New Lithium Battery, DC-DC charger

[Nick J]

Ha, I have the same problem.

Did you purchase the 200ah Ampere Time rated for 200amp load or 100amp load? My battery is set up for 120amp continuous load, so a 2000W inverter (2000 / 14 = 143amps) would trip the BMS' overcurrent protection. I set up another 2000W inverter and ran my heat gun to verify on my system. The BMS tripped within seconds. Not a big deal for me because I'm just going to use it for computer charging and other low power things.

 

[jrlago55]

I meat 4 awg wires not awful. Darn iPhone….

 

[jrlago55]

Ha, I have the same problem.

Did you purchase the 200ah Ampere Time rated for 200amp load or 100amp load? My battery is set up for 120amp continuous load, so a 2000W inverter (2000 / 14 = 143amps) would trip the BMS' overcurrent protection. I set up another 2000W inverter and ran my heat gun to verify on my system. The BMS tripped within seconds. Not a big deal for me because I'm just going to use it for computer charging and other low power things.

No it does not trip and I do use my heat gun quite often. I purchase the 200 ah. The 2000w inverter should handle 120 amp load. I see you use 14 v for your calculations. I use 12 vdc

 

[goldenstate]

Hello, Let me first say that I build my system to sustain my autopilot, nab lights and radio 24/7 while underway. Also, I will be relocating my boat to PR so I do not need zero degree disconnect. With this I installed a Renogy DCC50S box with 4 flexible solar panels and a 200ah ampere time battery. Even though outside of my requirement, I added a Renogy 2000W inverter which I connected with a manual transfer switch to the AC panel. My experience is that it works better than expected to the point that I’m no longer electrically tendered to the pier. Hope this helps

Cool!

Looking at the DCC50S product page, the unit can both take inputs from a lead-acid starter battery and solar panels and manage lithium batteries down stream. Do you have your charger hooked up to your starter battery and alternator too?

Thank you,

Tom

 

[goldenstate]

Ha, I have the same problem.

Did you purchase the 200ah Ampere Time rated for 200amp load or 100amp load? My battery is set up for 120amp continuous load, so a 2000W inverter (2000 / 14 = 143amps) would trip the BMS' overcurrent protection. I set up another 2000W inverter and ran my heat gun to verify on my system. The BMS tripped within seconds. Not a big deal for me because I'm just going to use it for computer charging and other low power things.

Is there a reason you will use an inverter to go to AC power and then step back down to a different voltage of DC power to charge a computer?

I went through this thought exercise recently too. I realized that I could buy a 12V adaptor and use it to charge my MacBook.

https://www.amazon.com/gp/product/B08TMDTQQV/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

It has worked so far.

 

[Nick J]

I try to go directly off of the 12 vdc system when possible, but we have a few older laptops that don't use USB c chargers and there's always a few 120vac items we would like to power away from the dock.

 

[jrlago55]

I try to go directly off of the 12 vdc system when possible, but we have a few older laptops that don't use USB c chargers and there's always a few 120vac items we would like to power away from the dock.

The reason I put the inverter is because I figure that sooner or later I would need 110 vac. Now, I do not have AC or a water heater. The manual transfer switch output is oviously to the AC panel input then, one side is to the inverter and the other to shore power which I haven’t had to use. So even if I had a water heater or and an air conditioner, they would work with shore power.

As far as my battery charger, I’m not sure I need one. But I do need a backup to the solar panels for this, I may put a wind turbine or a small generator, not sure yet.

 

[David Grimm]

I have an old Xantrex inverter hooked up that came with the boat. I have it set to Gel2 I believe now. That puts the float charge at the closest voltage for my lithiums. Been using it for two years now without a hiccup! I've never used a heat gun on the inverter, however I have ran a 5hp Ridgid vacuum for 20 min. The batteries barely dropped at all. The main use of the inverter is my Keurig coffee maker. Makes one cup really quick. Saves water too.

 

[jrlago55]

I have an old Xantrex inverter hooked up that came with the boat. I have it set to Gel2 I believe now. That puts the float charge at the closest voltage for my lithiums. Been using it for two years now without a hiccup! I've never used a heat gun on the inverter, however I have ran a 5hp Ridgid vacuum for 20 min. The batteries barely dropped at all. The main use of the inverter is my Keurig coffee maker. Makes one cup really quick. Saves water too.

