Charging battery with 1000w honda generator

[benjamino]

Got the generator now, still waiting for the charger. I noticed in the manual it says you can connect the DC output stright onto a battery to charge them up. Is this advisable? Will it damage the batteries in the long run? Presumably there is a reason why I'm paying £160 for the sterling charger?! Thanks for all your help Gibbo and othes.

[Gibbo]

Got the generator now, still waiting for the charger. I noticed in the manual it says you can connect the DC output stright onto a battery to charge them up. Is this advisable? Will it damage the batteries in the long run? Presumably there is a reason why I'm paying £160 for the sterling charger?! Thanks for all your help Gibbo and othes.

 

The DC ouput is seriously limited. Probably about 6 or 8 amps on a genny that size. Not very smart, usually unregulated, and usually too low a voltage. Don't waste your time!

 

Gibbo

[benjamino]

The DC ouput is seriously limited. Probably about 6 or 8 amps on a genny that size. Not very smart, usually unregulated, and usually too low a voltage. Don't waste your time!

 

Gibbo

 

Yeah it says 8amps. I wont bother - thanks Gibbo!

[smileypete]

"How long does bulk charge take ideally and to what % SoC roughly?"

 

Can't be answered.

 

OK, if you have batteries at 50% SoC, approximately what SoC can you recharge them to in 2 hours without excessive gassing and given ideal charging conditions?

 

cheers,

Pete.

[Gibbo]

OK, if you have batteries at 50% SoC, approximately what SoC can you recharge them to in 2 hours without excessive gassing and given ideal charging conditions?

 

It's different for each type of battery but a *reasonable* rule of thumb for *wet cells* (that won't be miles out) is that you can put back in 1% of the remaining discharge every minute.

 

So a 100Ahr battery at 50% SoC would accept 0.5Ahrs in the first minute (30 amps). That would leave 49.5Ahrs to replace. So the next minute would put in 0.495Ahrs (29.7 amps) etc etc.

 

You simply can't get any more current in than this. This is at (or just below) the gassing point. If you increase the voltage you get less charge current.

 

It's a bit rough and ready but it's about as close as you'll ever get.

 

Gel and AGM will take far higher currents than this.

 

Gibbo

[Scotty]

So under normal cruising conditions, say running the engine for 5hrs a day, it's unlikely that you will ever get your batteries back to 100%

Even with a genny you're hardly going to be running it long enough for the batteries to recover.

 

How much damage is this likely to do to a bank of wet batteries?

 

If I went for a month's cruising then hooked up to the shoreline on my return would they recover?

[Gibbo]

So under normal cruising conditions, say running the engine for 5hrs a day, it's unlikely that you will ever get your batteries back to 100%

 

It's almost a certainty that you won't

 

Even with a genny you're hardly going to be running it long enough for the batteries to recover.

 

How much damage is this likely to do to a bank of wet batteries?

 

Plenty

 

Not fully recharging is what kills most batteries.

 

If I went for a month's cruising then hooked up to the shoreline on my return would they recover?

 

Probably, though a normal charge won't do it. You'd need to equalise them. RTFM for the battery charger.

 

Gibbo

[smileypete]

It's different for each type of battery but a *reasonable* rule of thumb for *wet cells* (that won't be miles out) is that you can put back in 1% of the remaining discharge every minute.

 

So a 100Ahr battery at 50% SoC would accept 0.5Ahrs in the first minute (30 amps). That would leave 49.5Ahrs to replace. So the next minute would put in 0.495Ahrs (29.7 amps) etc etc.

Gibbo

 

Well a relatively simple way is you charge both banks to a fairly high level, then use an inverter/charger to fully charge one bank from the other.

 

How much can a battery be charged from 50% over 24hrs? Pretty full I'd expect.

 

How often should batteries in use get a 100% charge to avoid getting sulphated? Once a week or once a fortnight enough? So you wouldn't need to do the above every day...

 

cheers,

Pete.

[Gibbo]

Well a relatively simple way is you charge both banks to a fairly high level, then use an inverter/charger to fully charge one bank from the other.

 

Perpetual motion?

 

How much can a battery be charged from 50% over 24hrs? Pretty full I'd expect.

