Old citycar, alternator 65Ah, lead and LTO battery, some questions

[ch4]

hi to everybody, i'm ch4 from Italy

I have a old Fiat Panda 141, 1100 cm3, 55hp with an alternator of 65Ah

Ten years ago i had 4 38 with two zapco sp 3000.1 @ 0,5ohm, you can see a video here

It was very nice for me, we are talking about a car 3408*1494*1420 mm with 4 38 and it was my daily car

But, it was not confortable, i had 440Ah AGM battery pack (200+120+120), there were very heavy (140kg) and i had to charge with a Ctek the batteries @14,7 volt every months and some negative spikes (11.8 volt or less)

It was 8 years ago last time that i used my Panda, now i have another car, but panda is still my favourite one, so i think that i will use it again, but with some modification

I still have midranges, tweeters, amplifiers and subwoofers, probably i will sell the two zapco 3000 to buy one taramps md8000 1ohm

About batteries, for sure i will not use AGM but lithium, i don't know if LiFePO4 or LTO, probably LTO ( Lishen 18 ah are very interesting)

But, i need also a lead battery for the elettric things of my car, so i had so use two different type of batteries

My idea is do something like in the chart

1) is the alternator, nothing special i think, very old and i'm sure that if i try to charge a lithium battery with it, it will die soon
2) lead battery, a stock lead battery, probably a 45Ah
7) all loads of car, light for example, working around 14 volt when the engine is on

3) dc dc converter boost 1800 watt , you can find it with google, i can set maximum/ mininum voltage and maximum current, i will set it in this way to charge lithium batteries
maximum voltage, considering lto 6s, around 15.5 volt
minimum voltage, around 12,7 volt, it will turn off itself when the voltage from the lead battery is lower than 12,7 volt
maximum current, around 25A, i don't want to stress too much my alternator

4) batteries with 25A BMS, LTO or LiFePO4, maybe 54Ah or 72Ah Lishen

5) all things connected with audio system: stereo and amplifiers

6) chassis of the car, basically the frame

I know perfectly that after 5 minutes the charge of my lithium batteries will be very low, but it's ok

What i would know is if my chart is correct or there are some mistakes...

For example, i'm not sure that i can connect between 4 and 5 only the positive and connect the negative of 5 to 6 (if i can, i will have half cable)

Let me know what you think about my chart and my idea, thanks

Click to read more...

 

[hispls 5,000+ posts]

Best would be to add a second alternator, externally regulated to just run LTO bank/audio and leave the stock electrical system alone.

Next best would be delete AGM batteries entirely and just use LTO bank (Not under the hood! They will not like extreme heat). We use 240AH YingLong bank in my brother's Civic on a big 9K Korean board on tiny factory alternator and it supports that fine for burps or a few songs at full blast for demo. You might get away with less LTO bank, but considering they are meant to last 20 years and they are so small you probably won't regret going big now.

IF you buy Brazilian amp they may not like >15V. LTO batteries should not be charged higher than 15.5. You can always run 7S banks if you can find a nice 18V half-bridge amp for a good deal or have some old ones laying around.

My guy in China says Lishen brand is very popular now. I am waiting for him to get more stock so I can get some to test, but I will vouch for YingLong. Mine are still good as new 3 years after buying and there are a lot of other cars up in this area running them with great results.

Panda is a well known SPL competition vehicle. You should be able to get very loud with this and some modern amp and big battery bank. What a great car. Thank you for sharing your video.

 

[Firewalker]

I would keep those zapco's all day long over a brazlian full bridge. Those are nice amplifiers.

 

[hispls 5,000+ posts]

I would keep those zapco's all day long over a brazlian full bridge. Those are nice amplifiers.

I believe the """zapco''"" 3K and 5K sizes are just re-badged Korean fare, probably same board as the old Atomic. Rock solid, but not Robert Zeff design or anything like that AFAIK.

 

[Firewalker]

Yeah that much I know, still better though then probably the full bridge Brazilian he is looking at.

 

[ch4]

(1) Best would be to add a second alternator, externally regulated to just run LTO bank/audio and leave the stock electrical system alone.

(2) Next best would be delete AGM batteries entirely and just use LTO bank (Not under the hood! They will not like extreme heat). We use 240AH YingLong bank in my brother's Civic on a big 9K Korean board on tiny factory alternator and it supports that fine for burps or a few songs at full blast for demo. You might get away with less LTO bank, but considering they are meant to last 20 years and they are so small you probably won't regret going big now.

