Charging Lithium and AGM banks

[HKTim]

I have a new catamaran coming and am planning a 720 Ah lithium house bank with 2 AGM starter batteries. I have been considering a few charging options and currently am looking at this configuration:

1. Engines have factory standard 125 Amp alternators (Yanmar 4JH57)

2. Adding a smart regulator and taking charge from alternators directly to the lithium house (250 amps).

3. Use a DC converter to charge AGM starter batteries from the lithium house.

Lithium house will also get charge from genset, solar or from shore power when available. These will all automatically keep the start batteries charged as well.

Any obvious problems?

The alternative is to add a second alternator and dedicate one to the house and the other to the starter. This will put the same 250 amps into the house. But I'll end with 250 amps of alternator capacity to charge two 100 Ah engine AGM batteries whcih seems like a lot of wasted charging capacity.

Thanks

[Rustic Charm]

Originally Posted by HKTim

2. Adding a smart regulator and taking charge from alternators directly to the lithium house (250 amps).

Thanks

I'd suggest this one, and get yourself an Blueseas ACR which will take care of your starter batteries.

This is what I do. And my solar panels feed directly controller and then batteries, as does my 240v external charger.

[HKTim]

Thanks. Is you setup also a lithium house with AGM starters?

[smac999]

something like the balmar duo charge from house battery to each starter battery would work well. you can set them to agm


don't put acr's between your house and starter banks.

[Rustic Charm]

Originally Posted by HKTim

Thanks. Is you setup also a lithium house with AGM starters?

Sorry, I missed the lithium bit. My house are AGM. I have a wet cell starter.

Can you get AGM with heavier plates suitable for starting?

[HKTim]

Rustic Charm. I have been using Lifeline AGM 105 Ah batteries for my two engines and genset for the past 5 years with no problems. Usually the house configuration is also with the same brand AGMs. The charging set up for this is more straight forward. But because I am mixing battery types, need to control different charging requirements. Thanks for your help.

[Rustic Charm]

Originally Posted by HKTim

Rustic Charm. I have been using Lifeline AGM 105 Ah batteries for my two engines and genset for the past 5 years with no problems. Usually the house configuration is also with the same brand AGMs. The charging set up for this is more straight forward. But because I am mixing battery types, need to control different charging requirements. Thanks for your help.

[TeddyDiver]

Originally Posted by HKTim

I have a new catamaran coming and am planning a 720 Ah lithium house bank with 2 AGM starter batteries. I have been considering a few charging options and currently am looking at this configuration:

1. Engines have factory standard 125 Amp alternators (Yanmar 4JH57)

2. Adding a smart regulator and taking charge from alternators directly to the lithium house (250 amps).

3. Use a DC converter to charge AGM starter batteries from the lithium house.

Lithium house will also get charge from genset, solar or from shore power when available. These will all automatically keep the start batteries charged as well.

Any obvious problems?
Long runs of heavy wiring.. To avoid this maybe even bigger alternator for other engine and house bank close to it. Better loading for single engine as a bonus. Might get you without a separate genset. For the AGMs separate chargers from AC.. ?

The alternative is to add a second alternator and dedicate one to the house and the other to the starter. This will put the same 250 amps into the house. But I'll end with 250 amps of alternator capacity to charge two 100 Ah engine AGM batteries whcih seems like a lot of wasted charging capacity.
You could have smaller alternators, maybe 60 to 80amps for the AGMs

Thanks

Some thoughts..

[ramblinrod]

Originally Posted by HKTim

I have a new catamaran coming and am planning a 720 Ah lithium house bank with 2 AGM starter batteries. I have been considering a few charging options and currently am looking at this configuration:

1. Engines have factory standard 125 Amp alternators (Yanmar 4JH57)

2. Adding a smart regulator and taking charge from alternators directly to the lithium house (250 amps).

3. Use a DC converter to charge AGM starter batteries from the lithium house.

Lithium house will also get charge from genset, solar or from shore power when available. These will all automatically keep the start batteries charged as well.