 

Correct

 

How often should batteries in use get a 100% charge to avoid getting sulphated? Once a week or once a fortnight enough? So you wouldn't need to do the above every day...

 

It doesn't work like that. Batteries are consumeables like diesel or coal. Every time they are cycled they get some sulphate build up. Even charging to 100% leaves some sulphate on the plates.

 

The less often they are fully recharged, the more sulphate builds up.

 

Gibbo

[anhar]

So, the big question...

 

Is my practice of always leaving a charger on to keep the batteries on float all week good or bad in battery life terms.

Hello Dave

 

I've had motorcycles for many decades and I've always kept them on the charger permanently when in the garage having learned long ago that the way to prolong battery life to the maximum is to keep them fully charged. Sometimes I've left them on the charger for months on end without using a bike and it's fine if you have a smart charger which adjusts automatically to the battery's state of charge. The usual one that bikers use is the Optimate and it can be left on indefinitely whether the batteries are wet top ups or AGM/gel maintenance free. These days bike batteries are all MF.

 

On my boat I have a Victron Phoenix inverter/charger combi, the charger part of which is smart, and similarly can be left on indefinitely. Consequently, like you I always plug her in when I'm at the marina and am in no doubt that it can be left on without time limit. That maximises battery life and also ensures they are always fully charged for when I go cruising.

 

regards

Steve

Edited August 9, 2007 by anhar

[smileypete]

"Well a relatively simple way is you charge both banks to a fairly high level, then use an inverter/charger to fully charge one bank from the other."

 

Perpetual motion?

 

Well not quite, you isolate the banks from each other first!

 

cheers,

Pete.

[blackrose]

Hang on a minute Gibbo, there's something I don't quite understand (yes, there are a lot of things I don't quite understand and this is one of them).

 

I paraphrase here so I may be mistaken, but in a previous thread when I said I'd doubled the amperage output of my alternator at about 14.7v by installing an external regulator, you replied that the batteries must have been up around 95% charged anyway, in which case the regulator only "added value" to the tinyest final part of the charging and wasn't worth the expense & effort, but now you seem to be saying that this is the most important phase?

Edited August 9, 2007 by blackrose

[smileypete]

Hang on a minute Gibbo, there's something I don't quite understand (yes, there are a lot of things I don't quite understand and this is one of them).

 

I paraphrase here so I may be mistaken, but in a previous thread when I said I'd doubled the amperage output of my alternator at about 14.7v by installing an external regulator, you replied that the batteries must have been up around 95% charged anyway, in which case the regulator only "added value" to the tinyest final part of the charging and wasn't worth the expense & effort, but now you seem to be saying that this is the most important phase?

 

Hi,

 

I always take things like this with a pinch of salt unless backed up by some useful real world measurements.

 

While it's good to read/discuss around the problem there's no substitute for experience.

 

Bit like the RFI 'problem' with galvanic isolators, when finally someone took some real world (ie not just on a bench!) measurments the problem turned out not to be a problem after all!

 

cheers,

Pete.

[Gibbo]

Hi,I always take things like this with a pinch of salt unless backed up by some useful real world measurements.While it's good to read/discuss around the problem there's no substitute for experience.Bit like the RFI 'problem' with galvanic isolators, when finally someone took some real world (ie not just on a bench!) measurments the problem turned out not to be a problem after all!

That's a completerly incorrect conclusion. It *is* a very serious problem. You need to read the thread again.Gibbo

Hang on a minute Gibbo, there's something I don't quite understand (yes, there are a lot of things I don't quite understand and this is one of them).I paraphrase here so I may be mistaken, but in a previous thread when I said I'd doubled the amperage output of my alternator at about 14.7v by installing an external regulator, you replied that the batteries must have been up around 95% charged anyway, in which case the regulator only "added value" to the tinyest final part of the charging and wasn't worth the expense & effort, but now you seem to be saying that this is the most important phase?

The fact that one increases the charge voltage from 14.4 volts to 14.8 volts will hardly make any difference.Gibbo

[blackrose]

Hi,

 

I always take things like this with a pinch of salt unless backed up by some useful real world measurements.

 

While it's good to read/discuss around the problem there's no substitute for experience.

