Chinese gennies - again!

Submitted: Sunday, Mar 28, 2004 at 13:12
ThreadID: 11624 Views:3068 Replies:18 FollowUps:12
This Thread has been Archived
Afternoon all
Bought one of the GMC generators at Bunnings (price too good to pass by), and works fine on 240 volts - will run the 650 angle grinder no probs - but the DC output is around 19 volts (tested with a multimeter), rated at 8 amps in the literature, (but I don't know how to test that). The specs also say 14.4 volt is the DC ouput.

I want to use it mainly to charge the second (deep cycley) battery on longstays.

Two questions:

1. Is 19 volts too high for battery charging?

2. Can I run the Engel (E series) directly from the generator?

I've searched the forum but these questions don't appear to have been discussed.


Back Expand Un-Read 0 Moderator

Reply By: navaraman - Sunday, Mar 28, 2004 at 13:45

Sunday, Mar 28, 2004 at 13:45
Don't know about this particular generator. I test a lot of transformers at work and with no load the dc output is often higher than the the rated output. I suspect if you put a load on it it would drop to 14.4 or close to it and be ok for your fridge and charging batteries.
AnswerID: 52281

Follow Up By: Hendo - Sunday, Mar 28, 2004 at 14:17

Sunday, Mar 28, 2004 at 14:17

Thanks for the response - yes, I was hoping that would be the case.

If I was running the Engel from the generator, I would most likely run it at 240 volts,

An alternative would be to use the generator to charge the battery, and of course keep the Engel on 12 volts.

FollowupID: 314092

Reply By: Member - John - Sunday, Mar 28, 2004 at 14:21

Sunday, Mar 28, 2004 at 14:21
Hendo, one thing to consider is that the genny only charges at 8 amps, it will take a long time to charge your deep cycle battery. It will give you the sh***s running all day. Just something to consider. John
John and Jan

Lifetime Member
My Profile  Send Message

AnswerID: 52286

Follow Up By: Hendo - Sunday, Mar 28, 2004 at 15:07

Sunday, Mar 28, 2004 at 15:07

Yep, but, if it extends the time before I have to use the 4.2 litre turbocharged diesel generator, its worth it!! Also thought about solar panels, and they too have a relatively low amp rating, plus much more expensive and fragile.

The much vaunted Honda 1 kw generator also only puts out 8 amps in DC. The only one I've seen that is different is the Christie which is a Honda motor strapped to a 55 amp Bosch alternator, but it won't do 240 volts. But, they are up to about $1,000 and nearly as much as the Honda.

Also, it means I can run medium power 240 volt tools, and perhaps run the fridge directly from the generator during the hottest hours of the day. Gives me options.

A full charge of a deep cycle battery (and mine is 105 amp/hr) can take days!!


FollowupID: 314096

Follow Up By: Member - Brett H (QLD) - Sunday, Mar 28, 2004 at 17:26

Sunday, Mar 28, 2004 at 17:26
You may get more DC capability by using a battery charger powered by your gen set.
FollowupID: 314106

Reply By: Member Eric - Sunday, Mar 28, 2004 at 19:12

Sunday, Mar 28, 2004 at 19:12
you do have to run something to get the right voltage , get a battery and connect it to your 12 charger , make sure the battery is away from you and there is something like a panel nest you , also place a old towel over the battery . Start the Gen, and take a volts test. The reason for the precoutions , if it is charging 18 or 19 Volts , it will blow the battery in around 30 sec ,
AnswerID: 52307

Follow Up By: Hendo - Sunday, Mar 28, 2004 at 20:15

Sunday, Mar 28, 2004 at 20:15

Actually, this afternoon I hooked it up to an old car battery (still in my daughter's old Peugeot) and ran it for a few minutes, and the charge output dropped to about 14.5 to 15 volts "under load". The battery was already fully charged at about 12.7 volts, so that was an encouraging result.