Any obvious problems?

The alternative is to add a second alternator and dedicate one to the house and the other to the starter. This will put the same 250 amps into the house. But I'll end with 250 amps of alternator capacity to charge two 100 Ah engine AGM batteries whcih seems like a lot of wasted charging capacity.

Thanks

According to ABYC, your alternator has to charge your start batteries, without intervention.


Connect your alternators with corresponding Lithium Ion regulators to house bank.


Echo charger off house bank to AGM starting batteries. (If 2 x starters run 10 seconds at 200 A, this is only 1.1 A-hrs, a 15A echo charger will bring the starter batteries back up to 100% in about 10 minutes.)


Be vary careful with Li-Ion to avoid thermal run-away while charging.

[Maine Sail]

Originally Posted by ramblinrod

According to ABYC, your alternator has to charge your start batteries, without intervention.

Can you reference this in the standards? Charging sources feeding house first is very standard protocol on cruising boats.

Originally Posted by ramblinrod

Connect your alternators with corresponding Lithium Ion regulators to house bank.


Echo charger off house bank to AGM starting batteries. (If 2 x starters run 10 seconds at 200 A, this is only 1.1 A-hrs, a 15A echo charger will bring the starter batteries back up to 100% in about 10 minutes.)


Be vary careful with Li-Ion to avoid thermal run-away while charging.

LFP's for fractional C use generally charge between 13.8V and 14.0V, though some owners push as high as 14.2V, but it is quite unnecessary to do that. Lifeline AGM's want to see 14.4V to stay healthy..

An Echo Charger won't work in this situation because it will always be bleeding current and will never turn off because the LFP bank will rarely if ever dip below 13.2V and the Echo turns itself on at 13.0V. The Echo is designed for lead acid batteries where the resting/loaded voltages dip below 13.0V and turn it off.

There is no ideal solution for charging an AGM from an LFP bank because you ideally need a boosting battery to battery charger that also has an adjustable ON/excite voltage and adjustable OFF voltage.

Charlie Sterling has the almost ideal product to do this with, his B2B chargers, but he has yet to give us any custom settings for ON/OFF voltage parameters.

If you went GEL for the starting bank they would be pretty happy at 13.8V to 14.0V but AGM's will need an occasional absorption boost.

[georgec]

How about charging the AGM's from a separate battery charger powered from your inverter. After starting, the engines will be charging the house bank and also would be replacing the power the inverter would use to charge the AGM's. The battery charge would not need to be a high current charger as the AGM's would not need much charging after starting the engine.

[Bill whitmore]

Since the absorption, bulk and float charging voltages will be very different for the Lion batteries vs the AGMs you MUST have two completely separate charging systems or you are courting disaster

[Scout 30]

Originally Posted by Bill whitmore

Since the absorption, bulk and float charging voltages will be very different for the Lion batteries vs the AGMs you MUST have two completely separate charging systems or you are courting disaster

I'm certainly no expert but seems simple. One engine charges the starting bank & the other charges the house bank.

For me LI batteries are just too dangerous for boats.

[goboatingnow]

Originally Posted by Scout 30

For me LI batteries are just too dangerous for boats.

Why ? ( more dangerous then say the propane or the diesel in a tank or even all that sulphuric acid etc


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[Kim Klaka]

Why are you mixing Lithiums and AGM? Why not use all lithium, or am i missing something? I have used lithium for starting and house for a year, no problems. A friend of mine has been using them for 4 years, again no problems. You just need belt-and-braces voltage regulation
Re safety of lithiums, there is a lot of confusing info out there. I resolved some of the confusion when I realised there are different types of lithiums, some safer than others. You need to know what type of battery is being described when reading reports. Incidentally, there are some interesting comments on Lithium Ferrophosphate batteries (LiFePO₄) in the report on the stranding of the Volvo yacht Team Vestas Wind, released 3 days ago. http://www.volvooceanrace.com/static/assets/content_v2/media/files/m36616_team-vestas-wind-inquiry-report-released-on-9-march-2015.pdf