Electronics and Power Steering Pump draining Battery

[sfgregorini]

I checked with my boat dealer/mechanic. I was out on the water Thursday and currently running 4 graphs and power steering off my my two lithium cranking batteries. Both are brand new. After 9 hours of running all 4 graphs and not using my 300hp Merc and just my 15hp kicker I got a couple voltage warnings on the fish finders. Eventually the all went dead and my cranking battery wouldn't crank or trim my 300hp. Good news was I was fishing on a 20hp limit lake and my trolling motors and kicker continue to work since they are wired to my other 3 lithiums.

My question is has anyone ever had or heard of 2 cranking batteries going dead when using the graphs and not powering up the large motor to replenish some battery life? I currently dont have a switch to turn off the power steering pump but my mechanic wants to do this so I can turn it off when Im not using my large motor or just trolling for large periods of time. Does the power steering pump use that much battery over the course of 9-10 hours? Both batteries were fully charged when I went out on the water. Im rather new to this whole setup.

 

[Larry Williams]

Have your big engine alternator checked. If it malfunctions, there can be a heavy current draw on your batteries, even with the key in the off position.. I've had this issue not once- but two times, over a five year period. The alternator will become warm to the touch if you have this issue- with a continuous power drain on your batteries. Mercury has had issues with their engine alternators. This is the only engine issue I've every had.

 

[Tim_C]

It would very much if you tell us the size (Ah) of your Lithiums and the size of their BMS. When were the batteries last charged?

 

[JBoutfishn]

I am running a SeaStar power assist system on my 200 Pro XS. My pump only draws current when the key is on. There is no other switch. Not sure what the current draw is but it does have a 50 amp breaker on the pump side and a 5 amp fuse on the switch side.

 

[Ltwrangler]

My Lowrance 9 inch HDS live can draw up to 2.9 amps per hour. If you are running 4 graphs that could be as much as 116 amps in a 10 hour day. Like Tim had asked, what size batteries and were they fully charged

 

[sfgregorini]

It would very much if you tell us the size (Ah) of your Lithiums and the size of their BMS. When were the batteries last charged?

Im using 2 Tracker Lithium Super High Power Deep Cycle TLi80 12.8V 80Ah for the 4 graphs and cranking batteries as well as the power steering. Here are the specs to those batteries if you scroll down you can see the TLi80.

https://basspro.scene7.com/is/conte...ackerLiFePObatteryinfo_tli60-tli80-tli100.pdf
The only thing I can think of is that I was never using my big main engine(300hp) so there was not enough power charging them up. I only used the kicker which may not be enough to recharge. Add in the fact that I was driving around a lot with the kicker motor and the power steering was being used a lot that day???

the batteries were fully charged the night before. I took them off the charger right before I left for the lake. Im heading back out this Friday to the same lake and Im worried. I dont know what I can do to use less power from these batteries to give me a full day? I dont have a switch to turn the power steering off at this time. That will happen in the next few weeks when it comes in.

 

[sfgregorini]

My Lowrance 9 inch HDS live can draw up to 2.9 amps per hour. If you are running 4 graphs that could be as much as 116 amps in a 10 hour day. Like Tim had asked, what size batteries and were they fully charged

Im using 2 Tracker Lithium Super High Power Deep Cycle TLi80 12.8V 80Ah for the 4 graphs and cranking batteries as well as the power steering. Here are the specs to those batteries if you scroll down you can see the TLi80.

https://basspro.scene7.com/is/conte...ackerLiFePObatteryinfo_tli60-tli80-tli100.pdf
The only thing I can think of is that I was never using my big main engine(300hp) so there was not enough power charging them up. I only used the kicker which may not be enough to recharge. Add in the fact that I was driving around a lot with the kicker motor and the power steering was being used a lot that day???

the batteries were fully charged the night before. I took them off the charger right before I left for the lake. Im heading back out this Friday to the same lake and Im worried. I dont know what I can do to use less power from these batteries to give me a full day? I dont have a switch to turn the power steering off at this time. That will happen in the next few weeks when it comes in.