FollowupID: 314113

Reply By: Meggs - Sunday, Mar 28, 2004 at 19:13

Sunday, Mar 28, 2004 at 19:13
Hendo don't run your fridge from the 240v supply use the 12 v with a battery in parallel to smooth out the voltage peaks. I thought these generators were better than they are but I was wrong check post 11066. These generators are fine for battery charging, lights, and any resistive load or universal motors but due to the governor I would not use it on induction motors or any expensive 240v equipment eg computers.
I wouldn't worry about the open circuit voltage as they could be a bit like the charging circuit of some small outboard motors just half wave output. You would be better off using a 240 v battery chargerfrom the 240v output.
AnswerID: 52308

Follow Up By: Hendo - Sunday, Mar 28, 2004 at 20:20

Sunday, Mar 28, 2004 at 20:20

Yes, I'd already thought of running the charger from the generator (like most, I already own a 240 volt charger for home use) and then using the charger to keep the battery topped up. This would even out the spikes etc. Unfortunately it is a 6 amp charger, so would be even slower than the generator itself!!

Also, as mentioned above, the charger drops voltage once it is under load.

Also, if I run it with a surge protector (as against overload cutouts) that should provide good protection for AC equipment. Will this help protect the fridge?

FollowupID: 314115

Reply By: Meggs - Sunday, Mar 28, 2004 at 21:49

Sunday, Mar 28, 2004 at 21:49
Hendo I don't want to tell you a lot of rubbish but I can't answer your question about the voltage spikes. One thing I do know is that the charging of deep cycle batteries is different to cranking batteries due to their high internal resistance. As they are unable to accept high initial charging rates and they require a slightly higher voltage to fully charge them. I don't use a deep cycle battery just an Exide Extreme so I haven't researched the subject.
See if you can find out a bit more info on charging deep cycle batteries
AnswerID: 52335

Reply By: ianmc - Sunday, Mar 28, 2004 at 22:51

Sunday, Mar 28, 2004 at 22:51
Meggs has just reminded us of the problems with deep cycle batteries & the difficulties in charging them.
Most frig manufacturers advise that the frig should be run direct off a 12v battery, not a genny.
Today I was in Kmart & saw a Scorpion 800w genney at $249-.
As they are going for about that on Ebay PLUS $27 postage & no insurance I grabbed one and Kmart are usually good with returns of faulty stuff at least in out local store.
The Scorpion is said to be a Chinese Mitsubishi product & hopefully e bit better than some others. It seems to retail at tool outlets for $389 so big saving.
Have yet to open the box & may comment more later.Interseting comments above about getting the best charge rate, ie 240v charger or direct link.Would the 240v charger of the right amperage give more boost than the direct 12v connection?
Must read the instructions tomorrow.
AnswerID: 52343

Reply By: Rosscoe - Monday, Mar 29, 2004 at 12:00

Monday, Mar 29, 2004 at 12:00
Check out this site for info on charging batteries and other stuff!!!
AnswerID: 52389

Reply By: ianmc - Monday, Mar 29, 2004 at 13:18

Monday, Mar 29, 2004 at 13:18
I opened my Scorpion 950 $249 genny this a.m. & did the right thing & read the instructions first. There were a few jokes in the Chinese/English but generally made sense. Complete with diagrams & parts list too!
Recommended 50-1 mix which I tend to think is bit lean for an airccoled 2S.
Also says 40-1 summer. As 2S oils are relatively smoke free now I tended towards a bit richer for first start up anyhow.
Starts first pull each time when warm.
I overstretched it a bit and ran a 500W spotty & 550W 240v power drill at the same time plus link to a 12v battery for charging. This may not have taken much as it was near fully charged anyway but even tho it was overloaded it started & stran the drill a number of times with the other stuff in place & was fairly quiet.
Hope that helps folks.
AnswerID: 52397

Follow Up By: Meggs - Monday, Mar 29, 2004 at 16:31

Monday, Mar 29, 2004 at 16:31
Thanks for that I am about to go and get one did you ger the "Bonus" 4 outlet power board as well might as well get all that is offering.
FollowupID: 314208

Follow Up By: Hendo - Monday, Mar 29, 2004 at 23:42

Monday, Mar 29, 2004 at 23:42

i looked at the Scorpion on the web (Cairns mowers, from memory) and it appears identical to the GMC one being sold at Bunnings.

