Charging Lithium Batteries

PaulRainbow

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Confused now .................... where would the VSR go .......... immediately after the alternator I guess ??
View attachment 187140
This is incorrect, you are not going to use it to run loads, but to charge the Lithiums, surely ?

The DC-DC charger replaces the VSR. This allows the alternator to safely charge the Lithiums without overheating the alternator.

Solar and wind connect straight to the Lithiums.

Mains can go to both if it's a multi output charger, or to the engine battery if single output.
 

Sea Change

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Solar and wind connect straight to the Lithiums.
Slight thread drift, I've found myself in possession of a Silentwind and as far as I can tell I can't connect it directly to lithium using the supplied charge controller... What's the best way round this? I may just use it to top up the starter/windlass circuit and if it's producing enough power, the DC-DC should kick in and send some power to the lithium. This is assuming that I don't wire the DC-DC to come on with the ignition, but instead set it to start charging above a certain voltage.
(And I don't expect it to work very well since the Silentwind is unlikely to keep up with the 18A DC-DC)
 

Neeves

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Slight thread drift, I've found myself in possession of a Silentwind and as far as I can tell I can't connect it directly to lithium using the supplied charge controller... What's the best way round this? I may just use it to top up the starter/windlass circuit and if it's producing enough power, the DC-DC should kick in and send some power to the lithium. This is assuming that I don't wire the DC-DC to come on with the ignition, but instead set it to start charging above a certain voltage.
(And I don't expect it to work very well since the Silentwind is unlikely to keep up with the 18A DC-DC)
Surely one option is to ask Silent Wind.

Its in their interests to have a simple answer or they immediately deny their own access to a huge segment of their potential market. Most owners of a Silent Wind unit will also have solar and many will have Lithium batteries. Its difficult to believe you are the first to have an issue.

Jonathan
 

Trident

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How do you find the VHF interference?

I'm wondering about the Renogy DC-DC/MPPT myself as it seems very good value.
Personally I always fit DCDC and MPPT separately and I think I've only ever supplied the combined unit once.

It does save a little money if you buy the Renogy dual unit but its a single point of failure for all your charging then which seems like a bad idea on a boat.
 

Trident

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Are you suggesting that Sterling are not reliable? ( #9) I don't Know, hence I ask:rolleyes: They are a tad pricey though😵‍💫
With ref. to the alt. if it is continuously rated at 115a then it will run at that continuously. It should also run at 120% overload for 20 minutes.😁
If it is time rated i.e. 115a for 20 minutes Then that is a different story.
Just saying as it can be confusing to just quote, willy nilly, a rating . Sorry if above is all a bit of thread drift.
I have seen and heard more issues with Sterling stuff than any other. I had two failures on a customer's boat with their DCDC - both bought by him - the second being a replacement for the first that dies about 6 weeks out of warranty . (It was a 24v model) also the set up and display via a million christmas tree lights :)D) is not great. If I had to have a larger DCDC I would use two Victron or Renogy rather than one Sterling . Having said that, for balance they have lots of satisfied customers and some people on here swear by them so perhaps my experiences with them have been unusual.
 

Neeves

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Personally I always fit DCDC and MPPT separately and I think I've only ever supplied the combined unit once.

It does save a little money if you buy the Renogy dual unit but its a single point of failure for all your charging then which seems like a bad idea on a boat.
In previous posts others (and you?) have extolled Renogy - have you any background to Renogy failures, the DCDC units, the MPPT units and the combined units? (accepting you have only fitted one of the latter (but you might talk to others and get some background.

I suspect not - or you would have quoted them

What is the price difference and how big is the combined unit vs 2 separate units.

Edirt. Here the DCDC unit is 50 amp (with the MPPT controller) and list price is stg250 but its on special from a number of outlets at stg200. (10% sales tax)

Jonathan.
 
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Neeves

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Thanks all, very informtive and helpful, as usual. For info, I have 100W solar and a Rutland 913 wind. Will be looking to add a further 200W solar if I can find somewhere happy to mount it.
I suspect you might need a new and/or another solar controller - a combined DCDC and MPPT controller seems an interesting option.

Options for solar panels seems to include guard rails, stanchions, cantilevered out.
 

Sea Change

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Personally I always fit DCDC and MPPT separately and I think I've only ever supplied the combined unit once.

It does save a little money if you buy the Renogy dual unit but its a single point of failure for all your charging then which seems like a bad idea on a boat.
I'm thinking of fitting one alongside two other MPPTs so I would have some backup. I don't generally use my alternator to charge, I rely almost entirely on solar.
I'll probably just go Victron though... because it's available locally and I like them...
 

Trident

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In previous posts others (and you?) have extolled Renogy - have you any background to Renogy failures, the DCDC units, the MPPT units and the combined units? (accepting you have only fitted one of the latter (but you might talk to others and get some background.

I suspect not - or you would have quoted them

What is the price difference and how big is the combined unit vs 2 separate units.

Edirt. Here the DCDC unit is 50 amp (with the MPPT controller) and list price is stg250 but its on special from a number of outlets at stg200. (10% sales tax)

Jonathan.
My apologies - the Renogy DCDC is 60 amp not 50 - the MPPTDCDC is 50 amp

The MPPT version is £210 whilst the 60 amp DCDC is £149 UK
Obviously it depends how big an MPPT you need to make up the difference - A Victron 100/30 is around £60

I've not seen any failures so for with the Renogy MPPT stand alone units - and I've fitted well over a hundred over 5 years. Equally I can say the same with Victron which I've also fitted dozens or hundreds of.
No failures on DCDC from either but the Victron get hot and output suffers due to the lack of cooling.
The one guy who had a DCDC MPPT was on here and noted a lot of issues with getting to work in all modes properly but I think sorted it out in the end .

With my boat I am away from the dock for months or years at a time and so redundancy is key . I just wouldn't want to risk one unit doing everything. Of course if you have plenty of MPPT already and want a DCDC then the combined unit may be a good choice.
 
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