 

[sfgregorini]

Its also worth mentioning that I have Electro-Hydrolic power steering in my nitro.

 

[Gr8steven]

I suspect you know the answer to your own questions... but 4 screens is going to use some juice in a 9 hour day. Who knows how many transducers you have active and other annicillary devices/electronics. You need to use some math to determine how long you can use your electronics on a full charge. Garmin has a pretty good page on how to calculate amp draw... (or you can use your recent event and know you have about an 8 hour limit (give or take).

https://support.garmin.com/en-US/?faq=R6UQrZ6ORS9UtB73uldU58

 

[Tim_C]

OK. Those batteries only have a 60A BMS. They are not designed to be cranking batteries. I would bet your 300HP motor's alternator is outputing greater than 60 amps and the BMS is cutting off stopping any charging of the battery. Also you are probably sucking them dry just to crank that motor. Does your kicker motor have a charging alternator that is connectered to the batteries.

From what I read about your electro-power steering on the web, it draws 15-20 Amps just by itself under light use. At full use it can draw as much as 100A. Even with the two 80AH connected in parallel, It appears you are way under powered for that equipment.

If these are what your dealer/service mechanic said you needed, I would run like Usain Bolt to a new service dealer.

 

[sfgregorini]

OK. Those batteries only have a 60A BMS. They are not designed to be cranking batteries. I would bet your 300HP motor's alternator is outputing greater than 60 amps and the BMS is cutting off stopping any charging of the battery. Also you are probably sucking them dry just to crank that motor. Does your kicker motor have a charging alternator that is connectered to the batteries.

From what I read about your electro-power steering on the web, it draws 15-20 Amps just by itself under light use. At full use it can draw as much as 100A. Even with the two 80AH connected in parallel, It appears you are way under powered for that equipment.

If these are what your dealer/service mechanic said you needed, I would run like Usain Bolt to a new service dealer.

Tim, I had to go check after getting your reply. So it appears that the trolling motor batteries are the 80. I didn't realize that the two cranking are the 100. Group 31. They are also part of the spec sheet I sent you. Could you take a look and see what your thoughts are now that I corrected myself. I couldn't see the cranking batteries because of the straps and assumed they were all the same.

 

[maybrfd]

Lithium batteries are not the best choice for starter batteries. Yes the can be used, but due to the type of starter motor draws, which inrush currents can be upto 10x normal current draw of the starter motor can significantly reduce the charge. Also, the typical charging system on motors will be regulated at between 13.2 to 13.8 VDC. A fully charged Lithium iron phosphate 4 cell battery wants to be charged to 14.6VDC. You can place a voltage booster circuit in line with your regulator to solve this. The wonderful thing about Lithiums is you can charge most at 1C (ie if you have a 100ah battery and you charge it at 100 amps it will charge in 1 hour). Disclaimer most manufacturers will recommend a lower charging rate, most .8C..The purpose of all that was that 1. If you are relying solely on the alternator and your already starting with at about 80% charge state it takes time to recover. Also if you try to charge your lifepo4 at below freezing you will damage your battery unless it has a heater. Lead acids are still the best for starter applications and oh, if you perform battery matenance like your granddad did, by keeping it charged, checking it annually with a sg meter, adding water or sulfuric acid when needed, the lead acid life span might surprise you..I have several with more than 10 years on them and still going strong, 2 on a very high compression motor. The point I am trying to make is that different batteries perform differently under different load conditions and yes, you can use a lifepo4 as a starter battery, but as an electrical engineer of 30 plus years. I would recommend sticking to the lead acids for starting purposes, and by all means use the lifepo4 batteries for your electronic and trolling motors, of course with newer chargers which provide you with the best charge voltage. There are some very good web sites out there which do an actually fair comparison of the different battery types and charge discharge profiles if you really want the electrifying facts. Hope I didn't bore you or tick off the battery guys.