Been having issues with flat batteries over the last few weeks. We’ve had the obvious things checked and all seem ok. Is there any likelihood the night heater could be the problem.
FH v4, are renowned for flat batteries, the batteries cannot cope with the system, basically when you stop at night, before bedtime run it up for 15mins, also get Volvo to check the settings for shutting down the electriky circuit, mine shuts down after 2 hours, also remove the key from ignition on a night out.
Needs new batteries. Even if the systems don’t shut down for a few hours the capacity of batteries that’ve been charged throughout the day should be more than enough to cope with that and running a night heater without going flat. You’ve got well over 200Ah of capacity and I doubt the systems draw even 10Ah.
Batteries that are on the cusp of being knackered usually show their face when the temperatures drop.
Remove the key ill try that one. Mines not on the 2hr mode. Volvo are that good when I told them I was having issues with low battery warnings on the status they just disabled the system so no my status screen just says ‘unknown battery’.
Changed the batteries on my fh4 last week. Truck is 2.5 years old,so due to be changed.
If the night heater switches off during the night, then it’s most likely to be a battery problem.
If your batteries last more than 2 years on the new FH4 your doing very well . It would seem about 18 months is their limit unless you have the fancy gel-filed ones - less if your a heavy user of the tail lift lead . My first set went around 16 months with very similar symptoms to what your describing .
Geoffo:
Changed the batteries on my fh4 last week. Truck is 2.5 years old,so due to be changed.If the night heater switches off during the night, then it’s most likely to be a battery problem.
The night heater will cut out, depending on the settings in the computer, again key left in ignition, circuits will stay powered, remove key after 2 hours systems shut down, including night heater,… Basically the electrical systems over draw when stationary, it’s a known problem, hence the newest V4 have the option of gel batteries, to power the truck circuits, and wet lead acid for starting.
biggriffin:
Geoffo:
Changed the batteries on my fh4 last week. Truck is 2.5 years old,so due to be changed.If the night heater switches off during the night, then it’s most likely to be a battery problem.
The night heater will cut out, depending on the settings in the computer, again key left in ignition, circuits will stay powered, remove key after 2 hours systems shut down, including night heater,… Basically the electrical systems over draw when stationary, it’s a known problem, hence the newest V4 have the option of gel batteries, to power the truck circuits, and wet lead acid for starting.
Even when I take the key out of the ignition, my night heater stays on.
Settings can be changed so that the night heater stays on after 2 hours.
I do keep my key in the ignition at night though.
One of the biggest problems with the 6 leggers is the position of the batteries. They require maximum cranking amps as the cables are the length of the chassis. It’s been known to need a jump at 22volt before now. The 4 wheelers don’t seem to have as much of a problem
Volvo advises,
TOP CHARGE AT LEAST EVERY THIRD WEEK. A battery
should be recharged whenever possible, and you should
use an external charger (min 20A). If you use an alternator,
you can only top charge (up to 90%) if it’s at least +25°C
outside, due to regulations concerning charging voltage
(max 28.8V). The battery chargers we recommend have
intelligent charge controls and temperature compensation.
This ensures higher voltage charges and helps maximise
battery lifetime.
DURING LONGER STOPS – PLUG IN A BATTERY
CHARGER.
Examples of stop scenarios:
• The driver spends the night/weekend in the cab:
If possible, plug in a battery charger (min 20A).
• The driver leaves the truck for the night/weekend:
Always plug in a battery charger (min 20A).
This gives you fully charged batteries and saves fuel
since you won’t use the alternator to charge the batteries
while driving.
N.B. Charging by alternator uses approximately 1.5 litres
of diesel (€2) as fuel consumption increases by 1.5%
during charging.
I’ve got a FH4 500 67 plate and not had any issues yet but I will keep an eye on things over the next few months.
Don’t bother with the night heater- Mrs B’s arse keeps me warm all night. (You could incubate 1000 ostrich eggs with the thing 
)
beefy4605:
If your batteries last more than 2 years on the new FH4 your doing very well . It would seem about 18 months is their limit unless you have the fancy gel-filed ones - less if your a heavy user of the tail lift lead . My first set went around 16 months with very similar symptoms to what your describing .
This is right. Mine has just had new batteries at 21 months old. They never went flat but came up with warnings on the dash saying ‘start engine immediately, battery level critical’ even though the status on the dash said everything was OK voltage, current etc. And it started fine every time but volvo still changed them. I always leave the key in on a night out in position 1 as it stops everything turning off after 2hrs including the alarm, night heater timers and none of the lights work in the morning and I’ve never had flat batteries in the morning. The other thing about the status not working and unknown batteries on the dash is because they haven’t set it up right. When new batteries are fitted they have to tell the system they are new and which type are fitted. I had the same problem when my last FH4 had new batteries fitted (also under 2yrs). I took it back and they set it up correctly and the lad explained this.