I ran the angle grinder (rated at 650 watts) OK on it, but didn't add additional appliances.

My main question remains: unloaded, the DC puts out around 19v. Have you measured your Scorpion? As I said above, when I put a load on it the voltage dropped to about 14.5 to 15 volts, which I would be OK with.

Could you test yours, and let me know?


FollowupID: 314316

Reply By: Member - Bear - Monday, Mar 29, 2004 at 20:19

Monday, Mar 29, 2004 at 20:19
The GMC is only $199 at Bunnings with a 2 year replacement warranty..
AnswerID: 52474

Reply By: ianmc - Monday, Mar 29, 2004 at 22:57

Monday, Mar 29, 2004 at 22:57
Yep, I got the powerboard in the same box thanks!
There are two Scorpion gennys about the same power, ie about 650 & 800 watts by memory, one being 1 kg heavier than the other.
Mine is the 800. Dont know if its the same as the GMC as I am nowhere near Bunnings.
AnswerID: 52514

Reply By: Macca1 - Monday, Mar 29, 2004 at 23:17

Monday, Mar 29, 2004 at 23:17
Hi All,

Well I speak from experience about the battery charger. I ran the Waeco a little to long on the Navara and woke up to a dead battery (cranking with no backup).

My battery pack wouldn't even turn the motor over so I Hooked the battery to the Scorpion 950 Genny and about 80 mins later we were on our way.

As for the deep cycle battery, I think you'll need a long time get the charge back into it. I don't think I would run the Waeco direct from the charger without some checking on the consistency of the voltage.

AnswerID: 52516

Follow Up By: Hendo - Tuesday, Mar 30, 2004 at 06:04

Tuesday, Mar 30, 2004 at 06:04

How do you check the consistency of the 240 voltage? It would appear that it runs at 50 mhz (ie the system runs at 3000 rpm, which produces electricity at that frequency.

The literature on my Engel claims it is safe to run on generators, but I'm not sure they had a $200 Chinese jobby in mind when that statement was made!!

I guess the main use for the little genny will be to provide a backup, and at worst will be able to run a conventional 12 volt charger from the 240 volt outlet, which is probably the safest option for extending charge life of the deep cycle while camping (as against charging a flat starting battery).

FollowupID: 314330

Reply By: ianmc - Tuesday, Mar 30, 2004 at 10:54

Tuesday, Mar 30, 2004 at 10:54
Not sure where others have measured output but I tried several methods.
Firstly with no load ( & therefore low revs & output) the reading direct from the 12v outlet was 11.3 to 11.5v.
When I put a 500 w load on the 240v outlet the reading was 12.55 to 12.8+ which seems fine to me but I didnt get 14.4v.
If this is too low maybe someone could let me know .
AnswerID: 52534

Follow Up By: Meggs - Tuesday, Mar 30, 2004 at 11:58

Tuesday, Mar 30, 2004 at 11:58
Ianmc are you sure about Low revs as the generator needs to run at 3000 rpm to generate 50hz. Some of the more expensive Honda's can sense the output and run back to idle on No Load I didn't think these cheapies were in that league. I would guess that the speed difference might be just the quality of the governor. Speed should be either 0 or 3000rpm.
FollowupID: 314358

Reply By: ianmc - Tuesday, Mar 30, 2004 at 12:26

Tuesday, Mar 30, 2004 at 12:26
Hi Meggs, yes it does slow to a fast idle with no appliances attached then as you plug in say a 500w spotty it speeds up to a nice steady (probably 3000rpm)
and stays there. It starts easily & I have no problems with it for what it is & it seems well made & with only 3000 rpm from 63cc motor it should last a long time all other things being equal!
AnswerID: 52546