(3) IF you buy Brazilian amp they may not like >15V. LTO batteries should not be charged higher than 15.5. You can always run 7S banks if you can find a nice 18V half-bridge amp for a good deal or have some old ones laying around.

My guy in China says Lishen brand is very popular now. I am waiting for him to get more stock so I can get some to test, but I will vouch for YingLong. Mine are still good as new 3 years after buying and there are a lot of other cars up in this area running them with great results.

Panda is a well known SPL competition vehicle. You should be able to get very loud with this and some modern amp and big battery bank. What a great car. Thank you for sharing your video.

(1)
Put a second alternator is not possible for two reasons
1) is a forbidden modification, if police will stop me (and you can be sure they will stop me) i can have problems
2) i'm not able to do it
However, the engine of my car is not so powerfull, so another alternator could make more hard drive the car

(2)i will not have a AGM battery, just a normal lead battery, have just LTO battery is not possible because
(1) i will have ALL the car to 15,5 volt, too much i think for daily use, it's a old car
(2) in that way i have to change the alternator, internal resistance of battery is too low

(3) This is a interesting point that i didn't know, but it's easy fix it

Basically more than 95% of charge of LTO is under 2,5 volt, so also charging until 15 volt i will have good performance from my batteries, i will set the dc dc converter boost with a maximum voltage of 15 volt

7S and 18volt are too much for a daily car, also because i don't know if my stereo, JVC SH1000, can work until 18 volt

I would keep those zapco's all day long over a brazlian full bridge. Those are nice amplifiers.

To be honest, i want only one amplifier for subwoofer...and a small amplifier, as you can see, there is no space in my car, it's very small


This is the first zapco, as you can see, few mm of space, the second one is connected to the wooden box of the subwoofers, too much vibrations for a daily use

However, this is not the place where talk about which amplifier, for the moment i just want to know if my idea and my previous chart is correct or not

 

[hispls 5,000+ posts]

At what voltage does your car currently charge?

Say you just buy external voltage regulator (if needed) and charge up to 15V. There should be nothing that will be hurt by this. Delete lead batteries and be prepared to replace factory alternators. Using your alternator through an inverter into another inverter, into a charger just adds 3 more steps of inefficiency and over time your alternator is only working harder.

Any way you do this, you are going to be asking a lot of 65A alternator. Small aternators can be bought as rebuilt from auto parts stores for <80$. Even replacing it every year isn't so much cost.

I would not try to use battery isolator for high power car audio and there is really no good way to keep that system separate from everything else if you only have one alternator.

 

[ch4]

At what voltage does your car currently charge?

Say you just buy external voltage regulator (if needed) and charge up to 15V. There should be nothing that will be hurt by this. Delete lead batteries and be prepared to replace factory alternators. Using your alternator through an inverter into another inverter, into a charger just adds 3 more steps of inefficiency and over time your alternator is only working harder.

Any way you do this, you are going to be asking a lot of 65A alternator. Small aternators can be bought as rebuilt from auto parts stores for <80$. Even replacing it every year isn't so much cost.

I would not try to use battery isolator for high power car audio and there is really no good way to keep that system separate from everything else if you only have one alternator.

My car charges around 13.95/14 volt

I did understand why you are talking about two inverter and a charger, if you see my chart, from 14 volt of alternator i use a dc dc boost converter (efficienty around 75/80%), maybe an active BMS and that's all

However, i will fix the load maximum of dc dc boost converter, so the alternator will working always the same, but for a longer period of time

I have just some issues about connections, i did again my chart, maybe know is more clear, the orange "cable", i don't know if i can do it or not

 

[ch4]

My car charges around 13.95/14 volt

I did understand why you are talking about two inverter and a charger, if you see my chart, from 14 volt of alternator i use a dc dc boost converter (efficienty around 75/80%), maybe an active BMS and that's all

However, i will fix the load maximum of dc dc boost converter, so the alternator will working always the same, but for a longer period of time

I have just some issues about connections, i did again my chart, maybe know is more clear, the orange "cable", i don't know if i can do it or not

View attachment 30036

can anyone tell me if my chart is correct?

 

[hispls 5,000+ posts]

can anyone tell me if my chart is correct?

I have never seen DC/DC converter so I cannot say. Perhaps someone else has experience with these. Hopefully you can report back if you have luck with this method.