 

Bit like the RFI 'problem' with galvanic isolators, when finally someone took some real world (ie not just on a bench!) measurments the problem turned out not to be a problem after all!

 

cheers,

Pete.

 

Chris W kindly brought down his oscilloscope to my boat about 6 months ago and we tested my GI with lots of switch mode equipment running including 2 x 30amp battery chargers + a 20 amp charger, a TV, and some other stuff. We couldn't find any RFI but my GI has an operating range of 70 amps - Peak 400 amps with a turn on threshold of 2.4v, so perhaps with other setups there could still be a problem.

[smileypete]

Chris W kindly brought down his oscilloscope to my boat about 6 months ago and we tested my GI with lots of switch mode equipment running including 2 x 30amp battery chargers + a 20 amp charger, a TV, and some other stuff. We couldn't find any RFI but my GI has an operating range of 70 amps - Peak 400 amps with a turn on threshold of 2.4v, so perhaps with other setups there could still be a problem.

 

Spoilsport!

 

Why not take your GI out of the boat, and onto the lab bench...

 

Connect up some kit and look at all that RFI... biasing it into conduction!!!

 

Look how seeeriioouusss it is!!! :ph34r:

 

cheers,

Pete.

[Gibbo]

Spoilsport!

 

Why not take your GI out of the boat, and onto the lab bench...

 

Connect up some kit and look at all that RFI... biasing it into conduction!!!

 

Look how seeeriioouusss it is!!! :ph34r:

 

cheers,

Pete.

 

Now I see why you have such difficulty reaching the correct conclusion.

 

I'll try to explain with pure logic.

 

The fact that someone did NOT see a GI forced into conduction by the RFI filter capacitors on ONE installation is NOT proof that the problem cannot/does not exist.

 

The fact that someone else (in fact several) DID see a GI (in fact several) forced into conduction by the RFI filter capacitors IS proof that the problem CAN/DOES exist.

 

The problem becomes more severe with smaller boats, painted hulls, non-steel hulls and cleaner water (as found in rivers).

 

If (as you seem to think) the problem simply doesn't exist then why have so many GI manufacturers attempted to address the problem by building big capacitors into their GIs?

 

Has EVERYONE else got it wrong and you are right? I doubt it somehow.

 

Gibbo

[blackrose]

Now I see why you have such difficulty reaching the correct conclusion.

 

I'll try to explain with pure logic.

 

The fact that someone did NOT see a GI forced into conduction by the RFI filter capacitors on ONE installation is NOT proof that the problem cannot/does not exist.

 

The fact that someone else (in fact several) DID see a GI (in fact several) forced into conduction by the RFI filter capacitors IS proof that the problem CAN/DOES exist.

 

The problem does exist otherwise it probably would not have been identified - these things are seldom mere speculation & rumour - though how much of a problem it really poses is arguable.

 

If you want to isolate your shoreline then the answer has got to be to get yourself a decent GI with a reasonable cut in threshold which will not be forced into conduction by radio frequency interference. Either that or spend a lot more money on an isolation transformer (although I've heard that some issues have arisen around these devices too, such as whether they should strictly be kept onboard or on the shore).

 

My GI also has led indicators which will tell me if the diodes are in circuit so hopefully I'll be ok - there's only so much you can do.

Edited August 10, 2007 by blackrose

[chris w]

In fact on Blackrose's boat there was no RFI at all. There was certainly some very low level switching frequencies from the chargers but that was around 50KHz approx max so not RFI. The level of these switching frequencies was almost in the noise and nowhere near to putting his diodes into conduction.

 

Notwithstanding that, I fitted a GI with a large (25,000uF non-polarised) capacitor in parallel.

 

Chris

[Gibbo]

Just to clarify something.

 

Whilst RFI *can* cause an issue it isn't the biggest problem. The biggest problem is 50Hz forcing the GI into conduction. The 50Hz appears on the earth conductor as a result of the RFI capacitors. Not quite the same thing.

 

Gibbo

Edited August 13, 2007 by Gibbo

[chris w]

Just for the avoidance of doubt, on Blackrose's boat, there was no RFI, no switching frequency (50Khz) and no 50Hz that was present in any amplitude that threatened to put his diodes into conduction.

 

Chris