Follow Up By: Meggs - Tuesday, Mar 30, 2004 at 18:05

Tuesday, Mar 30, 2004 at 18:05
Ianmc what does it say about warranty and where is the warranty honoured? I rang up a 1300 number for GMC and they told me they don't do repairs just replace them up to 2 yrs from then but if there is aproblem in the first 30 days the store will replace it.
The only problem with me for GMC is that Bunnings in QLD don't have them yet and I want to get one in the next three weeks.
FollowupID: 314390

Reply By: ianmc - Tuesday, Mar 30, 2004 at 23:35

Tuesday, Mar 30, 2004 at 23:35
Just checked the guarantee. Its for 12 months & has to go back to distributor, Austech Industries, but no address for them on box or guarantee form.
Sure its available or Kmart would not deal.
Hopefully Kmart would act on problems as they do for other appliances.
AnswerID: 52602

Reply By: Blackie - Wednesday, Mar 31, 2004 at 16:44

Wednesday, Mar 31, 2004 at 16:44
There is an interesting thread on these generators on the MSN Caravaners Forum .
AnswerID: 52667

Reply By: Meggs - Wednesday, Mar 31, 2004 at 17:14

Wednesday, Mar 31, 2004 at 17:14
I went to Bunnings today and asked them about the GMC generators and they had them, I missed them before so I got one at $198. One of the main selling points was 2 year replacement warranty as to give a warranty like this they must be reasonable sure of the product as warranty work costs. I believe there are at least 6 of the same generators sold under different names proberbly made in the same prison in China.
I did some tests on mine the 240v output at no load 265v and 53hz and at a full 600w load (Toaster) it dropped to 51hz and 240v, these figures are acceptable.
The 12v side was more interesting. I had a battery that had been charged a couple of days before but was stuffed due to poor capacity and I connected this up to the 12v output. The current draw was 9.5 A and after about 20sec the CB tripped. I put this down to short leads and the normal initial high charging current. If you are relying on this for charging a flat battery you will have a problem. The best bet would be battery charger on the 240v side or some longer thinner 12v charging leads.
Other than the position of the starter cord I am happy enough with it.
AnswerID: 52672

Follow Up By: Hendo - Thursday, Apr 01, 2004 at 06:44

Thursday, Apr 01, 2004 at 06:44

Yep, thats the one I have bought, and unloaded, the DC output on mine is about 19 volts, but drops to 14 - 15 volts when hooked up to an already charged battery.

As discussed above, the best bet is to probable use a 240 volt battery charger to run the fridge, via the second battery in the vehicle.

But, at $198, can't complain about that!!

FollowupID: 314569

Reply By: Wizard1 - Tuesday, Apr 13, 2004 at 14:44

Tuesday, Apr 13, 2004 at 14:44
I was extremelly interested in this discussion string as I just purchased a GME 850 from Bunnings in Darwin for..........get this........$189 and they were literarly walking out the door.

About to test it out on a camping and fishing trip to Coburg Peninsula (Arnhem Land). We plan to run a couple of WAECOs as well as lights, etc. let you know how it went when we get back.


AnswerID: 54026

Follow Up By: Hendo - Wednesday, Apr 14, 2004 at 05:43

Wednesday, Apr 14, 2004 at 05:43
Wizard - really appreciate your comments on your return! A mate of mine told me last night that he had successfully run his Engel Fridge on one for 5 hours, with no harm. So, looks as if all is well!! He said they even run an 1100 watt saw on it (he's bought one for each of his company's work vehicles as a source of 240 volt power in the field).

I'm putting my 240 volts through a surge buster.


FollowupID: 315775

Reply By: Ferda - Thursday, Apr 15, 2004 at 09:16

Thursday, Apr 15, 2004 at 09:16


AnswerID: 54326

Sponsored Links