I do not know about the xantrex but I do know that gel (amg) and lithium are different chemistries you could, at least, loosing life on your batteries. At what rate, I do not know.

 

[goldenstate]

@jrlago55

I am curious how long you would have to run your engine to re-charge your batteries.

I read a little about your renogy MPPT/charger. It is rated at 50 amps, but if you have solar and the alternator hooked up, it will only allow 25 amps of either one through. (This makes sense for safety reasons). It looks great to have one device to bring solar AND lithium battery-alternator protection into your power system. Here is a Renogy video for anyone interested:

What is the total amp-hour capacity of your battery banks and what is the amperage rating of your alternator?

My concern is that even if I can affordably buy a large capacity lithium battery bank, it will be a huge pain in the rear and a waste of fuel if I have to run my alternator for 8-10 hours to properly re-charge the new battery bank.

Thank you in advance for feedback.

 

[Nick J]

I can't speak for @jrlago55, but for me the Renogy DC to DC charger solution allows me to upgrade my battery bank separately from my shore power charger and alternator to help keep cost down and spread out over time. In a perfect world, I would use off-the-shelf batteries with a Victron Inverter/charger, separate MPPT chargers, and a high end alternator with an external regulator designed for LiFEPO4 batteries. Unfortunately, that's not in the budget for me. It's a good compromise for us and how we use the boat...but it is a compromise.

 

[goldenstate]

I can't speak for @jrlago55, but for me the Renogy DC to DC charger solution allows me to upgrade my battery bank separately from my shore power charger and alternator to help keep cost down and spread out over time. In a perfect world, I would use off-the-shelf batteries with a Victron Inverter/charger, separate MPPT chargers, and a high end alternator with an external regulator designed for LiFEPO4 batteries. Unfortunately, that's not in the budget for me. It's a good compromise for us and how we use the boat...but it is a compromise.

How big is your battery bank in amp hours?
How big is your alternator, and do you know how many amps the DCDC lets through to your house bank?
How long does it take to charge the battery bank from the alternator?

 

[Nick J]

I haven't installed the system yet, but Here's the plan:

• new house battery is 270ah
• start battery is a group 24 80ah
• Battery charger is 20amp
• alternator is an internally regulated 80amp Hitachi (standard on the Yanmar 3YM20)

My bench setup doesn't have the capacity to put more than 20amps through the start battery, so I don't know if it will pass more than 25. It would be interesting to test the 50% allocation between solar and alternator.

 

[jrlago55]

@jrlago55

I am curious how long you would have to run your engine to re-charge your batteries.

I read a little about your renogy MPPT/charger. It is rated at 50 amps, but if you have solar and the alternator hooked up, it will only allow 25 amps of either one through. (This makes sense for safety reasons). It looks great to have one device to bring solar AND lithium battery-alternator protection into your power system. Here is a Renogy video for anyone interested:

What is the total amp-hour capacity of your battery banks and what is the amperage rating of your alternator?

My concern is that even if I can affordably buy a large capacity lithium battery bank, it will be a huge pain in the rear and a waste of fuel if I have to run my alternator for 8-10 hours to properly re-charge the new battery bank.

Thank you in advance for feedback.

100% correct. At 25 amps it would take 2 hours to top half the 100 ah starter battery. What I think and may be I’m wrong, is that starting with a good full battery that I only use to crank the engine topping it will be quicker. My house battery is a 200 ah ampere time battery from Amazon (the cheaper option). So far the battery is refilled every day by noon. The Renogy Dss50 box will trickle charge the starter battery after the house battery is charged. I think that by days end, the starter battery should be charged as well. Now, I have not tested this but will let you know how it goes.

 

[David Grimm]

I do not know about the xantrex but I do know that gel (amg) and lithium are different chemistries you could, at least, loosing life on your batteries. At what rate, I do not know.

This is from the freedom marine manual. My batteries request 14.6 charge voltage. The Freedom Marine is a little low especially as temperature climbs. However the new Xantrex 2000 inverter charger does lithiums at 80 amp max charge. Impressive. So is the $900 price tag which is now in my Defender Marine Cart.... lol. Just for fun. The Freedom Marine is doing fine. I'll keep it for now.

 

[jrlago55]

I would say if it works keep it working