Re: [MH-list] RE: Battery Performance

Simon Whitehead

This is a resend. I am having problems with emailing to this group...

I ditched the Gel batteries that were in the camper when I got it and replaced them with a couple of 85AH deep cycle wet types. I also have a 150 Watt solar panel on the roof. I wouldn’t have bought such a large panel if it wasn’t for ebay. It is 2nd hand and was a little under 1/2 price.
I also use the electroblok when mains charging but that isn’t very often due to the solar panel. The large current is measured after a night’s carefree use of the various power hungry devices – a laptop each and lots of lights plus radio etc. Usually the batteries are showing a drain of 15 to 20 AH (I have one of Sterling’s power consumption monitors) The charging current is more than a spike but it doesn’t last long – maybe 10 to 15 mins. Then it drops to something more reasonable like 10 amps or so.
I got rid of the Gels because a few years ago I found that when free camping in the winter I couldn’t get the charge back in unless I idled the engine for an hour or so and that is just unacceptable. Changing to wet batteries helped but it was only when I put in a decent alternator management system that things improved to the point that it is no longer an issue.
I am not strictly using an alternator management system. The device I bought from Sterling is the one that loads up the alternator to make it provide the charging voltage needed to do the job properly. It is a dual charger so the engine battery’s output does not take the voltage above the normal alternator output whilst the domestic battery is given the full amount. That way the vehicle electrics are not subjected to any voltages more than normal and they do not get confused.
I could have bought a battery-to-battery charger (and nearly did) but I was concerned that the alternator would not manage to keep up under severe loads. The virtue of the system I bought is that it forces the alternator to ‘give of its best’ until the world settles down.
I dare say that the alternator will fail sooner than it might have but since I, like most MH owners, only do a small mileage every year it wont matter to me (I hope!). Its a risk worth taking.

Now my boat (Cornish Crabber Mk 1) is another story. There are no sophisticated electronic controllers that require nursing so I have used a Merlin AMS for that. It beefs up the whole output and I use a diode splitter for the two battery banks. Since it is not unusual to find boats running engines to recharge batteries I think that this solution is OK for the moment.

In future I will probably always but AGM batteries because they seem so much more reliable and I really don’t want to have to check water levels all the time and on the boat sealed batteries are highly desirable to keep the salt out.

On 6 Nov 2010, at 10:47, ErnB wrote:

On 6/11/10 09:07, "Whitehead, Simon" <> wrote:

I have one of Mr. Sterling's products in my Hymer and I find that it is vastly
superior to Hymer's Electrolok. With the Sterling charging system I am able
to see charging rates of about 40 amps in a nicely controlled way. The
electroblok does a good job but at a much lower rate.
I do have some misgivings about Sterling though. On his website he doesn't
seem to have taken on board the latest range of AGM and AGM-Gell batteries. I
know his chargers will do the right thing but its his support comments that
seem out of kilter.
I am intrigued. How many of what type of battery do you have, Simon? You
measure the Amps. Did you note the voltage? High charge rates can only be
achieved by pushing the voltage, and gels, in particular, do not fare well
when taken above 14.5V.

I know that Stirling does some very clever things to achieve excellent
results with standard wet cells (Some boaters consider him the patron saint
of battery power.), but, and as you say, he seems to go into denial when
faced with other types and technologies.

Do you run the Stirling from mains or from a genny? I can see little or no
advantage when on mains. The Electroblok will do its thing eventually.


Contact the List Owner:
Motorhome List Website:
Files area:
Off-topic discussions:
For long term travelling/living in a motorhome:
Yahoo! Groups Links

Simon Whitehead

Join to automatically receive all group messages.