B2B Charger replacement option

[gscriba]

On my previous boat, I had an Ample Power "Eliminator", which was a 3 step B2B regulator/charger that was designed to charge the start battery from the house bank. It seems as though something like that would be great to use between my 12v LiFePO4 house bank and my start battery. Can't seem to find a small, simple similar product. Anybody know of one?
Alternatively, I was thinking about mounting a small (separate from my large solar array) solar panel with a solar charge controller specifically for the start battery. Could be a small flexible solar panel on the dodger. Anyone else with LFP do this?
Thanks.

[Tin Tin]

Try This https://www.victronenergy.com/batter...tery-combiners

[gscriba]

Just found this:
AMP-L-START Starting Battery Charger/Maintainer - Overview Page
Not as sophisticated as the "Eliminator", but might work great as a simple solution. Feedback and/or suggestions are appreciated.

[sailormed]

I installed a Blue Sea Echo charger exactly for that purpose. It is not a combiner, more like a high power diode.

[YANDINA]

Originally Posted by gscriba

On my previous boat, I had an Ample Power "Eliminator", which was a 3 step B2B regulator/charger that was designed to charge the start battery from the house bank. It seems as though something like that would be great to use between my 12v LiFePO4 house bank and my start battery. Can't seem to find a small, simple similar product. Anybody know of one?
Alternatively, I was thinking about mounting a small (separate from my large solar array) solar panel with a solar charge controller specifically for the start battery. Could be a small flexible solar panel on the dodger. Anyone else with LFP do this?
Thanks.

Yandina has released a LITHIUM compatible version of the Combiner 100 that will charge a Lithium house battery from your alternator and lead-acid starting battery.

There are also Lithium versions of the Trollbridge 12X24 and Trollbridge 36 for charging 23 and 36 volt Lithium batteries from the 12 volt alternator

[SkipMark]

I have 2 Alfatronix B2B chargers in my solar house and engine charging system.
https://www.alfatronix.com/dc-dc-battery-chargers


CTEK has some good alternatives as well. More capabilities, and a little more expensive:
https://www.ctek.com/no/products/vehicle/d250se


Marko

[Sternwake]

If you've got some Frugal DIY genes inside of you, you can get a simple 10 amp buck boost converter, and switch it on manually when start battery charging is desired.

Takes any input voltage, and outputs a Nearly constant perfect voltage, upto 10 amp and one can limit maximum amperage by the current trimpot.

I use these to speed control 24vDC fans, but have used them to EQ batteries at 16.2v.. The heatsinks are designed to accept a 50mm computer fan which would be wise to add if approaching their amperage limits.

https://www.ebay.com/itm/DC5-30V-to-...torefresh=true

One can get simpler Boost converters for even cheaper, assuming they always want to boost voltage, instead of buck it. They are more efficient too.

[stormalong]

Originally Posted by gscriba

On my previous boat, I had an Ample Power "Eliminator", which was a 3 step B2B regulator/charger that was designed to charge the start battery from the house bank. It seems as though something like that would be great to use between my 12v LiFePO4 house bank and my start battery. Can't seem to find a small, simple similar product. Anybody know of one?
Alternatively, I was thinking about mounting a small (separate from my large solar array) solar panel with a solar charge controller specifically for the start battery. Could be a small flexible solar panel on the dodger. Anyone else with LFP do this?
Thanks.

I think I still have an Ample power eliminator sitting in a locker in my boat. I replaced it with a Yandina battery charging relay about 20 years ago. I didn't like the low charging rate that it supplied. If you want it and I can find it it is yours for $10.00 plus postage. Send me a pm.

[smac999]

these are brand new and likly the best choice. as you can set the voltages correctly with 2 different types of batteries. but I've yet to get my hands on one. (could not a few months back)

https://www.victronenergy.com/dc-dc-...ion-tr%20smart

the balmar duocharge or xantrax echocharge are other less good options.

I would not use a combiner / relay

[Tin Tin]

Originally Posted by smac999

these are brand new and likly the best choice. as you can set the voltages correctly with 2 different types of batteries. but I've yet to get my hands on one. (could not a few months back)

https://www.victronenergy.com/dc-dc-...ion-tr%20smart

the balmar duocharge or xantrax echocharge are other less good options.

I would not use a combiner / relay

Why not, see Cyrix-Li-ct 12/24-120 and diagram at bottom of page 2


https://www.victronenergy.com/upload/documents/Manual-Cyrix-Li-ion-120-A-EN.pdf

[Cowpoos]

There are some smaller ones as well and they have lithium settings.

https://www.renogy.com/12v-60a-dc-to...ttery-charger/

[gscriba]

Went with an "Amp-L-Start G2", mounted it next to and wired it directly to my Blue Seas ML-RBS 7700 start battery switch and the main positive busbar. Monitors the start battery and sips amps from my LFP house battery (main positive busbar) when charging. Easy peasy.
Thanks for the response/input!