tests. I keep it hooked up and fully charged (onboard float charge only) I have just (on Friday) got the van back from Fiat main dealer (i';ve has the reversing judder mods done and under a seperate complaint raised 6 months agoasked them to once again check out the system) They said if your battery goes flat in three weeks its normal...I made them put it in writing and am noe planning to ask Fiat if this is true. what really annoys is that the main dealers who having just booked 22 hours at £80 an hour against Fiat effectively are telling me ( I have had literally hundreds of vehicles and like many have a few on the drive at any one time and never have I had a vehicle with it being normal for the battery to go flat within 3 weeks) that Fiat have desighned and manufactured a vehicle to do this. The problem we as motorhomers have of course is that chassis people blame van people and vice versa and us consumers are suckers in the middle . I have measured the drain on the battery at 0.6 amps with everything off exept alarm system which manufactures state has maximum current draw of less than 0.2 amps. I have heard some folk talking about canbus's etc. ..which are way beyond me!. Has anyone had or having similar problems. If i take the van to an independant vehicle electricians and get them to pinpoint the problem would it be legal and binding to send the bill to either of the warrantors?

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Last edited:
Feb 9, 2008
3,871
5,216
SW Scotland
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1,453
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LP Coachbuilt
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My Fiat battery will not start the engine if left for 3 weeks, I don't see this as a problem. My last car, a Subaru was the same. All I do is ensure that every week I change the charge over from leisure battery to chassis battery for one day. No problems.

Bill
 

chewy

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Apr 11, 2009
36
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6,232
My Fiat battery will not start the engine if left for 3 weeks, I don't see this as a problem. My last car, a Subaru was the same. All I do is ensure that every week I change the charge over from leisure battery to chassis battery for one day. No problems.

Bill
The electrobloc keeps both batteries fully charged for me but I suppose 3 weeks without charging is the new normal. I'm still not happy about it though!
 

Rickboy

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Dec 2, 2009
27
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9,541
Only trickle charge 3 or 4 amps or it is possible to damage the diodes in the alternator(expensive).It is possible to get away with a higher output but you are taking a chance.
Remember you are pushing charge in the "wrong" direction towards the alternator.
 

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